APL Colloquium

October 7, 2016

Colloquium Topic: LISA Pathfinder and the Road to Space-based Gravitational Wave Observatories

In September 2015, nearly a century after Albert Einstein’s publication of the theory of General Relativity, the Laser Interferometer Gravitational-wave Observatory (LIGO) instruments detected gravitational waves produced by colliding black holes in the distant universe. While that feat marked the end of a nearly six-decade quest to make the first direct detection of gravitational waves, it marks the beginning of a new an exciting field of astronomy that will use gravity, not light, to explore and understand our universe and the strange phenomena that inhabit it. Just as electromagnetic astronomers have developed a suite of instruments to cover a wide range of that spectrum, gravitational wave astronomers are developing instruments that are sensitive to different frequencies of gravitational waves. One of the most promising bands, expected to be rich in both number and variety of sources, is the milliHertz band, which is only accessible to a space-based observatory.

In 2015, the European space agency launched LISA Pathfinder, a technology demonstrator for the Laser Interferometer Space Antenna (LISA) concept. LISA Pathfinder’s primary objective is to demonstrate that a test mass can be placed in near-perfect free-fall and that it’s acceleration can be precisely measured using a laser interferometer. In this talk I will describe LISA Pathfinder, its key technologies, NASA’s role, and the preliminary results to date. I will also provide a look forward to the prospects for realizing LISA and the tremendous science output that it will achieve.

Colloquium Speaker: James Ira Thorpe

Dr. James Ira Thorpe is a researcher in the Gravitational Astrophysics Laboratory at NASA’s Goddard Space Flight Center whose research focuses on the technologies, mission design, and astrophysical science case for space-based gravitational wave observatories. Born in Santa Fe, NM, Ira attended Bucknell University in Lewsiburg, PA and graduated summa cum laude with degrees in Mechanical Engineering and Physics in 2001. Ira received his Ph.D. in Physics from the University of Florida in 2006, with thesis work on the laser metrology system for the LISA concept. Ira joined NASA/GSFC as a postdoctoral fellow in 2007 and converted to a civil servant in 2009. Ira is the NASA representative on the LISA Pathfinder Science Working Team and the study scientist for NASA’s L3ST, which is currently evaluating options for US participation in an ESA-led gravitational wave observatory.