LE BOURGET, France — The United States and Europe are moving
closer toward a full-scale collaboration in Mars exploration but have agreed to
go their separate ways, for now, in exploring the mysteries of dark energy,
according to U.S. and European officials.
The science directors of NASA and the European Space Agency
(ESA) are scheduled to meet in England the week of June 29 to craft an
agreement calling for NASA to launch Europe's billion-dollar ExoMars
lander and rover in early 2016 aboard an Atlas 5 rocket that will also
carry NASA's Mars Science Orbiter mission.
In a June 17 e-mail response to Space News inquiries, NASA
spokesman Dwayne Brown said a prospective agreement would require that ExoMars
lose enough weight to fit aboard the Atlas vehicle with the NASA orbiter.
"It will not be a simple task for NASA's orbiter to
carry the
large lander ESA has designed," Brown said. "Detailed studies and
analyses are required. Also considered will be ... the difficulty of the 2016
opportunity for landing due to orbital mechanics and dust storms."
An Atlas launch would help solve a longstanding ExoMars financing
problem at ESA. The mission's current budget of 850 million euros ($1.185
billion) is insufficient to finance the experiment payload and a launch
aboard a European Ariane 5 rocket. ESA has said its current ExoMars budget is
around 200 million euros short of what's needed to pursue the mission without
outside help.
ESA has been negotiating with Russia for a Proton rocket
launch, and for the commercial purchase, in Russia, of nuclear heaters to
provide electrical power and keep the ExoMars rover instruments warm on the
martian surface.
Under the agreement now taking shape with NASA, ESA would
use U.S.-built nuclear heaters, known as radioisotope thermoelectric
generators.
ESA Director-General Jean-Jacques Dordain, in a June 15
press briefing at the Paris Air Show here, said ExoMars will be unable to carry
a key science package — the Humboldt suite of instruments to study martian
geophysics — because of financial and weight-limit requirements. He voiced
support for a long-term Mars exploration collaboration with NASA, starting with
ExoMars.
ESA Science Director David Southwood said he hopes an
initial letter of intent can be signed with NASA on an ExoMars collaboration
during his June 29-30 meeting with Edward J. Weiler, NASA's associate
administrator for science.
NASA's Brown said the meeting might produce the outline of
such a letter, but that the two agencies "have not yet discussed an
official letter of intent since the accommodation studies and independent
reviews are not finished, and a final commitment on a 2016 partnership has not
been made." Brown confirmed NASA's interest in making ExoMars "the
first installment of a larger joint Mars exploration program between both
agencies — a joint Mars Architecture looking at missions in 2016, 2018, leading
to a joint Mars Sample Return mission sometime in the decade of the 2020s.
These plans are predicated on a successful 2016 architecture."
"This is a courtship," Southwood said. "What
we hope to accomplish is something that would be terrific for Europe, and for
the United States. For a future mission like Mars Sample Return — even the
United States cannot do that alone."
But if NASA and ESA are moving closer on Mars exploration,
the two agencies will be pursuing separate missions to investigate dark-energy
sources. ESA has included the Euclid dark-energy mission among candidate
missions to be evaluated late this year for future funding. Southwood said he
has concluded that Euclid cannot be combined with the Joint Dark Energy Mission
(JDEM) planned by NASA and the U.S. Department of Energy.
The main problem, he said, is the calendar. Southwood said
structuring a trans-Atlantic cooperative mission on dark energy in time to meet
ESA's competition deadline has proved impossible given the personnel changes in
the U.S. administration since January and the more-complex program management
owing to the Department of Energy's co-management of the program.
Jon Morse, NASA's astrophysics director, agreed that integrating
ESA as a full partner in the mission would be a challenge that would require
high-level approval in Washington and at ESA and might threaten Euclid's place
in the ongoing competition among future ESA programs.
"They did not want to jeopardize Euclid's standing in
the competition" by starting a long process of ESA-NASA-Department of
Energy negotiations, Morse said in a June 17 interview. "The discussions
with ESA have been deferred until the next steps [in ESA's future
mission-selection process], but this does not preclude a future
collaboration."
Morse said NASA's JDEM agreement with the Department of
Energy, spelled out in a November 2008 memorandum of understanding, has not
changed with the arrival of the administration of U.S. President Barack Obama.
The memorandum identifies NASA as overall mission manager, and says: "In
consultation with DOE, NASA will investigate the possibility for international
in-kind contributions. NASA will be the principal point of contact in
negotiation and conclusion of international agreements related to JDEM."
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