ESA green light for space-based gravitational wave detector LISA – Society

ESA’s Scientific Committee, together with NASA, approved the LISA mission, the first scientific attempt to detect and study gravitational waves from space.

At this stage, formally called “acceptance”, ESA recognizes that the mission’s concept and technology are sufficiently advanced and gives the green light to build the instruments and spacecraft. These works will begin in January 2025 once a European industrial contractor has been selected, says CSIC, which is involved in the project.

LISA (Laser Interferometer Space Antenna) is not one spacecraft, but a constellation of three. They will follow the Earth’s orbit around the Sun, forming an extremely precise equilateral triangle in space. Each side of the triangle will be 2.5 million kilometers long (more than six times the distance between Earth and the Moon), and over this distance the spacecraft will exchange laser beams. The launch of three spacecraft is planned for 2035 on an Ariane 6 rocket.

Across the universe, LISA will detect ripples in spacetime caused by the collision of huge black holes at the centers of galaxies. This will allow the team to trace the origins of these objects, chart their growth to masses millions of times larger than the Sun, and determine the role they play in the evolution of galaxies.

The mission is designed to capture the gravitational sound of our Universe’s first moments, as predicted by current theories, and provide a direct look at the first seconds after the Big Bang. Additionally, since gravitational waves contain information about the distance to the objects that emitted them, LISA will help the team measure the change in the expansion of the universe using a different criterion from the methods used in the Euclid space mission and other studies, supporting your point. Results.

In our galaxy, LISA will detect the merger of many compact objects such as white dwarfs or neutron stars, and will give us unique insight into the final stages of the evolution of these systems. By determining their positions and distances, LISA will improve our understanding of the structure of the Milky Way.

To detect gravitational waves, LISA will use solid cubes of gold and platinum known as test masses (slightly smaller than Rubik’s Cubes) that float freely in a special casing in the center of each spacecraft. The gravitational waves will cause small changes in the distances between masses on different spacecraft, and the mission will monitor these changes using laser interferometry.

This method requires firing laser beams from one spacecraft to another and then superimposing their signal to detect changes in mass distances down to a few billionths of a millimeter. The spacecraft must be designed so that nothing other than the geometry of spacetime itself affects the movement of masses in free fall.

LISA, led by ESA, was made possible through collaboration between ESA, NASA and the LISA science consortium. The Spanish contribution is led by ICE-CSIC together with the Institute of Space Sciences of the University of Barcelona (ICCUB) and the Polytechnic University of Catalonia – BarcelonaTech (UPC), through researchers all of whom are affiliated members of the IEEC.

Spain’s contribution focuses on the Science Diagnostic Subsystem (SDS), one of the three main flight subsystems. Its goal is to measure environmental disturbances on board each of the constellation’s satellites to distinguish them from the effect that gravitational waves might cause. SDS will have temperature, magnetic field and radiation sensors on each satellite.