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Problems affecting the fidelity of pressure measuring instruments for planetary probesDetermination is made of the nature and magnitude of surface-related effects that cause errors in pressure measuring instruments, with special reference being made to instruments intended for use in planetary probes. The interaction of gases with clean surfaces of metals likely to be used as gage construction materials was studied. Special emphasis was placed on the adsorption, chemical reaction, and electron-induced desorption processes. The results indicated that all metals tested were subject to surface processes which would degrade gage fidelity. It was also found, however, that the formation of inert adsorbed layers on these metal surfaces, such as carbon on platinum, greatly reduced or eliminated these effects. This process, combined with a system design which avoids contact between reactive gases and hot filaments, appears to offer the most promising solution to the gage fidelity problem.
Document ID
19730013665
Acquisition Source
Legacy CDMS
Document Type
Contractor Report (CR)
Authors
Hudson, J. B.
(Rensselaer Polytechnic Inst. Troy, NY, United States)
Date Acquired
September 2, 2013
Publication Date
November 1, 1972
Subject Category
Instrumentation And Photography
Report/Patent Number
NASA-CR-112320
Accession Number
73N22392
Funding Number(s)
CONTRACT_GRANT: NGL-33-018-066
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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