WASHINGTON — NASA expects to contribute up to $1.5 billion to a 2018 Mars mission with the European Space Agency (ESA) provided the two sides can agree on a plan to drill the martian surface and collect samples with a single combined rover instead of the previously envisioned pair.

Jim Green, director of NASA’s Planetary Science Division, said ESA member states are expected to decide by late May whether to proceed with a new mission concept that would combine science objectives planned for NASA’s Mars Astrobiology Explorer-Cacher (MAX-C) rover with Europe’s ExoMars rover, both of which were slated to launch atop a single United Launch Alliance Atlas 5 rocket in 2018.

“Both agencies are sitting down at the table and trying to chart a new course that fits the budget realities that we both have,” Green said during an April 22 meeting of the NASA Advisory Council’s Science Committee here.

Green said NASA could contribute roughly $1.2 billion to a revised joint mission plus an estimated $300 million for launch costs, or roughly $700 million less than the agency signed up for under the original dual-rover plan.

But with the White House under pressure to rein in spending, NASA says it will be unable to meet its roughly $2.2 billion commitment to the dual-rover mission, forcing the two sides back to the drawing board and prompting ESA in mid-April to halt work on its Mars program, which in addition to the ExoMars rover includes a joint ESA-NASA Mars Trace Gas Orbiter slated to launch on an Atlas 5 in 2016.

While ESA’s contractors have been ordered to stop all ExoMars work, Green said NASA will continue to fund development of the science instruments that agency has agreed to contribute to the ESA-led Mars Trace Gas Orbiter. NASA and its contractors are building four of the orbiter’s five instruments and paying for the spacecraft’s launch as part of a $500 million contribution to the 2016 mission.

“We are working in good faith with ESA and therefore we cannot stop work on our instruments because they deliver early, so our approach is we’re continuing to develop them,” Green told Space News April 22.

Looking ahead to a combined 2018 rover mission, Green said NASA hopes to lower the rover’s overall development cost by leveraging existing designs, including the entry, decent and landing capability that will be used for the agency’s $2.4 billion Mars Science Laboratory (MSL) mission launching in November.

“There’s no reason to invent a new one,” he said. “We have worked very hard to make sure MSL’s entry, descent and landing plans, blueprints and drawings are all available for us to turn around and remanufacture and make a duplicate.”

Green said NASA could also equip the new rover with a nuclear power source by utilizing a spare Multi-Mission Radioisotope Thermoelectric Generator that was designed for MSL.

“That’s part of the trade space,” Green said, adding that the plutonium-fueled battery could power the Mars rover if it is required to traverse dark areas of the red planet where solar arrays would prove useless. “It gives us great flexibility, and we may need it, but we have to do the basic mission architecture first.”

In the meantime the two sides have yet to determine who will lead the mission.

“Right now, NASA is the mission lead for 2018,” Doug McCuistion, head of NASA’s Mars exploration program, said during a meeting of the NASA Advisory Council’s planetary science subcommittee here April 18. However, under the revised 2018 mission, “there’s a very good possibility that the ESA team will be the rover lead.”

For the moment, McCuistion said ESA and NASA are more concerned with deciding which combination of existing assets and capabilities should contribute to the revamped Mars campaign.

“It’s not going to look like ExoMars, it’s not going to look like MSL; it’s going to be something new,” McCuistion said.



ESA Halts ExoMars Orbiter Work To Rethink Red Planet Plans with NASA

U.S., Europe Plan Single-rover Mars Mission for 2018