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PSSL — Precision Space Systems Laboratory
Mechanical & Aerospace EngineeringUniversity of Florida

LISA

The LISA mission aims to detect and measure gravitational waves using a space-based laser interferometer, opening a new window into astrophysical phenomena.

The Laser Interferometer Space Antenna (LISA) will be the first gravitational-wave observatory in space. Three spacecraft, flying millions of kilometers apart, will exchange laser beams to measure tiny ripples in spacetime caused by merging black holes and other extreme cosmic events. Inside each spacecraft, gold–platinum cubes — the test masses — float freely, and the observatory works only if nothing disturbs them.

LISA Constellation. Artist’s impression of the LISA constellation measuring gravitational waves with laser interferometry between three spacecraft.

Keeping LISA’s test masses electrically neutral

One unavoidable disturbance is electric charge: cosmic rays constantly strike the spacecraft and charge up the test masses, creating small forces that would mask gravitational-wave signals. The University of Florida provides the instrument that solves this — the Charge Management Device (CMD), the U.S. hardware contribution to the LISA mission.

The CMD discharges each test mass without ever touching it, by shining faint ultraviolet light that releases electrons from metal surfaces (the photoelectric effect). It consists of two flight components built and tested at PSSL: the UV Light Unit, which generates and precisely meters the ultraviolet light, and the Fiber Optic Harness, which routes that light through the spacecraft to the sensor housing each test mass. Our laboratory characterizes the harness’s UV transmission and carries out verification and flight-qualification testing of the complete device.

Simulation and ground testing

To guarantee in-flight performance, PSSL develops end-to-end simulations of the charge-management process — following each UV photon from the light source to its effect on the test-mass charge. On the ground, the UF torsion pendulum reproduces LISA-like conditions with a replica gravitational reference sensor, allowing direct measurements of discharge performance before launch.

Data analysis

PSSL also contributes to LISA’s science pipeline, developing methods that detect and remove brief test-mass disturbances (“glitches”) from the interferometric data, protecting the observatory’s sensitivity.

Project team

Publications