PARIS — The heads of the European and Russian space agencies signed a long-expected agreement March 14 to cooperate on a two-launch Mars exploration mission that will see a European telecommunications orbiter, a trace-gas sensor and a rover vehicle sent to Mars in 2016 and 2018 aboard Russian Proton rockets.

Russia also will provide the entry, descent and landing module for the 2018 mission, which will carry the European rover.

Meeting at the headquarters of the 20-nation European Space Agency (ESA) in Paris, ESA Director-General Jean-Jacques Dordain and Vladimir Popovkin, head of Russia’s Roscosmos agency, signed an agreement that makes it all but certain that the ExoMars mission will be completed.

On the European side, Dordain has yet to secure all the funding needed for ESA’s 1.2 billion-euro ($1.6 billion) share of ExoMars. But enough funds have been raised to keep the 2016 mission on track, and Dordain has proposed to raise further funds by enlisting the support of ESA’s science program.

Ultimately, a Russian Proton rocket may be used to carry ESA’s Juice satellite to Jupiter, with the cash saved at ESA to be invested in ExoMars’ 2018 mission. This scenario has yet to be approved by Europe’s Science Program Committee.

Russia’s arrival as the savior of ExoMars came after NASA said it could no longer fund the purchase of two U.S. Atlas 5 rockets for ExoMars. But NASA has not withdrawn completely from the mission. The U.S. agency will provide the Electra UHF-band telecommunications system for ESA’s Trace Gas Orbiter, as well as the Mars Proximity Link telecommunications package for the European entry, descent and landing module to be launched with the orbiter in 2016.

Because of technology transfer issues in Russia, a Russian nuclear-power source will not be onboard the European descent module in 2016, meaning the module’s expected operational life is counted in hours. With the Russian radioisotope thermoelectric generator, the lander might have operated for a year.

Dordain has said that bringing in Roscosmos as an ExoMars partner does more than save the mission. It also helps maintain the kind of bilateral exchange that occurs with Russia on the international space station, and that ESA would like to continue as part of a multinational global space exploration program coordinated by NASA.

“It has been a long way, and we have performed a large amount of work together,” Popovkin said in a March 14 statement after the ExoMars agreement was signed. “The ExoMars program is to become the second large project after Soyuz in Kourou. It confirms again that projects of such tremendous scale have to be implemented through international cooperation.”

Russia’s Soyuz medium-lift rocket is operated from Europe’s Guiana Space Center spaceport in French Guiana, on South America’s northeast coast, as part of an agreement between the Russian and French government and ESA.



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Peter B. de Selding was the Paris Bureau Chief for SpaceNews.