The X 37-B remains an intriguing mystery for space advocates and analysts, with the US Air Force remaining tight-lipped about the precise missions and capabilities that the drone-spacecraft (essentially a small, crew-less version of the decommissioned space shuttle). As the X-37 prepares for a third launch in late October an assessment of America's most publicly secretive drone seems in order.
Fortunately some proposed missions can be more or less ruled out. Most notably the X-37, much like its larger crewed cousin, remains a deeply inefficient satellite launch system. A payload bay measuring just over 2.1 meters on a side indicates extremely meager capacity for mission-specific cargo. Although the Pentagon would love nothing more than to launch constellations of communications and imaging satellites into orbit on short notice to support troops in the field, using a straight-forward rocket system remains cheaper and potentially more reliable than any reusable platform. After all, why waste a minimum of $90 million on a rocket lifting the wings and fuselage of a reentry vehicle to place disposable systems in orbit? Tracking potentially hostile space systems in orbit also seems rather outlandish, given that dedicated satellites could perform the job as well or better and at lower cost.
More likely the X-37 represents a (very expensive) R&D exercise. That doesn't make this particular space-drone uninteresting, however. The unusual conditions of operating a highly maneuverable satellite without a human crew will likely lead to interesting communications systems or an artificial intelligence system capable of handling ambiguous but risky environments for short periods of time. The lessons learned from either intermittent or maintained control in a complex electro-magnetic environment will likely generate important lessons for DoD planners envisioning drone operations in environments less permissive than Iraq or Pakistan's FATA.
Even more interesting are some of the potential missions other than satellite launch. Currently NASA has been exploring potential routes for refueling satellites or deep-space missions in space with orbital fuel depots, but the military and intelligence communities may find NASA's timetable somewhat lacking. The X-37 could provide some interesting capabilities to those communities, potentially restocking surveillance satellites with fuel or carrying out repairs to reduce the need to replace spacecraft that are expensive to build (see page 44) well as to launch. These capabilities could also, of course, provide future mission planners with proven satellite interface capabilities that other other space powers would prefer the United States not possess. Given the necessity of space capabilities to US military forces and the US economy and anti-satellite capability that doesn't fill low-Earth orbit with clouds of debris holds much more promise than blasting offending satellites out of the sky with high-powered rockets.
This dual nature of the X-37 B isn't unique to just that one system, of course. All space capabilities necessarily have multiple uses; cheap launches make satellites expendable, debris-removal systems become satellite-removal systems, GPS guides tourists as well as cruise missiles, and reliable large-scale rockets can of course become nuclear-warhead bearing missiles with distressing ease. Nonetheless the flexible and uninhabited X-37 B could herald a new age of ambiguous space vehicles.