NASA News National Aeronautics and Space Administration John F. Kennedy Space Center Kennedy Space Center, Florida 32899 AC 321 867-2468 _________________________________ For Release: June 19, 2001 Dolores Beasley NASA Headquarters 202/358-1753 George H. Diller Kennedy Space Center 321/867-2468 Susan Hendrix Goddard Space Flight Center 301/286-7745 Barron Beneski Orbital Sciences Corporation 703/406-5528 KSC Release No. 67-01 LAUNCH OF HESSI SPACECRAFT POSTPONED The launch of NASA's High Energy Solar Spectroscopic Imager (HESSI) spacecraft aboard an Orbital Sciences air-launched Pegasus XL vehicle has been postponed. NASA's Expendable Vehicle Program Office at the Kennedy Space Center has concluded that it would be prudent to wait until the X 43 failure board has released preliminary results and findings. This decision was reached in consultation with the Explorer Project at Goddard Space Flight Center, Greenbelt, MD. Once the failure review board has completed its analysis, the conclusions can be evaluated to determine if any aspects are relevant to the Pegasus/HESSI vehicle. A final engineering review will begin at that time after which a launch date can be established. The Orbital Sciences L-1011 aircraft carrying the Pegasus/HESSI vehicle will return to Vandenberg Air Force Base, Calif., on Thursday, June 21. # # #