Tight budgets are pushing the U.S. and European space agencies to consider a truly collaborative series of missions to Mars. What would it mean for science?
Did Mars ever harbor life? The multibillion-dollar quest to find out faces an uncertain future on both sides of the Atlantic. The European Space Agency (ESA) lacks the money to carry out its ambitious blueprint for putting a sophisticated lander and rover on Mars’s surface in 2016. And NASA is grappling with major cost increases and delays in its Mars Science Laboratory (MSL) that are eating up funding for future missions.
To avoid hanging separately, say scientists and managers in the United States and Europe, the two agencies must agree to hang together in an unprecedented partnership. This summer they intend to unveil a sweeping plan for a decade of collaboration that could kick off with a joint 2016 mission and culminate a decade later in the return of a martian sample to Earth. “This is a big change,” says David Southwood, ESA science chief. “But we have to think about Mars differently.” Adds his counterpart at NASA, Edward Weiler: “We’ve got to do this together.”
The financial motivation for the new strategy is obvious. A sample return mission alone could run between $6 billion and $8 billion, far beyond the means of either agency. But the two agencies and scientific communities will first need to overcome a host of political, cultural, and technical challenges. Some Americans fear ESA is not yet ready to oversee complex missions on the martian surface. Europeans worry about being tied to NASA’s annual budget wrangles. And both sides want the glory of landing rovers on Earth’s neighbor.
Gaining weight
Cooperation between NASA and ESA is nothing new, of course. ESA has long been part of the international space station, and it provided the Huygens probe that plunged into Titan’s atmosphere after riding on NASA’s Cassini spacecraft to the Saturn system. Likewise, NASA is slated to pay for two important instruments aboard a 2016 ESA mission called ExoMars. But none of these projects is truly a joint effort. Instead, one agency–usually better-funded NASA–has had the final say, and the other agency’s science has literally gone along for the ride. For the joint efforts now being discussed, each agency would take turns. For example, ESA and NASA are likely to alternate putting a lander on the surface, with the other providing a less expensive and technically challenging orbiter or related hardware.
The travails of ExoMars help to explain ESA’s interest in a joint effort. Last year, the 17 nations that make up ESA approved $1.1 billion for ExoMars, some $195 million less than agency officials had requested (Science, 5 December 2008, p. 1447). The lander, which would open like a flower to reveal a 270-kg rover, would drill down 2 m to examine organics and conduct geochemical studies on whether life ever evolved and prospered on the planet. ESA’s only other Mars mission, Mars Express, was a far more modest venture, and although its orbiter was a success after arriving in 2003, its U.K.-built Beagle 2 lander failed to survive the descent.
But the weight and complexity of ExoMars’s planned scientific payload has grown alarmingly. The estimated weight of a geophysical package called Humboldt, for example, has tripled. Lifting additional weight requires extra fuel and a roomier spacecraft, which increase costs. “There is not enough [money] to fully realize Exo-Mars as planned,” said Jorge Vago, ESA’s ExoMars project scientist, at a meeting earlier this month near Washington, D.C., and “no mechanism for financial shortfalls.” As a result, he says, scaling back the $1.56 billion project as well as bringing in U.S. participation “is unavoidable.”
CREDITS: © DENIS SCOTT/CORBIS; NASA
That effort is well under way. Last week, European engineers and scientists met in the Netherlands to decide the fate of 23 instruments, two of which would be NASA contributions. At the same time, Southwood is loath to scale it back too much. The ability to establish a presence on the Mars surface, he says, will allow ESA to “stand shoulder to shoulder with Uncle Sam.”
But some U.S. scientists worry that ESA lacks the experience to carry out such a difficult mission. “They have never successfully landed on Mars,” notes G. Scott Hubbard, a former NASA official and now a physicist at Stanford University in Palo Alto, California. “And ExoMars is more complex than MSL.”
Lean on me
NASA has long ruled the roost on solar system missions beyond Earth orbit, having a 3-decade-long track record of landing robots on Mars. But these days it needs a shoulder to lean on. Technical troubles and a $400 million cost increase for MSL recently forced Weiler to postpone the launch of the 900-kg rover by 2 years (Science, 12 December 2008, p. 1618). The overrun will eat into future Mars projects, endangering the agency’s decade-old plan to send a probe to Mars every 2 years.
That strategy was meant to capitalize on a 1996 paper in which scientists presented possible evidence of fossilized life in a Mars meteorite–evidence that has since largely been discounted. The failure of two probes in 1999 led NASA to revamp that schedule, however, and last year then-NASA science chief S. Alan Stern put forward yet another plan to streamline Mars missions and speed up a sample return mission. Scientists said the plan was unrealistic, however, and Stern resigned shortly thereafter in a funding dispute with the NASA administrator.
Now NASA has decreed that future Mars missions must fit into the more constrained budget. The U.S. agency still plans to send an orbiter to Mars in 2016. One of the scientific instruments aboard the Mars Science Orbiter (MSO) would monitor trace gases such as methane while cameras would provide data on future landing sites. In addition, a communications package would beam information from future U.S. and ESA landers back to Earth.
However, overruns on MSL have left NASA managers with only $700 million for the mission, far less than needed. NASA has also pledged to fund two U.S.-built ExoMars instruments, and the $50 million growth in the initial $80 million budget for them would come out of the 2016 mission. To fit a mission into that amount of money, NASA has proposed limiting the number of instruments. But planetary scientists say the current MSO budget is unrealistic. “What can you do with $500 million?” asks John Mustard, a planetary scientist at Brown University and chair of NASA’s Mars advisory panel. “Not much.”
Given the dire budget situation, U.S. scientists seem to agree that cooperation with ESA is vital. But exactly how that will be done remains unclear. Some engineers and scientists favor a combined 2016 mission in which a U.S., European, or Russian rocket launches a NASA orbiter to Mars, which then drops ExoMars to the surface. In 2018, the two agencies would switch roles, with an ESA orbiter dropping NASA’s proposed $1.3 billion to $1.6 billion Mars Prospector Rover. A network of landers designed to monitor Mars’s geophysical health could follow in 2020. The first portion of a sample return mission would leave Earth in 2022, with the second half following in 2024. NASA would likely be responsible for getting the Mars sample into orbit, with an ESA craft bringing the sample home to Earth 2 years later.
In alignment. NASA’s Edward Weiler (left) and ESA’s David Southwood hope for a tentative agreement this summer on joint Mars missions.
CREDITS: FRED PROUSER/REUTERS/LANDOV; ROBYN BECK/AFP/GETTY IMAGES
That tag-team approach has its critics. Jean-Pierre Bibring, an ExoMars principal investigator with the Institute of Space Physics in Orsay, France, fears that combining the 2016 mission with U.S. and perhaps Russian components could delay it until 2018–5 years beyond its initial target. And he says that “if ExoMars meets its goals, then the 2018 lander makes no sense.”
Bibring would prefer to see both sides do a sample return mission starting in 2018: “There is no other science rationale for waiting. The missions in between are really political and economic missions. They are a waste of time and money.”
Flag size
Neither Weiler nor Southwood want to tip their hand before meeting in June. “We’re still negotiating,” says Southwood. The goal, he says, is to avoid the difficulty that goes along with integrating complicated pieces of hardware–from shipping risks to import restrictions–by making each agency responsible for separate pieces of every mission.
One key stumbling block is that Europe lacks the tradition of long-term planning that characterizes NASA’s effort. The likelihood of ESA’s many masters approving an entire series of very expensive flights to Mars during a severe economic downturn seems small. “There’s a psychological barrier we’re dealing with,” acknowledges Southwood. “We’ve got to work with member states used to the idea of one mission at a time.” At the same time, he and other Europeans note that NASA’s penchant for long-term planning does not necessarily mesh with the uncertainty of Congress’s annual budget process.
Weiler admits that cooperation with ESA is a hard sell. “I may be the only person in NASA who believes that this is the right thing to do,” he says bluntly. “My toughest job is to get my view understood at all levels below me, and especially at certain NASA centers.”
Those centers–particularly the Jet Propulsion Laboratory (JPL) in Pasadena, which has built previous Mars landers and rovers–may be loath to relinquish U.S. dominance of the Mars program. JPL has never been shy about using its industrial partners and the powerful California congressional delegation to ensure its central role in solar system exploration. But Weiler is betting that JPL’s managers will realize that leading one Mars mission every 4 years is better than maintaining control over a bankrupt program.
There are subtler barriers to U.S.-European cooperation as well. American space scientists have less experience working with colleagues in other countries than do their counterparts. “There’s a lot of ignorance,” says Mustard, who has worked closely with French researchers for 2 decades. “So there’s a lot of anxiety.” And Europeans must contend with what Southwood says is “a bit of an inferiority complex” with NASA when it comes to managing major Mars projects.
But managers on both sides believe that the opportunity to do good science will ultimately trump all other concerns. Weiler admits that “psychology and nationalism … are tough nuts to crack.” But he warns that if scientists want a strong Mars program, “flag size cannot matter.”
Science 27 March 2009:
Vol. 323. no. 5922, pp. 1666 – 1667
DOI: 10.1126/science.323.5922.1666
Science-2009-Lawler-Can_a_Shotgun_Wedding_Help_NASA_And_ESA_Explore_the_Red_Planet-1666-7.pdf
