Microacceleration Experiment Platform - Abstract
Microacceleration Experiment Platform

Katy Barber, et. all

May 1990

Executive Overview

In the spring semester of 1990, the mg Group of the University of Texas at Austin accepted the task of studying microgravity experiments and Space Station's microgravity environment, as well as designing a Space Station Based Microacceleration Experiment Platform (MEP) for experiments with more sensitive requirements than Station will be able provide. The statement of work called for a teleoperated free flyer in Space Station's orbit , either leading or trailing it. However, the atmosphere at typical Space Station orbital altitudes is sufficiently dense to decay orbits over a period of months. Unfortunately, this decay occurs at different rates for bodies with with different drag characteristics. Since an objective in the design of a microgravity experiment platform is to minimize its incident drag forces rather than match them with Space Station's, the concept of a leading or trailing orbit was discarded. Taking this into consideration, the MEP was designed to perform orbital transfers for either boosting to a higher altitude to eliminate drag forces, or to transfer back to Station after their orbits have drifted apart.. The MEP was also designed to be a modular platform, with pieces launched either by the space shuttle or expendable launch vehicles, composed of modules which fit into a truss. Modularity was chosen to maximize the types of missions which can be performed. An optional mode of operation, highly recommended for appropriate experiments, is to eliminate drag by "levitating" experiments inside a module. Thrusters on the vehicle would fire to prevent the module and experiment from colliding. The MEP is composed of specific subsystems, tailored to meet microgravity environment requirements, including the structure, power, communications, utility connections, guidance, navigation, and control, propulsion, and thermal control. The MEP can carry individual experiments up to 1000 kg for durations of up to 2 years. Recommendations for future design work have been included in this report.