Abstract
The GRACE mission that was launched in 2002 has impressively proven the feasibility of low-orbit satellite-to-satellite tracking for Earth gravity observations. Especially mass transport related to Earth's hydrological system could be well resolved both spatially and temporally. This allows to study processes such as polar ice sheet decline and ground water depletion in great detail. Owing to GRACE's success, NASA and GFZ will launch the successor mission GRACE Follow-On in 2017. In addition to the microwave ranging system, GRACE Follow-On will be the first mission to use a Laser Ranging Interferometer as technology demonstrator to track intersatellite distance changes with unprecedented precision. This new ranging device inherits some of the technologies which have been developed for the future spaceborne gravitational wave detector LISA. I will present the architecture of the Laser Ranging Interferometer, point out similarities and differences to LISA, and conclude with the current status of the flight hardware production.
Highlights
Measuring Earth The advent of modern satellite geodesy made it possible to monitor spatial and temporal variations in Earth’s global gravity field [1,2,3]
The two identical GRACE satellites were launched in 2002 as a joint mission of the National Aeronautics and Space Agency (NASA) and the Helmholtz Centre Potsdam – German Research Centre for Geosciences (GFZ). They circle Earth in a common, freely decaying, low polar orbit of currently 380 kilometers altitude with an intersatellite separation of 170–270 kilometers, which is maintained by occasional orbit maneuvers
Spatial variations in Earth’s gravity field exert differential accelerations on the two satellites, which leads to length fluctuations in the intersatellite separation
Summary
Measuring Earth The advent of modern satellite geodesy made it possible to monitor spatial and temporal variations in Earth’s global gravity field [1,2,3]. The two identical GRACE satellites were launched in 2002 as a joint mission of the National Aeronautics and Space Agency (NASA) and the Helmholtz Centre Potsdam – German Research Centre for Geosciences (GFZ) They circle Earth in a common, freely decaying, low polar orbit of currently 380 kilometers altitude with an intersatellite separation of 170–270 kilometers, which is maintained by occasional orbit maneuvers. Spatial variations in Earth’s gravity field exert differential accelerations on the two satellites, which leads to length fluctuations in the intersatellite separation These length fluctuations are tracked with micrometer precision with a microwave ranging device. While the main science instrument on GRACE Follow-On will still be a microwave ranging device, the two satellites will carry a Laser Ranging Interferometer (LRI, [8]) as a technology demonstrator This novel instrument will greatly improve the intersatellite range measurements by more than one order of magnitude and deliver highly accurate beam pointing information. The LRI will prove the feasibility of interferometric laser ranging technology for next-generation geodesy missions based on high-precision intersatellite ranging
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
