In a unique transatlantic research program, NASA, the German Aerospace Centre and an international contractor team are working together to create SOFIA – a 2.5-metre-diameter reflecting telescope mounted in a modified Boeing 747SP.
SOFIA will, say its developers, be the largest airborne telescope in the world, making observations that are impossible for even the largest, highest ground-based infrared telescopes.
The contractor team, lead by the Universities Space Research Association will be responsible for the development and operation of the observatory for NASA.
With an expected operating lifetime of 20 years or more, it is scheduled to begin science operations in late 2002.
A large transport-type aircraft such as the Boeing 747SP, designed for extended cruising in the stratosphere, is said to be particularly well suited for infrared astronomy.
Because most infrared radiation is absorbed by atmospheric water vapour, ground-based observations are limited to certain wavelengths.
SOFIA will compliment satellite-based telescopes, which are able to observe all infrared bands with very high sensitivity, but have shorter lifetimes and can carry neither such large science instruments nor as comprehensive a set as an airborne observatory can.
Airborne telescopes that are flown at altitudes near 41,000 feet are above more than 99% of the Earth’s atmospheric water vapour and have virtually unrestricted access to infrared wavelengths.
In addition, instruments and other technologies can be easily upgraded to stay at the state-of-the-art over the life of the observatory, unlike space-based telescopes.