The Drag-Free Satellite

Lange, Benjamin

doi:10.2514/3.55086

Cited by 160 publications

(80 citation statements)

References 12 publications

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“…Drag-free technology, conceived of in the 1960s (Lange 1964; has been the most promising approach to breaking through these acceleration noise limits. Two drag-free approaches have been demonstrated on three separate missions.…”

Section: Introductionmentioning

confidence: 99%

Drift mode accelerometry for spaceborne gravity measurements

Conklin

2015

J Geod

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A drift mode accelerometer is a precision instrument for spacecraft that overcomes much of the acceleration noise and readout dynamic range limitations of traditional electrostatic accelerometers. It has the potential of achieving acceleration noise performance similar to that of dragfree systems over a restricted frequency band without the need for external drag-free control or continuous spacecraft propulsion. Like traditional accelerometers, the drift mode accelerometer contains a high-density test mass surrounded by an electrode housing, which can control and sense all six degrees of freedom of the test mass. Unlike traditional accelerometers, the suspension system is operated with a low duty cycle so that the limiting suspension force noise only acts over brief, known time intervals, which can be neglected in the data analysis. The readout is performed using a laser interferometer which is immune to the dynamic range limitations of even the best voltage references typically used to determine the inertial acceleration of electrostatic accelerometers. The drift mode accelerometer is a novel offshoot of the like-named operational mode of the LISA Pathfinder spacecraft, in which its test mass suspension system is cycled on and off to estimate the acceleration noise associated with the front-end electronics. This paper presents the concept of a drift mode accelerometer, describes the operation of such a device, develops models for its performance with respect to non-drag-free satellite geodesy and gravitational wave missions, and discusses plans for testing the performance of a prototype sensor in the laboratory using torsion pendula.

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Section: Introductionmentioning

confidence: 99%

Drift mode accelerometry for spaceborne gravity measurements

Conklin

2015

J Geod

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“…The basic operating principle of the differential optical shadow sensor was first described for application to drag-free satellites by Lange [5]. To our knowledge this concept has not previously been implemented in hardware.…”

Section: The Differential Optical Shadow Sensormentioning

confidence: 99%

“…A drag-free satellite is one that is freed from all forces other than gravity [5]. Uses range from navigation [6] to geodesy [4] to fundamental physics [7][8][9].…”

Section: Drag-free Satellitesmentioning

confidence: 99%

Differential optical shadow sensor for sub-nanometer displacement measurement and its application to drag-free satellites

Zoellner¹,

Tan²,

Saraf³

et al. 2017

Opt. Express

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Abstract:We present a method for 3D sub-nanometer displacement measurement using a set of differential optical shadow sensors. It is based on using pairs of collimated beams on opposite sides of an object that are partially blocked by it. Applied to a sphere, our 3-axis sensor module consists of 8 parallel beam-detector sets for redundancy. The sphere blocks half of each beam's power in the nominal centered position, and any displacement can be measured by the differential optical power changes amongst the pairs of detectors. We have experimentally demonstrated a displacement sensitivity of 0.87 nm/ √ Hz at 1 Hz and 0.39 nm/ √ Hz at 10 Hz. We describe the application of the module to the inertial sensor of a drag-free satellite, which can potentially be used for navigation, geodesy and fundamental science experiments as well as ground based applications.

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“…Each arm in the constellation is nominally 5 million km long and varies by as much as one percent with an annual period. Laser interferometry is used to monitor distance fluctuations between freely floating masses that are contained within the spacecraft at each end of the arm and are isolated from external disturbances using the technique of drag-free control [4,5]. A measurement resolution of approximately 10 pm (1 pm = 10 -12 m) is required for the interferometric measurement.…”

Section: Introductionmentioning

confidence: 99%

“…The noise suppression of TDI is primarily limited by knowledge of the nominal arm lengths, . With the assumption that a ranging system can track these arm lengths to 1m, TDI can meet the LISA measurement requirements if the phase fluctuations of the master laser are below 282Hz 2mHz 4 (1)…”

Section: Introductionmentioning

confidence: 99%

Arm locking for the Laser Interferometer Space Antenna

2009

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The Laser Interferometer Space Antenna mission is a planned gravitational wave detector consisting of three spacecraft in heliocentric orbit. Laser interferometry is used to measure distance fluctuations between test masses aboard each spacecraft to the picometer level over a 5 million kilometer separation. Laser frequency fluctuations must be suppressed in order to meet the measurement requirements. Arm-locking, a technique that uses the constellation of spacecraft as a frequency reference, is a proposed method for stabilizing the laser frequency. We consider the problem of arm-locking using classical optimal control theory and find that our designs satisfy the LISA requirements.

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The Drag-Free Satellite

Cited by 160 publications

References 12 publications

Drift mode accelerometry for spaceborne gravity measurements

Drift mode accelerometry for spaceborne gravity measurements

Differential optical shadow sensor for sub-nanometer displacement measurement and its application to drag-free satellites

Arm locking for the Laser Interferometer Space Antenna

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