The 2026 Harry Nelson Lecture in Astronomy will be given by Dr. Jennifer Lee of BAE Systems SMS. The Nelson Lecture is named in honor of Dr. Harry Nelson, 1935 graduate of Augustana College, long-time Professor of Mathematics at Augustana, and first director of the John Deere Planetarium. 

The talk "Optical Cavities for Gravity Sensing" will focus on two space laser missions. The GRACE (Gravity Recovery and Climate Experiment) and LISA (Laser Interferometer Space Antenna) spacecraft both use lasers to sense gravity. GRACE senses nanometer level changes between two spacecraft 200 km apart to derive Earth’s gravity field and observe surface land mass change and the water cycle.

LISA will derive picometer length changes between spacecraft spaced 2.5 million km apart to detect gravitational waves emitted from star forming events. These two missions share a common measurement method – using laser interferometry to sense tiny changes in spacecraft separation. This talk will discuss the optical cavities used for stabilizing the lasers (so they can measure changes smaller than an atom) and engineering them for use in space.

About Dr. Jennifer Lee
Dr. Jennifer Lee is an optical engineer at BAE Systems SMS. Her current role centers on the development of new instrument technologies for future space missions, spanning from visible and IR imagers and spectrometers to laser ranging systems. She has particular interest in new technologies that enable unconventional sensing modalities. Dr. Lee started at BAE as a radiation effects engineer, following a postdoc at NOAA working on lidar remote sensing for oceanography. She has a background in ultrafast optics and photonics and did her graduate work at Cornell University building fiber-based laser sources for multiphoton microscopy.