Open Door No Problem for Boeing 747

An open 15-foot door for a NASA telescope posed no flight problems for the $500 million Boeing 747

NASA reports positive results from initial open-door testing of its Stratospheric Observatory for Infrared Astronomy (Sofia), a research platform that includes a huge telescope mounted on a Boeing 747.

A 15-foot high door on the aft left side of the aircraft opens in flight to expose the telescope to a clear view of the sky between 23° and 58° of elevation. This open door had been a key concern among engineers.

The result of two decades of engineering at a cost of more than $500 million in modifications, the 747 includes "ramps" and fairings designed to isolate the telescope from atmospheric buffeting as the aircraft flies at M0.85 and 45,000 feet during observations.

"Everything looked nominal," says Sofia programme manager Bob Meyer. "Pilots reported no change in handling qualities and sound pressure levels were as we predicted." In 2010, NASA plans to open the operational envelope for the aircraft, including tests with the telescope's pointing control system activated and "first light" operations of the telescope itself. First science flights are planned for autumn 2010.

Flight Global