The design and performance of the Gravity Probe B telescope

Wang, Suwen; Lipa, J. A.; Gwo, Dz‐Hung; Triebes, K.; Turneaure, J. P.; Farley, R.; Davidson, Donald E.; Bower, K.A.; Acworth, Edward Buxton; Bernier, Robert; Huff, Lynn W.; Schweiger, Paul F.; Goebel, J. H.

doi:10.1088/0264-9381/32/22/224008

Cited by 10 publications

(11 citation statements)

References 15 publications

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“…The first class of systematic uncertainty is small effects not present in the model, such as unmodeled torques, telescope and gyroscope readout, and guide star proper motion. Papers 6 [23] and 8 [24] review the telescope and SQUID readout; paper 21 [35] reviews the uncertainty in guide star proper motion. 'Other nonrelativistic torques' in table 3 includes the mass unbalance and suspension effects discussed earlier and various parameters determined on the ground and onorbit.…”

Section: Resultsmentioning

confidence: 99%

“…The telescope (paper 8, [24]) was a folded Schmidt-Cassegrain fabricated from fused quartz, with a convex tertiary mirror centered in the primary, and a sophisticated beam splitter assembly on its front end corrector plate, seen in figure 7. The folded design eased the image divider layout and simplified the quartz block interface.…”

Section: The Telescope and Siamentioning

confidence: 99%

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The Gravity Probe B test of general relativity

Everitt

Muhlfelder

DeBra

et al. 2015

Class. Quantum Grav.

129

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: Resultsmentioning

confidence: 99%

Section: The Telescope and Siamentioning

confidence: 99%

The Gravity Probe B test of general relativity

Everitt

Muhlfelder

DeBra

et al. 2015

Class. Quantum Grav.

129

100

View full text Add to dashboard Cite

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“…Conceptually, the configuration is simple: a rotor, housed within a spacecraft, is placed in a circular polar orbit about the Earth. Gyro drift is measured relative to distant inertial space by means of an on-board telescope [5] tracking a guide star that ideally is in the orbit plane.…”

Section: Introductionmentioning

confidence: 99%

“…(4) Locating the four gyros close to the roll axis to limit the magnitude centrifugal acceleration. (5) Operating one gyro in drag-free mode, described below, to reduce residual rotor acceleration and the associated support force.…”

Section: Introductionmentioning

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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“…V below. Of course, performing the necessary angular measurement would require rotational stabiliza-tion (or real-time monitoring) of the orbiting spacecraft relative to an inertial reference frame (e.g., a distant set of stars and/or quasars; the approach used, e.g., on Gravity Probe B [GP-B] [173][174][175][176]).…”

Section: (H) Showing the Frequency Rangesmentioning

confidence: 99%

Asteroids for $μ$Hz gravitational-wave detection

Fedderke,

Graham,

Rajendran

2021

Preprint

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A major challenge for gravitational-wave (GW) detection in the µHz band is engineering a test mass (TM) with sufficiently low acceleration noise. We propose a GW detection concept using asteroids located in the inner Solar System as TMs. Our main purpose is to evaluate the acceleration noise of asteroids in the µHz band. We show that a wide variety of environmental perturbations are small enough to enable an appropriate class of ∼ 10 km-diameter asteroids to be employed as TMs. This would allow a sensitive GW detector in the band (few) × 10 −7 Hz fgw (few) × 10 −5 Hz, reaching strain hc ∼ 10 −19 around fgw ∼ 10 µHz, sufficient to detect a wide variety of sources. To exploit these asteroid TMs, human-engineered base stations could be deployed on multiple asteroids, each equipped with an electromagnetic (EM) transmitter/receiver to permit measurement of variations in the distance between them. We discuss a potential conceptual design with two base stations, each with a space-qualified optical atomic clock measuring the round-trip EM pulse travel time via laser ranging. Tradespace exists to optimize multiple aspects of this mission: for example, using a radio-ranging or interferometric link system instead of laser ranging. This motivates future dedicated technical design study. This mission concept holds exceptional promise for accessing this GW frequency band.

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The design and performance of the Gravity Probe B telescope

Cited by 10 publications

References 15 publications

The Gravity Probe B test of general relativity

The Gravity Probe B test of general relativity

The Gravity Probe B gyroscope

Asteroids for $μ$Hz gravitational-wave detection

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