Nasa announces new rover mission to Mars in 2020 Options

[djellison]

MSL is about characterizing habitability of past environments.

And the payload was competitively bid after the mission was selected. And MER was entirely focused on fitting in Pathfinder EDL and fitting what science they could within it. You're using very rose tinted programmatic glasses.

The payload will do what the mars science community want it to do. They will want it to do what the Decadal asked. You will get what you are 'looking for' - but not yet. Is it an ideal situation? No. Is it the best we can hope for given the Mars program budget profile - arguably, yes. Given the funding profile - it's simply not OK for HQ to flat out state this is step one of MSR. The payload has to be competed - the science community must decide what it's for. HQ are giving them the blank canvas that they can fill in how they see fit. If sample return is really what they want - then this vehicle can do it. If this were the other way around - we would see people complaining about HQ dictating the science goals of a mission rather than letting it be determined by the community's suite of available instrumentation competed for the ride.

Note - this decision doesn't come arbitrarily - it comes after the report that followed the summer long process of looking at the Mars program (engineering and science) with invited contributions from the full spectrum of the Mars science community.

This mission is an absolutely perfect enabler for MSR phase 1. The science community simply have to make it so.

[centsworth_II]

...I'm griping that this is a mission that has no declared science goal....

Or... there is an "off the shelf" science goal available.

There was talk of building two MSL rovers just as two MERs were built (look how well that turned out), and the choice between the last two MSL landing sites was hotly debated.

As I see it, an identical rover to MSL could be built and sent to the site that lost out to Gale and worthwhile science objectives that have already been thoroughly vetted could be realized. If a better payload is designed and a better site is selected, so much the better.

[Drkskywxlt]

Centsworth...that's certainly true, but such a mission is lower priority than a Europa mission (or any other flagship) per the Decadal Survey.

I think the reality is probably what Doug has suggested. There are programmatic (and the other "p" word) reasons why the announcement didn't say caching and it will be up to the SDT to declare it a caching mission.

[djellison]

The point regarding Europa is moot.

I explained why earlier in this thread and even linked to Casey's amazing article that explains it so very well
http://www.planetary.org/blogs/casey-dreie...in-context.html

[Drkskywxlt]

Doug, I see your and Casey's point, that this is Mars program money and isn't pulling funds from somewhere else. I grant that point, however it's a bit of a technicality. The Decadal Survey essentially said there should be no Mars program if it isn't doing sample return. There is only money in the budget for 1 flagship. This rover is a flagship mission.

[Don1]

I really don't understand what the scientific community is complaining about. They just got more rover for less money than the MAX-C proposal. This new rover has enough payload to keep everyone happy. The price that has to be paid is that existing hardware designs will have to be reused, which means no messing with the EDL or rover chassis. Those elements are working very well, so I don't see any problem there.

MSL has about 80kg of instruments, and something like an additional 30kg of drilling and sample processing hardware on a 67kg arm. The design for a core drill, arm and sample handling system for MAX-C worked out to weigh 24kg. There is no way to stop them from putting sample caching capability on the next rover. The space is there. Either the 40kg SAM instrument will be descoped and redesigned to be lighter, or the existing drilling and sample processing hardware will be redesigned and simplified. Neither option strikes me as difficult.

By the way, the payload for a MER class rover is about 20kg, but really only 8kg if you consider a mast and a pancam essential for rover operation. The desired core drilling and sample handling hardware simply won't fit. The requirement for core drilling kills that option stone dead.

The MAX-C study looked at a solar powered rover about twice the mass of MER and one third the mass of MSL, but that option worked out to cost over $2 billion. It turns out that reusing an existing design saves a lot of money.

[vjkane]

NASA appears to have made a strategic decision to put the bulk of is planetary funding towards Mars. I think there are good reasons for doing so (see my blog). However, there were other alternatives they could have pursued such as a ~70% down payment on a Europa mission or to fly a New Frontiers and a Discovery mission. Casey's post shows how the MSL-2020 announcement follows from the budget proposed last February and Emily's post describes why this is not an obvious evolution from the Decadal Survey's recommendations.

[djellison]

However, there were other alternatives they could have pursued such as a ~70% down payment on a Europa mission or to fly a New Frontiers and a Discovery mission.

No - this money was - at the presedential level - assigned to the Mars program. You cite Casey's article - but you've not understood it. The cost of the 2020 mission could not have been spent on a Europa or Discovery or NF mission.

NASA COULD NOT... let me repeat that - COULD NOT have spent this money on anything other than Mars.

The budget may not be flexible enough to respond to the Decedal - but this mission does the best it can to speak to the Decedal, for Mars, within the budget assigned.

[JRehling]

It will be interesting to see what opportunities there are for payload refinement based on Curiosity's results. Maybe some test that we couldn't yet foresee will become of burning interest. Maybe after Curiosity has ground truthed its instruments against the same martian samples dozens of times, one of them will prove redundant, at least in terms of the mission goals. And then the payload could include a new instrument in the freed-up slot.

I wonder about the value of a higher resolution microscope. Curiosity's MAHLI resolution is 14 microns per pixel, which is about a 2X improvement on MER. I suppose it depends on the objective.

[centsworth_II]

I wonder about the value of a higher resolution microscope.... I suppose it depends on the objective.

Shhhhh....

Already mentioned, but I'll put in my vote for a geochronometer. It's been very frustrating to have little idea how old the various layers the rovers have been studying are.

[JRehling]

A geochronometer is an excellent example of a kind of instrument where flying it just once on the right rover could do a lot of good. Dating, eg, the Hesperian-Amazonian transition in one location would anchor the absolute time of the transition anywhere on the planet, even if there are local variations.

The Urey mission was an early proposal to do dating in situ on Mars. Gale would have been an excellent place to have it happen, maybe the best of the MSL candidate sites. Maybe Athabasca, Holden, or Eberswalde will get such an instrument.

[Eyesonmars]

On the way to the surface MSL ejected about 300kg of dead weights of various masses. This, as i understand it, was required to give us a margin of safety for precision landing functionality. This compares to ~80kg of science instruments. It will be interesting to see if our engineers, after reviewing all the EDL data from MSL, can improve on this ratio. It is probably not this simple but would a 30kg reduction in rejected mass requirement be available for 30kg in additional scientific payload ?

[JRehling]

It would surely require redesign to buy payload at the cost of fuel. Also, note that instruments require power, and add to the complexity of the information processing system, not only mass.

Most of all, be mindful that Curiosity's wide margins aren't all slack for next time. There is still a bit of mystery to how Mars's atmospheric profiles vary with time, so the approach that just barely works perfectly in one instance might lead to failure in the same location and time of sol due to weather. And, as others have noted, higher altitude will cut the margins as well.

[djellison]

On the way to the surface MSL ejected about 300kg of dead weights of various masses. This, as i understand it, was required to give us a margin of safety for precision landing functionality. T

Margin? No. It fundamentally enabled the guided entry that allowed MSL to have a small landing ellipse.

You could add approx 100kg to the mass of MSL within the current architecture - but it's not coming from the ballast.

[centsworth_II]

Apparently another possibility for increasing payload size would be to move the launch date to 2018.


CNET News

Rep. Adam Schiff (D-Calif.) endorsed the new rover mission, saying in a statement that "an upgraded rover with additional instrumentation and capabilities is a logical next step that builds upon now proven landing and surface operations systems."

But he wants NASA to move up the launch date to 2018.

"While a 2020 launch would be favorable due to the alignment of Earth and Mars, a launch in 2018 would be even more advantageous as it would allow for an even greater payload to be launched to Mars," he said. "I will be working with NASA, the White House and my colleagues in Congress to see whether advancing the launch date is possible and what it would entail."

I'm pleasantly surprised to see a congressman take such an interest, but I fear this is too optimistic. We should probably be more concerned with what effect a slip to 2022 would have.