PSSC-2, or Pico-Satellite Solar Cell Testbed 2,NASA.gov ''STS-135'' Press Kit, p.97
/ref> also known as PSSC-Testbed 2, is a miniaturised satellite which was operated by the

United States Air Force The United States Air Force (USAF) is the air service branch of the United States Armed Forces, and is one of the eight uniformed services of the United States. Originally created on 1 August 1907, as a part of the United States Army Signal ...

as part of a technology demonstration programme. It was the last satellite to be deployed from a

Space Shuttle The Space Shuttle is a retired, partially reusable low Earth orbital spacecraft system operated from 1981 to 2011 by the U.S. National Aeronautics and Space Administration (NASA) as part of the Space Shuttle program. Its official program na ...

Overview

PSSC-2 was launched aboard on its final mission, STS-135. The launch took place from

Launch Complex 39A Launch Complex 39A (LC-39A) is the first of Launch Complex 39's three launch pads, located at NASA's Kennedy Space Center in Merritt Island, Florida. The pad, along with Launch Complex 39B, were first designed for the Saturn V launch vehicle. Ty ...

at the

Kennedy Space Center The John F. Kennedy Space Center (KSC, originally known as the NASA Launch Operations Center), located on Merritt Island, Florida, is one of the National Aeronautics and Space Administration's (NASA) ten field centers. Since December 1968 ...

, at 15:29 UTC on 8 July 2011. PSSC-2, along with a deployment mechanism, was carried to orbit in the payload bay of the Shuttle, attached to the right wall behind the

Orbiter Docking System The terms Androgynous Peripheral Attach System (APAS), Androgynous Peripheral Assembly System (APAS) and Androgynous Peripheral Docking System (APDS), are used interchangeably to describe a family of spacecraft docking mechanisms, and are also som ...

. It remained attached during ''Atlantis''' visit to the

International Space Station The International Space Station (ISS) is the largest modular space station currently in low Earth orbit. It is a multinational collaborative project involving five participating space agencies: NASA (United States), Roscosmos (Russia), JAXA ...

, and was originally scheduled to be deployed at 07:11 UTC on 19 July, the day after undocking. With the extension of the STS-135 mission, undocking, and hence deployment, was delayed by one day. STS-135 Picosat deployment

PSSC-2 is the second PSSC satellite, following PSSC-1 which was deployed from during

STS-126 STS-126 was the one hundred and twenty-fourth NASA Space Shuttle mission, and twenty-second orbital flight of the ''Space Shuttle Endeavour'' (OV-105) to the International Space Station (ISS). The purpose of the mission, referred to as ULF2 by ...

in 2008. It carries two technology demonstration experiments: Miniature Tracking Vehicle (MTV), and the Compact Total Electron Content Sensor (CTECS). MTV will test the satellite's ability to function as a reference body for tracking stations, whilst CTECS will observe the signals from

occulting An occultation is an event that occurs when one object is hidden from the observer by another object that passes between them. The term is often used in astronomy, but can also refer to any situation in which an object in the foreground blocks ...

Global Positioning System The Global Positioning System (GPS), originally Navstar GPS, is a satellite-based radionavigation system owned by the United States government and operated by the United States Space Force. It is one of the global navigation satellite sy ...

satellites in order to study the density of the

ionosphere The ionosphere () is the ionized part of the upper atmosphere of Earth, from about to above sea level, a region that includes the thermosphere and parts of the mesosphere and exosphere. The ionosphere is ionized by solar radiation. It plays an ...

. The satellite also carries cameras intended to capture the last images of a Space Shuttle in orbit, shortly after separation. PSSC-2 is a spacecraft which was built by the Aerospace Corporation, and is equipped with three-axis stabilisation,

adaptive communication Adaptive communications can mean any communications system, or portion thereof, that automatically uses feedback information obtained from the system itself or from the signals carried by the system to modify dynamically one or more of the system o ...

s systems, and systems to monitor the energy produced by its solar cells. Four

ammonium perchlorate Ammonium perchlorate ("AP") is an inorganic compound with the formula NH4 ClO4. It is a colorless or white solid that is soluble in water. It is a powerful oxidizer. Combined with a fuel, it can be used as a rocket propellant called ammonium pe ...

solid rocket motors, each capable of generating of thrust, will be used for manoeuvring one month after launch; either to raise the satellite's orbit or to deorbit it. PSSC-2 Replica

References

{{Orbital launches in 2011 Spacecraft launched in 2011 Spacecraft which reentered in 2011