MSL landing sites Options

[SFJCody]

Fifth MSL Landing Site Workshop presentations
http://marsoweb.nas.nasa.gov/landingsites/...op/program.html

Found UMSFer Edwin Kite's presentation to be very interesting. He's performing a valuable service- forcing people to question romantic assumptions about Martian sedimentary rocks. Is he the new Nick Hoffman?

[Deimos]

Holden seems like Gusev... to this armchair martian explorer, do we really want to look at another volcanic littered and billion year wind-swept and dust covered crater? Is there a Home Plate fumarole there to study... or mud volcanoes?

I truly do not see where this comes from. Light-toned layered deposits. Phyllosilicates. Fluvial channels within the driving range. And the complicating factor in the ellipse is alluvium (with ripples), not basalt. This is not one of my favorite sites .. but "like Gusev" misses the mark.

The delta of Eberswalde may not be easy to maneuver around; and its a negative delta, the braids, are now raised very high.

It would be great to get to the top. But you're right, MSL likely won't. But the science targets are reachable, and the driving to get there is easier than at Mawrth.

Mawrth... what a place. An extensive valley with everything at your landing spot.

Hmm. Everything in the ellipse. Well, mostly--the sulfates are outside the ellipse. But that's very different from everything at your landing spot. Especially with slow traverses. If Go-to capability is somehow limited, it hurts a Mawrth investigation less then the other sites--it does not let Mawrth off the hook.

And then the 150 mile Gale Crater. It has a Pike's Peak sized mountain in the middle. The experts don't know what it is or how it got there. Within the crater is a crazy deep and layered valley that we can cozy up to and study (albeit, from afar). The traverse up Pike should reveal many surprises.

Don't sell the mound short. It looks down on Pike's Peak. By a factor of 3. Peak altitude with respect to the mean datum is irrelevant--by that standard, Gale's mound is a bump; PP much taller. Stand at the base and look up. The mound is Mt. Logan; or Mt. Rainier on steroids (in size, and a little bit in shape--of course it is layered sediments). From the base, it is 5 km of exposed sediments, not a paltry 1.6 km ;^) . That said, of course MSL's investigation will be vastly less than 5 km; but there would be some pretty pictures.

Separately, I agree with Jim Bell. We have the capability to drive, to "go to" a site out of the ellipse. We should use it IF it gets us what we want, and that should be decided on the merits. The rallying cry should not become, "Why settle for the best when you can hold out for good enough." Many think Mawrth is best, and they certainly don't want to settle. But the Ruff-ian argument that those who favor other sites should forsake go-to as soon as Mawrth gets over some "good enough" bar -- well, that should waste the patience of explorers.

[Julius]

I'm still GO for Mawrth!! Lets get down to business straight away and not waste time driving .....we'll have time to study ancient martian history which we havent done yet from the ground..done with that, we can then drive to other sites provided the goals are met early in the mission.. all extra will be bonus!! Besides we dont have any guarantees the mission will last as long as MERs

[djellison]

Lets get down to business straight away and not waste time driving

If that were the case, we would be sending a lander. Mawrth, as with all the others, has specific targets that require driving. Moreover, all the sites have good science within their landing ellipses. Mawrth is not special in this regard.

Besides we dont have any guarantees the mission will last as long as MERs

We DO have a requirement for 2 years on the ground. All of the sites driving requirements and science requirements can fit within that time span.

They are essentially indistinguishable in terms of scientific merit and EDL safety.

[nprev]

Well said, Doug.

To me, it all comes back to a careful read of the stated science goals. Somewhat unfortunately, this isn't much of a discriminator; Mars has a very rich history as is increasingly revealed by MRO & other orbiters, reinforced by the ground truth of the MERs. On top of it all, the EDL system is purportedly robust enough to handle any of the four finalists

I can well understand the indecision. If we were to land on Earth, where would we go to achieve maximum science return? I don't even have a clue. Mars is not as environmentally diverse as Earth, but it's a hell of a lot more diverse than we originally thought not too long ago.

There's probably not a right answer. All remaining candidate sites have something to offer. Therefore, to be utterly pragmatic & honest, it's time to ask the engineers. They apparently are saying that they can set MSL down anywhere the scientists want it to be, but surely one of these sites is easier than the other three iin some respect. I suggest that they should be consulted for a high-res look at exactly which site offers the least landing risk if there are no other compelling discriminatory factors.

Bottom line is that there's gotta be a choice made soon. MSL has the potential to conduct a regional survey of its landing site. Which area would provide the maximum information with respect to the major questions about Mars and its history given that capability?

[Julius]

Of course I expect some driving to get to targeted sites but driving 1 km to get science is certainly preferable than having to drive 30km!! Requirement for mission success is 2 years for MSL which is more robust than MER... yes I see your point Doug but it doesnt mean that it will last that long.....dont get me wrong, I wish MSL all the success and better science returns than MER but you never know what MARS may hold for MSL!!??

[djellison]

but driving 1 km to get science is certainly preferable than having to drive 30km!!

I'll repeat myself : The sites all have interesting science within their ellipse, and, repeating myself again, Mawrth involves driving to science targets as well. Your entire premise is flawed. You clearly have not read the presentations that the landing site meeting put online.

t it doesnt mean that it will last that long

So how long do YOU think it will last. What assumption are you going to make about its lifespan that drives your preference to Mawrth. What drives your decision to think you know how long the vehicle will last better than the engineers responsible for designing, building, testing...and driving...the vehicle? The level 1 requirement is 2 years. To make ANY assumption regarding longevity other than that is folly.

but you never know what MARS may hold for MSL!!??

Yet you're making assumptions about Mawrth, and indeed the other sites, that the data simple doesn't support. If you wish to make a case for Mawrth, then you need to demonstrate that it is scientifically more attractive or safer to land on or drive around.

The project scientists and engineers were basically unable to do that.

[ngunn]

This is a beginner's question, quite possibly asked and answered before. Suppose Curiosity were heading with few distractions toward a distant target much as Opportunity is now, what distance is it expected to cover in one good day?

[Julius]

I'm hoping MSL will last a lifetime! I'm not in a postion to judge on the eventual site selected and I trust that the engineers and scientists will make the best choice at the end. All I am saying is that I prefer Mawrth for the simple reason that it represents the earliest Martian history compared to the other sites. Its like reading a book..u want to read from the start rather than start from the middle section for it to make more sense. This is my judgement. Whether I am right or wrong I'll leave it to the people directly involved in this decision.I'll be happy with whatever they decide. At the end of the day what counts is that we'll have another Mars mission to follow for years to come and that makes me excited wherever it happens on Mars!

[charborob]

They are essentially indistinguishable in terms of scientific merit and EDL safety.

I've been loosely following this discussion and the debate around the choice of the MSL landing site, so maybe my comment is ridiculous, but anyway...
If all the sites are equally rich scientifically, I suppose that means the interesting stuff at each site is accessible within the 2-year mission requirement. Of course, we don't know in advance if there will be any mission extensions. We can only hope. Or if MSL will die before 2 years on Mars (heaven forbid!). In any case, would it not be a good idea to plan a little bit in advance? We could take as a hypothesis that MSL will last longer than 2 years and ask ourselves: once we have studied the landing zone thoroughly, where do we send the rover? Suppose at one site the next interesting geology is (say) 50 km away, and at another site 20 km away (just throwing numbers around), then if all 4 sites have equal scientific merit, why not send MSL to a site having a higher "concentration" of various interesting geologic features?

[ilbasso]

To say that "To make any assumption other than [the design requirements] is folly" is not entirely accurate. If I may reference a manned program, remember that the first task that Neil Armstrong had upon getting onto the Moon's surface was to scoop up a contingency sample in case something unforeseen went wrong and he had to get out of there quickly. The design requirement for the LM was to stay on the Moon for 24 hours, but prudence dictated preparing for the unexpected.

Given the investment in the MSL platform and that there's just one shot at getting the science from her, prudence would seem to dictate putting her as close as possible to the priority targets of interest within the constraints of EDL etc. and not assuming that just because she's designed to last 2 years, she will necessarily have that long.

[ngunn]

Just one person's view, but I think it would be be good to lay off the landing site discussion. I live in Wales, FWIW.

[centsworth_II]

...what distance is it expected to cover in one good day?

A quote from The Planetary Society Blog, Sept. 2010 (and a comment to that blog):

"Sean Haggart, the mobility engineer doing the narration, mentioned in the video that Curiosity's top speed is 4 centimeters per second, which is actually slower than what I've heard quoted for Spirit and Opportunity's top speed (5 cm/sec)."

"I remember a JPL lecture in which it was stated that the maximum blind-drive distance per hour for MSL is 210-m, versus 180-m for MER.
#3 - Bob Ames - 09/21/2010 - 04:55"

So Curiosity really doesn't travel any faster than Opportunity.

The remaining factor is how long Curiosity can drive. She has more power than Opportunity, but it takes more power just to move that hulk. It may end up being a wash, with Curiosity not consistently outdoing Opportunity's best pace. It will be interesting to see how long Opportunity holds on to her Mars distance record.

[Explorer1]

How long do they have to decide on the final site? Could it even be left for after launch, or do course corrections and such have to be planned out way ahead?

[nprev]

I believe that it does have to be decided before launch, since MSL will be on a direct trajectory to Mars just like the MERs, Phoenix, and Pathfinder. (The Vikings were in Mars orbit first, so they at least could select from sites achievable from their orbital planes.) Don't think that the cruise stage will be capable of doing anything but minor course corrections & attitude adjustments.