Proteus Web SiteJanuary 14, 2006: Kwajalein residents came out in droves to give the pilots of Proteus a rock star-like welcome. Scaled Composites' Proteus is a high-altitude multi-mission aircraft that's capable of flying at altitudes above 60,000 feet and is able to remain on station up to 14 hours . The cabin is extremely small and I can only imagine how uncomfortable such a long mission would be. For the curious type, I didn't see a toilet. Scaled Composites also designed SpaceShipOne, winner of the X-Prize for becoming the first private manned spacecraft to exceed an altitude of 328,000 feet twice within the span of a 14-day period (October 4, 2004).