WASHINGTON  —  NASA is pulling the plug on the Gravity and Extreme Magnetism Small Explorer (GEMS) X-ray telescope, an astrophysics mission that was to have launched in 2014 to observe the space adjacent to neutron stars and black holes.

GEMS, a project managed by NASA’s Goddard Space Flight Center in Greenbelt, Md., failed to advance past a May 10 confirmation review, said Paul Hertz, director of NASA’s Astrophysic Division.

“The decision was made to non-confirm GEMS,” Hertz said June 4 at a meeting of the National Research Council’s Committee on Astronomy and Astrophysics here. “The rationale was that the pre-confirmation cost and schedule growth was too large.”

GEMS principal investigator Jean Swank, a Goddard-based astrophysicist, told Space News that her project team was headed to NASA headquarters June 5 to appeal the cancellation.

In its 2013 budget request, White House envisioned spending about $171 on GEMS through 2014, the year it was to have launched. When NASA picked GEMS as one of two Small Explorer missions in mid-2009, the agency set a price ceiling of $105 million, plus launch costs, and a late 2012 launch date.

The GEMS instrument was to be built at Goddard, with Dulles, Va.-based Orbital Sciences Corp. responsible for the spacecraft and mission operations. ATK Space of Goleta, Calif., was tapped to build a boom to place the X-ray telescope the proper distance from the detectors.

Dan Leone is a SpaceNews staff writer, covering NASA, NOAA and a growing number of entrepreneurial space companies. He earned a bachelor’s degree in public communications from the American University in Washington.