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.