PARIS — The heads of NASA and the European Space Agency (ESA) are scheduled to meet the week of Oct. 3 to determine how much further to reduce their already slimmed-down cooperative mission to Mars following NASA’s latest round of program cuts, a senior ESA official said Sept. 30.

NASA officials have told their ESA colleagues in recent weeks that the U.S. agency cannot provide an Atlas 5 rocket as was planned to launch Europe’s Mars telecommunications relay and an atmospheric-descent and landing module. The decision likely will force a cancellation of the 2016 launch if ESA cannot secure a Proton rocket from Russia as part of a barter effort that has not been negotiated, Thomas Passvogel said in an interview.

NASA Administrator Charles Bolden and ESA Director-General Jean-Jacques Dordain are scheduled to meet in Cape Town, South Africa, the week of Oct. 3 during the International Astronautical Congress, to select one of two scenarios for their joint Mars effort: A single launch in 2018 containing a NASA-ESA rover and a telecommunications package or a program that retains the 2016 launch date as well, despite the rocket uncertainty.

ESA has invested more than NASA in the 2016 mission, but the U.S. side was still expected to provide several science experiments for the orbiter. To preserve its options, ESA has agreed to continue funding work on the 2016 orbiter by an industrial consortium led by Thales Alenia Space of France and Italy through the end of the year, Passvogel said.

ESA has tentatively concluded that a single-launch ExoMars program will cost the same 850 million euros ($1.36 billion) that the agency has secured from its governments for the two-launch mission even if the 2016 launch is scrapped, in part because of the money already spent preparing the telecommunications orbiter, Passvogel said.

In the one-launch scenario, ESA would be responsible for integrating a telecommunications payload onto the spacecraft carrying the rover to Mars as part of what Passvogel called “an enhanced cruise stage.” That stage would remain in martian orbit and serve as a communications relay for the rover on the planet’s surface.

The budget pressures that drove ESA and NASA together in the first place have been severe on both sides of the Atlantic. ESA has been trying for months to coax the remaining 150 million euros it needs for ExoMars from its member states, and alternatively had raised the possibility of canceling the entry, descent and landing module that was to be part of the 2016 mission.

Even before NASA had decided it could no longer afford the 2016 launch, the entry, descent and landing package had been eliminated from the two-launch scenario to permit NASA to purchase a less-expensive version of the Atlas 5 rocket, Passvogel said. If ESA finds an alternate rocket, the package may be reinserted, depending on budget consequences, he said.

The Cape Town decision by Bolden and Dordain will be presented for approval to ESA’s 19 member governments during an Oct. 12-13 meeting of the agency’s ruling council, Passvogel said. If it is approved, the financial package could go to ESA’s check-writing body, the Industrial Policy Committee, for final approval late this year or early in 2012.

ESA and NASA in mid-2009 agreed to what both agencies’ science directors called a precedent-setting collaboration in Mars exploration. As agreed then, ESA’s 1 billion-euro ExoMars program and NASA’s Mars exploration effort would be merged into a two-launch mission aboard NASA-provided Atlas 5 rockets in 2016 and 2018.

At the time, each agency planned to provide its own rover for the 2018 launch. For the 2016 mission, NASA would provide some experiments aboard an ESA-built telecommunications relay satellite that would be needed for the two rovers arriving two years later.

ESA also planned to provide a 600-kilogram entry, descent and landing package as part of its broader effort to master atmospheric re-entry technologies.

In April, NASA informed ESA that it could not afford to provide a U.S.-built rover for the 2018 mission. The two sides agreed to join forces on a common rover for the 2018 launch.

While that decision eased budget pressure for both agencies, it also opened up new problems for ESA because some of its governments, notably Britain, had supported ExoMars on the assumption that its domestic industry would be given a large share of the rover work.

At ESA, ExoMars is considered a single program even if it includes two launches. As work-division decisions on the common rover had not been settled by this summer, ESA was obliged to slow work on the 2016 telecommunications relay until the major issues for the 2018 rover had been settled.

ESA had asked NASA during this past summer for written assurance that the U.S. agency would hold up its end of the 2018 mission. Bolden had been unable to offer such assurances in June, but had said he would try to do so by mid-September. That date, too, came and went with no NASA signal, Passvogel said.

Since July, NASA’s assessment of its budget prospects with respect to Mars exploration has only gotten worse.

Passvogel said that during negotiations between the two agencies in August and early September, NASA informed ESA that to save money on the purchase of an Atlas rocket for the 2016 telecommunications mission, ESA would not be able to bring its entry, descent and landing module aboard.

Then more recently, according to Passvogel, NASA said it would not be able to provide any Atlas rocket for the 2016 mission.

ESA’s Industrial Policy Committee had been unable to clear ExoMars program financing in June because of the confusion about the rover work, and no clear signal from NASA.

The committee met again Sept. 30, and heard ESA lay out the two scenarios that will be discussed in Cape Town and presented to ESA governments Oct. 12.

Under the first scenario, ESA will find a substitute for the Atlas rocket and thus maintain the 2016 mission. Passvogel conceded that only two possibilities seem feasible: A European heavy-lift Ariane 5 rocket, which would add more than $150 million to ESA’s already stressed ExoMars budget, or a Russian Proton rocket that the Russian space agency, Roscosmos, would provide as part of a barter arrangement.

The second scenario scraps the 2016 mission altogether. ESA and NASA would continue their collaboration on a Mars rover to be launched aboard an Atlas 5 in 2018. The spacecraft carrying the rover and its NASA-provided Sky Crane landing system would also be fitted with a telecommunications relay package to enable rover communications.

Whether the 2018 mission would be able to carry any of the science instruments that ESA had intended to put on its telecommunications satellite for the 2016 launch remains in question.

Passvogel said the weight of the spacecraft heading to Mars in 2018 is already estimated at around 3,600 kilograms, which would test the limits of what an Atlas 5 can carry into the necessary Mars-transit orbit.

In a written response to questions, NASA said it has been working with ESA in recent weeks “to determine how best to meet our jointly agreed program objectives within budgetary constraints on both sides … Results will be discussed between NASA and ESA senior management over the coming months.”

The statement, provided by NASA spokesman Dwayne Brown, referred specific ExoMars questions to ESA.


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France, Britain Reluctant To Recommit To Revised but ‘Risky’ ExoMars Mission 

Peter B. de Selding was the Paris bureau chief for SpaceNews.