Investigation of the Operational Envelope of the CHAFF-4 Plume and Contamination Facility
Abstract
Interest in realistic simulation of the space environment as applied to the study of spacecraft contamination and thruster plumes has led to the development of the CHAFF-4 facility. CHAFF-4 uses a multi-fin cryogenically cooled array (^20K) that completely envelops the interior of the chamber providing an available condensing surface area of 590 m(2) The geometry of the array capitalizes on the fact that both neutral and ion species from spacecraft propulsion systems predominantly undergo diffuse reflections when impacting at angles normal to the surfaces they encounter. Preliminary figures of merit for the equivalent altitude possible for various propulsion systems vary between 150-350 km (depending on thruster type). The effective pumping speed is predicted to be between 3x107 and lx 108 liters/sec. The facility is expected to accommodate thruster power levels up to 3500 w without the use of supplementary liquid helium, although infrastructure permitting its use is available. Developmental considerations and design issues are discussed in view of basic principles of plume testing and contamination, in order to ensure the integrity of phenomena that are observed in the facility. Provisions for the simulation of high-speed LEO flow environments have been incorporated in the design, and the corresponding pumping requirements are well within the capabilities of CHAFF-4.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 14, 1999
- Accession Number
- ADA408796
Entities
People
- Andrew D. Ketsdever
- E. P. Muntz
- Fred M. Lutfy
Organizations
- Air Force Research Laboratory