Laser Interferometer Space Antenna

Laser Interferometer Space Antenna. It is a planned space-based gravitational-wave observatory designed to detect low-frequency gravitational waves. Led by the European Space Agency with significant contributions from NASA, the mission will consist of three spacecraft flying in a triangular formation. This configuration will form a giant interferometer with arms millions of kilometers long, sensitive to a different part of the gravitational-wave spectrum than ground-based detectors like LIGO and Virgo.

Overview

The mission concept builds upon the successful technology demonstration of the LISA Pathfinder mission, which launched in 2015. Operating from a heliocentric orbit trailing Earth, the three identical spacecraft will precisely measure the distance between free-floating test masses housed within each vehicle. By monitoring these distances with nanometer precision using laser interferometry, the constellation can detect the minute spacetime distortions caused by passing gravitational waves. This observatory will open a new window onto the cosmos, complementing observations from telescopes across the electromagnetic spectrum.

Scientific objectives

The primary goal is to observe gravitational waves from massive astrophysical systems inaccessible to current ground-based observatories. Key targets include the mergers of supermassive black hole binaries, which are found in the centers of galaxies like Milky Way and Andromeda Galaxy. It will also detect the inspiral of stellar-mass black holes and neutron stars into such massive black holes in galactic nuclei, events known as extreme mass-ratio inspirals. Furthermore, scientists anticipate observing a background hum of gravitational waves from the early universe and from millions of compact binary systems within our own galaxy, such as white dwarf pairs.

Mission design and technology

The constellation will form an equilateral triangle with sides approximately 2.5 million kilometers long, following an Earth-like orbit around the Sun. Each spacecraft contains two free-falling test masses made of a gold-platinum alloy, which are shielded from all external forces except gravity. A sophisticated laser metrology system, involving frequency-stabilized lasers from Max Planck Institute for Gravitational Physics technology, will measure the distance between these masses across the vast arms. The spacecraft use drag-free control technology, pioneered on LISA Pathfinder, to precisely follow the test masses without disturbing them.

Development and launch timeline

The mission has a long history, with initial concepts studied jointly by ESA and NASA in the 1990s. It was selected as the L3 mission in ESA's Cosmic Vision programme in 2017, following the success of the technology-demonstrator LISA Pathfinder. The mission formally entered its implementation phase after adoption by ESA's Science Programme Committee in January 2024. The current schedule targets a launch in the mid-2030s aboard an Ariane 6 rocket from the Guiana Space Centre. After launch, the spacecraft will require several months to reach their operational orbit and commence science operations.

Collaboration and funding

The mission is an international collaboration led by the European Space Agency. NASA provides key hardware contributions, including the lasers, telescopes, and parts of the phasemeter system. Scientific and technical contributions come from a consortium of institutes across Europe and the United States, coordinated by the LISA Consortium. Major contributing agencies include the German Aerospace Center, the Italian Space Agency, and the French Space Agency. The consortium involves hundreds of scientists from institutions like the University of Florida, Stanford University, and the University of Glasgow.

Category:European Space Agency missions Category:NASA space probes Category:Gravitational-wave astronomy