One of the missions, known as LISA, short for Laser Interferometer Space Antenna, would have been the first dedicated space mission to search for gravitational waves, ripples in spacetime predicted by Einstein’s theory of general relativity. LISA’s design called for three identical spacecraft that would use lasers to detect minute movements of a 2-kilogram gold-platinum alloy cube inside each craft. The tiny motions would be evidence of the passage of a gravitational wave generated by sources such as merging supermassive black holes. Total cost of the mission is estimated at about $2.4 billion, of which NASA’s share would have been $1.5 billion.
The other disbanded mission, the roughly $5 billion International X-ray Observatory, would have cost NASA about $3.1 billion and was slated to use a large X-ray mirror to peer through dust and gas clouds to discover and examine some of the universe’s earliest supermassive black holes. The X-ray mission would have been a successor to two spacecraft now in orbit, NASA’s Chandra X-ray Observatory and ESA’s XMM-Newton Observatory.
Jon Morse, head of NASA’s astrophysics division, announced the decision to cut funding for both missions during an April 7 teleconference with a NASA astrophysics advisory board.
ESA is considering scaled-down versions of these and other missions, and NASA may play a minor role if such a plan goes forward. Although the U.S. president’s proposed budget for fiscal year 2012 provides money to continue studying the designs of LISA and IXO, the projects weren’t the top priorities in last year’s National Research Council report on recommended astrophysics missions for the coming decade (SN: 9/11/10, p. 10).
“This is the most exciting time ever in astrophysics, but it coincides with a very challenging time for funding,” says Michael Turner of the University of Chicago, a coauthor of the council report. He notes that while ESA was eager to collaborate with NASA on IXO, LISA and Laplace—a mission to Jupiter and its moons—it became clear that NASA’s budget wouldn’t allow the mission’s to be ready to fly in the 2020 timeframe that ESA had in mind.
“They have money now and need to produce good science with it or face the loss of contributions from member states,” says Turner. “Thus, they are forced into a position of going it alone on less capable versions of these missions.”
James Ira Thorpe of NASA’s Goddard Space Flight Center in Greenbelt, Md., predicts that overall, any design that ESA might propose for a revamped gravitational wave mission “will look a lot like LISA.” He adds that if such a mission is not selected for continued study by ESA, “I would expect the communities in the U.S. and Europe to regroup and propose a LISA-like mission to their respective communities for a future opportunity.”
NASA’s woes stem from a low budget for new astrophysics research, exacerbated by a $1.4 billion projected overrun for the James Webb Space Telescope (SN: 4/9/11, p. 22). “The JWST overrun—if taken all from astrophysics—would eat up almost all of this money for new things,” Turner says.
NASA Administrator Charles Bolden has suggested that the Webb telescope won’t launch before 2018, two years later than recently estimated. To meet that target, NASA would have to postpone the National Research Council’s highest-priority space mission, the proposed Wide-Field Infrared Survey Telescope, from a recommended 2020 launch to 2025, notes Alan Boss of the Carnegie Institution for Science in Washington, D.C. At that point, he says, the scientific timeliness of the mission to examine dark energy and exoplanets would have waned and support for the mission would have weakened.