AMPTE (Active Magnetospheric Particle Tracer Explorer) was a joint US - German - UK endeavor with the US providing the Charge Composition Explorer (CCE), an equatorial mission with apogee close to 8 Re, with Germany providing the Ion Release Module (IRM) with an apogee close to 20 Re and the UK providing the UK Subsatellite (UKS) in the same orbit as the IRM. It was designed to study the access of solar-wind ions to the magnetosphere, the convective-diffusive transport and energization of magnetospheric particles, and the interactions of plasmas in space.
The UKS (United Kingdom Subsatellite) served as a subsatellite of the IRM spacecraft. Its purpose was to help distinguish between spatial structure and temporal changes in the plasma phenomena initiated by ion releases from the IRM and in the natural magnetospheric environment. Measured quantities were similar to those of the IRM and include magnetic fields, positive ions, electrons, plasma waves, and modulations in ions and electrons. The spacecraft was spin-stabilized at 12 rpm and employed S-band communications. It carried a cold gas propulsion system and a VHF radar system for station keeping with the IRM normally at a distance of a few hundred kilometers. The spacecraft power supply failed on 15 January 1985.
Following instruments were onboard:
|Type / Application:||Research, Magnetosphere|
|Power:||Solar cells, batteries|
|Orbit:||1127 km × 113291 km, 27.7°|
|UKS (AMPTE 2)||1984-088C||16.08.1984||CC LC-17A||Delta-3924||with CCE, IRM, Solar Cell Experiment|