Anybody know if MSL will still be at JPL in early August or already shipped to the Cape? I'll be out there and I'd like to see her in person!

Here in this article about backshell incident
http://marsprogram.jpl.nasa.gov/msl/news/w...amp;NewsID=1126
there is info that rover and descent stage will be delivered to the Cape in June.

Already at the Cape. You'll miss it by a couple of weeks.

Bummer. Figured early August was pushing it.

Well despite years of experience, luck will no doubt play a part in getting MSL down safely onto Mars. The backshell could have been irriversably damaged......
I recall that satellite that fell off its stand.


Oh and now my status report is late, as I was reading UMSF !......

New article about MastCams doesn't say many news, maybe except that full-color 360° panorama (60° vertical) by MastCam 34 mm will require 150 images and 25 minutes to capture them.
What is really new (for me at least) is mosaic of almost full top view of the rover, at least upper deck is nicely visible in details.
I hope those fine red cables are there just temporarily to the temperature sensors for the test in space simulation chamber.



full res

Great new blog post from Emily (of course!) with two new views of Curiosity, one real - i.e. taken by herself - the other an artist's impression.

http://www.planetary.org/blog/article/00003051

Take a look at the latter... I'm getting a real "steampunk" vibe off Curiosity now...

It's good to see a familiar friend along for the ride.
Click to view attachment

The first thing I thought of....

Bolo!

Keith Laumer would be proud!

Oh I saw that deck picture earlier and did not realise it was taken by the Mastcam. Pretty cool, and very white...for now.

They're test-driving MSL right now, and it's on Ustream! I hope somebody here will be able to make a screen-cap animated gif

http://www.ustream.tv/nasajpl

First of all, hope the Curiosity program would be a reality after the launch in this year!

About the heat resistance of heat shield of Curiosity is almost twice bigger than ones of MER's (8.5 feet) and bigger than the ones of Apollo program by 15 feet vs 12.8 feet. As the Mars has thiner atmosphere than the Earth ones, and the lower landing entrance speed would dissipate less heat due to the air friction for Mars than Earth, Isn't it?

I recognize that the previous question was not clear so I am clarifying with a shorter question:

Which will the Landing Entrance of Curiosity and Apollo generate more heat caused by the air friction?

Not sure I understand your question.

Not counting the ejected cruise stage, the entry weight for MSL will be a little over 6,000 lbs, slightly less than half the weight of the Apollo command module. It will be entering the Martian atmosphere at less than 14,000 mph, about half the speed of the Apollo reentry. This translates to about a quarter of the kinetic energy per unit mass for MSL. So we're looking at, what? About one eighth the amount of total energy that needs to be burned off for MSL?

And you're burning it off with a bigger heat shield, more area.

So, the total heat pulse for MSL will be lower. Presumably, the peak temperature will be lower too.

One factor being left out here is that due to the thinner atmosphere, descending objects encounter a smaller braking force so you have a longer duration of high velocity heating, which in turn requires a MORE robust heatshield (and I'm going on recollections here, don't have relative numbers or specifics.)

Yeah, you're right the atmosphere is thinner, and more spread out from lower gravity (the drop in altitude to double the pressure is longer). But wouldn't you just need a slightly steeper decent angle? Get down lower faster to where the air is thicker?

My understanding for MSL is that from the time of entry to the time where the backshell drops (with the parachute already deployed) is on the order of four minutes. So the time you need heat protection is less than that. I don't know if that differs significantly from an Apollo reentry. Apollo blackouts typically lasted over three minutes, and they were still going a pretty good clip when they came out.

But I'm not really sure that the total heat load that the heat shield ends up soaking up is even the fact in question here. I was thinking more along the lines of peak watts of heat per unit area, or total energies needing to be dissipated. Could be wrong, though.

Lovely images those, that is for sure. I can't get over the way cables are just scotch-taped onto the deck in the first mosaic. I know all the reasons for it, but it still looks like such a slaphappy way to go about it. I really like it, because it goes so much against all sci-fi representations of gleaming white, streamlined machines. This is the real deal, with all excess weight shaved off. The engineering truth of "if no shielding is needed due to temperature or mechanical wear and tear then no shielding will be provided". Still expect to see a nice JPL logo and perhaps a US flag on the body.

That computer-generated image of Curiosity: wauw, talk about a lumbering hulk! - No daintiness about this girl! Of course I realised that, growing in weight, we'd move from mosquito legs to elephant legs, but still I hadn't expected the rough industrial look we see here, more reminiscent of the Shuttle launch pad crawler than any other JPL vehicle so far... - I know the foreshortened view enhances that impression, but still, the ant-like look I had conjured up inside my head earlier (due to the raised abdomen of the energy package) has definitely been replaced with a more industrial vision.

Thanks for the article Emily!

The peak deceleration for MSL is higher than for Apollo - that much I'm fairly sure of.

Peak MSL deceleration is significantly higher than Apollo's. Peak Apollo deceleration was 7.19g (according to http://lsda.jsc.nasa.gov/books/apollo/Resi...g/ts2c5-2.jpg); peak for MSL will be about 12.24g (calculated from http://www.unmannedspaceflight.com/index.p...t&id=24472) -- that's about 70% greater for MSL. To put that in perspective, it's a change in velocity of over 430 kph or 260 miles per hour, PER SECOND. Curiosity had best be wearing arch supports.

I am in doubt of this since its weight of MSL is about twice lighter than the Apollo ones and the
Mars' atmosphere density is of about 16 times lower than Earths'. Finally, the diameter of heat
shield of MSL is 15% bigger than the Apollo's. Hence, the deceleration of MSL would be lower
than the Apollo. According to the physical experience is that the deceleration is bigger at
lower speed than the higher speed. At all, it is rather complicated to get and see the real
numbers!

The density of the Martian Atmosphere and that of Earth are not that different where the heat shield will be operating as I understand it, although I'm not an expert by any means.

In any case although the density of the (re)entry body of the spacecraft and the shape\composition of the heat shield are important the main factors that decide what the deceleration is going to be are the velocity of the spacecraft and the angle of entry, provided the heat shield is up to the task of dissipating the energy that those choices require. The Apollo peak deceleration had to be kept to levels that wouldn't reduce the crew to jelly, MSL doesn't have to worry about soft squishy human cargo so there were more options.

Can copy that.
Apollo CM used Skip reentry. One of the reasons for that was to reduce peak heating and g-loads to the crew.
MSL instead will do direct atmospheric entry.

The wikipedia article in the link states: "The Apollo Skip Guidance was engineered, but never utilized in a manned mission."

From what I've read, the CM didn't use a "skip reentry", which compleatly leaves the atmosphere; but did use a "double dip reentry" where the CM would roll and use its offset center of gravity to change the angle of attack to shallow up the trajectory - but remain in the atmosphere. This reduced g load.

Monty is correct.
We should not go too much into the details about Apollo, being aware of forum rules, but at least in this diagram you can see Apollo 8 did two skips in altitude around 60 km.

Hmmmm.

Sobering reading...

http://oig.nasa.gov/audits/reports/FY11/IG-11-019.pdf

Reading that will make the accomplishment of a safe launch, landing and sucessfull mission even more remarkable.
Thats putting a positive slant on it .

The exponentially increasing complexity of sending laboratories to Mars points up the need to develop a viable way to bring samples back to labs on Earth...

On another note... here she is this past Monday:

Or alternately, do more smaller missions -- lot's of little labs. Less chance of losing everything due to single point of failure.

Someone calculated that six MER class missions could have been done with the money spent on MSL. Given that historically we've lost 50% of all missions to Mars three functional MER class rovers trumps a 50/50 chance of a small radioactive crater IMO.

I don't think this is at all indicative of MSL's chances. That 50/50 figure includes a steep learning curve (and missions out of NASA's control). Hopefully most of the hard lessons have been learned and although there is still a chance of failure, it is much, much lower.

NASA has been successful with four of it's last five landers. And successful with all of its last three. I don't think that is just luck.

They struggled to find 2 safe and scientifically interesting sites to land MER's. Safe and justifiable landing sites for 6 more? Good luck

Yes - MSL has cost approx the cost of 6 MER's. That doesn't mean that building six MER's would have, in any way, been a better idea.



The MSL team is 3/3. Pathfinder, Spirit, Opportunity.

ALL the landers that have worked, ever, have come from NASA.

The blot on the copy-book for NASA is MPL, which was designed and built by LoMart, and then fixed for PHX.

Trying to compute failures of Russian landers from 40 years ago as part of the statistical probability of MSL landing is just silly.

Moreover, what justification can you give for assuming that the performance of previous vehicles can forecast the performance of the next one?

Norm - you're being inflammatory and misleading.

Did it occur to anyone at NASA to provide specs for these balance masses and ask whether somebody is willing to develop a probe on their own $$$ which matches the specs? I mean, many universities and labs would kill and maim for a chance to send ~60 kg lander to Mars!

Den, I would think that the 60kg mass requirement wasn't firm until (at the earliest) CDR, which is fairly late in the developmental process. Given that, any second-party ridealong probe would have to be developed in record time...and, even more importantly, integrated with MSL (by which I mean the entire system, including EDL).

Uh uh. This adds a number of potential risks for what I'd call an extremely small potential gain. Remember that planetary launches are on very, very tight schedules, and also remember that a potential interface problem between the MARDI instrument & the Phoenix navigation system wasn't discovered until after launch...and the decision was made to disable MARDI in order to mitigate that risk. There just isn't enough time (and never enough money) to test all potential faults.

So: It would have been extremely unwise to endanger a Flagship mission just to carry along a very minor ride-along payload. The MSL team made the right call here.

I was looking at the report. The following drove my attention:

How true this reduction in performance can be? Do they really want to drive only 4.5km during first Martian year?

Report looks a little bit pessimistic but... The analogy...if I want to test a software I can create some test cases. For very simple program I can cover with my tests all instructions and condition branches. But the more complex my soft is the more tests I need. This number grows in exponential like way or even more. In the end it is impossible to cover everything and detect all possible bugs. I suppose similar happens with hardware. So if I'm correct when we upscale from Sojuner to MER or from MER to MSL the number of possible issues has grown not in linear but exponential way. Looks that sending probes is not an easy task.

In the end past successful missions also had its own problems e.g. Spirit had some issues with 1/10 chances of not opening airbags, Phoenix with landing radar being confused by separating heat shield etc. but somehow talented people at JPL managed to bring them safely on the surface of Mars. So I remain optimistic...

I wasn't sure what point you were making here, Doug. I think it was about the failure of Russian and Beagle not being seen as stacking the deck against MSL. But the point is, just because it worked before, there's no guarantee it will work again, even if the same team are involved at every step of the process.

Also helpful to point out that the landing technology for MSL is different from Pathfinder, Spirit, and Opportunity.

Regarding the report, anyone who has ever been involved with auditors and inspectors will remind you that these people are paid to look for holes and flaws in the system. Of course, it's a valuable, albeit painful, process to have to address the issues and findings. And no inspector would ever want to write a glowing report, only to have time and events prove them wrong later on.

Personally, I NEVER assume a Mars (or any deep space) mission is going to work. I prefer being pleasantly surprised to being disappointed!

He wasn't assuming that MSL would work, but rather, he was demonstrating how silly extrapolating the historic success rate to MSL was.

Maybe we are trying to make too big jumps? Does MSL need to be that much bigger and more complex than MERs? Maybe we need to make evolutionary, not revolutionary steps? Say, Hornet -> Super Hornet, not Hornet -> F35-huge-delay-budget-overrun?

I'm sorry you feel that way Doug, that was certainly not my intention. I was merely expressing my opinion without any intent to mislead anyone. I am not competent to argue the statistical likelihood of MSL's success in making a landing nor am I competent to judge the relative merit of MSL's possible science returns versus the possible science returns of six MER class rovers.

I would suggest that, as I remember it, there were many competing MER candidate landing sites and that the safest, commensurate with scientific returns, were chosen. I do not remember that the alternate sites were orders of magnitude more dangerous. But I don't have the advantage of being in the organization that you do and your information is, no doubt, more complete.

I truly hope that MSL launches during this opposition, succeeds in achieving a safe EDL, and a long and happy rove.

I would contend that MSL is evolutionary. Nonetheless, why settle on taking baby steps, succeeding in only spending money to collect a minor return versus taking a highly tested risk and collecting enormous amounts of data in the process? I don't think the US would be here, nor would NASA, if a few individuals weren't willing to take that risk in pursuit of furthering the human endeavor.

Let's take a step back here. The rather degraded discussion (which is frankly disappointing for UMSF) splits three ways

Chance of success:
I don't know how to land something on Mars. If I wanted to do so, I would find the most successful team in the world to do it. That's the MER and MPF team. I would ask them to do it. Calling out numbers or opinions ( 50%, or 'pessimistic' ) are totally and utterly meaningless unless you can actually say ' I think it will fail because of THIS'. You have to prove you have a grounds for such sentiments before it's worth presenting them. The MSL team will have to prove they're ready to fly before they do...as does every mission that launches. Are our memories so short as to have forgotten all the troubles with MER pre launch and pre landing? Finding pyros in drawers, launching a rover without surface phase software onboard, go re-read Roving Mars people..seriously. And 'Sojourner'. Learn from history. I trust the guys tasked with doing this thing because common sense dictates I have no choice but to do so. Even from the outside looking in, I held this view. Being in the very very lucky position of having had meetings with the EDL team and others (as part of the MSL animation team) my confidence in the team and what they have built has only increased.

Choice of vehicle:
I'm not a geologist, planetary scientists or exobiologist. But if I wanted to know what science to go and do on Mars, I'd ask people who are. It's the scientific community consensus opinion that comes up with such missions, and moreover, the same community proposes and builds the instrumentation onboard it. I don't presume to know better than them. SAM, Chemin, these are astonishing instruments that don't fit inside vehicles smaller than this. If you want to do that class of science, your options are a vehicle like MSL, or sample return.

Budget:
Big government projects go over budget, they go late in schedule. That's just the grim reality of doing very very hard things that have not been done before. Expressed in very approx 2010 dollars, Cassini cost about $1,900M more than MSL. Galileo about $200M more. Viking $1,500 more. This is a flagship class mission, and it's cost flagship class money. Why are we surprised? Is it disappointing that we still don't know how to better estimate these costs? Sure. This, like it or not, is how these things go.

I understood that the reduced performance values were the "minimum" mission success criteria, but that the expectation/reality is the vehicle will far exceed these (as has MER).

Of course there are no guarantees. But the chances are far better than 50/50.

It seems to me the principles and technologies are similar. The main difference I see is that rather than lowering the lander by tether to a point just above the surface, the lander is lowered to the surface.

That had a lot to do with them being solar powered. I'm willing to guess that improving on the power source would be non-trivial. Not least because there's not enough plutonium to go around. But mostly because of reengineering... it's not like something like an RTG is a snap-on. So, to continue the "exploding project cost" idea, doing MER-sized rovers with a different power source would in the end net completely re-engineered rovers that cost a lot more than expected. You see the idea of a "reusable" spacecraft architecture time and again, most recently with LADEE, and time and again different mission requirements preclude reusing spacecraft. Instruments is a whole other story, where they are often reused after development. MSL is ambitious in both the spacecraft technologies AND the instruments.

(The cynic in me notes that if MSL fails, its extremely expensive instruments will get bolted on something else that is heralded as "cheap" because all the instrument costs are sunk. See Observer, Mars.)

From the images : Has the descent stage been gum-dropped ~ wrapped like a boiled sweetie ~ and of to the Cape...?

Looking from the viewing gallery this evening - it's been boxed up for shipping.

http://twitpic.com/59rqb6/full

Did I get you right that you prohibit posts with opinions that MSL has less than 100% chance of successful landing unless said posts contain specific reasons why it may fail?

This is a discussion board heavy on science and engineering themes, after all. If you are going to make a specific categorical prediction it really should have some substance to back it up. If you don't like that you could go over to the Psychic Prophecies discussion board. I'm sure they don't require a lot of facts or reasons behind anyone's bold declarations.