Last week I blogged about a Chinese space launch that was feared to be a weapon of some sort. China is not the only country that may be working on space weapons. The U.S. military has been launching "robotic spaceplanes" on multiple test missions lately. The term spaceplane refers to the fact that these craft land on a runway like a conventional airplane after being launched into orbit atop a rocket booster.
The two X-37B Orbital Test Vehicles are reusable, unmanned spacecraft. They were built by Boeing Integrated Defense Systems at the Boeing Phantom Works facility in California. The shape is based on the U.S. Space Shuttle and the X-37B was originally intended to be carried into orbit by the Space Shuttle until it was determined that that would be too expensive. The craft was redesigned to launched by rocket boosters. The X-37Bs are carried into orbit by Atlas V rockets with Centaur second stages. The X-37B is twenty nine feet long and weights about eleven thousand pounds. It utilizes hydrogen peroxide and kerosene for fuel. It has a small payload bay about four feet by seven feet.
One of the stated purposes for the craft was to test rendezvous with and repair of orbiting satellites. The X-37B was also said to be intended to deliver astronauts to and from the International Space Station. The project started under NASA supervision in 1999 and then was transferred to the Defense Advanced Research Projects Agency (DARPA) of the U.S. Department of Defense in 2004 as part of the independent space program that DoD started in 1986.
In 2006, the X-37B's ability to land on a runway was tested after it was dropped from a carrier aircraft. The first orbital test flight was in 2010. Starting with the first test flight in 2010, the two X-37B spacecraft together have spent over thirteen hundred days in space during three different missions. The third mission was in orbit for six hundred and seventy four days, the longest flight of a reusable spacecraft. (The craft was originally designed to stay in orbit two hundred and seventy days.) The fourth mission of the X-37B was launched on May 20, 2015 from Cape Canaveral Air Force Station in Florida.
In 2010, there was an article published in Space Daily by Tom Burghardt which speculated on the purpose of the X-27B. He said that it could be used as a spy satellite or that it could deliver weapon strikes from space. The Pentagon has denied that the X-37B is being used to develop space weapons. The Chinese claimed in 2012 that one of the X-37Bs was used to spy on the Tiangong-1 space station. This claim was later disputed on the basis of the different orbits of the two spacecraft.
Whatever the stated purpose of the X-37B is, obviously it could be used for spying or testing space weapons. In any case, you cannot expect the Pentagon to reveal details about classified projects such as the X-37B.
