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NASA cancels small X-ray mission

NASA on Thursday cancelled a small astrophysics mission that would have studied the polarized X-rays streaming from black holes and neutron stars, after the mission was estimated to be running 20% to 30% over its $119 million budget.

The mission, called the Gravity and Extreme Magnetism Small explorer (GEMS), had been selected in 2009 as a winner in NASA’s small explorer competition, and was scheduled for a 2014 launch. The principal investigator was Jean Swank, an astrophysicist at Goddard Space Flight Centre in Greenbelt, Maryland.

“It was clear that they would not be able to complete it within their cost cap,” says Paul Hertz, NASA’s astrophysics division director.

Scientists in both astrophysics and planetary science have constantly reiterated the successes of its small, principal-investigator-led, competitive mission lines. Decadal surveys routinely plead for NASA not to gut the small mission lines as a way of supporting large flagship missions.

And while a few small missions, like GEMS, have had some trouble staying within their budget envelope, none have approached the budget-busting behavior of flagship missions such as the $2.5 billion Mars Science Laboratory or the $8.8 billion James Webb Space Telescope (JWST).

JWST is also managed at Goddard, but Hertz says GEMS is not being punished for the larger mission’s excesses. GEMS was selected under a competition with strict rules. “JWST,” he says, “is different.”

Image credit: NASA


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