European space scientists are scrambling to rethink—and redesign—massive potential missions after it was confirmed that NASA, whose budget is in
disarray, won't contribute significant funding to any of the efforts. NASA's decision "means in principle that none of the three missions is feasible
for ESA [European Space Agency]," notes Xavier Barcons of the Cantabria Institute of Physics in Spain, who has helped develop plans for the
International X-Ray Observatory (IXO) (pictured), one of three so-called L-class missions under consideration by ESA.
ESA was supposed to decide in June whether to spend about $1 billion on IXO, the Europa-Jupiter mission known as EJSM-Laplace, or a space-based gravitational-wave detector called LISA. But each L-class mission, which wouldn't launch until the next decade, has been developed with NASA as a would-be partner.
The beleaguered U.S. space agency has now told ESA it has higher priorities for its limited space science budget.
So ESA will press ahead on its own, delaying its choice until 2012. The agency has asked each L-class group if a significant fraction of the science
goals in their respective mission can be preserved within Europe's planned budget. "We've given them a year to come up with the answer," says Fabio
Favata, head of ESA's science planning office.
European scientists working on the three missions are now reviewing what can be cut from their projects. "It is
disappointing ... all three missions will have difficulty now, and all three will have delays and redesigns," says physicist Karsten Danzmann of the
University of Hannover in Germany, who is the European chair of the LISA International science team. "It is premature to say which science projects
will be cut [from LISA], ... but science will be lost."
At the same time, each group is pondering whether this new budget challenge gives anyone a particular advantage when it comes to ESA's choice. "LISA is
not relying on funding by [European Union] member states, like the other projects, so this is one potential avenue for funding," Danzmann notes. "We
are financially not quite as hard hit as the others [by NASA's decision]; … in addition, a lot of the hardware is being developed right now for the
LISA pathfinder mission and so a lot of it can be reused as is ... this will also help."
Emma Bunce of Leicester University in the United Kingdom and a lead scientist on EJSM-Laplace suggested in an e-mail to ScienceInsider that her
team's mission might be relatively easily revamped.
As far as the Jupiter mission is concerned, the original plan was to have two spacecraft—one ESA-led and launched, and one NASA-led and launched.
The ESA spacecraft alone was recently judged to fit within the 700 million Euro cost cap, and hence the European spacecraft could go alone … as it
currently stands. We would obviously forego the science which can be done by having two spacecraft in the system at the same time, but we would still
obtain outstanding science return in orbit around Ganymede, and more broadly within the Jupiter system.
As for IXO, Barcons remains hopeful that his team will rally from the bad news. "We're going to try very hard to present a new IXO mission which is
feasible within the new boundary conditions and still scientifically unbeatable," he says--although Barcons hopes ESA will consider raising the L-class
mission budget to €1 billion.
Surprisingly, ESA's Favata sees a silver lining in the hard choices ahead for the L-class teams. "There will be challenges, but they should look
forward to it," he says. "This is a good opportunity for Europe. Need focuses the mind. We are looking forward to leading in various sensor areas. I'm
And despite NASA's change of heart, ESA won't rule out a limited partnership down the road for the chosen L-class mission. "NASA participation on a
strategic level is ruled out, but if there is interest in the U.S., we would consider a reduced level of participation via one of NASA's competitive
peer-reviewed opportunities. It would be junior participations, with clear leadership in Europe," says Favata.