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Spacecraft Charging and the Microwave Anisotropy Probe SpacecraftThe Microwave Anisotropy Probe (MAP), a MIDEX mission built in partnership between Princeton University and the NASA Goddard Space Flight Center (GSFC), will study the cosmic microwave background. It will be inserted into a highly elliptical earth orbit for several weeks and then use a lunar gravity assist to orbit around the second Lagrangian point (L2), 1.5 million kilometers, anti-sunward from the earth. The charging environment for the phasing loops and at L2 was evaluated. There is a limited set of data for L2; the GEOTAIL spacecraft measured relatively low spacecraft potentials (approx. 50 V maximum) near L2. The main area of concern for charging on the MAP spacecraft is the well-established threat posed by the "geosynchronous region" between 6-10 Re. The launch in the autumn of 2000 will coincide with the falling of the solar maximum, a period when the likelihood of a substorm is higher than usual. The likelihood of a substorm at that time has been roughly estimated to be on the order of 20% for a typical MAP mission profile. Because of the possibility of spacecraft charging, a requirement for conductive spacecraft surfaces was established early in the program. Subsequent NASCAP/GEO analyses for the MAP spacecraft demonstrated that a significant portion of the sunlit surface (solar cell cover glass and sunshade) could have nonconductive surfaces without significantly raising differential charging. The need for conductive materials on surfaces continually in eclipse has also been reinforced by NASCAP analyses.
Document ID
19990024856
Document Type
Conference Paper
Authors
Timothy, VanSant J. (NASA Goddard Space Flight Center Greenbelt, MD United States)
Neergaard, Linda F. (Sverdrup Technology, Inc. Huntsville, AL United States)
Date Acquired
September 6, 2013
Publication Date
January 1, 1998
Subject Category
Spacecraft Design, Testing and Performance
Meeting Information
Spacecraft Charging Technology(Hanscom AFB, MA)
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.