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Atomic hydrogen on Mars - Measurements at solar minimumThe Copernicus Orbiting Astronomical Observatory was used to obtain measurements of Mars Lyman-alpha (1215.671-angstrom) emission at the solar minimum, which has resulted in the first information on atomic hydrogen concentrations in the upper atmosphere of Mars at the solar minimum. The Copernicus measurements, coupled with the Viking in situ measurements of the temperature (170 plus or minus 30 K) of the upper atmosphere of Mars, indicate that the atomic hydrogen number density at the exobase of Mars (250 kilometers) is about 60 times greater than that deduced from Mariner 6 and 7 Lyman-alpha measurements obtained during a period of high solar activity. The Copernicus results are consistent with Hunten's hypothesis of the diffusion-limited escape of atomic hydrogen from Mars.
Document ID
19780052865
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Levine, J. S.
(NASA Langley Research Center Hampton, VA, United States)
Mcdougal, D. S.
(NASA Langley Research Center Hampton, Va., United States)
Anderson, D. E., Jr.
(U.S. Navy, E. O. Hulburt Center for Space Research, Washington D.C., United States)
Barker, E. S.
(Princeton University New Observatory, Princeton, N.J., United States)
Date Acquired
August 9, 2013
Publication Date
June 2, 1978
Publication Information
Publication: Science
Volume: 200
Subject Category
Lunar And Planetary Exploration
Accession Number
78A36774
Distribution Limits
Public
Copyright
Other

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