Posted: Mon, Jun 11, 2001, 10:07 AM ET (1407 GMT)
The launch of a NASA spacecraft on a Pegasus XL booster has been delayed until at least June 20 because of the ongoing investigation into the X-43A failure this month. The launch, which had been scheduled for June 7, was delayed until the 12th, and then again to the 14th, before NASA officials decided late last week to push back the launch until after an Atlas launch scheduled from Cape Canaveral on June 19. The delay will give investigators more time to study what happened when a modified Pegasus XL, carrying the X-43A experimental high-speed aircraft, flew out of control several seconds after launch on June 2. Preliminary studies of the failure have focused on the Pegasus XL first stage; video of the launch showed several pieces which appeared to fall off just before the booster lost control. When this Pegasus XL is finally cleared for launch, it will place into orbit the High Energy Solar Spectroscopic Imager (HESSI) spacecraft, which will study the Sun at X-ray and gamma-ray wavelengths with a particular emphasis on collecting data that will allow scientists to better understand solar flares. The spacecraft was to be launched last year but was delayed when it was damaged during a vibration testing accident at JPL.

Related Links:

•  Spaceflight Now article about delay
•  HESSI web site at UC Berkeley