Posted: Mon, Jun 4, 2001, 9:19 PM ET (0119 GMT)
Concerns about the Pegasus XL launch vehicle caused NASA Monday to delay this week's scheduled launch of a science spacecraft. The High Energy Solar Spectroscopic Imager (HESSI) was scheduled for launch Thursday morning, June 7, on a Pegasus XL based out of Cape Canaveral, Florida. However, NASA officials said Monday they plan to delay the launch until at least June 12 after a modified Pegasus XL flew out of control and had to be destroyed Saturday during the first test flight of the X-43A experimental aircraft. The additional time will allow engineers to determine if there are any "associated technical issues" between that failure and the Pegasus XL that will launch HESSI. The HESSI spacecraft will study the Sun at X-ray and gamma-ray wavelengths from Earth orbit, 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:

•  NASA press release
•  HESSI site at NASA Goddard
•  HESSI site at UC Berkeley