Thermal metrology for a space-based gravity experiment

Stephen W. Allison, W. S. Key, Michael R. Cates, David L. Beshears, Alvin J. Sanders, R. J. Newby, Jonathan W. Campbell, R. Greg Schunk

Research output: Contribution to journalConference articlepeer-review

3 Scopus citations

Abstract

A proposed space-based test of gravitational theory requires unique performance for thermometry and ranging instrumentation. The experiment involves a cylindrical test chamber in which two free-floating spherical test bodies are located. The test bodies are spheres which move relative to each other. The direction and rate of motion depend on the relative masses and orbit parameters mediated by the force of gravity. The experiment will determine Newton's gravitational constant, G; its time dependence, as well as investigate the equivalence principle, the inverse square law, and post- Einsteinian effects. The absolute value of the temperature at which the experiment is performed is not critical and may range anywhere from approximately 70 to 100 K. However, the experimental design calls for a temperature uniformity of approximately 0.001 K throughout the test volume. This is necessary in order to prevent radiation pressure gradients from perturbing the test masses. Consequently, a method is needed for verifying and establishing this test condition. The presentation is an assessment of the utility of phosphor-based thermometry for this application and a description of feasibility experiments. Phosphor thermometry is well suited for resolving minute temperature differences. The first tests in our lab have indicated the feasibility of achieving this desired temperature resolution.

Original languageEnglish
Pages (from-to)95-102
Number of pages8
JournalProceedings of SPIE - The International Society for Optical Engineering
Volume3116
DOIs
StatePublished - 1997
Externally publishedYes
EventSmall Spacecraft, Space Environments, and Instrumentation Technologies - San Diego, CA, United States
Duration: Jul 27 1997Jul 27 1997

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