(WeberSat-LARES)*

LINKS

Proposal Summary

AMOS 2003 Technical Conference Briefing

AMOS Supporting Paper

International Laser Ranging Service

Kodiak Launch Complex

USNA Aerospace Department

 

 Mission

The positional accuracies currently attainable with the Global Positioning System (GPS) constellation require the inclusion of corrections for Special Relativity (time dilation due to relative velocity) and General Relativity (gravitational red shift due to gravitational potential difference). Gravitational red shift is really the mismatch of coordinate time and proper time within the curved spacetime surrounding a gravitational source. GPS currently uses the corrections appropriate for a static non-rotating gravitational source (the Schwarzschild metric); a future correction, should it ever be an operational necessity, would be the inclusion of effects induced by rotation of the source (the Kerr-Newman metric). Lense and Thirring (Phys. Z. 19:156-63 (1918), available in English translation in Gen. Relativ. Gravit. 16:711-750 (1984)) predict the existence of a gravito-magnetic effect often referred to as the dragging of inertial frames. A particle in radial free-fall toward the center of the source will experience a lateral deflection in the direction of rotation of the source; a gyroscope in free-fall will experience an anomalous precession over and above the Special Relativistic Thomas precession, and orbiting bodies will experience a non-Newtonian progression of the line of nodes. The existence of gravitational effects directly traceable to the angular momentum of the gravitating source has not been observationally established. Gravity Probe-B, scheduled for launch in the near future, consists of a supremely sensitive gyroscope capable of testing for the anomalous precession. Ciufolini (Phys. Rev. Lett. 56:278-81 (1986)) has proposed a second test based on a constellation of laser-ranged satellites. The The United States Naval Academy Small Satellite Program proposes to supplement NASA’s LAGEOS 1 satellite with a second laser-ranged satellite to be called WeberSat-LARES. The pair of satellites would fulfill Ciufolini’s requirements and permit a second, independent test of the Lense-Thirring effect to supplement that of Gravity Probe B. In addition, WeberSat-LARES will provide supplemental data from the 6000-km regime of non-gravitational perturbations as well as enhance the geodesy mission of LAGEOS 1 and 2.

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 *In memory of Dr Joseph Weber, USNA Class of 1940.