Propellant Management Devices

Communications Satellite

As a result of their demonstrated flight success and passive operation, surface tension Propellant Management Devices (PMDs) have become the propellant acquisition system of choice for earth-orbiting satellites, planetary spacecraft and, in some cases, launch vehicle upper stages. Many PMD functions in a low-gravity space environment cannot be tested on the ground. Consequently, design and qualification of a surface tension PMD requires a complete understanding of the mission requirements, a knowledge of surface tension effects, and a thorough knowledge of low-gravity fluid dynamics. The NASA Viking 75 Orbiter was the first long-life planetary spacecraft to use a surface tension PMD. The leader of the technical team that developed the Viking PMD in 1973-75 is a founder of Angeles Crest Engineering Inc (ACEI) and a staff member. The Viking PMD development started with concept generation and extended through flight qualification. Activities included the measurement of propellant surface tension and contact angle, drop tower model testing, neutral buoyancy model testing, prototype slosh testing, simulated fluid dynamic testing, performance modeling and simulation, and flight hardware design, fabrication and qualification.

A communications satellite with a PMD that was designed and developed by ACEI was launched in December 1999. Two additional communications satellite PMDs that were designed and developed by ACEI have successfully completed their qualification test programs. One was launched in October 2000 and the other is scheduled to fly in 2001. The design and development of the PMDs in the oxidizer and ethanol tanks of a commercial launch vehicle reaction control system were completed in July 1988.

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