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Status of the Gyro Test of Relativity in a Satellite, GP-B

Daniel DeBra


GP-B was launched April 20th this year and after several months of commissioning the gyroscopes, it has been in Science Mode since September. Designed to measure the effect of moving a gyroscope through a gravitational field to an accuracy of nanoradians, GP-B employs many new technologies. The experiment operates at 1.8K, utilizing superconducting circuits and shielding to achieve the unprecedented accuracies. The boil-off He from the Dewar is utilized as a propellant for attitude and drag-free control. The history of the experiment, the payload development and the satellite design will be described and the current status will be reported.


Professor Daniel DeBra is the Edward C. Wells Professor Emeritus in the Department of Aeronautics and Astronautics and the Department of Mechanical Engineering at Stanford University. He received his B.E. in Mechanical Engineering from Yale in 1952, his M.S. in Mechanical Engineering from M.I.T. in 1953, and his Ph.D. in Engineering Mechanics at Stanford University in 1962.

Current research interests include automatic controls, hydraulic controls, autopilot and attitude control, instrumentation, precision manufacturing and vibration isolation for gravity wave detectors.

Professor DeBra has received an Industrial Research Award 100 for the successful flight of a drag free satellite in 1973 and the I.O.N.’s Thurlow Award. He has been a Commissioner of the National Academy of Engineering, member of the Air Force Scientific Advisory Board, Chairman of the Aerospace Committee of the International Federation of Automatic Control (IFAC), member of the Aerospace Control and Guidance Systems Committee (ACGSC) of the Society of Automotive Engineers (SAE), and member of the NAS Committee on Geodesy.

In addition, Professor DeBra belongs to the following professional societies: Fellow American Astronomical Society, American Geophysical Union, Fellow American Institute of Aeronautics and Astronautics, American Society of Engineering Educators, American Society of Mechanical Engineers, CIRP, Institute of Electrical and Electronic Engineers, Institute of Navigation, Instrument Society of America, Sigma Xi, Society of Automotive Engineers, Fellow Society of Manufacturing Engineers, Tau Beta Pi, Association of Unmanned Vehicle Systems. Distinguished member of the American Society of Precision Engineers.

Professor DeBra consults on a broad range of topics including, inertial instruments, precision engineering and automatic control of aerospace vehicles and machine tools. He has published more than 100 technical publications.

Daniel DeBra Headshot
Daniel DeBra
Stanford University
EEB 105
18 Nov 2004, 12:00am until 12:00am