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.

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.

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.

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.

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.

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.

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 ?

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.

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.

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


CNET News

QUOTE

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.

He says "a 2020 launch would be favorable", but he doesn't say with respect to what. That's the crucial question. The 2018/20 opportunities should be compared with the 2010 2011 flight.

That would be an interesting comparison, but the payload of a future rover is dependent only on the 2018 vs 2020 dates.

From the same article I linked in my previous post:
John Grunsfeld, NASA's science chief... however, cautioned that "2020 is ambitious, and a lot of it has to do with the science instrument development. ... It might be possible to do it in 2018, but it would be a push. What it might do is exclude certain science investigations that might be possible if we had the extra two years. That's something downstream."

I don't know what use extra payload would be at the expense of "certain science investigations", especially if a geochronometer is a possibility in 2020 but not in 2018.

http://trs-new.jpl.nasa.gov/dspace/bitstre...2011_216988.pdf is an interesting study of potential improvements to MSL; one of the options discusssed is replacing the entry balance masses with an actively-controlled trim tab. Of course it's not clear how many changes to the MSL architecture are going to be possible for cost and schedule reasons.

The distance between Earth and Mars will reach a local minimum in the 2018 opposition, and will grow in each successive opposition through 2027 then decrease again before reaching the next local minimum in 2035.

2020, however, is only slightly farther than 2018. Then there's a steep climb with each successive opposition.

The Earth-Mars opposition distance isn't quite the same thing as trajectory energy for the launch opportunity, but I think they correlate very well.

Here's the C3 in km2/sec2 for the opportunities from 2009 to 2022. You can clearly see that 2020 is much higher (worse) than 2018.
Source: table 2 in Interplanetary Mission Design Handbook: Earth-to-Mars Mission Opportunities and Mars-to-Earth Return Opportunities 2009–2024, NASA/TM—1998–208533.

2009: 10.27
2011: 8.95
2013: 8.78
2016: 7.99
2018: 7.74
2020: 13.17
2022: 13.79

At least it's good to see that a mission planned for 2020 won't be much affected by a launch in 2022. On the other hand, a mission design based on a 2018 launch could run into big trouble with a slip of launch date.

I certainly stand corrected. It looks like there's a phase shift in the relationship between opposition distance and energy with the shift being about one launch opportunity.

Yeah - that (and others) were even looked at earlier in MSL development (my favorite was using tanks of mercury that could be pumped around the backshell) - but they were dumped just to keep the architecture simple. Mass wasn't a problem - complexity, reliability and schedule were - so they went with the simplest option.

To be honest, I'd expect them to do the same this time around.

So getting back to my question, this shows that 2020 is worse than 2011 in terms of delta v^2, so all else being the same a 2020 MSL2 could carry less payload than the current MSL. How easily can this delta v^2 difference be translated into a payload mass difference?

2018, on the other hand, is a bit better than 2011.

Not a foregone conclusion, since MSL probably wasn't using all of the C3 available.

In general I think C3 scales as the square of injected mass, but I haven't seen a detailed analysis of the 2020 opportunity. For 2018 there is a detailed breakdown in http://www.nap.edu/reports/13117/App%20G%2...gy-Explorer.pdf

Why not replace the entry balance masses with something useful such as Penetrators or Micro-probes

http://www.planetaryprobe.eu/IPPW7/proceed...ion7B/pr401.pdf

The usual reasons: cost, complexity, increased mission risk.

Volumetrically it's impossible to get a microprobe to weigh as much as a piece of tungsten. At some point it just wouldn't fit in the available space.

And they wouldn't be balanced very well either, which is the whole point of a ballast mass. Penetrators and others would need a dedicated mission of their own.

It would be neat happenstance if there happened to be a seismometer relatively near the impacts of those ballast masses.

The ones they have now don't need to be anywhere near the impact.

The rover is only about 1/4 of the launch mass of the MSL payload. Trimming science payload doesn't get you very far at all

Page 2-107 of - http://www.scribd.com/doc/16924557/Lockhee...-Planners-Guide is where Atlas V C3 spec's are listed.

MSL's launch mass was 3,893kg

On the Atlas V 541 is used - the max theoretical C3 was approx 22 km^2/s^2 - mcaplinger is right - the MSL launch was not using it's total performance envelope. A similar massed vehicle could make any of those launch opportunities with the same rocket. To put it another way - there was about a 25% mass margin on LV performance for MSL.

Does anyone have possible launch and arrival dates for the 2020 window?

- John in Cambridge

The reference I quoted upthread has the launch in July 2020 and arrival in January of 2021, but that may have been with a different set of constraints.

Solicitation beginning, any takers?

http://spaceref.com/news/viewsr.html?pid=42921

My input: fly the caching hardware and cut a deal with ESA to fly a copy of their ExoMars deep drill.

Actually, it would be interesting to see what the collective wisdom of this board would be on what should fly versus what the science team recommends.

I mentioned the portable rock dater being developed earlier in the thread, and I still think it should be seriously considered. Relative dating has served us well so far, but absolute needs to eventually happened (we can only rely on meteorites so often!)
Of course, the landing site selection is just going to get even more intense. Good thing it can be left for last.

Since opinions are invited I'd say take the technology to Mars rather than the reverse, so the dater wins over the cacher for me.

Allen Chen tweeted this yesterday:



https://twitter.com/icancallubetty/status/281827909415620608

I think that MSL sized rover can do both things - sample caching + dating.
This instrument suite with multiple spectrometers weights with cameras ~35 kg.
I don't how heavy is caching device, but I suppose that it can be done at weight less than 45 kg.

I hope all of you followed the link. It is fascinating how NASA projects are put together. The link above is a request for qualified people to send in a two page letter of application to be part of a 12-15 person Science Definition Team for the 2020 Mars Science Rover Mission (Mars - 2020). NASA will pick 12-15 people and a chairman. The committee will come up the Science Objectives (that several of you were prematurely complaining were missing) that will go into the Announcement of Opportunity---request for mission proposals.

More specifically from the link:

The members of the Mars-2020 SDT will provide NASA with scientific assistance and direction during preliminary concept definition (Pre-Phase A) activities. Near-term activities of the SDT will include the establishment of baseline mission science objectives and a realistic scientific concept of surface operations; development of a strawman payload/instrument suite as proof of concept; and suggestions for threshold science objectives/measurements for a preferred mission viable within resource constraints provided by NASA Headquarters. The products developed by the SDT will be used to develop the NASA Science Mission Directorate (SMD) Announcement of Opportunity (AO) that will outline the primary science objectives of the baseline mission and the character of the payload-based investigations solicited under open competition via the AO. The SDT will be formed in January 2013, and disbanded after the work is complete approximately four months later. All reports and output materials of the Mars-2020 SDT will be publicly available, and the SDT will be disbanded prior to any future Announcement of Opportunity (AO) for participation in the Mars-2020 mission, including provision of instrumentation and investigation support. Participation in the Mars-2020 SDT is open to all qualified and interested individuals.

I like the idea of a drill as vjkane suggested, and ESA have put a quite some work into the design so that addition would come at a bargain prize relatively speaking ofc.
With such subsurface work I think it would be a good idea to have one other Russian DAN instrument or a replica.
And there has been work on one lightweight mini sensor experiment called BOLD (Biological Oxidant and Life Detection) that might be added to such a drill or perhaps in any testing package for the second MSL.
If the rover are supposed to cache samples, it is my strongest recommendation that BOLD or a similar experiment is included.
This for a multiple of reasons, none the least that we need a measurement of organics since we even with good precautions may have return samples handled and contaminated by Earth organics - ruining the results of the very expensive return mission.

Dating rocks are also of interest, but forgive me for thinking that it is less needed if the rover would also serve the role as a cacher for one subsequent sample return mission. In that case such work could be done much more thoroughly on Earth. So IMO those are one either/or addition.

Analysis by any instrument sent to Mars could be more thoroughly done on Earth, however some on site analysis is required in deciding which samples to cache. This would ideally include dating. Also, many more sites and specimens could be tested on Mars than could be sampled for return to Earth.

Oh yes, that might be a valid point.

Yet it does not change my view that organic contamination is more of a concern that might ruin science results, so even sensors like SAM could tell us how much organics there were in the original sample so we would know what amount to expect in the lab at Earth, even if we do not have the exact composition. (So if there turn out to be more, then we would know to be cautious for a possible contaminated sample - or try again with the next that was brought back.)

Even so looking for organics beforehand might be a more critical need compared to rock dating which are less sensitive to contamination what I know of.
In addition the APX, CheMin and other instruments, even the cameras could give good hints of what kind of rocks or material that is sampled, yet those instruments are of less help for any characterization if there only be trace amounts of organics.
And if we happen on any such it would be of paramount importance to keep those as pure as possible if we ever are to find out if it originated on Mars or have been transported by one asteroid or comet.

Then again the question of possible organics might be to close to home for me since it is related to my field of study so I might be a bit biased on the idea of having more focus on organics here.
(& Merry Christmas to all on this forum!!)

One thing to keep firmly in mind when thinking about organics on Mars is that it is overwhelmingly likely that most if not all of such we'll detect--and, eventually, we will-- came from carbonaceous meteorites.

We've seen an inordinate number of iron-nickel meteorites on Mars already at Meridiani from Opportunity, probably because they are much easier to identify from appearance & location alone. Stony ones are quite a bit harder to identify esp. because the ubiquitous ocher dust covers everything in very short order, but they obviously must be present as well. Extremely carbon-rich soft objects like the Murchison fall in Canada a couple of years ago probably don't last too long on the surface even by Martian standards & get mixed into the soil sooner rather than later.

Not trying to be a huge downer here, but it will be most prudent to temper our expectations from the eventual detection of organics.

Not at all!
If organics are detected, then it is part of the Martian environment today. Regardless of where it got started.
Now if something is found the second step will then to find out where that material originated. So bring that 'stuff' back to me please!

The Viking experiments did hint that very little organics were present at those landing sites at least, a surprising find for the very reason that you pointed out - even the small amount transported by carbonaceous meteorites would have added enough to be detected by the Viking landers.
The Phoenix lander results with perchlorates and a soluble chemistry added a new spin to the question of what the Martian soils might contain.

Yet I do agree that little to no organic compounds are expected near the surface, but if we drill down as deep as the ESA type drill is supposed to be capable of, the result might turn out to be different. So if a drill is included it might be the most interesting mission so far... from my perspective and interest.

And so they've announced the SDT for the 2020 mission:

http://mars.jpl.nasa.gov/m2020/mission/missionteam/sdt/

- John Sheff
Cambridge, MA

Your link is broken; it's http://mars.jpl.nasa.gov/m2020/mission/missionteam/sdt/

Some well-known names!

Only one from GB, not really an european, and noone from ESA gives an impression of what NASA thinks a future cooperation. Very sad to read that list in that respect.

The persons I read are all more than qualified to do the job, they will do the right thing fast enough so lets wait for their report.

The 2020 mission is not a joint NASA/ESA mission. If you look at missions that have been, you'll see that the SDT has been jointly selected by NASA and ESA.

Future cooperation is all well and good (this isn't the appropriate forum to discuss the pros and cons of that), but this particular mission is 100% funded by NASA AFAIK. I'm not certain of the mechanics but I don't think NASA will pay the expenses of a foreign national, and since ESA wouldn't in this case, participation would have had to be self-funded (partly speculation on my part because I couldn't find the solicitation online any more, but I think likely.)

I believe that NASA has said that it is open to foreign instrument contributions for the mission that fit with the science goals that this science team will define

To reduce costs for NASA a lot of the instruments will be delivered from somewhere else. The insight mission is a good example for this all the big instruments are coming from europe.

To invite an scientis from ESA has nothing to do who will pay for the mission or that ESA has to pay for the travel it is a sign of cooperation and respect, this is missing in the decision.

The funding dynamics for a Discovery mission are considerably different than those for a mission where the instruments are selected in an open competition.

A more comparable situation would be the SHARAD instrument on MRO, which was funded by ASI rather than ESA. I'm not sure if ESA has a program similar to the NASA Mission of Opportunity, which provides funding for US instruments to fly on other nations' missions. I don't recall for sure, but I think that SHARAD was selected by a process outside of the general AO for MRO. DAN and REMS are similar situations on MSL.

It will be interesting to see what the 2020 AO actually says on the topic of non-US instruments, and whether ESA or the European national space agencies make funding available for European instruments.

I never heard of an ESA funded instrument so far. They are always funded by the national agencies. So the Exomars rover will cost 1.2 GEuro but this does not include the instruments because they are funded by the national agencies.

Insight my impression was insight was cheaper because it uses spare parts of Phoenix and the instruments come from abroad making it an appealing mission in a time of low budget because an increase in the price for the system is unlikely and a rise in the costs for the instruments is payed by somebody else.

One low hanging opportunity would be to use some of the ExoMars instruments in the 2020 rover. MOMA would be one opportunity, especially since NASA is contributing to its development. Some redesign would be needed for the ExoMars instruments to physically fit in the 2020 rover, interface with the sample delivery mechanism, talk with the 2020 rover computer, etc, but it should still be much lower cost than developing a flight instrument from a bread board design.

ExoMars instruments either from the Pateur-Payload or from the no longer existing Humboldt-Payload (geophysics and weather) are cheap for NASA with the exceptions of Urey and MOMA, both have some or all money from NASA. After a lot of instruments had to be left away from ExoMars there is a bunch of well developed instruments out there.

The work to make MOMA 2020 ready are easier in one part, because MOMA is using a lot of the technology developed for SAM (the same people at Goddard work on the hardware for the MS and the main electronics).

More interesting will be what the rover will become: Search for organics, geology or geophysics rover. The instrument selection comes well after this decision.

A PanCam is the only thing which is not left away.