(NASA)
A bit over a week ago, a one-ton spacecraft bearing the poetic name Curiosity touched down on the surface of Mars. The landing was widely celebrated, not just by the scientists and engineers at NASA's Jet Propulsion Laboratory (JPL) who worked for years on the mission, but by the general public-from those following the landing on the Internet to a crowd that gathered in Times Square to watch the event on a giant video screen. In the coming weeks, Curiosity will set out on a multi-year mission to explore its landing site, Gale Crater, and search for evidence of whether Mars was once capable-and possibly still is-of supporting life.
Lost in the euphoria of the landing, however, was a more sobering thought: Curiosity could be something of a grand finale for NASA's current era of Mars exploration. Currently, NASA has only one mission planned after Curiosity, a more modest orbiter called MAVEN that's slated for launch in 2013 and will study the planet's atmosphere. Budget cuts and an ongoing study of future missions suggest that it could be close to a decade before another NASA mission touches down on the Red Planet's surface.
As recently as a year ago, NASA's future Mars exploration plans were more upbeat. NASA had agreed to work with its European counterpart, the European Space Agency (ESA), on a joint series of missions called ExoMars. That program included a European-built, American-launched orbiter in 2016 and a joint lander and rover mission in 2018. (Mars missions are typically launched in brief "windows" every 26 months when Earth and Mars are properly aligned.) Scientists hoped the 2018 ExoMars mission would be the first phase of a long-term plan to return Martian rock and soil samples to the Earth.
However, when the Obama administration released its fiscal year 2013 budget proposal in February, it announced that NASA was terminating its participation in ExoMars. That decision came along with a proposed 20-percent cut in NASA's overall planetary sciences program, to $1.2 billion out of an overall budget of $17.7 billion. NASA's move forced ESA to scramble to keep at least the orbiter part of ExoMars alive; it's now hoping to bring Russia into the program to replace the U.S.
NASA has insisted that it is not stepping away from Mars exploration, but is instead restructuring it to better fit the realities of constrained budgets for the foreseeable future. Earlier this year, the space agency established an independent working group, the Mars Program Planning Group, to examine new approaches to Mars exploration, including what missions would be feasible to launch in 2018 or 2020. That group's final report is due to NASA at the end of this month.
Projected budgets could limit NASA's future mission options, though. "The budget in '18 is thin," Doug McCuistion, Director of NASA's Mars Exploration Program, said last week. "It probably can't support a rover or a lander" even though, he said, that would be the logical next step.
The administration's move has angered scientists and space exploration advocates alike. For scientists, the decision to withdraw from ExoMars runs counter to the recommendation of a National Academies report last year, which concluded that a sample-caching rover like the one planned for ExoMars was the highest-priority large, or "flagship," mission in the planetary sciences for this decade. Supporters of human space exploration also see such missions as vital precursors for the human missions to Mars that President Obama established as long-term goals for NASA in a speech in 2010.
So why cut spending on Mars exploration? The administration has offered little by way of explanation for its move. In congressional testimony earlier this year, NASA Administrator Charles Bolden said he initially thought ExoMars would return samples to Earth when he took office in 2009; when he learned it wouldn't, he decided the agency couldn't afford it.
"The only conclusion I can reach about why Mars and planetary science was proposed to be cut so significantly is because they thought they could," concludes Rep. Adam Schiff (D-Calif.), whose district includes JPL. "They thought the outcry would be so muted: Who are planetary scientists, anyway, when compared to some of the major commercial players?"
NASA's Mars program isn't entirely blameless, though. The Curiosity rover mission saw its costs soar from initial estimates of about $1.6 billion in 2006 to $2.5 billion today, and also missed its original 2009 launch opportunity, instead launching in late 2011. Moreover, NASA's science program has been squeezed by the ballooning costs of an even bigger mission, the James Webb Space Telescope (JWST). This successor to the venerable Hubble Space Telescope now costs $8 billion, but is considered a priority by NASA.
Schiff and others in Congress of both parties are still pushing to restore the funds the administration sought to cut in NASA's planetary science program. House and Senate versions of the relevant appropriations bills partially restore the cut, and Schiff said last week he hopes to secure additional money when a conference committee meets to reconcile those bills. "They have been astounded by the fury of the pushback," he said of the administration, "and that is the only thing that has saved us so far."
The success of Curiosity might also trigger more interest in, and support for, Mars exploration, but it's just as likely to get lost in the noise as the 2012 campaign kicks into high gear, given the low priority accorded to space policy in general. It may not be until early next year, when the fiscal year 2014 budget proposal comes out, that we know details more about NASA's future Mars exploration plans.
With that uncertainty, it's a good thing Curiosity is in good health and ready to start exploring the Martian landscape. While designed for a two-year mission, most involved in the project expect it to last much longer: Opportunity, a smaller rover that landed on Mars in January 2004 for a 90-day mission, is still working today. It could be a long time before those rovers have company on the Red Planet.
