Results 251 to 260 of about 69,393 (296)

Robust Digital Control of Drag-Free Satellites

IFAC Proceedings Volumes, 2003
Abstract A drag-free satellite is a small proof-mass (PM) shielded by a spacecraft cavity and moving only subject to gravitational forces. This can be accomplished by a drag-free control keeping the PM centered in the cavity and compensating the non-gravitational forces acting on the spacecraft. A constellation of drag-free satellites can be employed
CANUTO, Enrico, ANDREIS D.
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Drag coefficients for tumbling satellites.

Journal of Spacecraft and Rockets, 1967
Figure 3 shows how typical PLOT results are presented. For illustrative purposes, ROD is plotted as a function of normal countdown time, which is extended by the programmed hold. Gain in PLOT is plotted as a function of programmed hold-time; the gain is referenced to RCD for the normal countdown.
LEE H. SENTMAN, STANFORD E. NEICE
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Drag on the LAGEOS satellite

Journal of Geophysical Research: Solid Earth, 1990
The average drag on the LAGEOS satellite appears to be well understood. It consists of three types of drag: Yarkovsky thermal, neutral particle, and charged particle. Yarkovsky thermal drag depends on the LAGEOS spin axis position. The spin axis in the decade since launch appears to have stayed near where the engineering telemetry data put it at apogee
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New Satellite Drag Modeling Capabilities

44th AIAA Aerospace Sciences Meeting and Exhibit, 2006
This paper reviews the operational impacts of satellite drag, the historical and current capabilities, and requirements to deal with evo lving higher accuracy requirements. Modeling of satellite drag variations showed little improvement from the 1960’s to the late 1990’s. After three decades of essentially no quantitative progress, the problem is being
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Capacitive sensing for drag-free satellites

Classical and Quantum Gravity, 1997
We report the key results of a study of the optimization of capacitive sensing for LISA. This work was a component of an ESA study into drag-free satellite control. We discuss the problems associated with the capacitive sensing and control of a proof mass which is electrically isolated and develop models for candidate non-resonant and resonant ...
Clive C Speake, Peter L Andrews
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Interferometric sensing for drag-free satellites

SPIE Proceedings, 2004
ABSTRACT We discuss a polarisation based homodyne interferometer that demonstrates a promising sensitivity of approximately. This performance figure is limited above 10 Hz by the resolution of the current analogue-to-digitalconverter (ADC). Sensitivity below 10 Hz is influenced by environmental factors a nd / or noise inherent in the laser.
Clive C. Speake, Stuart M. Aston
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Drag-Free Satellite Control

2008
Scientific satellite missions trying to investigate questions regarding geodesy and fundamental physics have become increasingly dependent on ultra low disturbance environments. The precision demanded by the experiments has risen continuously as experimenters strive to deepen their understanding.
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Towards Next Level Satellite Drag Modeling

AIAA Atmospheric and Space Environments Conference, 2010
Orbital drag errors adversely impact many space missions including providing collision avoidance warnings for manned spaceflight and other high-value assets, accurately cataloging of all orbiting objects, predicting reentry times and estimating satellite lifetimes, on-board fuel requirements and attitude dynamics.
Frank Marcos, Shu Lai, Cheryl Huang, Chin Lin, John Retterer, Susan Delay, Eric Sutton   +6 more
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Satellite Formation Control using Differential Drag

53rd AIAA Aerospace Sciences Meeting, 2015
The ability to operate in formations is a great advantage of small satellites as many small satellites can be built and launched for the cost of one large satellite. Formation operations are valuable because they allow for an observational resolution in time and space not possible with a single large satellite. However, traditional methods of formation
Sanny R. Omar, J. M. Wersinger
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Design considerations for drag free satellites

AIP Conference Proceedings, 1998
Missions dictate the implementation of drag free satellites. A variety of missions are used to illustrate the various technologies associated with the TRIAD flight of 1972 and current and past proposed flights.
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