The US Air Force’s X-37B spaceplane began its fourth mission Wednesday, lifting off atop United Launch Alliance’s Atlas V rocket to begin a classified mission for Air Force Space Command. The Atlas departed from Cape Canaveral Air Force Station at 11:05 Eastern, the opening opportunity provided by two short launch windows on Wednesday.
Atlas V AFSPC-5 Mission:
Wednesday’s mission, designated Air Force Space Command 5 (AFSPC-5), is the fourth X-37B mission and is presumed to be the second trip into space for the second X-37B vehicle.
Also known as Orbital Test Vehicle 4 (OTV-4), the mission is believed to be demonstrating technology for future programs. One of the experiments aboard the spacecraft which has been publicised by the US Air Force consists of a Hall effect thruster for the AEHF series of communications satellites, allowing performance-enhancing modifications to be tested before they are introduced on operational missions.
The X-37 is also carrying NASA’s Materials Exposure and Technology Innovation in Space, or METIS, payload; building on research conducted aboard the International Space Station, METIS will expose an array of material samples to the space environment before returning them to Earth for study.
Developed by Boeing, the X-37B is an evolution of NASA’s proposed X-37A that was designed to be deployed from the Space Shuttle to conduct robotic satellite repair and research missions before returning to Earth independently.
The X-37A underwent a series of glide tests in 2006, however the program was subsequently cancelled. The US Air Force and Defense Advanced Research Projects Agency (DARPA) opted to continue development as a military program, with the first launch coming in April 2010 atop an Atlas V.
That first mission, OTV-1 or USA-212, lasted over seven months, ending with the successful recovery of the spacecraft via a runway landing at Vandenberg Air Force Base in California. Vandenberg has been the landing site for all X-37B missions to date and it is likely that AFSPC-5 will also touch down there once it reaches its conclusion.
Boeing constructed two X-37B vehicles, with the second taking flight in March 2011 and remaining in orbit for over a year before landing in June 2012. The third and most recent mission, marking the second flight of the first vehicle, began in December 2012 and concluded in October 2014 after almost two years in space.
In addition to deploying the X-37B, Wednesday’s launch also carried the UltraSAT payload consisting of ten small satellites for NASA, the US military and educational institutions.
Mounted on an Aft Bulkhead Carrier (ABC) attached to the rocket’s upper stage, UltraSAT is a Naval Postgraduate School CubeSat Launcher (NPSCuL) equipped with eight Poly-Pico Orbital Deployers (PPODs).
The third NPSCuL to launch, UltraSAT follows the OutSAT mission that launched with NROL-36 in 2012 and the GemSAT mission that flew with NROL-39 in 2013.
The LightSail-A satellite, a three-unit CubeSat which will be operated by The Planetary Society, is a prototype solar sail. The primary objective of the LightSail-A mission is to demonstrate deployment of the spacecraft’s sail, with a later mission – LightSail-B – intended to demonstrate the use of the sail when it launches in 2016.
The LightSail missions build on technology developed for 2005’s Cosmos 1 solar sail experiment which was lost in a launch failure of Russia’s Volna rocket.
The launch of LightSail-A has been sponsored by NASA under its Educational Launch of Nanosatellites (ELaNa) program, with the flight designation ELaNa XI. The remainder of the payloads were sponsored by the National Reconnaissance Office.
The AeroCube-8 mission, consisting of two 1.5-unit CubeSats built by The Aerospace Corporation, will test the use of carbon nanotubes in spacecraft construction and radiation protection and investigate electric propulsion technologies. Also known as IMPACT, the two satellites are identical and will be deployed together from a single PPOD.
The US Naval Academy’s Ballistically Reinforced Communication Satellite Propulsion Test Unit, or BRICSat-P, is a 1.5-unit satellite which will be used to demonstrate the use of plasma thrusters for attitude control and orbital manoeuvring. It will share a PPOD with ParkinsonSat-A (PSAT-A), also developed by the US Naval Academy, which carries a communications experiment.
Equipped with a bidirectional transponder, the satellite will collect and relay data from buoys and remote stations in support of the Ocean Data Telemetry Microsatellite Lint (ODTML) as well as acting as a relay for amateur operators.
A further payload was carried for the Naval Academy is the USS Langley, or Unix Space Server Langley. A three-unit CubeSat, Langley is intended to demonstrate the use of off-the-shelf components to operate a Linux-based web server in space. This will be connected to the internet via the satellite’s ground stations.
The Globalstar Experiment and Risk Reduction Satellite 2 (GEARRS-2) is a three-unit CubeSat intended to demonstrate whether the Globalstar satellite constellation can be used to relay commands and telemetry for a small satellite mission. It follows on from the GEARRSAT spacecraft deployed from the International Space Station in March after its launch aboard a Cygnus spacecraft last September.
Three Optical CubeSats, or OptiCubes, were also carried for the California Polytechnic University (CalPoly) to serve as tracking and calibration targets for studying small satellites and debris in orbit.
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