Astrophysics Satellites Crippled After Launch

4 November 1996 8:00 pm

Astrophysics Satellites Crippled After LaunchOne astrophysics spacecraft is dead and another crippled following a trouble-plagued launch off the Virginia coast on 4 November. But NASA officials say they are hopeful that at least some data can be gleaned from the instruments on board.

The third stage of a Pegasus rocket failed to disengage from the two satellites early Monday afternoon, and flight controllers expressed little hope of separating the stage from the spacecraft. Dead on arrival is the High Energy Transient Experiment (HETE), a Massachusetts Institute of Technology satellite that was to use three cameras to gather data on gamma-ray bursts and x-ray emissions and search for faint ultraviolet emissions over the next 6 months. HETE is trapped under the other satellite, and its battery died 6 hours after the failed launch.

Clinging to life is the Scientific Applications Satellite-B (SAC-B), a joint U.S. and Argentinean project to study solar flares, gamma-ray bursts, and the background radiation in the cosmos. Argentina's National Commission of Space Activities built the 181-kilogram spacecraft, NASA provided the launch, and Argentina, Italy, and NASA contributed astrophysics instruments to the mission. The U.S. and Italian instruments still might provide data, but the third stage blocks the view of the Argentinean one, says Jerry Hartman, international projects manager at NASA's Goddard Space Flight Center. NASA controllers were able to contact SAC-B and open its solar panels to provide power, so the two spacecraft and the spent stage could remain in orbit for a year or more, agency officials say.

It's too early to pinpoint what went wrong, says J. R. Thompson, launcher division chief at Orbital Sciences Corporation, which built the rocket. This was the fifth launch of this version of the Pegasus, and the only failure, although earlier versions of the rocket encountered numerous problems. The loss is particularly devastating for Argentina, which is trying to gain expertise in satellite construction and space science. Officials at the Argentinean Embassy said they had no comment until more information was available on the spacecraft's state.

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