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Posted by: remcook Jan 22 2005, 01:21 PM

did it got mentioned that the site was launched last week or so?


http://phoenix.lpl.arizona.edu/

Posted by: tedstryk Jan 22 2005, 01:34 PM

Thanks for the link! This is much better than the old Phoenix site!

Posted by: BruceMoomaw Jan 22 2005, 07:34 PM

Indeed it is -- although the other previous one ( http://planetary.chem.tufts.edu/Phoenix/-- a copy of Phoenix's very first website ) still contains some stuff which isn't in this one.

However, there is some new news in this one. The science payload has been mildly augmented since I last heard about it, with the addition of a 1.2-meter mast for air temperature profiles, some more Danish magnets on the deck, and two chemical pellets which will be dropped into each of the four MECA Wet Chem cells to improve the search for carbonates, sulfates and oxidants. A few months ago, William Boynton told me that they were seriously considering adding a chemical filter to the mass spectrometer so it could distinguish atmospheric methane from atomic oxygen, but there's no mention of it here. Also, he told me that the landing hazard avoidance system had been cancelled -- but this site describes Phoenix as carrying one based on "a cruise missile system". I intend to inquire into both these points.

Finally, this site includes a good new description of the planned operating schedule of Phoenix's experiments on the surface.

Posted by: BruceMoomaw Feb 2 2005, 02:01 AM

From Doug Lombardi:

"We have made a slight modification to the [mass spectrometer] instrument and we are carrying methane detection as a lower priority requirement. However, if during calibration and characterization, operating the instrument in the fashion required to obtain the methane measurement compromises any of the original science requirements or goals, we may need to descope the methane measurement. We do not foresee any reason this should happen. Also, atomic oxygen is still 'in.' " (I imagine this "modification" has something to do with varying the degree of ionization that the M.S. will inflict on the molecules entering it.)

He also confirms that the landing hazard avoidance system will not be carried on Phoenix -- the new website was wrong about that.

By the way -- although he seemed to be alone among the Mars Strategic Roadmap Committee members on this -- Steve Squyres is apprehensive that the near-polar ground ice mantle may actually be so patchy (below the resolution of any of the current Mars orbiters' instruments) that Phoenix may be unlucky enough to land on an iceless area. As he says, though, there's nothing to be done about this in any case.

Posted by: Gsnorgathon Feb 2 2005, 07:29 AM

Bruce -

Do you know if there are any plans for flying an instrument capable of detecting isotopic fractionation in the methane, or any other organics that might be found? With three independent teams all reporting methane, it seems the logical next step, but I have no idea how hard it would be to do such a thing. (Where "do" might include designing such an instrument and getting it to Mars, or just getting the funding for it in the first place...)

Posted by: YesRushGen Feb 2 2005, 03:40 PM

Regarding the patchyness of the ice mantle, they should either:

a. figure a way to mount some small wheels on the lander's legs, or...

b. scrap the lander itself, and move the scientific payload onto a MER chassis.

The thing doesn't lanch until 2007 - there's plenty of time.

Posted by: tedstryk Feb 2 2005, 03:46 PM

The payload wouldn't survive a MER landing. And the legs would have to be majorly reconfigured for wheels, if that is even possible, certainly busting the budget cap.

Posted by: djellison Feb 2 2005, 03:51 PM

There's <2 years before final ATLO ops - there isnt time to fart, let alone bolt wheels on it.

Doug

Posted by: TheChemist Feb 2 2005, 05:16 PM

I have much appreciated the MERs after reading the whole Martian Chronicles series
at : http://www.astrobio.net/news/article611.html :

"Martian Chronicles I
Mars Life Summary (Sep 29, 2003): The Martian Chronicles, a multipart series, show the inside story of what it is like to join in a four-year space mission, in preparation for the dramatic landing sequence planned for January 2004. From the science diaries of Cornell's Steve Squyres, the principal investigator for the Mars Exploration Rovers' science package, this first-hand account shows exactly what it takes to plan and build a mission to another planet."

Posted by: BruceMoomaw Feb 5 2005, 09:26 PM

In reply to Gsnorgathon: I believe (although I'll double-check this) that the MS on Phoenix isn't sensitive enough to detect the extremely small amounts of trace-isotope methane that may exist in Mars' atmosphere. However, the "SAM" instrument on MSL -- which is that mission's central instrument -- definitely WILL look for them, both in the atmosphere and in the emissions from heated surface samples.

Posted by: Gsnorgathon Feb 6 2005, 12:52 AM

Thanks, Bruce. Guess we'll just have to be patient and bide our time, then. :@)

Posted by: tedstryk Feb 7 2005, 06:05 AM

Some Phoenix SSI info (courtesy the SSI team). This should produce one hell of a panorama. And, looking over Viking views, it will be neat to see a site change with time, although, given its solar power and northern location, Phoenix might not be much longer lived than Pathfinder.
____________________________________________
The MVACS SSI used a 23 micron/pixel CCD with a 23 mm EFL lens to
get the resolution of 1 mrad/pixel. The PHX SSI design uses a 12
micron/pixel CCD from the MER with a 50 mm EFL lens giving 0.24 mrad/pixel,
and almost the same FOV. The MER rovers use the same CCD with a shorter lens
giving about 0.27 mrad/pixel. So the PHX SSI will have slightly higher
resolution then the MER rovers from the same CCD's.
We kept the entrance windows, filters, and first fold mirrors from the MVACS
SSI design, everything after that was different. We almost managed to fit it
in to the same space. The PHX SSI will have some bumps on the top cover to
package everything in. Sort of like a hood bulge on a hot rod.

Posted by: RedSky Aug 24 2005, 05:00 AM

I ran across this page of the Phoenix landing animation done by Maas Digital in the same great style of the MER animations. I may have missed it, but I haven't seen this mentioned here yet... and its certainly worth a viewing. Fantastic realism, again!

The entry looks similar to the MER animation, but clearly is aimed at high latitudes. Also, the chute opening shot is more dramatic. But what especially makes one almost gasp is when the cable is cut and the top shell/lander plummet toward the surface. When the shell is jettisoned and the lander's thrusters fire... it almost seems too real in that the lander appears to really struggle keeping itself oriented upright until it finally gets to the surface. After seeing this animation, I really worry about this landing a lot more than I did for the MER airbag method. Guess we didn't know how lucky we were with two successful thruster-style Viking landings almost 30 years ago.

http://phoenix.lpl.arizona.edu/multimedia/videos/phoenix_animation.php

Posted by: helvick Aug 24 2005, 06:08 PM

That link led me to dig around on the site a bit and I found that some of the team are posting news and updates in http://phoenix.lpl.arizona.edu/features/weblogs/

Very nice to see the folks putting stuff like this out there, I certainly appreciate the effort it takes.

Posted by: Redstone Aug 24 2005, 08:17 PM

Dan Maas did an animation for the 2001 Mars Lander for the APEX project (Athena Precursor EXperiment) with Steve Squyers as a "Technical Consultant". It was the first one Maas did I think. The 2001 animation went from launch, through EDL, to surface operations.

Naturally there's many similarities between the 2001 and 2007 versions, but some interesting differences too. Some are of course due to the changes to the spacecraft. The 2001 lander back then was supposed to carry a copy of Sojourner, which was to be lifted down from the lander deck to the surface by a robot arm. And the camera mast was like MER's, not like the simpler one on Phoenix.

Other differences include the latitude of arrival, so in the 2001 version we don't see the polar cap and there's less ice on the ground. And the landing kicks up more dust! And the 2001 animation had a soundtrack too!

Posted by: BruceMoomaw Aug 25 2005, 12:17 AM

I'm very skeptical of that part about the lander rocking wildly back and forthe throughout most of its rocket-propelled descent -- the Vikings and the lunar Surveyors didn't do that. I suspect that part was stuck in for dramatic effect. (Either that, or it was based on the assumption that Phoenix would still have a landing obstacle avoidance system, which it does not anymore.)

Posted by: Decepticon Aug 25 2005, 01:08 AM

The lander will only last a few months!?

I find this mission less appealing every time I hear about it.

This lander should have the ability to move around.

Posted by: ElkGroveDan Aug 25 2005, 03:49 AM

Perhaps the same way the MER landers were only supposed to last a couple of months (90 days)? We're about a year and a half now on both of them. I bet at least one of them hits 2 years.

Phoenix is likely made of similar stuff. I guess a lot of it depends on whether or not there are frequent "cleaning events" at that location.

Posted by: jamescanvin Aug 25 2005, 04:38 AM

It won't matter how much dust is on the solar arrays when the polar night comes...

Posted by: BruceMoomaw Aug 25 2005, 05:18 AM

Yes, the problem with this one (as with Polar Lander, had it succeeded) is the inevitable coming of the polar night. But as for its lifetime not being long enough: it will achieve 90% of its official science goals in 2 months, for Heaven's sake -- with the rest (weather data) being achieved during the next 3 months.

And to say that it's not scientifically worthwhile is nonsense. While the MERs explored Mars horizontally, this one will explore it vertically by being the first subsurface mission -- and also the very first examination of a Martian environment water-rich enough to be potentially habitable by current-day microbes. (Given its mass spectrometer's ability to detect methane and surface organics, it's also the first potentially biological Mars mission since Viking.) Despite all the official claims about the selection of the first Scout mission being "fully competitive", the word at the first Mars Strategic Roadmap meeting was that NASA HQ virtually demanded this mission precisely because it fits in so well with the central thread of Mars exploration -- and does so at minimum price by using an already-built spacecraft. To quote Bette Davis, don't ask for the Moon when you have the stars.

Posted by: edstrick Aug 25 2005, 08:29 AM

I really wish it were possible to put minimal crawler treads on instead of footpads to give the vehicle some tens of meters mobility, but it ain't!

This mission, though heading for sub-polar dirty-ice and/or icy-dirt deposits instead of the polar layered dust and ice deposits will achieve many of the same critical science objectives lost with Polar Lander. An essential in climate modelling is information on the adsorbed CO2 and H20 capacity of generic Mars Dust. That info is crucial in modelling atmosphere / climate behavior during precessional climate cycles and we have nothing approaching real numbers, just wild-ass-guesses.

Posted by: akuo Aug 25 2005, 09:02 AM

But Phoenix has a real microscope and even an atomic force microscope! That's so cool, the resolution of images that we have from Mars will be magnitudes better again.

Also looking at the MOC images of the Phoenix landing sites, it doesn't really need any mobility. The scenery looks like a frozen wasteland everywhere with no details at all.

Posted by: helvick Aug 25 2005, 09:49 AM

There is a much greater need for ground truth data at high latitudes than having another rover right now. IMO Phoenix would be justified solely as a platform to land the http://phoenix.lpl.arizona.edu/technology/met.php and get lots of real data from this far north to test the atmospheric models.

Sure in an ideal world it would have an RTG and be a rover and ... but the only reason it's flying at all is because it can be flown on a shoestring without cutting the sort of corners Beagle did.

Posted by: BruceMoomaw Aug 25 2005, 08:25 PM

Actually, there is one real reason to wish it had limited mobility -- Steve Squyres worries that the distribution of near-surface ice in the landing areas may be much patchier than we can tell from our current low-resolution maps. But I would imagine that the data from the Mars Express and MRO radar sounders -- even if they don't punch very far into the surface of Mars -- will at least provide us with a far higher-resolution map of that ice distribution.

Posted by: tedstryk Aug 25 2005, 11:33 PM

To be fair, I think this was good manipulation. Using already designed instruments on an already built lander allows a mission to fly for less than it would have cost (yes, if you calculate the true total cost you would count original develoment, but it isn't like the already spent money can be reallocated) that will provide valuble science. The competing Urey proposal, while interesting, had, from what I have read, a high probablility of an even more severe busting of the cost cap.

Deception: I have to strongly disagree. This will be an essential science mission. The people on this board, myself included, have a strong bias towards image data because we like to work with it - and in that sense, a rover would be much more appealing. But in terms of science, I am really glad this mission is going to fly (and, as has been said so well by others, it will, in addition to trench imagery and a pan of some semi-polar terrain for the first time, the highest resolution imagery of the martian surface to date, thanks to its microscopes.

Posted by: tedstryk Aug 25 2005, 11:34 PM

Of course, there is the slim-but-unlikely chance it will wake up afterwards. Very unlikely though, but worth a contact attempt or two.

Posted by: Decepticon Aug 26 2005, 12:21 AM

Another issue I have is the depth that the lander can dig at. 15cm is not that deep.

4 to 8 feet deep would have been a better depth for finding ice.

Posted by: tedstryk Aug 26 2005, 12:52 AM

Actually, it will dig about .5 meters (1.6 feet). It will sample every 15 centimeters.

Posted by: BruceMoomaw Aug 26 2005, 03:04 AM

Yep -- and I can tell you they're virtually certain it will find ice, given that digging depth.

Posted by: Gsnorgathon Aug 26 2005, 07:33 AM

Is there any chance Phoenix will be able to 'hop,' as Surveyor 6 did?

Posted by: djellison Aug 26 2005, 07:47 AM

Once it's on the ground, any remaining fuel would quickly freeze. From a systems point of view I'm not sure a hop is even possible, there are things you'd want to have bolted back down to the deck when you do it - and cant be 're-stowed' so would likely be broken under the force more engine activity ( met boom, SSI mast etc )


Doug

Posted by: BruceMoomaw Aug 26 2005, 01:01 PM

I've been told flatly by Peter Smith: can't be done.

Posted by: tedstryk Aug 26 2005, 02:06 PM

Again I will say, lets be honest. We are image junkies, and image junkies prefer rovers to stationary landers. Worse, with MSL likely slipping to 2011, once Spirit and Opportunity die, we will have an addiction we are no longer able to feed, so a 2007 Mars rover would be nice. So would a longer-lived vehicle. But with the opportunity to get the science we will be getting out of this mission at a relatively low cost, given the already-spent money, I think that this mission will be a great one. And, as has been said by myself and others, there will be imaging consolations (the microscope, the new kind of terrain - and I wonder if we will see deposition of frost a la Viking 2 before Phoenix dies).

Posted by: gpurcell Aug 26 2005, 02:50 PM

I agree..but I also think we're going to find it very bittersweet when we can't look over that rise 15 meters away....

Posted by: Decepticon Aug 26 2005, 02:54 PM

Can phoenix be put into Hibernation during the winter?

Posted by: Gsnorgathon Aug 26 2005, 08:33 PM

I dunno if there will be a rise 15 meters away, or 15 kilometers away. The MOC images of the region around -120W 70N make the place look even more featureless (less featureful?) than Meridiani. Of course, the precise coordinates haven't been set yet, so maybe they'll pick some place that's chock full of tormenting vistas...

Posted by: BruceMoomaw Aug 26 2005, 09:19 PM

It can't be put into hiberation any more than simply shutting it down (except for the command receiver) over the winter and praying that the batteries don't freeze -- which they probably will. They will, of course, try to contact it again come spring, but th odds are very much against success. Keep in mind that the only additional data they'll be getting from it after its first 2 months on the surface is meteorological (including visual observations of the skies and frost).

Posted by: paxdan Aug 26 2005, 10:36 PM

yeah true, but then the imagery is all we are given to play with... i wonder how many of us would become mini-tes, mossbauer, APXS, thermal, insolation, every measurement made on mars junkies with access to the full data stream from the MERs. http://www.unmannedspaceflight.com/index.php?showtopic=1315&pid=18484&st=0&#entry18484 about how imagery is regarded as the poor relative of the remote sensing 'real science' being done, and sure, people strive for decades sometimes to get 'their' instrument in orbit/on the surface, careers are made on the results, but why on earth (or mars) isn't the rest of the data available? (even in a degraded form like the raw imagery).

so what if only a handful of people have the inclination, knowledge or skill to process it, surely this information should be available to the amatuer community in order that it can be shared by those who can to those who want to know.

Doug, if i had my one question to ask steve it would be parsed from the above. Given the interest in the missions, why isn't more raw data made available?



edited to include link to thread i referred to

Posted by: Bob Shaw Aug 26 2005, 10:47 PM

Imagine if Phoenix had set down where Opportunity landed, in the only crater for miles, with an outcrop a metre beyond the reach of the sample arm...

...Viking 3 style limited mobility would save the day. Or Marie Curie...

Posted by: helvick Aug 26 2005, 11:17 PM

As one of the few amateurs with enough interest in the engineering of the machines themselves to work on figuring out how well they are working I'd add to that a request for the engineering data too.

For the record I've just spent the last two weeks building a reasonable insolation model based on badly scanned pdf's served up by the Nasa Technical reports server - all of the data I have is in poor quality scans from appendices in typed reports from the 90's. I'd have a field day with some real raw engineering data from the MER's but it 's very sparse.

To be fair NASA\JPL are light years ahead of everyone else and for that I am really grateful but it is worth pointing out that there is an outreach benefit there that is being lost.

Posted by: elakdawalla Aug 27 2005, 12:19 AM

Unfortunately engineering data is one of those details that falls into the yawning chasm of "stuff you can't publish because it could benefit the terrorists," that is to say, it falls under ITAR. (International Trafficking in Arms Regulations.) ITAR is a terrible, awful drag on any attempt to do anything on any mission with anybody who is not a U.S. citizen, and it severely limits what technical information on missions can be published. I can't describe to you the absurdity and complexity that we had to go through in order to get permission for the teenage kids participating in the http://planetary.org/rrgtm/studast.html program to access the tiny amount of engineering data necessary to permit them to run the software to put the hour markings on the MarsDial images. In the end, it was only because the same data was being released to the folks working on Maestro that they were permitted the access. A couple of the foreign scientists who were working on the mission were initially told that THEY WOULD NOT BE ABLE TO TOUCH THE COMPUTERS at JPL because ITAR forbade it. Later, the absurdity of this position was at last overcome, but I think for some months they still were not given logins to the computers; they had to get an American to log in for them! To give them credit, everybody on the engineering and science teams on MER were doing everything they possibly could to help the foreign scientists, and our students as well. But those security people weren't having any of it.

Sigh.

Emily

Posted by: BruceMoomaw Aug 27 2005, 01:05 AM

Bob, the really big qualitative difference between Phoenix and the MERs is that the latter were designed primarily to investigate ROCKS (for which you have to travel long distances horizontally), while Phoenix is designed to investigate SOIL -- which is far more evenly mixed in the horizontal dimension.

This was a major consideration in the design of Polar Lander. I have several 1995 documents from its science definition team during their consideration of its proper payload, which stated that its single most important goal was to look at the makeup of "evenly mixed substances" on Mars -- namely, the soil and the atmosphere -- for the clues they could provide on the very-long-term climate history of Mars over its entire global extent. Rocks were described as very minor scientifically for MPL. Phoenix has exactly the same traits, except that it will place more emphasis than MPL would have on the biological habitability of the near-surface ice layer.

By the way, the science groups determining the exploration strategy for Europa have also emphasized that the need for horizontal mobility on Europa is relatively trivial -- it's vertical mobility that is of overwhelming importance there. It will be a long time before we see any Europa rover.

Posted by: Bob Shaw Aug 27 2005, 01:15 AM

Bruce:

I accept all that you say, but they *would * say that, wouldn't they? © Christine Keeler 1962.

It'd still be a tragedy if, after driving miles across Gusev (etc) we're defeated by inches when Phoenix lands.

As for Europa, the icy surface is of little interest compared to the depths, but even there some horizontal discretion could be the difference between boom and bust...

Bob Shaw

Posted by: gpurcell Aug 27 2005, 02:27 AM

Bruce, I really wonder about that. I really think Phoenix, while a cool mission, will sudder from the MER comparison and cause a lot of people to sit back and say "No immobile missions anymore."

Posted by: BruceMoomaw Aug 27 2005, 05:05 AM

Once again: the reason they're willing to fly Phoenix is that:

(1) It will be investigating something that is spread evenly across thousands of km of the surface, and is therefore just about impossible to miss (although, as I say, those more detailed radar ice maps will be important in firmly nailing down a final landing site). It's conceivable that they might manage to land in an isolated patch where the ice is too deeply buried to sample, but that risk is small and therefore worth running.

(2) It can be done CHEAPLY. As a way to investigate Meridiani (as was originally planned), Phoenix would have been a fiasco. As a way to investigate the precise chemical and physical nature of the near-surface ice layer -- in itself extremely important -- it's a cut-price bargain, since it utilizes an already-built craft. it is, in fact, hard to visualize any other way to properly utilize this craft. ("Urey" was relatively cost-ineffective because age-dating is required in several different places on the Martian surface, not just one.)

Posted by: helvick Aug 27 2005, 05:31 AM

I don't know - it depends an awful lot on what you're trying to do. Landers that gather long term weather data (Tau, insolation, ambient temperature, ground temperature, sky temperature profile, wind speed and direction, high energy radiation, atmospheric composition) or that have a primary aim of putting an array of really good seismometers on the ground don't need to be mobile at all.

IF target selection and EDL are good enough then the Phoenix team should be able to avoid landing on a large slab of bedrock, that's the most likely situation I can see that would prevent the soil analysis experiments.

I'm really looking forward to Phoenix and live in hope that with less of an imaging bias that Nasa will feed out more data from the other sensors on a regular basis. In any case I'm going to be cheering the little Fire Bird on all the way.

Posted by: BruceMoomaw Aug 28 2005, 12:30 AM

Network missions aside (and of course very small landers that carry out seismic, weather and other network science will be immobile), there are going to be too general types of big Martian landers from now on: rovers and drillers. The latter are crucial to explore the very scientifically important Martian subsurface, but they're also going to stay in one place. Phoenix is the very first of this category of lander, albeit a specialized version.

Posted by: RNeuhaus Aug 29 2005, 03:23 PM

I think that the "main problem" of the Phoenix Mission is the budget restriction. I am sad of this. It is like to take a very expensive trip to a very exotic place at another side of Earth to visit only for 3 days instead of one month in order to be satisfied with the spent money.

So that Phoenix mission would be more worth is that it can

1) last longer than few months, perhaps one to two Mars years to work as a full edition meteorological and seissmic station,
2) be able to drill as deep as many meters,
3) by able to hop to a another close interesting place (remains fuel will freeze???, what happens with during its cruise travel to Mars for many months in a very cold space -don't really know what is the real Kevin temperature is in the space- without freezing the fuel?? as Doug has said previously).

Rodolfo

Posted by: djellison Aug 29 2005, 03:36 PM

1) Cant happen with solar power - you'd need a big, heavy, unavailable, expensive RTG.

2) You'd need a much larger spacecraft to do that

3) All sorts of reasons why phoenix cant do that

What're you suggesting isnt changed to Phoneix - is a $1Bn mission all of its own called Mars Deep Drill

Doug

Posted by: RNeuhaus Aug 29 2005, 03:56 PM

Very big tag price!! Re-thinking, I would prefer to save some money of Phoenix to be put for MSL project.

Rodolfo

Posted by: djellison Aug 29 2005, 04:01 PM

Phoenix is important as a GRS groundtruth for near sub surface ice. It's work that needs to be done as part of the grand scheme of things.

Doug

Posted by: Phil Stooke Aug 29 2005, 04:31 PM

Bruce said:

"As a way to investigate Meridiani (as was originally planned), Phoenix would have been a fiasco. "

I hadn't heard this about Meridiani. Can you tell us more, Bruce?

Phil

Posted by: tedstryk Aug 29 2005, 04:50 PM

With the way the program works, I would add that we are thinking falsly if we think that "hmmm...., instead of Phoenix, why don't we save up a few more years for a bigger mission?" If we didn't launch Phoenix, that money would probably be allocated out of the Mars program. And without Phoenix, the Mars program would currently have no projects in advanced development, making it a dangerous target for budget cutters.

And I don't agree with the three days to a month analogy. It is more like going to visit a college before deciding to go study there. Sure, Phoenix is limited in scope, but in addition to doing good science, it will help us prepare for when a real drilling mission like Mars Deep Drill is designed. Sort of like how Pioneer was sent to scout for Voyager. The Pioneers made many discoveries in their own right, but also did a lot to prepare the way.

Posted by: tedstryk Aug 29 2005, 04:53 PM

I think he was referring to the fact that this was going to be the site for the Mars 2001 lander. It might have been frustrating, but not if it landed where it did. I think Marie Curie, which would have flown on that mission, would have at least been able to explore the Eagle outcrops. And such discoveries might have allowed for MER to carry better-suited instrumentation (actually, probably not much, given the lack of time between the missions, unless one of the MERs were delayed. But for Phoneix, there is a much longer gap before the proposed drilling mission).

Posted by: BruceMoomaw Aug 29 2005, 05:26 PM

Yeah -- it was actually sloppy language on my part; I was referring to the originaly planned mission of the 2001 Mars Surveyor Lander (after they stripped it of its REAL initial mission of being the landing platform for an MER rover. As a stationary lander, its ability to study the phenomena of Meridiani would of course have been pathetically limited, and the additional data its MECA package would have obtained would not remotely have been an adequate exchange for that loss.

But, regarding Phoenix: inspection of the Martian ice -- as soon as possible -- is a very important goal in the overall program, and one that simply cannot be done with MSL because of the limitations on its landing latitudes. We need to know more about the potential that the ice may have as a domicile for extant Martian microbes -- and we need to know more about Mars' climate cycles, both over periods of just a few years and over its 150,000-year long obliquity cycles (as ice is repeatedly deposited and then removed again from various latitudes). This mission is the perfect way to do that relatively cheaply and quickly. Any time you're tempted to gripe about it, just remember what I said earlier: this is the very FIRST biological space mission to another world since Viking. If it finds complex organic compounds in the ice, it is going to get extremely interesting extremely fast.

Posted by: tedstryk Aug 29 2005, 08:43 PM

Yes, but it had Marie Curie, with a properly-set-up and brush-equiped APXS, had it landed where Oppy did, it could have done a lot of science. Not as much as an MER, but it definitely wouldn't have been the waste you describe.

Posted by: vjkane2000 Aug 29 2005, 11:08 PM

While I agree with Bruce on the importance of these topics, there is a substantial chance that Phoenix's results will be inconclusive about both them and any biology. Just as with Deep Impact, this is a new terrain that we know very little about. Any of many factors -- like landing a few meters away from the right site or some type of soil gardening that erases context -- could prevent us from learning much about these goals.

That said, I think it's worth the effort. We need to take risks and then not blame the spacecraft team if we get skunked.

Posted by: tedstryk Aug 30 2005, 12:27 AM

I agree. I know there are those who insist that we should send a mobile vehicle with a large drill that can also take more samples, etc., etc. Well, while we're at it, why don't we put a manned module in orbit to control the rovers in real time. And, add sample return capacity, of both soil, rock, and ice cores. Sure, there are limitations of the mission thanks to budget, but that is just reality.

Posted by: algorimancer Aug 30 2005, 06:07 PM

I suspect that dismissing the importance of roving capability on Europa will turn-out to be short-sighted. We have pretty-near zero experience on the surface of an icy satellite (barring those fuzzy pics from Titan, which isn't a conventional icy satellite). At the very least, surface ice is likely to have originated from the internal ocean, and analysing the ice could reveal evidence of organic chemistry and (perhaps) life. It may be useful to have the capability to drive a few kilometers to find more recently exposed ice, and who knows what interesting "eurology" might be encountered.

Posted by: BruceMoomaw Aug 30 2005, 06:24 PM

Detection of relatively recently exposed ice -- or, more precisely, ice with a lot of other stuff mixed in (particularly organics) -- is indeed important, but the current emphasis is on doing it from orbit and then dispatching landers to those spots to probe it vertically.

Posted by: craigmcg Aug 31 2005, 01:06 AM

what impact will the descent thrusters have on the soil it ends up landing on?

Posted by: Bob Shaw Aug 31 2005, 11:19 AM

Probably a bit less than if they turn the suckers off too early again!

Hehe.

Posted by: Marcel Aug 31 2005, 12:13 PM

http://www.space.com/businesstechnology/050831_phoenix_tech.html

Which says it is of major concern to the science team.
How could they NOT have thought about this before ?

Posted by: djellison Aug 31 2005, 01:56 PM

"As the ice starts advancing off Mars’ northern polar cap and moves southward, Phoenix will become entombed in several feet of solid carbon dioxide. The lander is not designed to survive being buried in solid ice for six to seven months, Smith said."

LOL - didnt think it would be that bad!

The exhaust plume contamination of local soil was something I read about w.r.t. MPL years ago - so I'm sure it's not something they've just thought of.

Doug

Posted by: Marcel Aug 31 2005, 02:17 PM

Ah, that's good to read. But what can be done ? Nothing i'm afraid.

I think the physical disturbance of the soil (stripping it's top layer) is probably not such a big issue. The real fear of it probably lies in the detection of organics and the interference that hydrazine and by-products could have on the measurements within the chromatograph column. I don't know enough about the field to know if this can be subtrancted easily from the rest. Probably the mix of unburned fuel and the products that are left after combustion are a very complex mix of organics that are hard to distinct from (possible) original (Martian) soil organic matter.

The ice layer of a meter or so also surpises me highly ! The thing will probably not wake up afterwards. It would surprise me if it did......maybe it's like freezing wet laundry:if it thaws without motion, it's intact afterwards. If it is moved (especially cables) in a brittle state, it snaps instantly. Don't know at which temp. this happens for the materials used. And most probable, the electronics itself will not survive months of exposure to -120 C. Does it have radioactive heaters like MER ?

Posted by: RNeuhaus Aug 31 2005, 04:42 PM

The Phoenix's probably specific landing site will be selected based on detailed reconnaissance of candidate sites still to be conducted by spacecraft orbiting Mars. The
candidate sites will lie between the northern latitudes of 65 degrees (the equivalent of Fairbanks, Alaska) and 75 degrees (the equivalent of northern Greenland).
I am not sure if that by that zone there is permafrost snow because according to the following URL http://phoenix.lpl.arizona.edu/science/ shows that above than 80 degree has a greater change of abundance of water. Will Phoenix land on nude soil or ice surface?

About the budget of Phoenix is not considered as a cheap mission comparing to MERs ones:
Phoenix's relatively low cost: $US 386 M with 90 days of high activity (primary operations) and other between 30-60 days of low activities (meteorological station). and the MER costs with $US 400 M each one with 90 days of high activity mission.

The difference is around $US14 Million.

The extract from the dailyspace news:

Is it worth that the Phoenix has own mobility with the $US 16 M as the MER but with four hidden band rovers which will push down after landing in order to move away from its landing place in order to avoid the laboratory misleading analysis results?

Rodolfo