The Environment of Earth-Orbiting Systems

Abstract

A review of the chracterization of the environment encountered by an earth-orbiting spacecraft is presented. Of special relevance for microgravity experimentation is the quality of the gravitational environment that can be achieved in an orbiting spacecraft. There is a variety of disturbances resulting in accelerations precluding the spacecraft from ideal zero-gravity conditions. This may affect the results of various experiments as described in Chapter XVIII. The most dominant disturbances are discussed. Special attention is given to the gravitational environment of Spacelab and the planned Space Station. Other features of earth-orbit environment may be of interest to the experimentor as well. These are: radiation, atmospheric conditions, high energy particles, electric and magnetic fields. The high ratio of the orbital velocity to the mean thermal velocity of the atmospheric species, abundant at altitudes considered here, may be exploited to device extreme ultra high vacuum research facilities. Other characteristics, such as high energy particle flux may lead to experiment or sample degradation. This review provides the experimenter with the relevant information as a first basis for a more detailed analysis.