SOFIA Observatory Finishes Open-Door Flight Tests

Posted Aug 15, 2010 by Kim I. Hartman
NASA's SOFIA flying observatory recently completed the second series of envelope-expansion flight tests with its telescope door open. The airborne observatory will begin infrared astronomy missions late this year.
NASA’s Stratospheric Observatory for Infrared Astronomy 747SP checks out operation of its telescop...
NASA’s Stratospheric Observatory for Infrared Astronomy 747SP checks out operation of its telescope cavity doors while a NASA F/A-18 mission support aircraft keeps pace alongside during a test flight in preparation for Early Science missions.
NASA - Jim Ross
The highly modified SOFIA 747SP aircraft now has a telescope cavity door-open flight envelope fully cleared for astronomical science missions at up to 45,000 feet altitude and all observing elevations.
The second segment of flight envelope expansion tests included 12 flights totaling 49 hours in the air. Test points included evaluation of the performance, handling qualities and structural characteristics of the aircraft. Test data was collected to quantify airframe and telescope cavity acoustic and vibration characteristics at the highest elevation angles. Results of testing during these and previous flights were used to establish airworthiness of the 747SP flying observatory.
Test crews reported a “negligible increase in drag with the door open. The aircraft has also safely landed three times with the door open. After reviewing data following the Aug. 4 final flight, the SOFIA engineering team has cleared the aircraft to proceed to the final verification and validation ground testing of all systems required to begin science observation flights, said Brent Cobleigh, SOFIA aircraft project manager.
The SOFIA plane was built by Boeing and is based at NASA's Dryden Aircraft Operations Facility in Palmdale, California. The plane will be able to maintain a maximum of 12 hours in flight, with an average duration of 8 hours per mission.
SOFIA is a joint program by NASA and the German Aerospace Center.
The SOFIA is considered a world-class airborne observatory that will complement the Hubble, Spitzer, Herschel and James Webb space telescopes and major Earth-based telescopes
Astronomers are now competing for early places on NASA’s SOFIA airborne observatory as the start of science missions nears. Sofia will cruise at altitudes up to 45,000 ft. , and it is expected to provide astronomers with 1,000 science observation flight hours per year for at least 20 years.
The SOFIA program is working toward a goal of routine operations eventually reaching 960 research hours per year, flying three to four nights per week.
As the world's largest airborne astronomical observatory, SOFIA will provide three times better image quality and vastly increased observational sensitivity than the Kuiper Airborne Observatory. SOFIA's ability to return to earth after each flight will enable frequent opportunities to upgrade and install new science instruments. This in turn will stimulate and enable the development of new astronomical technology throughout its lifetime.