PARIS — The European Space Agency (ESA) has found $450 million in likely new sources of funding for its ExoMars missions to Mars, a two-launch effort being hurriedly redesigned with Russia following NASA’s pullout, according to an ESA document summarizing the program’s status.

Few of the funding sources are certain. Some of them require unorthodox methods that will need formal approval from ESA government ministers when they meet in November.

The fresh ExoMars funding sources include ESA new member fees from Poland and Romania, added investments from cash-strapped ExoMars backers and the Russian contribution of a third Proton rocket, this one for Europe’s mission to Jupiter in 2022.

Dated May 14, the 23-page document was used to persuade ESA governments on May 16 not to pull the plug on ExoMars, at least not until they meet again on June 14 to look at it again and decide whether further funding is warranted given the program risks.

For a year or more, ExoMars — a telecommunications orbiter and atmospheric gas detector, two stationary landing modules and a rover to be launched in 2016 and 2018 — has been funded in three-month slices. This gives skeptical ESA member states a way to reduce the agency’s at-risk financing if ExoMars is canceled.

The latest cash injection, totaling 64 million euros ($83 million), was agreed to in March and continues ExoMars work through June. In all likelihood, the ESA’s ruling council meeting June 14 will agree to a further slice of funds to carry the program through the late-November meeting of ESA government ministers.

Including the latest funding slice, ESA by late June will have spent 401 million euros on ExoMars, according to the document. Seventy percent has been to prepare for the 2016 launch of the telecommunications orbiter and an entry, descent and landing module. Thirty percent has been spent on the 2018 launch, to carry a European Mars rover and a Euro-Russian descent module.

This money has been committed and cannot be returned, whatever the fate of ExoMars.

Both missions are to be launched by Russian Proton rockets contributed by the Russian space agency, Roscosmos, which was brought into ExoMars in 2011 to replace NASA when the U.S. agency said its budget no longer had room for the mission.

Russia’s arrival saved ExoMars, but also added new costs. ESA governments in 2008 had agreed to spend up to 1 billion euros on ExoMars, but in the four years since have been able to secure commitments for just 850 million euros.

With Russia’s replacement of NASA, ESA must now build its own rover instead of building one in collaboration with NASA. ESA also must provide parachutes, digital electronics and radar, guidance and navigation subsystems for the Russian descent module as part of the 2018 mission.

ESA also must modify its own descent module, and the 2016 telecommunications orbiter, to account for the presence on board of a Russian nuclear heating unit, called a radioisotope thermoelectric generator (RTG), that uses the decay of plutonium-238 to keep the lander warm on Mars.

This will permit the lander to survive for a full martian year. But the RTG is generating heat all along the voyage to Mars. Its proximity to the telecommunications orbiter and lander instruments will require a new thermal control system.

All told, Russia’s involvement means ESA needs to find 1.2 billion euros for ExoMars — no easy task for an agency that over four years could not secure the 150 million euros needed for its previous billion-euro project ceiling.

Without ExoMars, ESA’s exploration program all but vanishes — one reason the agency’s director-general, Jean-Jacques Dordain, has taken on ExoMars as a personal priority and employed the full power of its office to unearth the 350 million euros missing in the ExoMars budget.

As described in the document presented to ESA’s May 16 council, the agency has found nearly 483 million euros in possible contributions. After removing those that are viewed as having only a “medium” or “low” probability of bearing fruit, the document says, there remains 346.7 million euros of funds given a “high” probability.

Here are several of the biggest |contributors:

  • ESA has asked Russia to contribute a Proton rocket for ESA’s planned Juice mission to the Jupiter region in 2022. This would become a joint ESA-Roscosmos mission.

Replacing a European Ariane 5 with a Proton would save 170 million euros, according to ESA. Some 50 million euros would be used to enhance the Juice mission to include an ESA share of the Russian Ganymede lander mission to Jupiter’s largest moon. The remaining 120 million euros would be used for ExoMars.

  • In an unusual step, ESA is proposing to use part of the mandatory contributions of Poland and Romania for ExoMars. Romania has just joined, and Poland is expected to join by the end of the year. Taking 55 percent of these two nations’ planned ESA dues for 2013-2017, plus 100 percent of their ESA entry payments, would yield 84.7 million euros, according to ESA. Diverting funds this way would require the specific approval of ESA ministers in November.
  • ESA believes it can squeeze the current ExoMars contributing nations for an additional 60 million euros in contributions.
  • ESA’s science program will be asked to approve Mars as a “Mission of Opportunity,” a decision that could generate 50 million euros. The agency cannot use these funds without going through the usual science program approval procedure. An advisory committee will meet to discuss this in mid-October, with the Science Program Committee, the final arbiter, scheduled to take up the issue at a meeting in mid-November, just before the ESA ministerial council.


ExoMars Wins One-month Reprieve

ExoMars Missions Back on the Brink

ESA Ruling Council OKs Funding for Mars Mission with Russia

Europe To Press Ahead with ExoMars Plans Without NASA

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