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Mission Overview

The Active Magnetospheric Particle Tracer Explorers (AMPTE) programme was a joint project of the Federal Republic of Germany, the United Kingdom and the United States to explore plasma phenomena in near-Earth space (the magnetosphere, magnetosheath, solar wind and the boundaries between these regions). These studies included not only passive measurements of the natural plasma but also active experiments in which tracer ions were released into the space plasma environment.

Each country contributed one spacecraft:

• the Ion Release Module (IRM) from Germany;
• the United Kingdom Satellite (UKS) from the UK;
• the Charge Composition Explorer (CCE) from the USA.

The three spacecraft were launched together by a Delta rocket on 16 August 1984. The CCE was placed in an equatorial orbit with apogee of 8.8 Earth radii and a perigee of 1103 km. Thus for the most part it patrolled the magnetosphere. The IRM and UKS were boosted together into very similar orbits with a much higher apogee of 18.7 Earth radii, which allowed them to cross both the magnetopause and bow shock. The orbital inclination of 28.8 degrees indicates that IRM and UKS crossed the ``low-latitude" regions of these two boundaries. The two spacecraft remained close together (1 to 1000km) so that UKS could provide local plasma diagnostics during ion releases. The perigee of IRM and UKS was 557 km, giving an orbital period of 44.3 hours.

For full details of the mission, the reader should consult the May 1985 special issue of IEEE Transactions on Geoscience and Remote Sensing, GE-23(3), which contains 24 papers describing the three spacecraft, their instruments and data handling.

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