I thought I explained this in my last posts, but again, consider the following: The MER mission is the most advanced robotic surface mission on Mars ever. Yet all of the science returned in its five years of operation could have been plausibly achieved by a team of two astronauts in four days.
It's entirely possible the rovers simply drove past a lot of interesting science. There are limits to what one can anticipate. An astronaut, on the other hand, can whip out a camera and take video of dust devils even if they're not anticipated at all, or can turn over rocks looking for bugs, if the circumstances suggest.
This isn't the right forum for that level of detail. You see, the way it works is like this: At the start, one convenes a panel of planetary scientists to identify and negotiate the overall science goals of exploration. Once this is done and prioritized, then it goes to a different team to handle mission design, where different concepts -- some pure robotic, some crewed -- are formulated to accomplish these science goals, balancing factors of risk, cost, schedule, and so on. Each mission, in turn, requires a number of capabilities for success, and this goes to design teams and researchers of new technologies.
You seem to be oscillating between the first and the third set, at once trying to manage science goals and capabilities. It's not that simple. I'm not a planetary scientist, and I have only a little experience with mission design. My work lives primarily in that third tier. But giving you the long answer is serious work.
Now, I can take a stab at the others, but I'm guessing at the most important and desirable science goals. This is why in my previous posts I came up with a simple motivating goal, namely the search for extraterrestrial life. This is one of the three primary goals of NASA, so it's pretty high on any list. I also identified an extremely rough mission concept, i.e. a surface campaign to search for and recover microorganisms or fossils potentially in subsurface. I then identified a key capability, viz. ability to drill up to 1 km depth and recover samples intact.
This capability could potentially be done either with robots or with humans. But it's vastly easier with humans. Martian drills have been on the wish list of the Mars Technology Program for over a decade, and the cutting edge of development right now is good to only about two meters. Of course, we still don't know how to get astronauts alive to Mars, so there is no alternative at the moment, but once that problem is solved we can look at the tradeoff.
No. The astronauts I have in mind are scientists, PIs in their own right, not just mechanics. They would be able to perform limited repairs and improvisation, but their judgment is much more important.
Taking my 1 km core as an example, it's one thing to build a device that can drill that deep and operate it remotely -- but if it breaks, or say jams on a chunk of volcanics at 100 m depth, our ability to react is slight. Next best, we have operators on scene who can see it, hear it, pick up the early warning signs and shift their location, or work out a way to bust through troublesome strata. But the best is if the researcher herself is on scene, looking right at the samples, feeling the grains for morphology and moisture, smelling them for traces of organics, and then making the call of where to continue and what tests to apply.
Robots will be a long time before reaching this level of sophistication, if ever.
At present, there are none. We do not know how to get astronauts alive to Mars. Once that problem is licked, the solution will drive mission feasibility.
The cost you refer to here applies to crewed or robotic drilling. Robotic drilling will be much more expensive and have a lower yield. Humans by their presence alone will be risky and expensive to provision. Which is better? Can't tell.
There is some degree of consensus, and not just at NASA, that Mars exploration is a valuable and worthy goal. But the reason it hasn't been proposed, again, is that we can't do it. Cost hasn't yet entered the discussion.
There is no question that it's more attractive. The real question is price/performance, and we have no data to make that comparison yet.
Nobody's proposing it right now. I also lean away from colonization as a viable argument, as I explained before.
Again, can't be done today, so the question is moot. The better question is what are we willing to invest to develop that technology.
As for risk, space exploration in general is risky. Risk is not necessarily a problem. We have lost people before and we will again, yet we have a brave and willing astronaut corps, and they will literally fight for the chance to go to Mars when the time comes. Imagine if Columbus or Zhang He never left port, afraid that some of his crew might be killed in the voyage?
What we need to avoid is not risk, but stupid risk. Risk that has the potential for huge returns, risk that we can learn from and improve, is something that NASA is uniquely suited to tolerate. If there's no risk then we're not trying hard enough.
I am, and there are. Maybe not worth it to you, but that's a political question.
As I mentioned before the search for life can potentially pay for itself. But even if this weren't the case, it shouldn't stop us. NASA is not a for-profit venture and should not be treated as one. It's a research institution, and one that pioneers technology and exploration itself.
Just as an example, three days ago there was a successful Falcon 1 launch. This rocket is intended to have a total access cost of under $10M per launch. Yet none of this would have been profitable or even possible had NASA not already invested many billions figuring out what works and what doesn't, how to run ops, what the launch environment was like, pathfinding legal and safety issues, etc. ad infinitum. It's OK that NASA doesn't turn a profit if future entrepreneurs do.
As always, all opinions mine alone, all work done on my own time with my own materials, I do not speak for anyone in the agency or the agency itself.
