Frank Morring, Jr. Washington and Michael Mecham San Francisco

NASA space-science managers and the scientists they serve want to use the newly announced Curiosity 2.0 rover to collect samples for eventual analysis on Earth.

But with U.S. federal spending teetering on the “fiscal cliff,” the space agency's White House overseers are not ready to commit to a mission that is pointless without an expensive follow-on to develop a way to get the samples back.

Instead, NASA is setting up a “science definition team” to decide how to use the proposed Curiosity-derived rover when it reaches the surface of Mars in 2020. The instruments that will ride on the big rover will be chosen in an open competition based on that team's work, starting with an announcement of opportunity next summer. Like Curiosity, the new rover will again use the “sky crane” technique to touch down.

Mars Sample Return (MSR) remains the top priority of the planetary scientists polled by the National Research Council for its latest decadal survey on the subject. A pickup committee of experts NASA pulled together after the U.S. bailed out of a joint sample-return effort with Europe last year reiterated that goal this fall. But in announcing the agency's decision to spend $1.5 billion—give or take $200 million—to launch another rover to the surface of Mars in 2020, NASA'S science chief was careful to keep his options open.

“The science definition team is going to have to weigh what science do we want to get done; how much mass and power do we have available; what can we get to the surface and where do we want to go,” says Associate Administrator John Grunsfeld. “[The team] may decide that they want caching [or] they may decide that they would rather use that weight and volume for additional in-situ science to go to some really interesting place that would emerge from what we discover in the next six months to eight months on Curiosity.”

NASA's plan to build another Curiosity-class rover, announced Dec. 4 in San Francisco at the American Geophysical Union Fall Meeting, follows a decision to place an astrobiology instrument on the European Space Agency's (ESA) planned 2018 rover mission to drill deeper than ever below the Martian surface. The Mars Organics Molecule Analyzer (MOMA), will use gas chromatograph mass spectrometry and laser desorption mass spectrometry to analyze samples retrieved from as much as two meters below the surface by ESA's ExoMars drill. It also reestablishes some of the coordination with ESA in Mars exploration lost when NASA pulled out of ExoMars for budget reasons, and the European agency turned to Russia for launches and other help (AW&ST Feb. 20, p. 33).

Coupled with Curiosity's findings as it explores the rock layers in the central mountain that rises from the floor of Gale Crater, and detailed data collected from the Mars Odyssey orbiter, Mars Reconnaissance Orbiter (MRO) and ESA's Mars Express orbiter, results from the U.S. instrument on ExoMars should help guide the 2020 mission to a likely site for evidence of life on Mars, says Scott Hubbard, a Stanford University professor who was NASA's first “Mars czar,” and has written a memoir—“Exploring Mars”—based on that experience.