WASHINGTON — NASA and the European Space Agency (ESA) will scale back plans to send a pair of rovers to Mars in 2018 and instead build a single vehicle that would drill into the red planet’s surface and store soil samples for eventual return to Earth, according to NASA officials.

Jim Green, director of the Planetary Science Division in NASA’s Science Mission Directorate here, said the agency could contribute roughly $1.2 billion to the mission while also covering the cost to launch the craft.

Speaking to members of the NASA Advisory Council’s planetary science subcommittee April 18, Green said ESA member states are expected to decide by late May whether or not to proceed with the basic architecture concept, which would combine science objectives planned for NASA’s Mars Astrobiology Explorer-Cacher (MAX-C) with Europe’s ExoMars rover, both of which were slated to launch in 2018.

“Our merged rover’s design leverages both partners’ goals and capabilities and assets,” Green told the subcommittee, adding that NASA would remain focused on developing a caching system capable of collecting soil samples from the martian surface, a top priority in the U.S. National Research Council’s most recent 10-year survey of planetary science goals released in March.

Although the survey listed a robotic sample-return mission to Mars as its top priority, it recommended that NASA pursue the estimated $3.5 billion MAX-C rover only if the price-tag could be reduced to $2.5 billion, an amount NASA says is still too steep for a planetary science budget that is expected to decline in the coming years.

With the U.S. contribution to the joint campaign expected to be around $1 billion, the two sides returned to the drawing board in early April. As a result, Green said, “a number of things were decided that will enable us to bring the costs down significantly that were suggested in the decadal,” including the option of achieving U.S. and European science objectives with a single rover.

Green said a joint engineering working group established April 6 is drafting a technical solution to the joint mission objectives given NASA’s funding constraints. In addition, a joint science team is being formed to establish mission objectives and requirements for the 2018 campaign.

Doug McCuistion, who heads NASA’s Mars exploration program, emphasized that the two sides are still sorting out who brings what to the table. However, he told the subcommittee that NASA would provide the rover’s descent stage, based on the Mars Science Laboratory (MSL) mission slated to launch to the red planet later this year, while ESA would likely develop a drill that was originally slated to fly on Europe’s ExoMars rover.

“We’re going to look and see what the best combination of capabilities and assets are and how we go about building a joint rover,” McCuistion said. “It’s not going to look like ExoMars, it’s not going to look like MSL; it’s going to be something new.”



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