Bonn 2025 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 8: Laser Systems – Optical Methods (joint session K/Q)
Q 8.5: Talk
Monday, March 10, 2025, 12:15–12:30, HS XI ITW
Laser Ranging for Satellite Gravimetry: GRACE-FO and beyond — •Malte Misfeldt1,2, Vitali Müller1,2, Gerhard Heinzel1,2, Kai Voss3, and Kolja Nicklaus3 — 1MPI für Gravitationsphysik, Hannover — 2IGP, Leibniz Universität Hannover — 3SpaceTech Immenstaad GmbH
The Laser Ranging Interferometer (LRI) aboard the GRACE Follow-On (GRACE-FO) mission represents a groundbreaking advancement in satellite geodesy. Designed as an experimental addition to the established microwave ranging system, the LRI employs laser interferometry to measure inter-satellite distance variations with nanometer-scale precision. The enhanced sensitivity enables improved tracking of Earth's gravity field variations, offering refined insights into critical climate change processes such as polar ice mass loss. The LRI's successful deployment and operation have set a new benchmark for the accuracy and resolution of space-based gravity measurements.
This presentation will discuss the key technologies of the LRI. As evolved LRI instruments will be the primary payload in future satellite gravimetry missions, we will highlight lessons learned from several years of successful operation in orbit and their relevance to the design. Finally, we will address the new challenges in transitioning the LRI from a technology demonstrator to a primary payload. These include meeting stricter performance requirements, enhancing robustness for long-term operation, and adding a new sub-unit to measure the laser's wavelength in-orbit to better than 25ppb.
Keywords: Space Laser Interferometry; GRACE Follow-On; Laser Ranging Interferometer; Satellite Gravimetry