Shuttle/Payload Contamination Evaluation (SPACE) - A Systems Level Contamination Model

The Shuttle/Payload Contamination Evaluation (SPACE) computer program was designed to three dimensionally synthesize the dynamics of the induced on-orbit molecular contaminant environment of the Shuttle Orbiter and a number of Spacelab payload carrier configurations. The concept of the SPACE computer program originated during the Skylab Program where extensive contamination control activities were conducted. SPACE has the capability to accept any instrument or spacecraft configuration for contamination evaluation through manipulation of program input data . It represents a significant advancement over previous analytical or modeling techniques in that it is the first integrated systems level model of its type to collectively consider geometry (emphasizing surface shadowing), any arbitrary contaminant source(s) and the contaminant transport mechanisms of: 1) direct source-to-surface; 2) return flux due to molecular collisions with the ambient atmosphere and other contaminant molecules and 3) reflection/reemission from structural surfaces. SPACE Program outputs include: 1) the molecular density or thickness of the contaminant cloud through which a scientific instru-ment might view; 2) the contaminant flux to spacecraft or payload surfaces and 3) the level of deposition accumulated on sensitive surfaces. The SPACE Program is operational on CDC 6500 and UNIVAC 1108/1110 computer systems. This paper provides an overview of the SPACE Program, its capabilities and applications.