Next phase reached in definition of Mars Sample Return mission
http://www.esa.int/esaCP/SEMJAGNFGLE_index_0.html
A very good article :http://www.spacedaily.com/reports/Returning_To_Sample_Mars_999.html
In resume: This mission must be of international cooperation.
Rodolfo
Sample return has been highlighted as a key priority for future planetary missions in discussion meetings held at the first European Planetary Science Congress in Berlin.
http://www.europlanet-eu.org/index.php?option=com_content&task=view&id=76&Itemid=32
Prof. Bernard Foing, Project Scientist for the SMART-1 mission, said, “Europe has now looked at the Moon, Mars and Venus and we have put our finger on Titan. These are great achievements. But for the future, it is not enough to briefly ‘kiss’ the surface of other solar system objects. We must bring them back to Earth for analysis.”
Isn't it a coïncidence! Mark Adler is talking about his own experience on the subject on TPS blog today and tomorrow here : http://www.planetary.org/blog/article/00000701/
Funding a Mars sample return mission is not a good idea. This is a very expensive and complex mission. However since the ways to test space technologies on Earth are limited the possibilities are quite high that a Mars sample return cannot be achieved on the first try. Thats the way it is. But I don t think because of the high cost the public and many "space enthusiast" will have tolerance for a failure on the first try. The political climate is simply not right for high risk missions. So imagine the bashing after ... .
First watch how the russians will be doing by returning the Mars' moon samples with the Phobuss-Grunt spacecraft. Phobus-Grunt is scheduled for launch in 2009. This is indeed cheaper than landing on Mars.
In order to go on on the MRS project be feasible that the man feel highly confident for the success of the project. I think, up to know, we are still close and need about 5-10 years more in order to improve the technology and also to collect money and support from many nations. Up to now, not only russians are doing it but also along with ESA and China.
More details, visit on http://www.unmannedspaceflight.com/index.php?act=ST&f=9&t=1844
Rodolfo
Recent written comments by Alan Stern indicate that he wants to initiate MSR, Mars
Sample Return, in the near future, perhaps in FY2008.
Also, the National Academy of Sciences now recommends a new approach to MSR.
Instead of one Grand mission, it should be spread out over several years. It suggests
that all future Mars rovers be equipped with a sample caching system. After several
missions, NASA/ESA would decide whcih site held the best samples, and a retrieval system
would be sent. Once the samples were launched into Martian orbit, they could linger there
until an orbital rendezvous vehicle was sent. This would spread the risk and cost over
several years, instead of gambling everything in one Battlestar Galactica mission.
The recent Orbital Express mission has been a pathfinder for an unmanned rendezvous
and docking craft that would be an important part of MSR. However, it's mission is ending
before NASA has a chance to fully utilize it. See the article on this link -
http://www.space.com/missionlaunches/070630_orbital_express.html
Another Phil
Here is a view from Orbital Express. Imagine that someday, someday this will
be the view from Martian orbit as the Mars Ascent Vehicle closes in for docking with
the Earth Return Vehicle. The background view will be slightly different. We will see
the Martian deserts below, but only empty river channels and rift valleys.
On the surface that sounds like a good idea, only sending the "retrieval system" to the interesting caches, but I think that would end up being just as complicated as the BSG style missions. The retrieval system would end up requiring rover-like mobility, since it has to reach the cache in the previous mission. It could probably forgo most instruments, but it would still be a large, precision landed rover. It makes more sense to develop a sample return canister/rocket to be taken on each Mars mission, with the rendevous occuring in space instead of on the ground. The space retrieval bus could even collect multiple canisters before returning home.
It all comes down to what you really want out of an MSR mission. Remember, Mars is a fairly big planet as far as rocky planets go. It has a significant gravity well which requires a lot more energy to escape than, say, Luna requires. It also has an atmosphere that gets annoyingly in the way as you try and leave, requiring more energy to achieve orbit from the surface than an airless body would.
So, sending a sample off the surface and back into Mars orbit is not an insignificant operation; it takes more fuel than you'd think. If you include the fuel needed to inject the sample into a trans-Earth trajectory, as well as the heat shielding needed to get it back to Earth intact, you're landing an awful lot of mass on Mars that is dedicated to the return-to-Earth systems. (I'm trying to get y'all used to the idea that an MSR return-to-earth stage on a lander is going to need to be a *lot* bigger, beefier and energetic than, say, the upper stage used by the Russian Luna sample return landers. It's not the "model rocket on a Viking" setup some artists have imagined, it's more like landing a Thor or a Delta on Mars and having it ready to launch with no ground support equipment beyond that you bring with you.)
It would take an Ares V to get such a lander onto Mars with the ability to return more than a few grams of soil and rocks. Such a lander would be so heavy with just the fuel and other things needed to get your sample back to Earth that you'd have no mass left for roving to look for and pick up good samples, much less for a comprehensive survey sensor package.
So, even though it requires three separate launches and spacecraft busses, the concept of splitting the mission into three major pieces -- the survey spacecraft, the surface launch spacecraft and the return-to-Earth spacecraft -- lets you distribute the weight required into pieces that don't all have to be landed and don't all have to support Earth return. Remember, the same booster can get kilograms into Mars orbit that can only get grams onto the surface.
So -- if you want a single scoop of Martian soil, a sample that weighs no more than two or three kilograms, then a single spacercaft architecture is usable. If you want to return tens of kilograms of samples, and not just whatever a scoop can pick up from off the side of the lander deck, you're actually better off with the three-spacecraft architecture. Until and unless we make some propulsion system breakthroughs, it's just not energy-economical to do it with the single spacecraft concept -- not to get enough of a sample back to make the mission worthwhile, anyway.
-the other Doug
I don't think it can be done easily but I don't think the mass penalty is quite that bad. My back of the envelope scratchings based on some Delta-V and typical Isp's from http://www.pma.caltech.edu/%7Echirata/deltav.html
Martian Surface to LMO ~ 4.1 km/sec
Mars LMO to Earth C3 orbit ~ 2.9 km/sec
Total ~7km/sec Delta-V.
To get a 1 kg sample of mars dirt to Earth C3 orbit.
Assume we have motors with an Isp of about 280 (like ammonium perchlorate solids)
Two stages:
(1) LMO Stage - Motor, shell and supports for the mars launch first stage weigh ~ 5kg
First stage then needs ~ 37kg of fuel to get 11kg to LMO ( its own 5kg dry weight plus 6kg for the initial mass of the Earth Transfer Stage)
(2) Earth Transfer stage weighing 2kg dry (container+2nd stage motor+1kg payload+beacon)
Requires 4kg of fuel to produce +-3.1 km/sec Delta-V
Total initial mass = 48kg.
Alternatively.
Single Stage to LMO
Mars Surface to a Mars orbit stable over a couple of years. Say we need 4.4km/sec Delta-V (LMO + some margin) and the dry weight including payload we are working with is ~ 6kg.
Total initial mass = 29kg.
There's lots of holes in these of course (launch stage drag, no earth capture component ... ) but I reckon you can get 0.5-1kg of sample back for <100kg of landed mass. That's not possible today of course but it isn't warp drive level science fiction either.
That said we are limited today to landing something less than a ton or so onto the Martian surface even with the biggest launch vehicles so without something comparable to the Ares V no-one is ever going to return more than a kilo or two.
Drifting a bit OT here, but its obvious to all that MSR will be:
1) VERY expensive
2) Technically risky
3) Possibly providing limited 'bang for the buck' even if it succeeds
Might sample return better be conducted as part of a MANNED precursor mission - one that simply orbits Mars Apollo 8 style (plus visits to Phobos etc). Small surface probes/rovers could then be dispatched from orbit, controlled in near real time etc etc. I know such missions have been proposed, and I'm aware of the objections to them, but MSR is one of those missions that, like controlled fusion, is so hard and so expensive that its always 20-30 years in the future.
P
Antipode, funny you should mention that, as I am now writing up a description of a mission which includes some elements of what you describe. More on this later.
Phil
Sounds like one of the old Soviet manned Mars mission proposals, IIRC.
Such a mission has a lot to be said for it. For one thing, it's easier to send a lot of lab equipment to, say, Phobos than to the surface of Mars, and it's likely cheaper (in terms of energy) to get the mass of the equipment you want to use to study Mars rocks to Phobos than it is to bring the rocks all the way back to Earth.
So, you set up a manned microgravity habitat on/in Phobos, outfit it with the best analysis tools you can easily get out there, and send down small sample return probes that bring you up a few kg of carefully selected rocks and soils every few months. Your PIs live on Phobos and send the detailed data back to colleagues on Earth.
What would be the minimum lab requirements for a Phobos geological analysis base? You'd want to have fine-scale composition and isotope analysis, as well as the best rock dating equipment you can afford to transport. You'd also want equipment for examining micro-fossils (just in case) and for examining ices and such for possible biological activity or remnants.
What suite of instruments would best serve your purposes in such a set-up? What are their power requirements? And how much of it can be feasibly transported via rocket from Earth to Phobos? Those are the questions I'd be asking right now...
-the other Doug
One fairly big problem that I see with the idea though is that the stuff that you loft up from the Martian surface would also have to land on Phobos and do so incredibly precisely and without damaging your lab. That's pretty hard if you ask me - It seems to me that it would be a lot easier to send stuff all the way back to Earth. The Delta-V difference between "Mars-Surface to landed on Phobos" and "Mars-Surface to Earth C3=0 orbit" is only 1.5km/sec.
Well, it depends... the PIs have to get their results published before they can come home, after all...
-the other Doug
Publish or perish?
Literally!
-the other Doug
http://www.aviationweek.com/aw/generic/story.jsp?id=news/mars070607.xml&headline=Mars%20Mission%20May%20Be%20Moved%20Up%20&channel=space
By Frank Morring, Jr.
Aerospace Daily & Defense Report
July 6, 2007
Didn't know where to put this...
http://www.space.com/scienceastronomy/070726_mars_samplereturn.html
This is how I like to hear them talking!
gndonald:
"Was this by any chance the 'Mars Twilight Flyby' that NASA was planning in 1966? "
No. It's about Phobos, and has evolved into my abstract for the Phobos conference.
Phil
[...]
I get your point, JR. In all fairness, though, there does seem to be some precedent for the strategy. Ranger/LO/Surveyor were all precursors to Apollo, so since Mars is the espoused future goal for US manned exploration it's getting the lion's share of UMSF attention.
Not necessarily saying it's the right way to go, but merely speculating on the apparent reason for the focus.
I think you missed the "far into the future" part. Mars sample return is going to be harder than the current missions, and it's likely to take a lot of time. And it can fail like any other mission, for technical or monetary reasons. We can get into the situation when specialists are waiting for additional financing, and there are no working rovers on Mars. The sample return mission is just too big for the pipeline now.
A think we need an "entry" strategy - how to implement ambitious missions efficiently, so that we don't end up with another over-expensive and unsustainable Apollo-like program.
[...]
Mars is also special because it the easiest extraterrestrial planet to research. Try getting samples from Mercury or Venus. Now that would be hard!
The Moon and asteroids are easier, but some questions can only be answered by researching planets. Mars is a natural stepping stone for planetary research. We may learn enough about Mars at some point, but the technology developed for Mars will be reused for other celestial bodies.
A massive one-off project would be less useful for further exploration than smaller specialized missions. MER-like robots can be driving on Europa one day.
A question here: If you have a ~30-40 kg small satellite and you want to launch it from mars surface into mars leo, how much energy do you need for it? And how big would be the rocket? Is there any more detailed study on this online?
Thanks
You can find some of my back of the envelope calculations on that question in an early post in this thread ( http://www.unmannedspaceflight.com/index.php?showtopic=2570&st=0&p=94079&#entry94079 )
The delta-v that you need is 4.1km/sec to from the martian surface to LMO. Assuming you're using an engine with performance similar to an ammonium perchlorate solid motor (ie an Isp of around 280), then you will need at least 135kg of fuel. You will need an actual launch shell to put it all in which would add another 10-20kg + another 30-60kg of fuel to cope with that extra initial mass.
Note I've made no allowances for atmospheric mass here and that will be significant even though the martian atmosphere is not very dense.
Excluding drag you are talking about an initial mass of at least 215kg to get 40kg to LMO.
And finally you need a (martian) ground assembly to hold it all before launch and I've no idea how to estimate how massive that might be.
[...]
I'm probably going to get my head handed to me for saying this, but can't a case be made for a Mars sample return with a direct Mars to Earth trajectory, bypassing a rendezvous in Mars orbit with an Earth return stage?
The obvious counter to this idea is that the size/weight of the Earth return rocket on Mars would be MUCH larger than that needed to reach low Mars orbit. OK, agreed. But there are a lot of advantages to direct to Earth launchings from Mars. One: A Mars orbiter to receive the sample canister wouldn't be needed. That eliminates an entire launch from earth and an entire spacecraft. Two: No need for a rendezvous in Mars orbit. This is an extremely complex operation to do unmanned, and I think it is the pacing technology for when a sample return could be done. It also raises the cost of the mission enormously.
The alternative is to launch a single massive spacecraft to Mars, have it collect and store samples by whatever means is preferred, wait until the next alignment of earth and Mars, then launch the sample return spacecraft directly to earth (no orbiting Mars first). This would require the use of a much larger launch vehicle from Earth than a standard sample return scenario, but that cost would be offset by requiring no Mars orbiter launch, and the much greater simplicity of the Mars to earth portion of the mission (which should also reduce costs greatly and, more importantly, give a greater chance of success).
I've made my case, let the carnage begin.
Well - yes - carnage indeed. Instead of a 5kg litle satellite to launch from the surface - you have to land, and then launch again - a much larger launch vehicle, to launch not only the small sample cache but also a complete, fueled, spacecraft and entry capsule - able to not only enter the Earth's atmosphere at the other end - but navigate with TCM's between Mars and Earth. A full up proper spacecraft - perhaps 100kg (complete guess). Landing and then launching your return capsule is not easier.
You're making the requirements of the MAV an order of magnitude larger - and thus the landing requirements an order of mag larger (when we don't know how to land >750kg on the surface) and thus the first launch vehicle from Earth being an order of magnitude larger....which doesn't really exist
I think from a biohaz perspective (even if it's just paranoia) - taking a small cache from orbit, putting it into another large entry capsule that is then sealed makes a lot of sense. If you have the entry capsule on the surface, you've exposed it to the Martian environment as well.
I can perhaps see the case for single launch - a viking like split between lander and orbiter, and then then a re-rendezvous on orbit for the return to Earth - but taking EVERYTHING you need to get from Mars back to Earth ( a complete spacecraft) all the way to the surface and back makes the entire problem much more difficult than it needs to be. Also- orbit rendezvous and return offers the option for multiple samples collected and launched from multiple sites to be returned via a single orbiter.
Thanks, Doug. I knew I was going to be defeated on this, but reading the details answered a lot of questions I had.
It's not 'defeated' - I mean, there's merit to making as few manouvers in the system as possible. If you could make a spacecraft with the necessary Delta V and entry ability to do the Mars to Earth flight - but <10kg - perhaps it could be done - but I'd want my return vehicle to be very big, very reliable, and packed full of redundent systems.
Doug
Of course the points Doug mentions are valid and pretty serious drawbacks for the Direct-to-Earth approach.
However, there is (at least) one point in favor for it: ISRU, aka the Zubrin Fuel Processor.
By far the greatest part of the mass of the return vehicle must be fuel, so if you can somehow land with empty tanks and then do a refill the whole plan makes more sense. You probably can't do DTE without ISRU. But even in a split mission approach ISRU could perhaps be an interesting option.
There is also another issue with the split mission architecture. Is it really possible to automatically rendezvous with a completely passive cannister? Something that doesn't have a radio, position control, an energy source, etc... How do you know its orbit with enough accuracy? But if it can't be a passive cannister, how much hardware must be added before you can find it in orbit? What does that do to that 5 Kg mass number?
Actually, I don't believe in such small numbers, it will probably be more like 100 Kg. At least.
I think a sample cache cannister would have a small battery and a beacon radio.. It'd be interesting to know how much intelligence was required on the 'dumb' part of the recent DARPA orbit rendezvous demos when doing the automated undocking and redocking.
Here's a thought. You could make your sample cache a derivative of a cube sat.
Doug
A cube-sat? Hmmm, I believe at Delft University (Holland) they actually are developing something like that called a nano-sat. As I recall it was 30 cm. (12 inch) on each side, or something. (And it carried a radio) I will see if I can find some more information on it.
Cubesats are a well established and popular platform ( you'll even find extensive info about them here )
It's 10 x 10 x 10 cm and no more than 1kg
You can extend the platform into a double or triple cubesat ( 10 x 10 x 20 and 10 x 10 x 30 , 2 and 3kg respectively) for added performance.
Doug
So I guess the 'cannister' could look something like the http://www.delfic3.nl/index.php?option=com_content&task=view&id=67&Itemid=109
This one doesn't have active attitude control, but that's basically all it's missing for being a perfect MSR cannister. Work is also being done to develop autonomous rendezvous, where nanosats would catch up with big satellites for maintenance or repair. This cube-sat development could really be extremely useful for MSR architectures!
So, I'm willing to lower my bid to 10 Kg!
2 Kg of samples.
5 Kg for the standard cubesat bus
3 Kg for attitude control, thrusters and a docking mechanism.
This may be WAY off base, but has anyone considered a purely ballistic MSR mission profile?
What I'm thinking of here is a single-stage (or two at the most, if the upper stage has robust thrusters & agile nav capability) DTE reentry vehicle from the surface of Mars...minimal course correction requirements, tight launch window, maybe even solid-fueled at least for the initial boost phase. Advantages: Relatively simple G&C. Disadvantages: (1) very tight launch window, (2) probably high velocity wrt Earth for entry phase. Don't know without a formal risk analysis how these very coarse factors would play out, nor whatever other dragons there may be.
(BTW, thinking of grams, not kilograms, in terms of sample return quantities: even a very little bit of Mars would go a long. long way in terms of answering fundamental/nagging questions such as the presence or absence of superoxides, carbon abundance/source, iridium ratios, etc., etc., ...)
Good question. Solid fuels have a great track record in space...I think there has been one possible failure in 300+solid propellant motor ignitions in the vacuum of space.
Or the CONTOUR kick stage
Doug
Or the two HS-376's on PAM's of STS 41-B
Or the IUS on STS-6
Hmm. Doug & Jim, if you had to shoot from the hip, would you favor liquid or solid propellant for an MSR return vehicle? Expanding on that, do you think that a DTE strategy would be better than, say, a Mars orbit rendezvous with a return vehicle? Seems as if there might be some significant risk analyses needed to make the best possible decision, but interested in your thoughts.
Here are some comments about "how to get off of Mars" for an affordable sample return mission. We really are talking about a miniature launch vehicle. Mars ascent is far more difficult than any rocket maneuver ever done except earth launch, while Mars ascent needs to be done with about one thousandth the mass of earth launch vehicles.
A Mars ascent vehicle needs to be about 75 percent propellant, e.g. 4200 m/s at 310 seconds Isp. If the rocket stage without payload is 80 percent propellant, then the whole vehicle has to weigh 16 times the payload (12 parts propellant, 3 parts stage hardware, and 1 part payload has the 75% and 80% ratios). If the rocket stage can be as good as 90 percent propellant, then the whole vehicle weighs only 6 times the payload (4.5 parts propellant, 0.5 parts stage hardware, 1 part payload). Much better.
For example, a 20 kg Mars ascent payload means that 80-percent rocket stage technology results in 320 kg launching off Mars, while 90-percent technology needs only 120 kg. That's likely the difference between "not possible" and "possible," given forseeable sizes for Mars landers. I believe the latter can actually be done, if the avionics and batteries can be squeezed into the 20-kg payload allocation -- the rocket engineer perspective on what constitutes payload .
So the scale (and therefore cost) of the entire Mars sample return mission depends very strongly on the relative masses of propellant and stage hardware, which in turn is limited by the strength of metal and the difficulty of miniaturization. Whole stages of earth launch vehicles are 90 percent, but there is no precedent for achieving such high numbers in the 1-ton range, let alone on a 100-kg scale. While the above analysis assumes one stage, and multiple stages make it easier in theory, the miniaturization challenge is even more difficult for an upper stage.
Existing flight-qualified solid rocket motors on the scale of interest (~100 kg) are about 90 percent propellant, so it is very tempting to think the problem is solved. However, it is necessary to add directional control. The extra parts could easily over-burden a Mars ascent vehicle. A useful technology development effort might be to build and test-fly a series of small solid rocket stages, all the while working to reduce the auxiliary weight.
For liquid propellants, entirely new custom hardware would have to be developed, because liquid propulsion parts used on satellites and spacecraft are too large and heavy. One possibility for reducing hardware weight is to use a pump-fed engine like launch vehicles do. The principle is to reduce tank weight by making the walls thinner (low pressure), while making the engine more compact (and less massive) by running it at high pressure.
The organizations that build spacecraft propulsion systems have not been asked to design rockets completely from scratch since about 1970 (perhaps a few exceptions), and launch vehicle organizations only build big things. A learning curve should be expected. A bit of good news is that building a Mars ascent vehicle promises to be a very exciting project to inspire the next generation.
John W.
mepag.jpl.nasa.gov/Announcements/Stern_MEPAG_Summary.pdf
The above has a summary of a meeting between MEPAG scientists and Alan Stern on September 24. It sheds a little new light on Stern's thoughts about an MSR, as well as the MSL descopes, and the 2013 Mars Science Orbiter. He actually makes a 2020 MSR mission seem feasible, even affordable, with the sacrifice of one Mars opportunity mission. Both sides brought out new points I hadn't heard officially before. Worth checking out.
Thanks to monitorlizard for pointing out the Sep24 MEPAG meeting notes with Alan Stern. To summarize the key points that I noticed regarding MSR:
1. The notion is that skipping one Mars launch opportunity next decade would save enough money to develop and launch MSR in 2020.
2. Planning for science, mission architecture, and curation (sample handling in Houston) are proceeding.
My analysis:
MSR needs two large spacecraft: a lander that carries the Mars Ascent Vehicle (MAV), and an orbiter that carries the Earth Return Vehicle (ERV). Either of these alone is most likely a heavier and more expensive spacecraft than the one single science spacecraft that would be sacrificed in order to pay for MSR. It doesn't appear to compute financially.
Maybe it will be affordable if the 2009 MSL lander works like a charm, and is just copied without new lander development. Then the challenge is back to building a very small MAV, and likely also a new ERV that is small enough to send to Mars orbit in the first place.
All this says that aggressive innovation in down-sizing propulsion technology is needed. Meanwhile, mission architecture studies (number 2 above) can easily have big errors in the estimates of mission mass (and cost) in the absence of the rocket technology.
We have to hope that the science community will appreciate the need for high-risk rocket technology work. There's essentially nothing out there that can be bought and modified or adtapted in order to successfully launch off of Mars.
John W.
"There's essentially nothing out there that can be bought and modified or adapted in order to successfully launch off Mars"
That may very well be true, but there's one possiblity I can think of that might just barely do the job: the ASM-135 ASAT antisatellite weapon that was successfully tested in 1985. It was a two stage (solid propellant?) rocket, with a third stage that I think was just the kinetic warhead itself. The first stage was taken from the Boeing AGM-69 SRAM cruise missile (specifically the Lockheed SR75-LP-1), and the second stage was the Vought Altair III. The third "stage" featured a hydrazine attitude control system to allow a direct hit on the target. Such a control system seems to fit well with the requirements for a rendezvous in Mars orbit with the Earth-return vehicle. (all facts taken from Wikipedia)
The ASAT missile was launched from an F-15 at around 85,000 feet, which is like having an extra stage for your rocket, but I'm wondering if the lower gravity at Mars might make it possible to launch from the surface without an extra stage. The ASAT was described as being able to reach altitudes greater than 350 km (the satellite it hit in 1985 was at 555 km), which seems more than adequate if used at Mars. The weight of the entire ASAT missile was 1180 kg, which seems within the range of possibility for an MSR mission.
I have no idea if such a rocket could actually be used for an MSR, and it might need to be so highly modified that starting from scratch might be better, but I think this is the only already-built system that could meet the weight and performance specs needed. It would be a great sword-to-plowshare moment if it could be used. If MSR is a joint mission with ESA, it could be an ITAR nightmare, but this is supposedly a retired system.
Rats! I see I'm off by a factor of ten in the weight of the MAV envisioned for an MSR. Pity. I was thinking like a Soviet engineer in the 60s.
"Jim from NSF.com" noted earlier today that a pump-fed minature launch vehicle may not be viable due to inefficiencies. That's probably true if miniaturization is attempted for centrifugal pumps powered by turbines (aka turbopumps).
Tests on a positive displacement miniature pump indicate that only 2% of the total propellant would provide enough power to run fuel and ox pumps, which is efficient enough. See JPL's Mars Technology Program website for a synopsis at (hope it's still there):
http://marstech.jpl.nasa.gov/content/detail.cfm?Sect=MTP&Cat=base&subCat=LCMT&subSubCat=&TaskID=2289
It's agreed that pressure-fed propulsion is nice and simple and reliable, but you end up having to make tank walls thicker and heavier than you would like them to be, and also engines larger than you would like them to be. For decades, people have envisioned pressure-fed liquid launch vehicles to get off of earth (Bob Truax, "Big Dumb Booster," Beal Aerospace, Microcosm, etc.), but so far none has succeeded. Even using the strongest materials (carbon fiber), the stages end up being closer to 80 percent propellant than 90 percent, and that makes all the difference (in displacing payload with rocket hardware, or in requiring the whole vehicle to grow huge for the same payload).
Regarding monitorlizard's comment about the 1985 ASAT test rocket, the altitude it reached does not necessarily indicate capability to attain orbit (earth or Mars). Reaching orbit requires velocity in addition to altitude. NASA's goal for Mars sample return is to park the sample package in a circular orbit at 500 km altitude. Given only a quarter of orbital energy (half the velocity), it's possible to launch straight up to 500 km (sort of like the ASAT rocket did), but then you fall straight back down again.
"Soviet engineer in the 1960's," is an especially appropriate comparison since their return vehicles that launched off the moon (Luna 16, Luna 20, and Luna 24) weighed about a metric ton. The Mars ascent vehicle has to be a tenth that mass, and just to get to Mars orbit it needs a much higher velocity (4200 m/s) than going from the moon all the way to earth (2800 m/s, which the Soviets did nicely using only one rocket stage).
Great discussion!
John W.
It seems that for sake of economy and simplicity a solid first stage would be ideal. However, I can't think of anything else but a liquid-fueled (hypogolic?) second stage to achieve orbit; it has to have a throttle & restart capability, esp. if the first stage under- or over-performs, and of course to circularize the orbit. Perhaps pressure-fed tanks controlled by valves alone would overcome the pump problem; pressurize the hell out them with Martian air before launch, then leave the feed pumps on the surface...
Not even touching the autonomous G&C requirements here. This will not be easy.
I concede now that I was way off with the ASAT idea. It just seems a pity that the Air Force has so many missiles of different sizes and ranges but none seem to be usable as the basis for an MAV.
As long as I'm throwing crazy ideas to the crowd... What if instead of thinking in terms of a 1 kg or larger Mars sample , we go much smaller, say ten grams. Someone has already pointed out here that you could extract a huge amount of science from such a sample size. So you get maybe a small pebble and a little soil. Now the MAV can be smaller, though I admit you still need the same guidance systems, attitude control, radio beacon, etc. (maybe some systems could be made slightly smaller in proportion to the smaller capsule needed for the sample).
Using a balloon to raise an MAV to an altitude of several thousand feet would be a way to make the MAV even smaller, acting as a sort of first stage for the rocket. I don't know how the trade-offs would compare, but if everything were of minimal size, it might be doable. I know it probably seems unnecessarily complex and not worth the effort, yet the U.S. Defence Department studied this very same concept before Sputnik as a way to achieve Earth orbit before the Soviets.
Maybe the fact that they never did it should tell me something.
You're right, nprev, that a solid first stage is very attractive. NASA's reference design concept for a MAV has been a 2-stage solid more or less since about 1999. The good news is that solid rocket motors on the scale of interest (100 kg give or take a factor of 2) are existing technology, and they are a whopping 90 percent propellant. However, there's devil is in the details. The thrust of such small solid motors is way more than is needed. It would reach high speeds while still low in the Mars atmosphere, so there's somewhat more aerodynamic drag than for a liquid MAV. Worse, perhaps, is that the high thrust also requires the directional control system to be larger and heavier than would otherwise be needed, and control must be very responsive (quick) to steer correctly for the 20 seconds or so before the first stage motor burns out.
Solid motors and their payloads are usually spinning when used for space maneuvers. Launching a spinning MAV would require the lander to have a spin table rigidly anchored to the ground so it doesn't start wiggling when the MAV is spun up. The landing orientation cannot be guaranteed, so the launch platform would require tilt adjustments on two axes, and then still be rigid when it starts spinning. How to design such a lander or estimate its weight to compare with other options? A spinning MAV was considered at NASA in 1998-1999 and ruled out.
Pressurizing the "heck" out of tanks and leaving the pumps on Mars is not a solution because the high-pressure tanks would be way heavier than pumps.
You hit 2 nails on their heads, monitorlizard.
1. There are so many different kinds of rockets and missiles out there, that it is way too easy for the "collective consciousness" to assume that it is possible to just go and buy something that can launch off of Mars. Therefore there has been no NASA (or ESA) money dedicated to aggressive technology development, most likely necessary.
2. Minimum size for avionics is really what determines the smallest MAV. Who wants to make the agonizing decision about how much telemetry to put on board? If it doesn't reach Mars orbit, how much data is needed to know why the multi-billion dollar mission failed (the painful lesson from Mars Observer 1992).
Rising through the atmosphere with a helium balloon before launching the rocket would be the ideal way to get off of Venus, if only the balloon could be kept from melting.
So for Mars ascent there are several possible solutions, none of which is existing technology. Ideally, some amount of engineering effort (building and testing things) would be affordable for each candidate, to help sort out what makes sense to pursue further.
John W.
Thanks, John.
Hmm...sounds like a real challenge in systems engineering...so many interdependencies! I've got some former classmates still looking for thesis research topics; this sounds like a goodie. Will see if anyone's interested.
There are some hybrid rockets, that have a solid fuel core and a liquid oxidizer. I believe the SpaceshipOne rockets were of this type provided by SpaceDev. They have throttleable and restartable rockets. So only one pump needed:
http://www.spacedev.com/spacedev_hybrid_prop.php
Hate to even bring this up, but it sure seems like we might need to fly a pathfinder technology demonstration mission before committing to the real deal...and the nasty part here is that there's no place to do it & gain any value at all in engineering terms but Mars itself.
Aside from the truly formidible problems of designing a MAV, there are a bunch of other systemic complexities and event dependencies to consider, far more IMHO than in any other UMSF effort to date. I wonder if a high-risk Discovery-class mission could designed to send a few grams back of any random Martian surface material as a bonus; the real value would be assessing the performance of all these subsystems.
[...]
And wouldn't you know it, I bet there isn't any leftover Martian orbital ascent hardware lying around anywhere, is there?.
I dunno, Dan -- the last MSR concept I saw (back in the late '90s) used some leftover, off-the-shelf solid-fuel military missile as its basis for an ascent vehicle. I bet there are at least two or three of them left that haven't been fired in anger yet...
-the other Doug
Well, don't want to start any debates but remember:
The very first unmanned (Lunar) sample return mission:
http://en.wikipedia.org/wiki/Luna_16
basic MSR JPL-weblink
http://mars.jpl.nasa.gov/missions/samplereturns.html
Indeed an awkard looking spacecraft and this 'thing' had a weight of almost 2000 kilograms with the ascent stage over 500 kilograms... and the upper 'ball' (in fact the sample re-entry capsule) had a diameter of 30 centimeters... of course the whole thing 'only' had to escape the Moon's gravity
When we compare the 1971 Mars 2 or 3 spacecraft configuration, it looks almost identical to the Luna 9 or 13 surface capsules. So probably a Soviet-Russian MSR craft might have looked like the 'ugly' Luna 16?
Might be worth considering & contrasting US & old Soviet-era (SE) design approaches when thinking about MSR. From what I gather, most SE flight hardware was very rugged, implying that functional modules were optimized for their specific performance, and holistic system interfaces/dependencies were minimized in order to reduce risks. The US approach was almost diametrically opposite, relying instead on a robust C&DH capability to adaptively sequence critical events, which in turn allowed more trade space with respect to subsystem performance margins.
Wonder if there just might be a truly optimal middle ground, here...
Fascinating & ingenious; really doing more with less. Thanks, John!
Maybe the way to approach this is to design a mission based on what we know we can do, rather then what we hope to be able to develop. (This is not meant to limit technological advance, but instead to constrain the problem). For example, if we assume direct EDL and payload DTE return, this simplifies the mission requirements considerably in some ways but possibly complicates them in others (one being the ability to meet really tight launch windows from Mars to Earth).
Just throwin' that out there...
There's been discussion elsewhere of the concept of sending a vehicle with a supply of fuel (typically liquid hydrogen), then after landing extracting liquid oxygen from the Martian atmosphere by breaking-down CO2. There was even a plan to fly a test version of the system on one of the recent landers (possibly MPL, doesn't really matter, it was dropped). This seems like a promising direction for MSR. Further, with the more recent establishment of the existence of water ice near the surface over much of Mars, simple electrolysis (via solar power) would allow production of both fuel and oxidizer on site, so this simplifies the MSR problem to that of delivering an empty launcher to the surface, along with associated equipment to generate the oxidizer (and perhaps fuel).
Understood. KISS has to be the guiding principle here, which is why I was pushing emulation of the Soviet design philosophy, at least for the Mars-to-Earth return phase. There are some truly formidible risks there that must be mitigated.
What about using a coilgun to give the payload an initial boost? I think a 2+km/s gun should be feasible to launch a small payload, say 20kg. The beauty is the simiplicity, you just charge some capacitors, load the projectile, steady yourself against the ground, and launch. If the design is done well, it might be possible to launch multiple return projectiles, say one every month with charging.
IEEE Spectrum just recently had an article about the history of railguns and coilguns and the like:
http://spectrum.ieee.org/jul07/5296
Course, might as well be wishing for magic ponies to fly the MAV off of Mars.
[...]
Even without the heat a take-off from Venus is almost as difficult as from Earth, and that thick atmosphere means extreme drag and dynamic pressure. You would probably have to lift the booster out of thickest stuff with a balloon before ignition
As a matter of fact a Titan sample return would probably be rather easier (and more interesting) than a Venus sample return.
International Group Plans Strategy For Mars Sample Return Mission
http://www.marsdaily.com/reports/International_Group_Plans_Strategy_For_Mars_Sample_Return_Mission_999.html
Some pretty good news, I would say.
Thanks, Cugel.
I like the extensive international cooperation, but worry about 'requirements wars'. It can be pretty damn difficult to reach a consensus with a large cardinal number of stakeholders from different organizations. Hopefully, the mission definition will be as clear-cut as possible to avoid this mess, 'cause it ain't fun at all, plus such wars tend to really jack up costs...
Some 'current events' which indicate an increasing emphasis on MSR:
January 2008: This month's issue of Aerospace America has an article titled "Mars Exploration: Digging Deeper," by Leonard David, contributing writer. MSR is featured prominently. The argument is made that the Mars Program needs to keep doing new and exciting things to justify its 46% share of NASA's planetary budget. More orbiter and rover missions alone might not be enough to maintain excitement and political support. On the other side of that coin is a concern that MSR might displace ongoing Mars efforts to such a large degree that there would be a net detriment to the Mars Program and to Mars science. One interviewed science leader expressed the importance of having MSR become an ongoing program to encompass multiple missions, rather than one win-or-lose flagship mission.
Given all these concerns, a way must be found to make MSR affordable for multiple attempts within the current budget (just over a half billion US dollars per year). However, the article did not delve into the unique technology needs for MSR.
My own comments: Is there anything that affects the mission scale and cost more so than the need to deliver a launch vehicle and its ground support equipment to another planet? Is there a more direct path through the above dilemma than building a miniature launch vehicle (or at least finding out definitively how small one can be)?
February 20-21, 2008: The Mars Exploration Program Analysis Group (MEPAG) is meeting in Southern California. Sample return is on the agenda for this discussion among (mostly) geologists. See http://mepag.jpl.nasa.gov/meeting/feb-08/index.html
April 21-23, 2008: A science meeting in Albequerque is named "Ground Truth from Mars: Science Payoff from a Sample Return Mission." Sponsors include the Lunar and Planetary Institute and NASA. Discussion topics include Mars exploration strategy, sampling strategy, and specific topics in geology and astrobiology. See www.lpi.usra.edu/meetings/msr2008/8
Also in the near future, NASA is planning a MSR Technology Workshop to discuss the following topics:
1. Rendezvous and Sample Capture (in Mars orbit).
2. Earth Entry Vehicle (the part that lands in Utah like Stardust did).
3. Returned Sample Handling Technologies on Earth.
4. Sample Acquisition, Sample Handling, and Encapsulation on Mars (packaging for shipment to Earth).
5. Forward Planetary Protection and Organic Contamination (how to not contaminate Mars with Earth life and related chemistry).
6. Entry, Descent, and Precision Landing (for Mars arrival, improved from prior Mars landers).
7. Back Planetary Protection (how to avoid any possibility that Mars life or molecules could harm life on Earth).
8. Mars Ascent Vehicle.
[...]
Of course, nothing can compete with a well documented Mars sample returned to Earth, but I would like to say a few good words about Mars meteorites. They provide ground truth for parts of Mars' surface, we just don't know what parts of the surface. But just maybe CRISM or some future hyperspectral imager will be able to correlate some Mars meteorites with specific areas of the Martian surface. It won't be perfect, but Mars meteorites are an extraordinary bargain (cost-wise) that really do tell us a lot about Mars.
I think, maybe it was pointered to from here, that there's a major hi-geo-geek-level book coming out on the geochemistry, igneous petrology, and all the implications of that from the mars rock meteorites for the geology, geophysics and history of mars.
[...]
Well, here's another thought -- instead of relying solely on Mars Orbit Rendezvous (MOR) to collect up all of your separately-launched samples, why not add to this with an element of Mars Surface Rendezvous (MSR)?
It seems to me that the most challenging part of this architecture, both to land on Mars and to get back up off of it again, is the ascent vehicle.
If you want to sample six types of terrain, would it make sense to land six ascent vehicles and then go hunt their easter eggs in Mars orbit, using up tremendous amounts of propellants in rendezvous maneuvers? Or would it make *more* sense to land only two ascent vehicles, each of which is loaded with samples from three different rovers? (I'm thinking that it *must* be easier and cheaper to design, build and fly two MAVs which can each place 30 kilos of samples into orbit than it is to fly six such vehicles which can each loft 5 kilos of samples.) Yeah, you'd "bunch up" each set of three rover sites into something like 100-km circles around each MAV (assuming your rovers can drive as far as 50 km to deliver their samples), but that seems a small price to pay. Besides, there must be many locations on Mars where you can access several different and interesting geological units within a 100-km circle.
Granted, you'd be betting that your rovers would be able to navigate to your ascent vehicles. But again, success could be a graded event -- if only one of your ascent vehicles worked, or if only one or two rovers were able to deposit samples in each, you'd still be looking at a pretty successful mission.
And you'd only need enough fuel in your Earth return/orbiter vehicle to make two rendezvous maneuvers, not six. That could be a truly substantial mass savings.
Yes, we're talking about spending something similar to what Apollo cost just to get 50 or 60 kilos of Mars back to Earth -- at least four major Ares V-type launches, probably more, and a *lot* of spacecraft all operating at once cost a lot of money. But it's a fraction of what putting men on Mars will cost, and a lot of people would argue it's scientifically justifiable.
-the other Doug
[...]
Well -- in re rendezvous issues, my thoughts come back to the fact that the U.S. has yet to prove a capability of autonomous rendezvous. A DoD test was attempted a few years ago, and it ran out of fuel before it achieved station-keeping with its target.
I grant you that the Russians have been doing it for years, and the Europeans will be jumping into the fray within the next month. But that's in LEO, where ground tracking data can be instantaneously incorporated into a vehicle's on-board solutions.
I'm also thinking of how rendezvous works. Your sample-carrying pods will have to be the passive targets -- your weight penalties are highest for the vehicles that you actually land on Mars, so the extra prop you need for rendezvous maneuvers will all have to ride in your orbiter. Making multiple rendezvous means you have to adjust the orbiter's orbit for every object you want to meet up with. Unless the sample pods are all in nearly identical orbits, and most importantly are in nearly the same place in those orbits at a given time, you could require from weeks to months of operations trying to reach each one. And if you end up with any significant out-of-plane elements, you exceed the available energy required to rendezvous pretty quickly.
So, for example, if you end up with two sample containers in nearly identical orbits but, say, separated by 120 degrees of orbit arc, you'll need to phase your orbiter back or forward through a third of an orbit, which is pretty energy-intensive.
And remember, you have to loft all of the fuel you need to reach your sample pods all the way from the surface of the Earth into Mars orbit. For every ounce of fuel you deliver to LMO, you have to spend thousands of pounds of propellants just to get it there.
Until and unless we demonstrate an autonomous rendezvous/docking capability in LEO that allows a satellite to travel around to various objects in various orbits, I'm not certain we're talking about sometihng that's within our technical competence at the moment...
-the other Doug
[...]
An essential ingredient in my utterly unofficial vote for a landing site would be the number of essentially DIFFERENT geologic units sampled. Meridiani, other than the sands on top, is essentially one geologic variations-upon-a-theme. Gusev has 2 major players: the basalt plains that buried what we really went there for, and the much older and much more complex and variable materials of the Columbia hills. The more essentially different materials a site has within the primary misison investigation range (and more beyond it), and the more of them that are of "special interest" in terms of paleo-habitable-environments or the like, the better. It would be great to have phylosilicates and sulfate deposits, plus deep seated igneous rocks and eolian layered sediments and channel wash deposits and ... and ... and...
Meridiani is wonderful.. and it's also boooooringgggggggg.
The journal Science just published a lengthy article on the Mars sample return debate. Unfortunately, Science is a subscription only journal. Much of the article rehashes history that is familiar to those of us who have followed the debate on this forum. I've put a couple of quotes from the article below on new information from the recent MPEG meeting:
"An expert panel assembled at the request of White House budget officials to vet the plan concludes that it doesn’t hold water. “You have to come clean,” says planetary scientist Philip Christensen of Arizona State University, Tempe, who chaired the panel. “Either you fund the program, or you accept the fact that it will be significantly reduced for the next decade.” Christensen laid out the panel’s conclusions at a 20 February meeting of the Mars
Exploration Program Analysis Group in Monrovia, California, with Stern sitting in the front row. The agency’s science chief insists that the new plan is sound and that the community is needlessly worked up about the proposed changes. “No missions have been canceled—none, zero, zip, nada,” he told Science. “The Mars program is really healthy,” he adds, noting that NASA might even hold a competition soon for a new Discovery mission that could be devoted to Mars...
"Christensen’s panel says that fiscal plan won’t fly. “The phasing is just wrong,” says Christensen. “Our assessment is that it just won’t work.” Preparing to launch a sample return by the end of the decade would require a big boost in spending earlier in the decade. The group determined that NASA would have to cancel everything after MSL—including the 2013 Scout and the 2016 missions—to fly a sample return by the second half of the next
decade. Stern, meanwhile, has slapped an $800 million cost cap on the 2016 mission, which he acknowledges would rule out the complex astrobiology field lab. Several scientists say that cap might also eliminate the rovers.
An alternative scenario would preserve the Scout mission and move the sample return back to 2022. But that would require using a poor orbital trajectory and create a dozen-year gap in U.S. landings on Mars, notes planetary scientist Lars Borg of Lawrence Livermore National Laboratory...
"Early estimates put the overall cost of such an ambitious mission at $5 billion to $6 billion. Stern says that NASA can contribute no more than $3 billion, and he hopes to attract another $1 billion or so from Europe— which is eager to participate— and possibly Japan." [The article goes on to say that the price would be lower if samples were returned that had been collected by MSL or ExoMars. It doesn't state that the MSL cache would be a jumbled cache of pebbles. However, it quotes the MPEG chairman, John Mustard, as saying that such a quick grab sample wouldn't be worth the trouble since we already have Mars meteorites.]
All in all, the article does a good job of describing the problem that Stern is trying to address in balancing the overall science program with the Mars program. Science is a highly reputable source, so I presume that the controversy over the feasibility of the program given projected funding is real. Stern seems to have his feet solidly planted on the ground, so I expect that there is another side to the story, though.
Thanks for the summary of the article, vjkane.
Err, by the way, the group is MEPAG, not MPEG
Thanks also for the excellent summary, VJ; much appreciated!
Sounds kind of scary, but at the same time hopeful; MSR is being seriously discussed, and that's really a first. Agree with the point that 'grabbing pebbles' may be fruitless; think we need to do a very focused sample recovery, and IMHO this probably means that we need to do more localized analysis missions al a the MERs & Phoenix, assisted by orbital recon before selecting a target for MSR.
"Focused" is probably too vague; what I mean is most likely to achieve prime science goals, and maybe it's time to refine those. We'd all like to see clays or sediments, and to be fair many would like to see igneous samples from the older terrain. Unfortunately, we'll have to make a choice; unless we're very lucky, no single site will provide a diverse sample set.
A really naive question:
Could you do a remote modular assembly of both the MAV (Mars Ascent Vehicle) and the RTE (Return to Earth) vehicle at Mars?
Final assembly/coupling would in Mars orbit (for the RTE vehicle) and on the martian surface (for the MAV).
You would require multiple vehicles to Mars, but you'd get the capability to spread the weight over several trips.
I picture a martian version of DEXTRE bolting together the MAV on the martian surface.
The tricky stuff to develop would be the remote orbital rendezvous capability (ESA's Jules Verne could become a test bed) and the autonomous remote assembly of spacecraft or structures. (Which seems like a really handy technology to develop.)
How whacked of an idea is this?
-Mike
Controlled by someone on Earth or controlled by someone in Mars orbit?
--Greg
Automated sequence. Program sequence uploaded from Earth.
["SCRW DMNT" = the screw it, dammit! command ]
-Mike
What would be the requirements ( size, mass etc ) for a MAV with cubesat-to-orbit type ability. I'd have thought it would make a lot of sense to forgo any on-Mars assembly at this stage and just take a solid fueled vehicle in one piece.
Of course, in the future, as a precursor to ISRU methane production - a liquid fueled MAV would be an interesting project - but with something with so many weak links and challenges as MSR - I think where the potential is there to KISS, it would be crazy to do otherwise. You want as few launches as possible.
Of course, even with an MSL or ExoMars cache - we have to presume they're dead. So you need to land close to them, and then go and get them with a rover ( MER-scale I guess) That's going to lead to something very special - revisiting a dead vehicle.
Doug
Reading back through the thread, Climber posted a link to two excellent Planetary Society blog posts by Mark Adler on the two aborted MSR mission projects he worked on (post #4). (I'd forgotten those, if I ever read anything about them in the first place.) It looks a lot more practical than I thought, but even the most recent would only have returned a "grapefruit-sized" sample container; and you would probably want two landers at least, and it would have clearly been very expensive.
http://www.planetary.org/blog/article/00000701/, http://www.planetary.org/blog/article/00000701/.
As Climber pointed out, at the end he says he doubts a sample return will happen in the 2020 timeframe, or for "a few decades" to come.
(Link to http://www.planetary.org/blog/article/00000703/)
[...]
It seems to be a foregone conclusion among many that MSR is the next major goal for Mars exploration.
I'm confused by this for two reasons (neither new to this forum but worth reminding everyone of):
1) I haven't seen any objective evaluation of the cost of sample return versus the cost of in situ measurements. For some large class of measurements, in situ would be far cheaper. Presumably this was the motivation for the "Astrobiology Field Lab". Is there a "sample return mafia" pushing for samples?
2) Fear of the "Andromeda Strain" scenario (justified or not) will impose all kinds of sterilization requirements on the returned samples, making MSR even more expensive.
I think MSR would be extremely cool, but I fear it won't happen for a long time.
I also note that Stern was pushing MSR back in mid-07, which seems at odds with the perception that he was advocating fiscal responsibility.
The project of MSR has one of the roots which is to develop and test the architecture for the future returning men's Mars explorers. Hence, the budget for this project must be split into several purposes such as this forum was discussing and also for the future men exploration to Mars.
[...]
Hmm. Lot of food for thought there, JR, as per your usual.
Your comments may imply that the Mars exploration strategy should be split into two different realms, geology and astrobiology. Framed in that way, then MSR would appear to be less important for geology, which these days relies more and more on remote sensing even for terrestrial applications. Therefore, MSR targets would be primarily selected for biological potential.
Of course, there would still be considerable opportunistic overlap between the two, but separating them administratively into much more distinct focus areas might refine mission objectives and proposals.
However, if we can find just one tiny little currently active hot spring then the whole astrobiology debate's over; that's where we'll go! An orbiter with an ultra high-res IR imager as well as with a fast visible imager to search for active, small plumes or sudden landscape changes might be the best investment we could make to limit overall mission creep. Life is more likely in chemically active areas.
Not cheap, but quite probably cheaper then 15 or 20 smaller missions to look for likely habitats. I'm still hoping that we get lucky with MRO.
We unfortunately seem to be lacking a geochemist on this board who could explain the difference between instruments you can fly on a spacecraft/rover and instruments available in labs.
There are basically two problems with spacecraft instruments. The first is in the preparation of the samples. For example, it is very common to very thinly slice rock samples for study. Routinely done in laboratories. Virtually impossible, as I understand it, to do on a spacecraft. The second problem is the resolution and sensitivity of the instruments you can fit into a spacecraft. For example, rock samples are regularly dated on Earth with great precision by examining subtle differences in ratios of elements. No one has ever figured out a way to duplicate those measurements in situ (except with some proposals that dedicate a lander to essentially one instrument and then accept very large error bars in the results). If a spacecraft finds organics on Mars, is the source simple chemicals from comets or simple single cell organisms a few microns across? Really hard to do with instruments small enough and light enough that you or I could carry them
I'll update an analogy I once heard. What you can fly on a spacecraft with its limits on space, weight, power, and shock (those craft get really knocked around during launch and landing) is to what you can do in a terrestrial lab as a computer you can carry in your pocket (think of smart phones, which really are small computers) to the best super computers available in dedicated facilities with room for thousands of processors, unlimited power, storage, and bandwidth.
"...and I can't think of a single change in Apollo that came out of Surveyor experience..."
Yes. A *lot* of engineers and managers didn't have heart attacks. Surveyor did a lot to protect us from both "Things we didn't know" and "Things we though we knew but weren't so." There were very few of the latter.
"...Apollo returned more than 100 pounds of samples before it returned a single conclusive chunk of anorthosite to pin down the majority composition of the terrae. And this was *years* after in-situ chemical analyses (with an alpha scattering spectrometer) demonstrated a terrae composition "compatible" with an anorthositic gabbro...."
I think it was John Lewis (Lunar and Planetary Lab? / Arizona State?) who looked at the diversity of rock and mineral-grain fragments in Apollo 11 soils, found a distinct non-local population of non-mare feldspar rich rocks, and pronounced them almost certainly highland derived and that the highlands were probably anorthositic. This was in time (I think) for the first Lunar Science Conference: the Apollo 11 Lunar Science Conference. I'd have to dig my copy of "Lunar Science, a Post Apollo View" by Stuart Ross Taylor out to most speedily find the correct reference off net. Probably easier to find it on-net....But I'm lazy.
I'd like to see a spacecraft do 1.) Uranium/Lead, 2.) Potassium/Argon, 3.) Rubidium/Strontium 4.) Neodymium/Samarium and 5.) Rheinium/Osmium isotope dating, as well as rare-earth-element geochemical analysis of a rock chip. (Yes, I've left out a few.)
That's one of the things that Squyres has mentioned in the past iirc. Usually, at the end of a talk, people will ask 'how old are the rocks' - and he replies with something alluding to the fact that the instruments to do that science, no one's figured how to put them in a shoebox yet.
Doug
Has anyone studied the costs and feasibility of putting testing equipment in orbit around Mars vs. all the complications of atmospheric entry and landing? I would venture that you could put more equipment and larger equipment and more fragile equipment into orbit in some kind of automated Mars lab than you ever could land on the surface. The sample retrieval then becomes one of merely getting the sand and rocks up to a defined orbit and nothing more. It would have the benefit of sample analysis from multiple locations at a much smaller cost than either multiple sample returns or multiple rover/lander-labs.
Just shooting from my armchair here, though Mark makes a real good case for Earth sample return.
I know that a case has been made that a human mission to Mars might be justified even if you never landed the humans on the surface. They could hang out in their pressurized, non-dusty, climate-controlled station in orbit (or on Phobos) and, without the hassle of lengthy two-way light-times, or the risk, complexity, and cost of landing and eventually taking off again, they could joystick vehicles across the surface, retrieve samples for analysis, etc. But I seriously doubt that an early human mission to Mars will include more than a few "shoebox-sized" pieces of science equipment, so that doesn't really solve the problem we're discussing here.
--Emily
The more I contemplate the cost versus benefits, the more inclined I become to drop MSR indefinitely in favor of multiple rover missions. For that matter, fond as I am of Mars exploration, post-MSL I would be inclined to trade any 2-3 Mars rover missions for 1 non-Mars rover. Places like Ceres, Vesta, Europa, Callisto, Ganymede, Titan, and Triton could each use one or more rover missions, though personally I would put Europa and Titan at the head of the list, closely followed by Ceres. Ceres is likely the cheapest option; planning a Ceres rover to arrive in time to be supported by the Dawn orbiter might just be a heck of a good idea.
Is having MSR a necessary prerequisite for manned exploration of Mars? If Mars gets put back into the Exploration program, there will surely need to be unmanned precursor missions to test equipment...ISRU, etc. A manned mission would surely bring back tens if not hundreds (?) of pounds of samples...could we just not skip MSR and push stronger towards manned exploration? If MSR is looking at only bringing back 1-10lbs for $5-10 billion, would it not be just as cost effective to bring back 100+ lbs for $100 billion?
[...]
There's obviously a trade-off. The rover (mobile) or in-situ (e.g., orbital or on-the-ground) lab approach yields lots of imprecise, necessarily ambiguous data from a handful of instruments for a large number of sites or samples. People here, including me, love that the rovers provide superb imaging (i.e., geological context) for each site. The MSR approach yields wonderful, incredibly precise, incredibly detailed geochemical, isotopic, microscopic, mineralogic, crystallographic, etc. data (independently confirmed at multiple laboratories) on a relatively small number of samples, whose geological context may be less well constrained. Given severely limited budgets, we have to choose. If we choose the MSR approach, we have to be super-careful about geological context.
My conceptual problem - I'm not sure that 20 rovers, imaging and crudely analyzing various occurrences of cross-bedded salty fines and spherules, would unambiguously tell us much more than we know now after imaging and analyzing such rocks at 2 sites (and, in the case of the respective MER teams, coming up with completely different interpretations). If each rover studied different rocks, that would obviously be ideal. That ideal is, however, difficult to achieve when engineering constraints restrict landing sites largely to equatorial flat areas, whose surfaces tend to be dominated by deposition/erosion via late impacts and the wind. Geologists long to study more challenging features such as "young gullies" formed only on steep slopes and the layering exposed in steep canyon or crater walls. Can the present generation of rovers, however long-lived, ever satisfy that longing?
-- HDP Don
UNNECESSARY QUOTING REMOVED
Don, excellent arguments, and I believe those that the Mars community (you may be one of them!) are making. Spacecraft instruments simply are crude, and there's a limit to the finess of the of hypotheses you can test with them. The the question is, are we willing to spend $3-5B for those answers? And do we know enough yet to know where to send that one sample mission?
Also, remember that there are four separate craft that must work: Lander, rover, ascent vehicle, Mars orbiter/Earth return craft. The level of risk for this mission will always be high.
The scientist in me wants samples. The mission manager worries about the impact on the rest of the program and the consequences of failure.
At the risk of catching a lot of arrows, I think HDP Don made an excellent point that argues against MSR: What should we spend 5 or 6 billion dollars on to return?
Mars is increasingly appearing far more diverse than originally thought when MSR was first conceived. How in the world do you prioritize potential targets? I can't see any single site capable of satisfying the needs of all stakeholders (and there are a whole bunch), which implies requirement creep, possibly to the point of extinction. It'll be a project manager's nightmare.
A manned mission, on the other hand, has to meet one overriding contraint: the site has to be safe for the crew to ingress & egress. This would tend to cut down on community infighting. Moreover, as others have pointed out, the quantity of samples returned would be MUCH larger then MSR could provide, and with any luck also offer some regional diversity (as we saw at Gusev; Home Plate is surrounded by locally typical terrain, and it was a relatively small traverse from the landing site.)
Unless there's a really cheap & much less risky way to do it, I just don't see what MSR can offer for its price beyond the long shot of finding a living native Martian organism. No current concept can provide anything like a representative area survey in terms of tangible payload return, and frankly the MERs have shown that in situ remote sensing is much more effective in this regard.
What does the Cassini-Huygens mission cost?
The total cost of the Cassini-Huygens mission is about $3.26 billion, including $1.4 billion for pre-launch development, $704 million for mission operations, $54 million for tracking and $422 million for the launch vehicle. The U.S. contributed $ 2.6 billion, the European Space Agency $500 million and the Italian Space Agency $160 million.
These figures are from the press kit, "The Jupiter Millennium Mission," which was prepared in October 2000. You can see it at http://www.jpl.nasa.gov/news/press_kits.cfm, where you can also find the press kit that was prepared for the launch in 1997.
announcement for the date for their Mars SAR Mission -- 2018
http://news.bbc.co.uk/2/hi/science/nature/7500371.stm
cheers
full inline quote removed - Admin
Nice to see that the powers that be are still pushing for MSR to happen. However the conceptual video depicts a mere "grab-and-go" mission that the Mars science community is violently opposed to (versus careful sample selection). Perhaps worse (and my own pet peeve), the Mars ascent vehicle is depicted as 2 stages built according to satellite-type propulsion methodology. When is the Mars community as a whole going to appreciate that the necessary miniature launch vehicle needs about a decade of aggressive new rocket technology development. Let's see, 2018 minus a decade is today, but (for example) NASA's Mars Technology Program this year is barely breathing.
Yes I know it's just a marketing video but it reinforces the ingrained prejudice that all planetary missions can be done using satellite parts!
John W.
That ESA animation has been doing the rounds for years - I would read exactly nothing into it, especially when Europe is far more likely to build the return-leg orbiting component.
Doug
My favourite nonsense SAR image is this (lifted from nasa site)
I was also surprised by that 2018 date, but the more I thought about it the more it made sense.
History suggests that whatever date you propose for a mission like this almost inevitably slides, for both technical and political reasons.
So, why propse a more technically reasonable date like 2020, or 2022, if it is only going to get slipped by the political process into 2024?
Seems like a reasonable gambit to propose 2018, and then have to suffer a slip into 2020 or 2022, which is the soonest you can be ready anyway.
Hi again,
Re the past couple days of comments above, OK fair enough to not read anything into artist conceptions, and fair enough to set a date that may later slip.
The source document underlying the July 10 news item is available from the Mars Exploration Program Analysis Group at http://mepag.jpl.nasa.gov. Click MEPAG Analysis Reports, then scroll all the way down to the bottom, to download the Preliminary Planning for an International Mars Sample Return Mission, Report of the iMARS (International Mars Architecture for the Return of Samples) Working Group. This document has 31 authors (the Working Group) and is dated 2008Jun1.
The Mars Ascent Vehicle (MAV) is listed as the second item in the table on page 21 (p. 25 of the pdf). The third column, "Technology Development Needed," lists 3 items for the MAV as follows.
1. Propellant and materials for long-duration storage and performance in Mars environment.
2. Launch from low-mass landed platform.
3. Low-mass avionics.
"Propellant and materials" development? Strangely, no mention of the need to create and design and build a miniature launch vehicle!
The only place in the text I could find mention of the MAV is on page 29 (p 33 of the pdf) which merely says there needs to be a MAV. Other items for the mission are discussed in more detail.
The very next page shows a schedule for technology development (Figure 5). Major headings are Orbiter Technology, Lander Technology, and SRF Technology (Sample Receiving Facility in Texas). The MAV should logically be one of the major headings, but it is lumped in as a mere item within Lander Technology.
Based on the iMARS report, I again submit that the MAV challenge is way underestimated. There simply is no community of people who have experience building miniature launch vehicles, which is consistent with a lack of lobbying for recognition and funding of the MAV problem.
John W.
I believe somebody mentioned the idea of having another look at the mid-80s US ASAT missile, which was launched from an F-15; might be a good idea as a starting point.
Only as a starting point, though, and probably only as a case study in compact solid booster design. I agree with you, John; this is a formidable problem that had better not be underestimated. The ASAT payload certainly wasn't designed to do anything but find & hit a target, and a MAV needs to be a whole hell of a lot smarter & adaptive for this stunt to have a prayer of working.
The ASAT missile weighed a ton, more than the lander, MAV, rover, etc. combined (assumed future affordable capability based on the expectation that the 2009 MSL will successfully land almost 1 ton total on Mars).
A popular definition of "space" is expressed in terms of altitude, but achieving orbit is more about velocity. The ASAT missile merely went straight up to about 500-600 km, which needs a very minor fraction of Earth's orbital velocity. Mars orbital velocity is 45 percent of Earth's. The MAV needs to accelerate zero to 9,000 MPH in 5 minutes.
Generally, rocket motors for military missiles have less raw propulsive performance than space motors, because the former have to be cheaper for quantity production, structurally more robust for abuse in the field, etc. We shouldn't pin our hopes on the possibility that something better than existing space propulsion hardware is available from behind the scenes in the military world.
Overall nprev is right that existing technology gives us "only a starting point." The question is when and how and who is going to move forward to develop a MAV? Part of the reason that the aerospace engineering community does not have a cadre of experts who are spooled up to develop a MAV, is that rocket technology development reached diminishing returns circa 1970, and the expertise in the field faded (along with funding cuts). Today's rocket experts implement relatively small evolutionary departures from existing technology.
John
Ironically, I'm not even sure that MAV is the long pole in the tent for MSR; there are a bunch of them. For example, the automated Mars orbit rendezvous, capture, and sample transfer process to the Earth return container seems like it might turn out to be fiendishly complex, and will require extremely robust software with autonomy bordering on AI capabilities.
On the happy side, such a technologically challenging project is just what the doctor ordered for NASA & ESA. As John pointed out, there's been some damping down on rocket development over the last few decades, and thatt's probably true for other disciplines as well since the focus is almost uniformly on staying on time and within budget. The sheer amount of R&D and innovation that will be needed to fly MSR would greatly benefit UMSF overall in the long term, and probably produce a number of significant spin-offs for non-space applications.
Don't usually double-post, but just had a wild thought: Why can't MSR be deferred until the Orion/Constellation Mars landing architecture is developed?
Rationale here is that it might make more sense to frame MSR as both a critical science mission and a critical test of the future manned Mars landing effort. At some point, there will need to be a realistic test of the crew descent/ascent vehicle; why not fly one with a rover or two that could pick up several hundred kg of samples while executing a nominal manned mission profile? A shakedown cruise of the system seems very desirable in any case.
Big bucks, yes...but also access to a different and much larger pot of money...
- 1.5 The manned vs unmanned debate will be never ending, always heated, and it is not allowed on this forum
Three posts deleted.
That's interesting. I was under the impression solid propellants have less than 300 s Isp (the figure for Shuttle SRBs is 285 s in vacuum) while hydrazine/NTO is said to have 340 s in vacuum. I'm using vacuum level Isp because Mars' atmosphere is obviously much closer to a vacuum than Earth sea-level pressure.
Then again, the solid fuels I looked at were optimized for rocket strap-on boosters which could be optimized for high thrust rather than high Isp. Don't know, I'm really not an expert.
Even if the Isps were 285 and 340, that's only a 20% advantage for biprop, which could easily be offset by the mass of tankage, pressurant, plumbing, and thermal control to keep the propellant from freezing. I'd say solids were still viable based on that.
It's true that's only 20% in Isp difference. However, for a given desired delta-V, the fuel mass varies with exp(deltaV/(Isp*9.81)). For low target velocities that's similar to the Isp difference. Say you wanted to reach Mars orbital velocity, 3.52 km/s. That amounts to 22% higher prop mass for solids. If you wanted to reach martian escape velocity, 5 km/s the difference becomes 33% which is starting to look more serious. Add into consideration gravity drag and the delta-V needed to reach orbit exceeds that of orbital velocity by at least a few hundred m/s. Mars has one thing going for it regarding gravity drag - lower gravity and less dense atmosphere allowing a more agressive acceleration profile. Then you come back to the thrust of the ascent stage, in which case solids are better.
A 25% increase in mass doesn't seem that high to justify the complexity of liquid propulsion, agreed, but what about the mass required to land the extra 25% mass in the first place? I have a feeling that doesn't scale linearly either. It's a tricky design to optimize indeed.
I have always wondered...
What about two separate launches from Earth -one for a lander+MAV and one for an orbiter and entry capsule? What about a single-stage MAV plus unmanned docking in Low Martian Orbit?
In actuality, I truly don't think the issue is really designing a MAV -- no offense, John, but it's really not that hard to design a rocket that can do the job. You don't need revolutionary new propulsion technologies to get off Mars and into MEO.
The problem is that with most any existing rocket technology, you have to land a very large mass onto Mars to make MSR work. Not as large a mass (or set of masses) as for a manned landing and exploration, but a very large mass, indeed. And the problem is that we've maxed out the amount of mass we can land on Mars with something roughly the mass of MSL. Much heavier and you run smack into the Mach 5 problem that has been discussed here extensively; the mass required for a MAV is large enough that friction with Mars' thin atmosphere isn't enough to slow it to a speed from which rocket braking can take over and reduce it to a landing velocity before the vehicle crashes.
Let's face it, it's probably just not possible to build a MAV powerful enough to do the job and that is yet light enough that it can be landed (even in pieces) with our current ability to do a successful EDL.
So, the EDL challenge would seem to me to be the limiting factor. If we can beat the Mach 5 problem, then it just becomes a matter of spending the money needed to get that mass to Mars in the first place.
-the other Doug
Yes of course, oDoug. If you define the problem as (1) "accomplish MSR within existing program budgets," then you have to develop a ~100 kg MAV. If you define the proglem as (2) "design MSR around a practical MAV that can be built with existing technology," then you need to develop a bigger EDL system and spend lots more money. To the best of my understanding, such a MAV would mass several tons, i.e. an order of magnitude in mission scale and cost.
Given that mission costs are about 1-2 million dollars per kilogram placed on Mars, it would seem to be worth a hundred million dollars to develop ANY new Mars technology that can make the mission scale 100 kg smaller. However organizations need to grow, so organizations tend to favor the second scenario even when there is very little hope for increasing funding. Is it possible that MSR is caught in a stalemate such that we can't pay for the necessary work to make the mission affordable?
By the way, the Mach 5 problem could be solved by pushing hard on new innovative propulsion technology. Just use better propulsion instead of a parachute from Mach 5 on down.
John W.
John - what you suggest has been reviewed. There's no way to fire the thrusters during the hypersonic descent. Imagine driving your car in the center of a hurricane!
I do understand your point, John. The problem with just inventing better rockets to drop the mass from Mach 5 down to zero is that, as the mass of what you're landing goes up, the total amount of its entry velocity that can be shed solely through atmospheric drag becomes less and less. And the more velocity you need to shed using rockets, the more propellant you need to carry, and the less effective drag slowing becomes. It's a vicious circle.
And besides, if you're going Mach 5 and you're a kilometer above the surface, and you have no more than about 30 seconds to remove the remaining velocity, just how many G's would you have to pull to avoid crashing? A 50-G deceleration would probably be outside the limits for Mission Success in any manned or unmanned mission I can imagine, and I can't imagine the required deceleration being much less than that.
If you use chemical rockets, you're going to keep coming up against the isp limits we've already identified as barriers to growth. We need truly revolutionary advances in propulsion technology, not just engineering tweaks of known technologies, to get the performance-to-mass ratios required for an effective MSR, much less for manned landings. IMHO.
If you look at it as a Venn diagram, I'm just afraid that the set that contains what's possible to do with chemical rockets, and the set of the mass of vehicles required for MSR, are sets which do not overlap...
-the other Doug
p.s. -- please bear in mind that I'm qualifying all of this when I say we need an EDL breakthrough for an *effective* MSR. I do not consider spending 15 billion dollars to bring back less than a kilogram of samples to be effective. That's an awful lot of money to return, frankly, far less material than we already have to analyze from Martian meteorites. -dvd
very funny doug!
My hack at the problem...its just a broad outline...please turn flame throwers to idle
There is probably nothing new here, other than independent parallel invention
To do the Mars SAR mission and to bypass the mach 5 problem (not enough atmosphere for heavy landers to decelerate safely)
then it must be a divide and conquer solution.
the spaceships required are
* earth-to-mars vehicle that carries a single return-to-earth vehicle with return fuel
* earth-to-mars vehicle(s) that carry one or more of the 2 required landers
Assemble the fleet in mars orbit (use a circularizing method, aerobrake or engine) fly in formation
The two landers:
* One with the MAV 1stage and launch platform (2000lb of propellant) -- use a tested EDL & a sky crane
* the other: a beefy rover with the MAV 2ndstage (1000lb of propellant), also the sample return container/nosecone -- use a tested EDL & a sky crane
The MAV 1stage lands first.
a few days later the Rover/MAV 2nd-stage lands-- very near the first (2 km?) -- precision landing required
The rover loads a contingency sample into the return container
The rover & second stage set out and find The MAV 1st stage. The MAV stages are mated (both stowed horizontally)
Rover still has access to the sample container (which has the contingency sample locked and loaded)
The rover (sans 2nd stage) goes on a science mission to find the best samples (2-6 week mission, 2-20km )
The Rover comes back and loads the samples
MAV is erected vertically - checkout - launch
Rendevouz with Earth return vehicle - sample container stowed
Leave orbit and head back to earth
Rover continues science studies until it dies
I don't think there is any new or breakthrough science needed here
Just alot of complicated machinery that needs to be robust and elegant.
ok...flame throwers set to stun....
Cheers
I think that the biggest problem won't be the anything concerning the landing phase, but the MAV itself. We all know how complex launching a single rocket is with all problems, delays and so on. A MAV (or a mars rocket) has to be fully autonomous and, of course it has to work flawlessly. That's why I suppose that it will be solid-fueled because it's the simplest design and there aren't many options for failure.
I think that the two-launch scenario (an orbiter plus lander) is the best. The orbiter, while waiting for the MAV to arrive may be busy collecting atmospheric samples using aerogell (already tested on Stardust and Genesis). The MAV may be delivered on the surface using a skycrane technique, specially redesigned for this purpose. I can't think of a better idea. Though I know how difficult fully automated docking may be.
I suspect that when the failure modes are analyzed that the lander/rover/launchers combination contains the overwhelming portion of the MSR risk. I think that having two sets of lander/rover/launcher should be baseline. If both deliver samples, great. However, if you send one and it fails, then the entire $5-8B is gone.
Why don't we just land a tank on Mars? It can rove around, picking up interesting samples and loading them into rocket-assisted shells. Once it is ready to launch, it can use a compressed air gun (remember the post-Columbia tests? ) to fire the shells upwards, one at a time. Fill the tank with CO2, heat it up nice and hot, and BLAMMO! Rifling on the barrel handles the guidance task for the first "stage". That's got to be good enough for a dozen or two km of altitude on Mars. Ignoring drag, 300m/s gives you 12km; 500m/s gives you 34km, enough to reduce the atmospheric pressure by 95%. Then, WOOOSH, your rocket boosts you to orbit!
Problem solved!
I CAN HAZ 8BIZZILLION DALLARS NOW?
K TNX
(Sorry, in a goofy mood)
[...]
[...]
Just exactly how much sample do you expect to return to Earth with a MAV that weighs, grand total with sample container and fuel, 100 kg?
No more than a gram, I would imagine -- and that would be pushing it.
Can I ask exactly what you think we can do with a gram or less of Martian surface materials? And why we would spend a billion dollars (or multiples thereof) for such a miniscule amount?
Just... curious.
-the other Doug
The MSR mission is very pricely. Why so much difference?
As an example, the most expensive mission to Mars would be for MSL by between 1-2 thousand millions dollars (I don't say billons -> millions millions). And the MSR would be between 3 to 5 times more expensive than MSL with just adding a few hundred of kilograms of weight to the spacecraft in order to return a 1 kg of sample. Well, I too agree that by sending as many in-situ spacecrafts to Mars would yield a better cost-benefit to science. Just a thought
The cost of the mission is sure to be a political trouble magnet, no doubt about it. And I'm among those who have doubts about the likelyhood of this all coming to pass.
But, in defense of the benefit of the mission, consider this.
We are rapidly getting into a point of diminishing returns on the Mars unmanned missions. Mars Global Surveyor was a huge step forward in our understanding of the planet, but can anyone reasonably think that we could find another 300 million dollar orbiter to make another quantum leap forward? The next generation of orbiters, MRO, cost more than double that figure at around 700 million.
Same thing with Phoenix. For about 500 million we get a nice little chemistry lab at the north pole. We should learn a lot of good fundamental information, if for no other reason that we have only had a small handful of landers on Mars before this. But fly a second mission of that class, and the ammount you advance your knowledge is somewhat smaller. Do you learn 4 times as much flying 4 more of them? Not likely. I really doubt we will see many more landers like Phoenix.
MSL is a great mission, but in order to advance beyond the MERs, we had to jump in cost from 800 million to 1.9 Billion. Now, to improve on MSL, what next? Do we move up into the 2-3-4 billion dollar range?
So, while there is still a lot we can learn with the in-situ unmanned missions, it starts to cost more and more to advance less and less.
Eventually Mars Sample Return, as expensive as it is, starts to look cost effective in the 'bang for your buck' department.
Hmm. Food for thought, Mariner.
The only real heartburn from a data return standpoint I have is that MSR would bring us a sample from one, count it, one, very small area of Mars. The planet's geological diversity is really becoming apparent (esp. from MRO & MEX), so much so that I wonder what the real value of a sample from a landing-friendly area of Earth would be as far as drawing conclusions about global, or even regional processes.
Maybe I'm underestimating our present understanding of context here, and perhaps not appreciating objectives. Certainly this argument could be applied to anything short of a full geological survey of Mars. That being said, MSR does need to define very specific sampling objectives, IMHO. Do we want phyllosilicates, sediments, evaporites, or what, and what specifically are we trying to find out?
Sorry for the devil's advocate position here, but when we're talking about spending this kind of money critical questions will be asked; better be some really good answers.
Exactly. If our $10 billion would buy us 100kg of samples, gathered by and trundled back to the MAV(s) by capable MSL-type rovers, picked up from a variety of landforms and geologic expressions, then I'd be all for it.
But if our $10 billion buys us a kilogram or less of soil and a few rock chips from within a grab-sampler-arm's reach of the MAV, then I don't care if God Himself is going to analyze the samples, the chances of finding anything truly instructive about Mars would, I think, be far less than if we spent the same money on three or four more MSL-capable rovers.
I strongly believe in bringing samples back from Mars. But I don't think a kg (or less) for $10 billion is worth the money. Not even worth $6 billion. IMHO.
-the other Doug
Most of the documents I have seen indicate that the baseline mission calls for collecting samples via rover for at least 6 months. Unclear to me if there is a large stationary lander with MAV mounted on it, with a rover returning with samples in tow, or if the lander is one large rover with MAV mounted on it.
In any event, it means that while you won't have samples from all over Mars, you at least get samples taken from a number of locations possibly ranging up to 10-20 kilometers away from the landing site.
Compare this to the MSR studies done in the 1980s. At that time there was a belief that Viking orbiters told them all they needed to know to get a site selected. And some studies even ommited any idea of a rover, and just had the lander grab rocks with a long robotic arm.
So really, 3 or 4 MSRs would be nice, but even just the one mission in 2020 would still be a tremendous advance in knowledge, and unlike the 1980s, we wouldn't be taking a shot in the dark on a location.
Maybe it really is time to bite the bullet and go for it. I keep thinking about Alan Stern's comment to the effect of "it's better to get 80 percent of something, than 100 percent of nothing".
In other words, no matter how long we wait, we're not likely to get the perfect set of MSR missions all over the planet, so why not at least get one?
One good argument for a Mars Sample return, even for just a small sample, is that a full and complete characterization of a Martian rock sample at one specific location using the full set of Earth-based instruments and equipment would give a solid benchmark to compare with all other locations on Mars.
This location would become the "home base" that we could use to reference all the other sites on Mars. It doesn't necessarily need to be representative, although it would be nice.
Well, I thought that the one of the good justifications to send the MSR mission is to have a very good evidence that the rovers or stationary spacecraft have found something very interesting that they are unable to identify or they have found some signals of past-present life. After that, everybody will nod "yes" to spend money for this mission.
No obstant, when I have learned that the http://www.marsdaily.com/reports/Russia_To_Study_Martian_Moons_Once_Again_999.html spacecraft would cost an astonishing small amount of money: USD 65 millions. I know that this mission would require much less mass and energy to accomplish but its difference is about 10-15 times that leads me to think about what NASA can improve the space program costs.
I can't believe that $65 million is the entire cost of Phobos-Grunt. That may be what Russia plans on spending on just the spacecraft development and construction. I can't imagine it also includes launch costs or operational costs of mission ops, and I bet it assumes that a good deal of the overall cost will be borne by international partners.
AFAIK, even for Russian launch vehicles, $65 million won't even cover the launch costs.
And, like anything, I will believe these projected budget numbers out of Russia when the craft actually flies. Russia has been known in the past to make rather wildly inaccurate statements in terms of projected costs, just to try and convince others to help fund their programs.
-the other Doug
[...]
I agree that the 5 billion plus price tag makes this a very tough sell. I get the same sinking feeling when I read that NASA is considering delaying the Outer Planets Flagship by up to 4 years, and possibly raising the price to 3 billion in the process.
You compare that to MSL's budget busting 1.9 Billion, and it gets even scarier.
I'll believe in MSR when I see us 5 years and a billion dollars into this project, and not before.
- but ....
On the flip side, far from this mission not having any political appeal, I think it actually has a lot of appeal.
The general public doesn't really 'get' the science side of planetary exploration, but they get interested when we really go somewhere they can relate to. And generally that means landers.
Ten years ago Mars Pathfinder swas a media sensation, yet if I were to compare the relative contributions of Pathfinder vs. Mars Global Surveyor, I'd say MGS learned a lot more. Yet who remembers MGS?
Everyone knows about the MER rovers, but how many people even know that MRO, Mars Express, or Mars Odyssey exist? And how much would we really know about Mars if we only had done MER? Especially if we had used Viking data to select a landing site?
The public hardly noticed NEAR for the year it orbited Eros. But when it was gently set down, and spent a couple weeks gathering data (from only one instrument), it made headlines all over the world for being the first spacecraft to land on an asteroid. Probably less than 1% of the value of the NEAR mission came from that week on the surface, but it got 90% of the attention.
But even though MER excited the public, after we fly MSL, and then likely fly another rover in 2016 or 2018, just how excited are people going to be about rovers? They will be old news by then.
I think the public would be far more likely to get excited about actual samples returning from Mars.
Might be a double-edged sword, though. The "Andromeda Strain" theorists will make a LOT of noise over it; the mission would not be without controversy.
Phoenix has actually retired this concern for me, since the soil pH determination seems consistent with abiological interpretations of the Viking results. I was a bit afraid that there was a very sparse population below the detection limits of really tough, active bugs that went wild over the Viking nutrients...not the kind of thing you want to get flushed down a lab drain or crash-land in the ocean.
If MSR happens and the $5-8B is spent, then that is an acceptable outcome. If it is decided soon that that budget is too much, and a smaller amount is spent on other rover/orbiter/network missions, than than is an acceptable outcome.
The real risk, in my mind, is that a number of leading space agencies "commit" to MSR, but then the whole thing collapses due to cost growth, a recession, or whatever. Then we may have forgone a decade of Mars exploration with no return. We lost a decade on Europa/Jupiter exploration while NASA committed itself to two technically unworkable solutions (the <$1B Goldin dream and then the >$$$$B Icy Moons Nuclear Propulsion fantasy). MSR is probably technically possible. I have severe doubts about multiple agencies securing the needed funding for almost 15 years to pull it off.
Mariner9 makes a number of interesting points, but I would have to wade in and say:
Pathfinder was a media sensation because it marked the birth of what we see today: images and data online (in all-but realtime) from a mission. The contrast to the pre-Internet era of space exploration and subsequent outreach was - as we've read many times on UMSF - gigantic. Therefore I would argue that Pathfinder's timing was as important to this sensation as much as its inherent success and spectacle.
The MERs longevity has counted against them in the media sensation stakes. They occasionally bubble up into the public consciousness, at least judging from my reading of the UK press, but it's hard to maintain any sort of momentum when the story appears to be: "Sol 1600 - more pictures from Mars" or "Spirit not quite dead yet". The missions are technologically impressive (very much so) but it's not "new News".
It's obvious that MSL will gather more detractors from the "it's got nukes" and the "but we've done rovers" camps nearer the time of its launch. IF MSR is lurking in the wings at that time, and with a guaranteed multi-billion price tag, then I can't see it surviving the usual short-termist criticisms that will no doubt be fired off by disgruntled politicians keen to raise their media profile.
4/ If you want to garner public support for future Mars exploration post MSL, then I'd agree with you - there needs to be a bit of the wow factor and showmanship - science led, naturally, but not averse to the sort of "money shot" we recently saw from MRO of Phoenix. And it needs to be affordable. My personal preference would be that it's maybe time to look at ballooning again: better range than a rover. Opportunities to touch down in multiple regions. Views of the envelope from orbit. What's not to love?
Andy
NH got off the bad with barely a squeek from the anti-RTG crowd. I'd expect the same from MSL really.
Doug
[...]
The EGA was extra spice that allowed the hard core anti-nuke crowd to outdo themselves in painting doomsday scenarios and attracting more followers. Those folks get worked up even over the RHUs in MER.
But regarding the EGA, the canceled "Fire and Ice" Europa orbiter used a direct trajectory while the EGE and most of the Jupiter mission reference trajectories in the recent OPAG reports use an EGA. I had always wondered if that was just due purely to favorable planetary alignments, or was there some high-level policy involved.
The NH EIS included opposing responses from many of the same names involved in the Cassini protests. MSL will likely get about the same as NH, which, to be sure, is less than the circus raised for Cassini.
Hopefully not too OT, here, and definitely non-partisan from a political standpoint, but TPS has a very short survey in progress right now about the issues that they should advocate during the next US Presidential administration (whoever that might be): http://planetary.org/special/vision
I used the 'ask a question to the candidate(s)' section to push for more advanced propulsion research precisely so that transit times for missions can be reduced. I too want to see at least one more Flagship to the outer system before I croak, and of course something very effective in terms of cost and efficiency that might be available in time for MSR would go a long way towards making it happen.
As for the "Andromeda Strain" thing, is this just a matter of public paranoia? I really don't see how Martian bacteria adapted to a cold, alkaline, low-pressure environment could possibly survive in a human body. We can't even catch fish diseases ... is something from another planet even possible?
[quote name='Juramike' date='Sep 10 2008, 03:40 PM' post='125657']
Probably not as a direct "pathogen/host" relationship.
But there are many examples of introduced things that have untoward consequences:
<snip>
***
At the same time, one of the purposes of Mars sample return will be to look for life, the possibility of life, or the signature of life. It will be imperitive that one can say that life detected from a sample from mars is uniquely martian with no possibility of laboratory contamination.
Either argument means the highest level of sterilization/containment/isolation of any martian samples will be necessary.
-Mike
/quote]
Oh, I didn't think of the possibility of confusion - It makes sense, especially since Mars life might well be derived from Earth through an ALH-like meteorite.
[...]
As I recall, Mike Collins noted in re the Apollo quarantine procedures that you take a very, very small number -- the chance of an organism that could destroy life on Earth being returned from the Moon -- and you multiply it by the extremely large number of the damage that such an organism would cause. The result of that equation is a small but significant number, and on that basis a certain amount of precaution must be taken.
-the other Doug
It's an exercise in arbitrary risk assessment. How do you quantify the multiplier of potential damage? Why stop at a quintillion? If the potential damage is destruction of all life on Earth then you have a damage multiplier approaching infinity, and then the risk becomes very large too.
Let's not worry about imaginary risks we can't quantify and get on with the business of exploring. When we have the slightest reasonable shred of evidence of life somewhere then we can start crunching numbers. Until then it's an empty, meaningless pursuit.
In a favorable growth environment, E. coli will double in number every 20 min. Unchecked, we'd be hip deep in E. coli in just a few days. A culture oven, agar growth media, and bam! it takes off.
If something from Mars was just scratching a living and barely surviving on the (sub)surface at real low temperatures, then got put on Earth with warmer temps, plentiful water, organic food sources abundant, and higher pressure atmosphere it might grow unchecked. (If the biochemistry was too alien, maybe nothing on Earth would consider it food!). The stuff could make life miserable just by overrunning everything. Space kudzu!
There are risks, we should be cautious, but we shouldn't stop exploring.
-Mike
[...]
Yeah. To paraphrase any number of people, the Universe ain't safe. It's beautiful, it's fascinating, it's glorious -- but if you want safe, go hide under your bed. (And even then, you ain't safe.)
The possibility of finding an alien microbe that could do great damage is probably on the same order as the Earth passing directly through the focused emission from a nearby gamma-ray burster. Either holds the potential of ending all life on Earth. The real difference is that we can take steps to make the threat from alien microbes even more remote than it already is, while there is nothing we can do about a close GRB (or a close supernova, or the passage of a large dark body through the inner Solar System, etc., etc., etc.) except to hope for just enough warning to insert our heads deeply between our knees, so we can kiss our arses g'bye!
-the other Doug
Why don't you ask the biologists It's simply impossible for an alien microbe to do any damage to our organisms
What worries me more is yet another delay of the mission.
OK, sorry. I'm a biologist and will correct myself. The chance is extremely low.
I am surprised that Mars news from earlier this week seems to have escaped the notice of most. I am referring to NASA's solicitation on December 1, 2008 for Mars Ascent Vehicle Technologies, including concepts for MAV propulsion.
This is absolutely great! It seems that MSR has officially begun with this solicitation. What I like about this is NASA's desire to begin to reduce the technology risks for MSR as early as possible. I imagine that they have learned some lessons from MSL's mess stemming from an insuffficient Phase B and insufficient Mars Program technology development.
Here is the link to the solicitation -
http://www.spaceref.com/news/viewsr.html?pid=29993
Another Phil
This seems to me hugely significant and very welcome. (Admins please delete if it's already appeared in another thread or move to a new thread if wou think it warrants one.) Mars sample return will now presumably be a joint venture.
http://www.planetary.org/blog/article/00001763/
Going furthur back, there were all the MSR studies at JPL in the 80s. The cost estimates were rather large, and MSR dissapeared for a decade or so while NASA moved on with Pathfinder and MGS.
And remember the late 90s? At that time Mars Sample Return was supposed to happen with the 2005 Mars launch opportunity. Somewhere along the line the French were going to provide the orbiter that would pick up the sample and return it to Earth.
Then Mars98 went down in flames, and NASA initiated a slate of more feasable (and properly funded) missions with MER and MRO.
The French orbiter turned into Netlander, then dissapeared altogether.
The bottom line is, MSR is tough to do, expensive as hell, and the launch date has been slipping for decades.
I'll believe MSR is happening about the time they bolt the first spacecraft to a launch vehicle.
I agree with those who point out that Mars Sample Return is tough to do and can be expensive. Let me suggest one way in which NASA can make MSR less difficult and less expensive.
I poropose that NASA omit any rover on its MSR Lander payload. If you scan through recent documents discussing the details of an MSR mission, then you will see that they include some type of rover. This rover would be designed to fetch a sample cache from an earlier rover and/or obtain samples of its own. In fact, one area of concern expressed in a recent document is that the MSR rover, if it does not pick up a sample cace, but must collect all of the samples for the MSR, will have only a few months to accomplish its mission.
I propose that NASA make the next planned rover, the Mars Prospector, an integral part of MSR. This will take care of several issues at once. The elimination of any type of rover on the MSR Lander will immediately result in savings of mass and a reduction in complexity. Both of those aspects will save a lot of money, both by allowing a less expensive booster to be used and by simplifying design, construction and testing of the Lander element of MSR. Without the need to stuff a rover on the landing platform, NASA will be able to focus on designing a reliable Mars Ascent Vehicle. In addition to the MAV, the Lander element could have a deep drill for sampling, as well as a simple scoop for contingency sample acquisition. Those aspects of the Lander element have already been prposed in recent MSR documents.
If the MSL rover proves that it is as long-lived as the MER rovers, then this will only add further support to my proposal to use the Prospector Rover as the primary means of sample acquisition for MSR. It will have had at least 1 year to prove itself before the MSR Lander is launched. By the way, adding a rover to the MSR Lander will not guarantee success, as that rover could go belly-up from day one of the mission.
By using the Prospector rover for MSR, we can make MSR more plausible. This does add a bit of risk to MSR, but I feel that not utilizing one of NASA's long-lived rover assets would be a waste. MSR must be made to be affordable or it will continue to be deferred.
My guess is that the Mars Prospector Rover could be launched in 2018 or 2020, with the NASA Lander/MAV and ESA Orbiter elements launched in 2020 or 2022.
I am guessing that there are a number of JPL and NASA folks who read UMSF. Can you tell me why this idea is not the way to go in this age of limited budgets?
Another Phil
With regards to recent NASA/ESA discussions, it looks like the 2016 "Mars prospector" mission is already starting to merge with ExoMars - there may not be a separate NASA mars rover mission - especially with the MSL overrun. However, assuming there is a Mars Prospector type mission prior to MSR, there are going to be a lot of "if's" - is it going to survive the x year gap between missions? How accurately are you going to land MSR? Sure we have been lucky with the MERs - but is MSL even going to be going as long as these?
Another point worth mentioning - unless someone starts making some Pu238 soon, any future Mars mission is not going to look like, or be based directly on MSL, since, as we all know, there is a dire shortage of Pu238 - and no one wants to stamp up the dollars ($250m Clinton era- probably closer to $0.5-1bil now?) to build a reactor to make more. RTGs only look cheap when using up Cold-war era stocks.
I think the problem is even wider than that. For instance, given the difficulty Phoenix had in getting volatiles delivered, just a few feet and in a day, to the science instruments, how much more difficulty is there in doing this and safely returning such samples, uncontaminated and complete, over a year later, to Earth? If MSR is just one large major mission like MSL, how much is it really going to be telling us about Mars as a whole? Remember with the moon missions, we had multiple impactors (Rangers), soft landers (Surveyors) and then 6 Apollo missions - and we still didn't find out about the potential volatiles at the poles until the 90's. Given that one objective is to prove Mars is sufficiently sterile that a manned mission would not ruin it, I would have thought more than one sample point is desirable.
I am sure someone more qualified will correct me, but I had the impression that the real show-stopper for MSR is the landed weight for a return rocket (even the more modest orbital docking version) - rather than the rover/mobility aspect. One interesting proposition by a space enthusiast (will dig up a ref later) suggested a much more modest MSR mission - using a very small solid booster rocket *just* sufficient to deliver a small Mars sample package to low orbit, together with a beacon - the package would have no manuevering capacity. The sample is picked up in orbit by the return craft. That way, all the weight and complexity of Earth-return is shifted to the orbital craft - the landed portion could be modest in size. The advantage to this approach could be having more than one sample return lander - one or two orbital pickup/return craft could collect samples from many smallish landers..
Edit: Can't find the article I was looking for, but this is http://homepage.ntlworld.com/bobparkinson/Mars/MSR.doc.
I clicked on this link because I was naturally excited to hear a local firm is involved in a Mars mission. Iassumed, before reading, it was related to MSL... turns out it's an ESA sample return mission...?
http://www.cumberland-news.co.uk/workington_firm_to_play_key_role_in_mars_mission_1_516996?referrerPath=business/
It looks like they're talking about ExoMars there Stu...
I guessed that. I was just surprised by the details about the "sample return" plans.
Exactly -- recall that NASA tried to turn the ALSEPs back on in the early 1990's and none responded. The best theory as to why none responded was that the voltage being generated by the RTGs, less than 25 years after emplacement, had fallen below minimum levels for operating the transmitters.
-the other Doug
Battery lifetime wasn't something that I'd considered. The LiIon batteries for MSL and the power management\battery control subsystem will be pretty similar to those used on the MERs so the best data we have on that is the MER experience, I'm pretty sure they are actually running longer than the longest tests of those batteries so the best we can say is that MSL's batteries should at least be able to match the MER's. The detailed engineering performance data on the MER batteries should give a much better idea of precisely how long they can be expected to last but the only reports that I can find online for free say that the MER batteries had degraded by ~10% in terms of charge capacity after 30 months of operation. With an RTG power source the management of the battery lifetime on MSL should be easier than on the MER's but it's pretty much guaranteed that the mission planners will be driving the batteries hard during the primary mission, at least I certainly hope they will. So 5 years with the batteries still capable of supporting mobility is pretty much guaranteed.
Thanks for the Degra link Mike - I'd just (stupidly) pulled some data from a source that said the Voyager RTG's were delivering 80% of their initial power after 23 years. I should have thought that was a bit off. The report you link puts the actual power drop off at ~30% after 30 years which is more or less equivalent to an effective 40 year half life. Using that as a better model MSL's RTG should degrade to 17% below the planned EOM power levels after 11 years.
In any case she will have more than enough power to keep running in some fashion for a very long time after the end of the 1 year primary mission.
"Workington engineering firm Gravatom will help design a lab to hold rock samples from the red planet, following a planned trip in 2016."Would I be interpreting that correctly as somebody contemplating an MSR mission for 2016? Or has somebody simply made a typo (for 2018; or 2026)?
Quoting the article:
A rocket will be launched that will send a rover to the surface of Mars to drill into the surface and test for any evidence of organic material.
A subsequent ‘Mars sample return mission’, involving all of the major world space agencies, will then be launched.
How I read that is the 2016 mission would be only a rover, and that that rover would have a sample cache on it.
The subsequent mission would be the MSR, launched at a later date.
Now, given that MSR has been studied in different forms for well over 20 years (including joint missions with ESA and or the French), I don't think this is anything close to a sure bet.
Wouldn't it be more interesting to thoroughly analyze and understand the martian dust background and ice background to remove that noise and provide a 'blank' profile for the hundreds of in situ analysis? I.e. if the clays, carbonates or perchlorates that Phoenix detected ever go airborne, knowing about them beforehand would have been useful to design the TEGA and MECA instruments.
What could be the cost of landing on top of Olympus Mons, sit idle collecting atmospheric dust and ice, and send it to LMO --including lower biohazard costs, a smaller sample, and simpler sampling hardware--, as opposed to a fully fledged MSR mission?
This week's Carnival of Space (the 101st) is being hosted at the "Robot Explorers" blog of writer David S.F. Portree. http://robotexplorers.blogspot.com What's that got to do with MSR? Well, David's site has lots - and I mean LOTS - of very detailed info about MSR missions that have been proposed and dsigned over the years. If MSR is an interest of yours, go take a look.
I still don't understand the necessity of biohazard precautions, except as a PR move. I understand the idea that even a tiny chance of a big disaster is worth avoiding - but the idea that Mars microorganisms could cause disease in Earth life is biologically laughable. (And 'gray goo' scenarios are just fear-mongering nonsense, whether biological or nanotechnological).
No Mars organism could survive Earth - even if the pressure, temperature, and radically different chemical environment wasn't fatal, the island biogeography effect would cause it to die off almost immediately. Lots of invasive species are a problem on Hawaii, but we don't see Hawaiian pests invading the continents. This is the same thing, but (literally) more than a million times moreso; Mars can't possibly have a biosphere complex enough for anything on it to be competitive with Earth life.
In a way, it can be compared to the LHC paranoia - except that we understand the reasons why a Martian organism CAN'T cause disaster far better than we understand the implications of high-energy particle physics.
EDIT: The main reason why I care is that I think we need to leave the option of direct-to-Earth MSR open.
EDIT again: At risk of a tl;dr:
In a hypothetical case where the funding was provided now (say *insert multibillionaire here* said "here's a blank check, do MSR") how soon could it be done, and what would the biggest challenges be?
It is better to use the caution for the media which will say we don't know what can be brought back better to follow the slow procedure.
This has passed relatively unnoticed, but it could be a step forward for an affordable Mars Sample Return Mission
http://www.nasa.gov/home/hqnews/2009/aug/HQ_09-194_ALICE.html
I have never been a fan of in situ resource utilization, I think its benefit must be weighted against the added complexity, but this seems relatively straightforward
Unfortunately there is not much technical information on ALICE on the net. The only thing I could find was the first page of the AIAA paper. Perhaps we could contact the authors and ask for a full copy
I'm looking for a map that I am sure I've seen, but now can't find. Can anyone help?
This was a map of a projected Mars Rover Sample Return mission with rover traverse. Back in c. 1988-90 there were several studies of these missions, especially at a set of ten sites identified at USGS by Harold Masursky and colleagues. Most of those sites were mapped in detail and published in the USGS Misc. Investigations series, identified as 'Science Study Areas'. Some of those maps (Olympus Mons, Memnonia, Mangala Valles etc.) showed the rover routes, others didnt. Some of the missing routes were shown in the Mars Landing Site Catalog.
But I'm missing one... Chasma Boreale. I am certain I've seen a map of a possible rover traverse in Chasma Boreale. Now I can't find it. It's not in the Mars Landing Site Catalog as I had mis-remembered. There is a version in a 1988 MEVTV workshop but it's not what I'm thinking of. Does anyone have any idea where it might be?
Phil
Chasma Boreale is the polar region traverse? ...here is Masursky's map for that region (bottom-ish)
nph_iarticle_query.pdf ( 241.41K )
: 550
Thanks... but unfortunately that's the MEVTV workshop one that I have already. There's another one out there somewhere that I'm missing. But I'm grateful for you for finding that one.
Phil
Phil whenever I've searched and searched for something I eventually turn to the amazing Google Book Search. A lot of old books are there full text, but a most are just a reference. Anyway, here are a couple of candidates that you might be able to track down in a library or the Library of Congress.
http://books.google.com/books?client=firefox-a&q=Chasma+Boreale+%22sample+return%22&btnG=Search+Books
Also thanks for this! Sadly those don't include the map I'm looking for. I'm sure I've seen it, but I'm drawing a total blank now I'm trying to find it. I was so sure it was in the Mars Landing Site Catalog (the second of your links), but that has only text, not the map.
Truth is, if it could be found easily on Google I would have it already. I'm hoping somebody involved in this work might see this and remember it.
I really appreciate people trying to help with this!
Phil
This is a real long shot, but might it be from "Viking Rover Studies", NASA Contractor Report 140391? This is from my (rather poor) memory, but I recall rover traverse maps for something like three different landing sites. It seems like one was a polar site, but it could have been the Martian south polar area. Anyway, the report is from July 1974, so it probably doesn't fit your criteria, Phil.
Thanks... that was indeed the south. I'm beginning to wonder if I dreamed the whole thing. I would have sworn that it was in the Mars Landing Site Catalog, but it isn't. The site is, but not the rover traverse. Did I confuse it with one of the traverses that is in the Catalog? Maybe. I'll post a few of the traverse maps I've made next week to show what I'm doing.
Phil
I'll give it one more try,Phil. My best guess would be something from The First (or Second, or Third) International Conference on Mars Polar Science and Exploration. The First was held in 1998, the Second in 2000, and the Third in 2003.
The abstracts were published by LPI and may be available online, but are definitely available in print (First and Second) and CD-ROM (Third) form. Other than that, my only other guess would be an LPSC abstract. Good luck.
Indeed, LPI has a few books on Mars Sample Return.
The Beyond Apollo weblog has been posting a series of articles on Mars Sample return missions, the latest article covers a 1976 proposal to collect a sample of ice from the Martian South pole using modified Vikings.
See: http://beyondapollo.blogspot.com/2009/10/mars-polar-ice-sample-return-1976-1977.html
I should add that David Portree is trying to help me find that missing traverse map, but I've come to the conclusion I was confusing it with one of the others in the Mars Landing Site Catalog, possibly one at Durius Valles (site 079 in the Catalog). I was just so sure I had seen it, but that is, increasingly, a bad sign!
Phil
Here is an example of a set of perhaps little known traverse suggestions dating from the Mars Surveyor 2001 planning phase. Mars Surveyor 2001 was originally going to land an Athena rover similar to MER, which might travel a few tens of km. At the first landing site workshop, these traverses were suggested as well as lots of other sites without specific traverses. Then the mission was descoped and the rover would be similar to Sojourner with a maximum range of about 1 km. Then it was cancelled, and eventually the spacecraft flew as Phoenix, without a rover.
Phil
Full inline quote removed. Hey - it was Phil's idea. - ADMIN
...And I like the "Thyra" crater site, because it's a few km away from our Columbia Hills in Gusev crater !
Every time I look at that place I want to call it 'Thyra', but I have to force myself to correct it - it is officially 'Thira'.
(PS - you'll get into trouble for that big quote!)
Phil
These days, 16.-17.6. 2011 is http://mepag.jpl.nasa.gov/meeting/jun-11/index.html taking place in Lisboa, Portugal (I guess first time out of USA).
Another clear sign of NASA taking European guys more into the club.
At least 5 presentations about MSR are available today already - scientific objectives, sample size, number of samples, sampling priorities and strategies, etc., etc.
Here might be the best place to ask a question I always have when it comes to MSR.
The rocket which launches the capsule from Mars needs a certain size, but the images I have seen are always impression from artists, and from the ExoMars rover I know how wrong this "impression" can be.
What is the rocket size to launch a 100kg satellite to a stable orbit around Mars?
I assume that that will be a solid fuel rocket with one or two stages.
Is there a nice program to do the calculations?
BTW, http://web.stanford.edu/~cantwell/Recent_publications/Boiron_AIAA_2013-3899.pdf is a good review of the history of MAV and ISRU development from the same group that's pushing this hybrid design. I'm afraid they are glossing over a lot of the system complexity issues with their design, but that's pretty typical for this area.
Greetings - here's an announcement of opportunity about MMX for Martian Moons Sample Return.
http://www.spaceref.com/news/viewsr.html?pid=48736
I haven't seen last month's MSR news on UMSF yet and this is the place where it should go:
http://www.planetary.org/blogs/jason-davis/2017/20170828-mars-2020-sample-return.html
It seems like there's a disconnect between the short time between now and 2026 and the complexity of the architecture. I suppose it's possible to start a multi-mission sample return before the architecture is finalized (and perhaps, in the form of the 2020 rover, we already have), but that seems a bit risky with the stakes and costs so high.
If the Mars Ascent Vehicle has no rover and relies upon an already-active rover to survive long enough to deliver samples to it, that simplifies the architecture enormously, but risks the failure of the rover before the MAV arrives. I suppose a simplicity-and-risk tradeoff is inevitable with something as big as this.
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