— Donald

However, using rockets to hop a lander about seriously increases the risk of something going wrong; rolling about on wheels is less stressful to the hardware and certainly less dynamic (all it takes is to have one landing pad hit a rock when the other 2 or 3 don’t…let’s not forget that Viking 2’s tilt may be due to its having set down on a boulder. As we’ve seen, a stuck wheel doesn’t necessarily cripple a rover; a stuck landing thruster could very well flip the vehicle over.

Now, if the “hoppers” can be made sufficiently cheap that you won’t mind losing a few (say, 3 out of 10) for the sake of the experiment, it might be worth it. But it will STILL be a pretty sizable investment.

— Donald

If we do go for MSR, I hope there’s a robost set of precursor landers to identify and collect good samples to take back, and I hope the MSR isn’t just a single mission itself, but rather that it’s used several times to get the most for the development effort.

— Donald

However, I nevertheless agree with Donald (which I usually don’t since I’m clearly biased towards the robotic side) about his worries about the Mars Sample Return mission. I’m also skeptical that MSR will keep in its budget, since it’s had a lot of trouble in past iterations. Apparently it’s a really hard engineering problem. There’s a danger that MSR will take away the funds for a lot of other Mars robotic missions. It also strikes me as a mission where an awful lot can go wrong. I wouldn’t want to see a repeat of Mars Observer on a bigger scale. Part of me is also worried about public support, since I think the public likes lots of pictures, rovers, and the like, and isn’t as thrilled as the scientists by bringing back samples. I’m not sure how MSR will compare to other Mars missions in how it improves general engineering capabilities, but that’s at least a concern, too.

I hope NASA can alleviate these concerns by coming up with a reliable but cost effective MSR architecture, sharing major parts of the cost, etc.

Personally, I’d be inclined to take a conservative approach with the grand Mars plan unless some really good engineering is first done to show that MSR isn’t “a bridge too far”. Start with a much easier sample return, like the old Discovery proposal to do something like Deep Impact with one of the Martian moons and return a sample of that, or perhaps of Martian atmosphere. Meanwhile, keep up the steady progress with rovers (there’s a LOT of diverse geology we haven’t seen up close yet), landers, and perhaps balloons, airplanes, and impactors. Do low-level MSR technology work. After a decade or more of that, we may have a lot better idea which samples we want to pick up, we might have better commercial support (e.g: CATS) to make MSR less of a budget hit, and we might even have a human Mars mission on the books which the MSR can feed technology into (or the human mission could just do the MSR!).

Ames/MSFC politics seem to be a dangerous area – hopefully MSFC is happy with their piece or have gotten something else they want even more. Otherwise, I wouldn’t totally discount the budget in this respect. Even if Congress wants to ignore the 2009 budget, I’d expect the Ames Senators and Congressperson to want to protect this part, especially if Ames is getting to work on some of it soon.

This is just as false a statement. First of all, I don’t believe $2 billion for a second — the original $5 billion is probably far closer to the mark. That aside, any $2 billion MSR will obtain its samples from very shallow depth and from a small and probably very close-together set of locations (far more so than even an initial human mission). Thus, it will almost certainly be irrelevent in the search for life, the primary reason given for this mission. Even on Earth, fossils are far too scattered to successfully be collected by such a mission and extant life is unlikely to be near the surface. If locating life is your goal, you’d be far better off following up the circumstantial evidence for methane and other out-of-equilibrium gasses — the kind of search that could be automated at reasonable cost and efficiency. If obtaining geochemical samples is your goal, you’d be better off continuing to look for them on the antarctic ice (or on Earht’s moon), which is likely to find more samples from a greater variety of locations and (more importantly) depths on Mars. Since an MSR is unlikely to have any non-scientific benefits, I stand by my statement. At least lunar sample returns are relatively cheap and directly applicable to near-term exploration.

Anon’s suggestion for a mission to test local resource utilization makes much more sense to me, especially since it could help an MSR if you really insist on doing one.

The automated budget should be saved for use on things that human scientists cannot do in the next several decades no matter how much we spend — e.g., exploring Europa.

— Donald

I would be more interested if the sample return mission implemented ISRU — by converting Mars C02 to Methane, and a LOX-Methane engine to return the sample to Earth.

This would be a great way to prove out the Zubrin-ISRU capability for Mars.

But I doubt this will happen.

– Anon