WASHINGTON — NASA has postponed the launch of its Nuclear Spectroscopic Telescope Array (NuSTAR) mission for an unspecified number of weeks because of suspected problems with its Pegasus launch vehicle’s flight software, the agency said March 16.

“The launch will be rescheduled to allow additional time to confirm that the flight software used by the launch vehicle’s flight computer will issue commands to the rocket as intended,” NASA said in a press release. The decision was made after a March 15 launch status meeting, NASA said.

The Pegasus XL is an air-launched rocket built and operated by Orbital Sciences Corp. of Dulles, Va.

NuSTAR, which will observe black holes, ultra-dense neutron stars, supernova remnants and the sun, had been slated to launch March 21 from Kwajalein Atoll, a U.S. Army-operated missile range in the Marshall Islands.

NASA said the time required to complete the flight software review will cause NuSTAR to miss its March launch window. Although NASA has not set a new target launch date, the agency said it is working with range officials to find a launch opportunity sometime “within the next two months.”

The Pegasus XL has logged 26 successful launches since its last failure in 1996. The rocket’s most recent launch was in 2008, when it lofted NASA’s Interstellar Boundary Explorer satellite.



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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.