The launch, the sixth X-37B's mission was the second-ever by the U.S. Space Force. Image © NASA Marshall Space Flight Centre
In 1999, NASA selected Boeing Integrated Defense Systems to design and develop an Orbital Test Vehicle (OTV), a reusable robotic spacecraft boosted into space by a launch vehicle that re-enters Earth's atmosphere and lands as a spaceplane.
An early requirement for the spacecraft called for a total mission delta-v of 7,000 miles per hour (3.1 km/s) for orbital maneuvers.
The original goal for the program was for the OTV to rendezvous with satellites and perform repairs. The OTV was originally designed to be carried into orbit in the cargo bay of the Space Shuttle, but underwent redesign for launch on a Delta IV or comparable rocket after it was determined that a shuttle flight would be uneconomical.
The U.S. Air Force, which owns two X-37B vehicles, has historically been reticent to comment on the capabilities of the X-37B
Over a four-year period, a total of US$192 million was spent on the project, with NASA contributing $109 million, the U.S. Air Force $16 million, and Boeing $67 million. In late 2002, a new $301-million contract was awarded to Boeing to build the X-37 OTV at Boeing's Phantom Works in California.
On 13 September 2004 the X-37 project was transferred from NASA to the Defense Advanced Research Projects Agency (DARPA) from which date the program became a classified project. DARPA promoted the X-37 as part of the independent space policy that the United States Department of Defense has pursued since the 1986 Challenger disaster.
Over a four-year period, a total of US$192 million was spent on the project.
The X-37 first flew during a drop test in 2006. Four years later,in April 2010 its first orbital mission was launched on an Atlas V rocket and returned to Earth in December 2010. Subsequent flights gradually extended the mission duration, reaching 780 days in orbit for the fifth mission, the first to launch on a SpaceX Falcon 9 rocket.
On 13 April 2015, the Space Foundation awarded the X-37 team with the 2015 Space Achievement Award "for significantly advancing the state of the art for reusable spacecraft and on-orbit operations, with the design, development, test and orbital operation of the X-37B space flight vehicle over three missions totaling 1,367 days in space".
On 17 May 2020, the sixth time since 2010, the X-37B OTV has returned to orbit when it launched from Cape Canaveral Air Force Station aboard a United Launch Alliance Atlas V rocket. Strong ground winds at Cape Canaveral Air Force Station in Florida caused the postponement of the launch mission on Saturday. However, the Atlas V finally blasted off a day later. The X-37B will perform experiments in low-Earth orbit while testing and integrating new reusable space vehicle technologies. This sixth mission will also carry unique experiments for NASA, the Naval Research Laboratory and the U.S. Air Force Academy.
The secrecy behind the X-37B's missions suggests that the X-37B may have an assignment to serve as a covert satellite deployment platform.
The U.S. Air Force, which owns two X-37B vehicles, has historically been reticent to comment on the capabilities of the X-37B and what it does during its extended time in space, aside from admitting to hosting scientific experiments.
The launch, the sixth X-37B's mission was the second-ever by the U.S. Space Force and the 80th under the National Security Space Launch effort. Earlier in the month, the Air Force disclosed that a number of the experiments will be conducted onboard, most notably one that will deliver solar power to the ground from space via radio frequency microwave energy.
Additionally, the spacecraft will also deploy the small satellite FalconSat-8, which was developed by the Air Force Academy and carries five experimental payloads. The X-37B will also host two NASA experiments that will study how seeds used for food products are affected by radiation and the space environment.
This sixth mission will also carry unique experiments for NASA, the Naval Research Laboratory and the U.S. Air Force Academy.
The secrecy behind the X-37B's missions suggests that the X-37B may have an assignment to serve as a covert satellite deployment platform and may indicate the OTV's are part of a covert intelligence program. Speculation has been rife that the X-37B, that has unique performance attributes with regard to maneuverability, may have counter-space military capabilities and could be used to test offensive technologies.
The Space and Missiles Systems Center plans to launch seven other missions this year.