The European Space Agency (ESA) is hoping to unlock the secrets of the elusive gravitational wave with their new space mission. As part of their Cosmic Vision science program, they have selected the Laser Interferometer Space Antenna (LISA) for a large scale mission.
The LISA program will consist of three separate spacecraft, set in a triangular formation positioned about 1.6 million miles apart from each other. They will trail the Earth as it orbits around the Sun. Much like its ground based equivalent that first detected the waves in September of 2015, the spacecraft are measuring the distances between each other, looking for variations caused by gravitational waves. Each spacecraft will have two test masses that are undisturbed by the surrounding craft, this process is called drag-free flight. The instruments will be measuring any miniscule change in distance between these masses.
Ever since the first measurement, NASA and the ESA recognized the need to measure these disturbances at longer distances and with less interference from conditions on Earth. The distance of 1.6 million miles will allow for greater fidelity and the detection of different phenomenon like mergers of supermassive black holes and binary systems with neutron stars. With the current land-based mission, only smaller disturbances can be detected, like the merger of two stellar-mass black holes. They are also hoping to measure the background ‘noise’ of gravitational waves that were created in the earliest moments of the Universe.
Technological advancements in laser measuring and micropropulsion are making this feat possible. With the plan in place and an expected launch in 2034, NASA and ESA must begin the long process of designing and developing the LISA program.
In the same meeting, the Planetary Transits and Oscillation of stars (PLATO) mission was accepted by the ESA Science Programme. Similar to Keplar, PLATO will monitor stars, looking to detect the dip in brightness that characterizes a planet orbiting a star. The mission will focus on identifying earth-sized planets that may be capable of hosting life. PLATO is scheduled for launch in 2026.