The European Space Agency (ESA) and its Russian counterpart, Roscosmos, are making plans to carry out the international ExoMars exploration program without help from one of the project's original partners: NASA. The U.S. space agency may have to pull out of the project if the Obama Administration's 2013 budget request to Congress, to be released on Monday, includes expected cuts in the agency's funding for Mars programs.
ExoMars has had a long and tortuous history and its launch has been postponed multiple times. Originally an ESA-only project to put a single lander on Mars, it was merged with NASA's program in 2009 and became a two launch effort: a craft called the Trace Gas Orbiter would be launched in 2016 along with a small static meteorological lander; a larger ExoMars rover would launch in 2018, possibly accompanied by a smaller U.S. rover called MAX-C.
Last year, NASA officials made it clear they could not fulfill all of their commitments to ExoMars as a result of government cost cutting and budget overruns by the James Webb Space Telescope. In response, ESA approached Roscosmos in the autumn to see if the Russians could come aboard, too. In particular, ESA wanted to be able to replace American Atlas V rockets, which were the planned launch vehicles, with Russian Proton rockets. Roscosmos officials were initially skeptical, according to the Web site russianspaceweb.com , but scientists ultimately embraced the opportunity to fly instruments developed for other failed Russian Mars missions, including Mars96 and Fobos-Grunt . A mid-November meeting of the Russian Academy of Science's Space Council endorsed participation and even suggested replacing the static lander in the 2016 mission with a clutch of small landers developed for Mars96.
ESA's Rolf De Groot says that talks between the three agencies began in November, but at a meeting in December NASA officials said they could not participate in further discussions until they knew their 2013 budget. "We decided to study a plan C with Russia on a bilateral basis. Studies were carried out over Christmas and in January," De Groot says. Details of that bilateral plan have not been revealed, and a Russian researcher involved in the discussions declined to comment. Now, Russian and European officials are waiting to see what happens in the United States.