ARGUMENTS ABOUT A MARS SAMPLE RETURN MISSION:

At the Mars conference, placing an expensive sample return activity on the exploration agenda, perhaps at the expense of other projects, sparked some anxieties.

“I’m cautiously optimistic,” said Philip Christensen, a leading Mars scientist and professor in the Department of Geological Science at Arizona State University in Tempe. “I am concerned that the sample return mission would take over the Mars program. If you put that mission too far into the future, with not much in between, then you lose a lot of momentum … a lot of young talented scientists and engineers,” he said.

Christensen added that he sees “a real serious challenge” in carving out enough money in the near-term to pay for Mars sample return and still maintain a dynamic program.

“It’s going to take a careful, delicate balance to be able to afford the sample return and yet maintain some measure of a program,” Christensen told SPACE.com at the Mars meeting in Pasadena. “I have no expectation that the program will be as dynamic and vigorous as it has been if we’re going to pay for a sample return. Something’s got to give. But at the same time you can’t just give up everything.”

Plus, of course, there’s the issue of back contamination.