arsampson":2yk8csgu said:
There seems to be an assumption that future rover missions would contain instruments similar to what have already been used. What about more capable rovers?
What instrumentation would it take for a rover to be able to deliver a substantial portion (say, 80%) of the results possible from a sample return mission? If one were to look back at the Apollo samples, what earth bound instrumentation produced the most information from the samples? If those instruments could be provided on a rover, would sample return even be a reasonable avenue?
One of the big advantages of sample return (other than the ability to use instruments which are unfeasibly large for a lander to carry, such as electron microscopes) is that it doesn't limit you merely to what instrumentation is available now, or to what kinds of experiments people are able to think up during the design phase. Scientists continue to study the Apollo samples today, in novel ways that may not have been considered forty years ago. So the sample return mission buys you the chance for *future* study using new instrumentation or techniques not conceived of when the mission flew.
But that does come at a price, mainly the lack of flexibility in obtaining those samples. A sample return mission would most likely take a sample from a predetermined position. Rovers can pick their targets months after they land -- or even years, as the MERs are demonstrating. So you trade flexibility in study of the samples for flexibility in selecting the samples.