Goddard Engineering and Technology Directorate

Laser Interferometer Space Antenna

LISA will observe a passing gravitational wave directly by measuring the tiny changes in distance between freely falling proof masses inside spacecraft with its high precision measurement system. Credit: AEI/MM/exozet
LISA will observe a passing gravitational wave directly by measuring the tiny changes in distance between freely falling proof masses inside spacecraft with its high precision measurement system. Credit: AEI/MM/exozet

What is LISA?

LISA is a space-based gravitational wave observatory building on the success of LISA Pathfinder.
Led by ESA, the LISA mission is a collaboration of ESA, NASA, and an international consortium of scientists.

LISA’s Size and Precision are Out of this World

LISA consists of three spacecraft that are separated by millions of miles and trailing tens of millions of miles, more than one hundred times the distance to the Moon, behind the Earth as we orbit the Sun. These three spacecraft relay laser beams back and forth between the different spacecraft and the signals are combined to search for gravitational wave signatures that come from distortions of spacetime. We need a giant detector the size of the Sun to catch gravitational waves from orbiting black holes millions of times more massive than our Sun. NASA is a partner in the European Space Agency (ESA)-led mission, which is scheduled to launch in the mid-2030s and we are getting ready for it now!

LISA's enormous detector size and orbit, trailing behind the Earth as it orbits the Sun, are illustrated here. Credit: AEI/Milde Marketing
LISA’s enormous detector size and orbit, trailing behind the Earth as it orbits the Sun, are illustrated here. Credit: AEI/Milde Marketing

What are Gravitational Waves?

Gravitational waves were first theorized by Albert Einstein. They are created during events such as supermassive black hole mergers, or collisions between two black holes that are billion times bigger than our Sun. These collisions are so powerful that they create distortions in spacetime, known as gravitational waves.

Gravitational waves detectable by the LISA mission could also come from other distant systems including smaller stellar mass black holes orbiting supermassive black holes, known as Extreme Mass Ratio Inspirals (EMRIs).

What do Gravitational Waves tell us?

There are many astrophysical phenomena that are either very dim or completely invisible in any form of light that astronomy has relied on for 400 years. Gravitational waves are a powerful new probe of the Universe that uses gravity instead of light to take measure of dynamical astrophysical phenomena. Studying gravitational waves gives enormous potential for discovering the parts of the universe that are invisible by other means, such as black holes, the Big Bang, and other, as yet unknown, objects. LISA will complement our knowledge about the beginning, evolution and structure of our universe.

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