First flight for Sofia observatory.

NASA's Stratospheric Observatory for Infrared Astronomy (SOFIA), completed its first test flight on 26 April following extensive aircraft modification and telescope integration by L-3 Integrated Systems (L-3 IS). Sofia is a Boeing 747SP extensively modified to carry a 45,000-pound (20 metric ton), 98.4-inch (2.5-meter) diameter infrared telescope assembly provided by the German Aerospace Centre, DLR. Sofia will fly at altitudes up to 45,000 feet (13.7 km)--above more than 99 percent of the Earth's water vapor--to capture infrared images and spectra not possible by even the largest ground-based telescopes.

The programme was awarded by NASA in 1996 to a combined US and German team that includes L-3 and the Universities Space Research Association (USRA). In addition to aircraft structural modifications and the telescope assembly installation, ma or aircraft activities included:

* installation of an approximately 16-foot (more than 4.5-meters) tall cavity door designed to open in flight to permit telescope observations;

* installation of a complex liquid-nitrogen

cooling system used to pre-cool the telescope cavity to match thermal conditions when the cavity door is opened at altitude;

* performance of heavy depot-level maintenance and service bulletin incorporation on the 747SP, which flew in commercial service from 1977 to 1995.

USRA is a nonprofit consortium of universities established in 1969 by the National Academy of Sciences and now comprised of 101 member universities.