Laser Interferometer Space Antenna

Laser Interferometer Space Antenna

Artist's conception of LISA spacecraft
Mission type	Gravitational waves observation
Operator	ESA
Website	www.lisamission.org
Start of mission
Launch date	2035 (planned)[1]
Rocket	Ariane 6
Launch site	Kourou ELA-4
Contractor	Arianespace
Orbital parameters
Reference system	Heliocentric
Semi-major axis	1 AU
Period	1 year
Epoch	planned
Cosmic Vision ← ATHENA

The Laser Interferometer Space Antenna (LISA) is a planned space probe to detect and measure gravitational waves^[2]—tiny ripples in the fabric of spacetime—from astronomical sources.^[3] LISA will be the first dedicated space-based gravitational-wave observatory. It aims to measure gravitational waves directly by using laser interferometry. The LISA concept features three spacecraft arranged in an equilateral triangle with each side 2.5 million kilometers long, flying in an Earth-like heliocentric orbit. The distance between the satellites is precisely monitored to detect a passing gravitational wave.^[2]

The LISA project started out as a joint effort between NASA and the European Space Agency (ESA). However, in 2011, NASA announced that it would be unable to continue its original LISA partnership with the European Space Agency^[4] due to funding limitations.^[5] In response, ESA continued developing the mission and in 2017, NASA re-engaged with LISA, contributing technology and scientific expertise to the mission.^[6] The project is also a recognized CERN experiment (RE8), collaborating with CERN on precision measurement techniques.^[7][8] A revised, scaled-down design – originally known as the New Gravitational-wave Observatory (NGO) – was proposed as one of three large-scale projects in ESA's long-term plans.^[9] In 2013, ESA selected “The Gravitational Universe” as the theme for its third large-class (L3) mission under the Cosmic Vision program. This decision set the foundation for LISA’s selection as the space-based gravitational wave observatory planned for launch in the 2030s.^[10][11]

In January 2017, LISA was proposed as a candidate mission.^[12] On June 20, 2017, the suggested mission received its clearance goal for the 2030s, and was approved as one of the main research missions of ESA.^[13][14]

On 25 January 2024, the LISA Mission was formally adopted by ESA, marking the transition from conceptual design to hardware development. As part of its renewed participation, NASA is contributing laser systems, telescopes, and charge management devices, all critical for detecting gravitational waves.^[15] This adoption reflects that the mission’s technology is now sufficiently advanced to begin full-scale construction of the spacecraft and instruments.^[16] In March 2024, NASA and ESA signed a Memorandum of Understanding (MoU), officially defining NASA’s role in supplying key mission components.

The LISA mission is designed for direct observation of gravitational waves, which are distortions of spacetime travelling at the speed of light. Passing gravitational waves alternately squeeze and stretch space itself by a tiny amount. Gravitational waves are caused by energetic events in the universe and, unlike any other radiation, can pass unhindered by intervening mass. Launching LISA will add a new sense to scientists' perception of the universe and enable them to study phenomena that are invisible in normal light.^[17][18]

Potential sources for signals are merging massive black holes at the centre of galaxies,^[19] massive black holes orbited by small compact objects, known as extreme mass ratio inspirals,^[20] binaries of compact stars,^[21] substellar objects orbiting such binaries,^[22] and possibly other sources of cosmological origin, such as a cosmological phase transition shortly after the Big Bang,^[23] and speculative astrophysical objects like cosmic strings and domain boundaries.^[24]