The Scaled Composites Model 281 Proteus
is a tandem-wing high-endurance aircraft designed by Burt
Rutan to investigate the use of aircraft as high altitude
telecommunications relays. The Proteus is actually a multi-mission
vehicle, able to carry various payloads on a ventral pylon.
An extremely high-efficiency design, the Proteus can orbit
a point at over 65,000 feet (19,800 m) for more than 18
hours. It is currently owned by Northrop Grumman.