Abstract
The Laser Ranging Interferometer (LRI) instrument on the Gravity Recovery and Climate Experiment (GRACE) Follow-On mission has provided the first laser interferometric range measurements between remote spacecraft, separated by approximately 220 km. Autonomous controls that lock the laser frequency to a cavity reference and establish the 5 degrees of freedom two-way laser link between remote spacecraft succeeded on the first attempt. Active beam pointing based on differential wave front sensing compensates spacecraft attitude fluctuations. The LRI has operated continuously without breaks in phase tracking for more than 50 days, and has shown biased range measurements similar to the primary ranging instrument based on microwaves, but with much less noise at a level of at Fourier frequencies above 100 mHz.
- Received 15 April 2019
- Revised 1 June 2019
DOI:https://doi.org/10.1103/PhysRevLett.123.031101
Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI.
Published by the American Physical Society
Physics Subject Headings (PhySH)
Focus
Spacecraft Separation Measured to the Nanometer
Published 19 July 2019
A pair of satellites 200 km apart has demonstrated a record-high precision in distance determination, which will be useful for mapping out Earth’s gravitational field.
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