Results 261 to 270 of about 4,818 (307)

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
openaire   +1 more source

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.
openaire   +4 more sources

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
openaire   +1 more source

Stability of Gravity-Stabilized Drag-Free Satellites

AIAA Journal, 1971
In a drag-free satellite, the relative position sensor null point and the thrustor lines of action will not be coincident with the vehicle mass center. Thus, attitude motion is sensed by the translation control system. The resulting coupling between the attitude and translational motions can cause attitude instabilities in a gravity stabilized drag ...
Fleming, Alan W., DeBra, Daniel B.
openaire   +1 more source

Embedded Model Control Application to Drag-Free and Satellite-to-Satellite Tracking

2006 14th Mediterranean Conference on Control and Automation, 2006
This paper describes the realization of a generic simulator for formation flying satellites, and the design and application of Embedded Model Control (EMC) to the spacecraft control, as potentially applicable to a constellation of drag-free satellites.
MASSOTTI, Luca, CANUTO, Enrico, SILVESTRIN P.   +2 more
openaire   +2 more sources

Attitude and Drag Control: An Application to the GOCE Satellite

2003
The Gravity held and steady-stale Ocean Circulation Explorer (GOCE) satellite, currently planned to be launched in the course of 2006, will require a precise drag compensation and a fine attitude control along the Local Orbiting Reference Frame (LORF) of a polar Sun-synchronous low orbit, allowing the Earth gravity field to be recovered with ...
CANUTO, Enrico, MARTELLA P, SECHI G.
openaire   +3 more sources

Satellite Drag Perturbations in an Oblate Diurnal Atmosphere

AIAA Journal, 1975
Analytic expressions are derived that describe decay rates in period and eccentricity, and rotation in perigee argument for orbits of small eccentricity ...
openaire   +1 more source

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
openaire   +1 more source

The Effect of Atmospheric Drag on the Orbit of an Arfificial Satellite

The Mathematical Gazette, 1969
The study of artificial satellites is today a subject of topical interest and naturally much work has been completed in the field of satellite orbits. Many aspects of this work involve the use of differential equations. Unfortunately very few of these may be solved by ordinary analytic techniques.
openaire   +1 more source

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.
openaire   +1 more source