Abstract: The Gravity Recovery and Climate Experiment (GRACE) is a joint NASA and DLR mission comprised of twin satellites using a microwave ranging system to measure the inter-satellite displacement with micron sensitivity. Monthly models of Earth’s gravity field are extracted from this data, enabling key aspects of Earth’s climate to be monitored. The GRACE Follow-On satellites will include a laser ranging instrument based largely on technology developed for the gravitational wave detectors LIGO and LISA.
This talk will provide an overview of the laser system and will highlight technology developed at the Australian National University for GRACE Follow-On. This includes development of a prototype corner cube to route the laser beam around the existing microwave hardware, and discuss the acquisition scheme for initially acquiring the inter-spacecraft laser link. I will also provide a brief overview of digitally-enhanced interferometry (DI), a new technique for optical metrology which promises improved sensitivity, flexibility and simplified optical hardware. DI combines spread spectrum phase modulation with digital signal processing to allow the phase of multiple interferometric signals to be measured using a single photodetector. Sub-picometer displacement sensitivities have been demonstrated using a DI readout.
Bio: Danielle Wuchenich is a PhD student in her final stages of writing her dissertation on inter-satellite laser interferometry in the Centre for Gravitational Physics at the Australian National University under the supervision of Prof Daniel Shaddock and Prof David McClelland. During her PhD she has spent time at the Jet Propulsion Laboratory in Pasadena, CA and the Albert Einstein Institute in Hanover, Germany working on missions such as GRACE Follow-On and LISA.
Time: 4:15 – 5:15pm
Location: Physics/Astrophysics Bldg.,Conference Room #232 (Map)
(Light refreshments available 4:00pm; Presentation begins 4:15pm
Open to All