Precision attitude control of the Gravity Probe B satellite

Conklin, John; Adams, M.J.; Bencze, W.; DeBra, D.; Green, G; Herman, Luc; Holmes, Tim; Muhlfelder, B.; Parkinson, Bradford W.; Silbergleit, A. S.; Kirschenbaum, J

doi:10.1088/0264-9381/32/22/224015

Cited by 14 publications

(17 citation statements)

References 13 publications

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“…Centered to within 25 μm on the telescope boresight, each gyroscope was set within a transverse 0.05 m diameter, 0.2 m long superconducting shield, with the shields and readouts referred in pairs to the two telescope axes, the planes for Gyros 3 and 4 being at right angles to those for Gyros 1 and 2. As the Spacecraft rolled around the line to IM Pegasi the amplitude and phase of each SQUID signal provided determinations of Ω g and Ω fd , roll phase being known from the Attitude Reference Platform described in paper 15 [29]. To ensure stability, we developed a unique silicate bonding technique (since widely adopted in the optics industry) based on hydroxide catalysis.…”

Section: The Gyroscopementioning

confidence: 99%

The Gravity Probe B test of general relativity

Everitt

Muhlfelder

DeBra

et al. 2015

Class. Quantum Grav.

121

100

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The Gravity Probe B mission provided two new quantitative tests of Einstein’s theory of gravity, general relativity (GR), by cryogenic gyroscopes in Earth’s orbit. Data from four gyroscopes gave a geodetic drift-rate of −6601.8 ± 18.3 marc-s yr−1 and a frame-dragging of −37.2 ± 7.2 marc-s yr−1, to be compared with GR predictions of −6606.1 and −39.2 marc-s yr−1 (1 marc-s = 4.848 × 10−9 radians). The present paper introduces the science, engineering, data analysis, and heritage of Gravity Probe B, detailed in the accompanying 20 CQG papers.

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Section: The Gyroscopementioning

confidence: 99%

The Gravity Probe B test of general relativity

Everitt

Muhlfelder

DeBra

et al. 2015

Class. Quantum Grav.

121

100

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“…Spacecraft operations were minimized to limit disturbances. Nominal operations consisted of one gyro in drag free mode [43], three gyros in suspended mode, a guide star within the linear range of the telescope and SQUID readout measurements of gyro orientations. The SIA temperature was stabilized by active temperature control.…”

Section: Sciencementioning

confidence: 99%

The Gravity Probe B gyroscope

Buchman¹,

Lipa²,

Muhlfelder³

et al. 2015

Class. Quantum Grav.

Self Cite

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The Gravity Probe B (GP-B) gyroscope, a unique cryogenically operated mechanical sensor, was used on-orbit to independently test two predictions of general relativity (GR). Here, we describe the development and performance of the GP-B gyroscope, its geometry and fabrication, spin-up and vacuum approach, magnetic considerations, and static charge management. The history of electrically suspended gyroscopes puts the current work in context. Fabrication and ground testing of the GP-B gyroscope are detailed, followed by a review of on-orbit initialization, calibration, operation, and performance. We find that the performance was degraded relative to the mission goals, but was still sufficient to provide excellent new tests of GR. The degradation is partially due to the existence of gyroscope torques due to an unanticipated interaction between patch potentials on the rotor and the housing. We discuss these patch potentials and describe the effect of related torques on gyro drift. It was essential to include models for the effects due to the patch potentials in the complete data analysis model to yield determinations of the two GR effects.

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“…In recent years, drag-free spacecraft have been successfully used in space missions that require ultra-high stability such as space high-precision earth gravity field surveys [ 1 , 2 , 3 ], space general-relativity verification [ 4 , 5 ], and space gravitational wave detection [ 6 , 7 ]. The success of these missions has greatly encouraged more scholars to research drag-free control systems.…”

Section: Introductionmentioning

confidence: 99%

Robust Control Allocation for Space Inertial Sensor under Test Mass Release Phase with Overcritical Conditions

Zhang

Tao

et al. 2023

Sensors

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This paper proposes a robust control allocation for the capture control of the space inertial sensor’s test mass under overcritical conditions. Uncertainty factors of the test mass control system under the overcritical condition are analyzed first, and a 6-DOF test mass dynamics model with system uncertainty is established. Subsequently, a time-varying weight function is designed to coordinate the allocation of 6-DOF generalized forces. Moreover, a robust control allocation method is proposed to distribute the commanded forces and torques into individual electrodes in an optimal manner, which takes into account the system uncertainties. This method transforms the robust control allocation problem into a second-order cone optimization problem, and its dual problem is introduced to simplify the computational complexity and improve the solving efficiency. Numerical simulation results are presented to illustrate and highlight the fine performance benefits obtained using the proposed robust control allocation method, which improves capture efficiency, increases the security margin and reduces allocation errors.

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Precision attitude control of the Gravity Probe B satellite

Cited by 14 publications

References 13 publications

The Gravity Probe B test of general relativity

The Gravity Probe B test of general relativity

The Gravity Probe B gyroscope

Robust Control Allocation for Space Inertial Sensor under Test Mass Release Phase with Overcritical Conditions

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