Spacecraft control system for the relativity mission

Dougherty, H.; Hegel, Daniel; Kirschenbaum, J; Beukel, J. Vanden; Reeve, Whitham D.; Kasdin, N. Jeremy

doi:10.1016/0967-0661(95)00105-4

Cited by 5 publications

(6 citation statements)

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“…This was achieved by incorporating a piston in the device that could be moved to restrict the helium flow rate. Ground testing demonstrated that the thrust was proportional to the pressure in the restriction [11]. This prompted the incorporation of a pressure measurement in the flight hardware to measure and control the thrust on-orbit.…”

Section: Actuationmentioning

confidence: 99%

Precision attitude control of the Gravity Probe B satellite

Conklin

Adams

Bencze

et al. 2015

Class. Quantum Grav.

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The Gravity Probe B satellite used ultra-precise gyroscopes in low Earth orbit to compare the orientation of the local inertial reference frame with that of distant space in order to test predictions of general relativity. The experiment required that the Gravity Probe B spacecraft have milliarcsecond-level attitude knowledge for the science measurement, and milliarcsecond-level control to minimize classical torques acting on the science gyroscopes. The primary sensor was a custom Cassegrainian telescope, which measured the pitch and yaw angles of the experiment package with respect to a guide star. The spacecraft rolled uniformly about the direction to the guide star, and the roll angle was measured by star trackers. Attitude control was performed with sixteen proportional thrusters that used boil-off from the experiment’s liquid Helium cryogen as propellant. This paper summarizes the attitude control system’s design and on-orbit performance.

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Section: Actuationmentioning

confidence: 99%

Precision attitude control of the Gravity Probe B satellite

Conklin

Adams

Bencze

et al. 2015

Class. Quantum Grav.

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“…In this drag-free system, the gyroscopes act as the sense accelerometers and the GSS sends the measurements to the space vehicle's attitude and translation control (ATC) system (Dougherty et al 1995). The ATC uses these measurements to match the trajectory of the vehicle to that of the sense gyroscope.…”

Section: Drag-free Sensormentioning

confidence: 99%

The Gravity Probe B electrostatic gyroscope suspension system (GSS)

Bencze

Brumley

Eglington

et al. 2015

Class. Quantum Grav.

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A spaceflight electrostatic suspension system was developed for the Gravity Probe B (GP-B) Relativity Mission’s cryogenic electrostatic vacuum gyroscopes which serve as an indicator of the local inertial frame about Earth. The Gyroscope Suspension System (GSS) regulates the translational position of the gyroscope rotors within their housings, while (1) minimizing classical electrostatic torques on the gyroscope to preserve the instrument’s sensitivity to effects of General Relativity, (2) handling the effects of external forces on the space vehicle, (3) providing a means of precisely aligning the spin axis of the gyroscopes after spin-up, and (4) acting as an accelerometer as part of the spacecraft’s drag-free control system. The flight design was tested using an innovative, precision gyroscope simulator Testbed that could faithfully mimic the behavior of a physical gyroscope under all operational conditions, from ground test to science data collection. Four GSS systems were built, tested, and operated successfully aboard the GP-B spacecraft from launch in 2004 to the end of the mission in 2008.

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“…Aubrun provided Dougherty [5] with the final step in the evolution towards the flight design. A piezoelectric pressure transducer was placed in a small chamber between the controlled flow resistance and the thruster throat.…”

Section: Thruster Design Evolutionmentioning

confidence: 99%

“…Attitude and residual acceleration requirements were met using a precision six-degree-offreedom attitude and translation control (ATC) system that operated 16 proportional thruster actuators. The thrusters utilized the dewar's helium boil-off gas as a propellant [5]. The generated force for each thruster could be varied as needed in a continuous fashion by the ATC software.…”

Section: Introductionmentioning

confidence: 99%