The stated intention of the X-37 is to “demonstrate reusable space technologies” intended for orbital spaceflight missions. The X-37 is approximately 29 feet long and has a relatively small cargo bay that’s no larger than a pickup truck’s bed.
The first X-37B mini-shuttle was launched in 2011. It has since completed three unmanned flights with the fourth flight USA-261 having launched on May 20, 2015. That flight was launched from Cape Canaveral mounted onto a United Launch Alliance Atlas 5 rocket and is still in orbit (1).
The X-37 missions are the topic of much speculation. What makes this mini-shuttle so intriguing is that the project began in 1999 under NASA’s wing but, in 2004, the project was transferred to the US Department of Defense (DOD) as “part of the independent space policy” within the Defense Advanced Research Projects Agency (DARPA) (2).
The X-37B is a variant of NASA’s X-37A. Currently, the Air Force flies two X-37B research vehicles. The “spaceplane” was designed to maintain orbit up to 270 consecutive days; however, it has subsequently the orbits have grown longer (3):
–> OTV 1: 2010 – 224 days (Vehicle 1)
–> OTV 2 : 2011 – 469 days (Vehicle 2)
–> OTV 3: 2012 –675 days (Vehicle 1)
While the X-37B is a classified project operated by the US Air Force, the military has released various photos of the vehicle on the launch pad at Cape Canaveral in Florida and the California Vandenberg Air Force base. The latter site is where the X-37B lands autonomously.
Speculation over Classified Secret Missions
Because of the secrecy surrounding the project, there’s a great deal of speculation about the missions and exact purpose of the X-37B.
According to a statement made by the Secretary of the Air Force, the OTV program focus is “risk reduction, experimentation, and operational concept development for reusable space vehicle technologies, in support of long-term developmental space objectives.”
Boeing Chief Engineer Arthur Grantz speculated during an aerospace meeting that the X-37B could be modified to carry passengers.
Interestingly, prior to the 2015 launch the Air Force along with NASA revealed that two payloads consisted of NASA science experiment materials and “ionizing thrusts” that the Air Force was testing.
Space Flight Now speculated about what these two pieces of information revealed about the purpose of the program. It was theorized that the Hall thrusters that produce small steady thrusts could be useful for several kinds of spacecraft, especially “military communications satellites already in orbit”.
This type of thruster could be used for lower orbit reconnaissance satellites ideal for ground target photography. Amateur astronomers using telescopes have spotted the X-37B in “relatively” low orbits of 200 miles above the Earth. That’s lower than the ISS (International Space Station). These sightings of the X-37B have bolstered various theories.
Some other possible uses include:
–> Advanced Surveillance Sensors
–> Anti-Satellite And Counter-Anti-Satellite Operations
–> Reconnaissance Satellites
–> Spy Satellite
–> Deliver Space-Based Weapons
–> Surveillance (4)
Air & Space Smithsonian quoted James Andrew Lewis, director and senior fellow in the Strategic Technologies Program at the Center for Strategic and International Studies, that the Air Force is interested in the development of advanced small sensors. He said that the Air Force is “looking to figure out how to transition from big, expensive satellites to smaller but equally capable satellites” (5).
A Fleet of Spaceplanes
With two X-37B research vehicles already being used, some believe the Air Force will soon have an operational fleet of spaceplanes.
Defense budget analyst for the Center for Strategic and International Studies, Todd Harrison speculates possibly bigger spaceplanes in the future would be deployed regularly to retrieve military satellites in need of repairs or maintenance back on Earth.
That’s assuming that the logistics of launching a spaceplane larger than the current X-37B was possible.
Whatever the purpose(s) of the X-37B, it’s clear that speculations will continue over such a highly publicized, yet classified project.