When Michael Mumma, of Goddard Space Flight Center in Maryland, finally published his methane-on-Mars results in Science, it certainly caused a stir. So far, the people tasked with picking a spot for the Mars Science Laboratory rover have resisted the allure of a landing site that sits within a broad methane hotspot, arguing that the hotspots are still too uncertain. Well, NASA is going to get to work on that uncertainty: it announced today that it is considering a “Mars Science Orbiter” (MSO) mission in 2016 that would specifically look to see when and where Mars is belching up the natural gas. (Methane can be produced via natural geologic processes but could also point towards hives of microbes living and burping underground.)
NASA Mars Program Chief Doug McCuistion described what the agency calls its “baseline” plan at the Mars Exploration Program Analysis Group meeting in Virginia on Tuesday, a chance for the science community to offer feedback on these long-term plans, which are often very tentative — and very fluid. The plan would include an MSO in 2016 followed by a exobiology lander or rover mission launched during a particularly juicy launch window in 2018 (the best since the Spirit and Opportunity rovers, McCuistion says). That plan would satisfy two longstanding NASA program requirements: keeping continuous communications orbiters in place for lander missions (Odyssey and Mars Reconnaissance Orbiter will be getting old), and continuous practice with the tricky task of landing spacecraft on the surface (gotta keep those engineers employed). The plan would also follow a natural progression: MSO would map the methane; the lander or rover would go after it with a suite of astrobiological instruments.
What the plan leaves unclear is how NASA would collaborate with the European Space Agency with its 2016 ExoMars lander and rover, which would also look for life on Mars (and drill down two meters below the surface to find it). The NASA and ESA science chiefs have already declared, in no uncertain terms, that they want to pursue a joint mission in 2016, and moreover, that they want a common mission architecture for Mars in general. But saying it is one thing — getting the pieces of the puzzle to actually line up is another. “Both NASA and us thought it would be easier to converge,” says ExoMars project scientist Jorge Vago.
One way to keep the mission joint would be to launch MSO and ExoMars on the same rocket in 2016. And on the trading table from NASA, it appears, is an Atlas V rocket. ESA has also pursued getting a Proton rocket from Russia, and is trying to keep the ExoMars design compatible with the European-built Ariane 5. But there would have to be some serious trimming in order to fit both a robust MSO methane mission and a heavy ExoMars mission on the same rocket.
And both agencies are short the cash needed to pursue the deluxe version of each. In particular, ESA is 200 million Euros short of the 1.2 billion Euros it needs for a full ExoMars mission. Vago says that designers will have to cut the proposed 22 instruments in half — both to save on money and weight. One way to do that, he says, would be to postpone the lander (“Humboldt Station”) and pursue the rover alone (“Pasteur”). Would that be enough trimming to make the 2016 mission joint? McCuistion says they want to have it all figured out by June, when the ESA and NASA science chiefs will meet for an important bilateral meeting.