NASA’s Stratospheric Observatory For Infrared Astronomy (SOFIA) is a modified Boeing 747SP passenger liner built to carry a large telescope into the stratosphere to make infra-red observations of the cosmos. By lifting the telescope high above air pollution and atmospheric water vapour, SOFIA can see in wavelengths which are not visible from the ground. The ‘SP’ variant of the 747 was about 14 meters shorter than the regular model, which made it lighter and capable of longer transoceanic flights (This was before the advent of modern, more fuel efficient engines). NASA bought this plane from PanAm in 1997 and has since modified it heavily. A huge hatch has been cut into the side of the fuselage, which opens to expose the observatory at cruising altitude. Behind this door, a 2.5 meter infrared-capable telescope (10 centimetres more than the Hubble) is mounted on a gyroscopic stabilising platform to provide reliably steady images. The telescope assembly also doubles as a seal to maintain pressure in the rest of the cabin, which is stuffed with computers and control gear where the operators will be seated. There is even provisioning for passengers – reporters and educators who will be able to tour the operations and watch the telescope at work.
The project has been in development for thirteen years and should become operational in 2014. Once it is completed, SOFIA will not only provide valuable infrared views of the cosmos that are impossible from the ground, but do so at a cost far below that of dedicated orbital observatories. And I certainly wouldn’t mind being one of the lucky passengers who gets to go along for a ride!