INTERACTIONS BETWEEN THE SPACE EXPERIMENTS WITH PARTICLE ACCELERATORSPLASMA CONTACTOR AND THE IONOSPHERE

Space experiments with particle accelerators (SEPAC) on Atlas-1 space transportation system (STS-45) included a plasma contactor to neutrali ze charge buildup on the orbiter due to electron accelerator operation s. The SEPAC plasma contactor operated the same as it had during testi ng in the laboratory. During SEPAC electron accelerator operations, th e contactor emitted currents that helped balance the electron beam cur rent. The Langmuir probe measured the charge exchange ions and the the rmal electrons emitted by the contactor. The electric field wave data showed an order of magnitude increase in the 4-8 MHz band. There were no reports of contactor operations interfering with either orbiter sys tems or other Atlas-1 experiments.