LISA Pathfinder

Launched by the European Space Agency in 2015, LISA Pathfinder was designed to test the core technologies required for a future space-based gravitational wave observatory. It successfully demonstrated that two free-falling test masses could be shielded from external forces like solar radiation pressure. This proved that a larger, multi-spacecraft mission was technologically feasible.

After launching, the spacecraft traveled to the Sun-Earth Lagrange point L1, which is located about 1.5 million kilometers away from Earth. This deep-space location provided the stable, gravity-free environment necessary for the highly sensitive experiments. The location allowed the spacecraft to orbit the Sun alongside Earth without major gravitational disturbances.

By successfully placing two gold-platinum alloy cubes in a near-perfect free fall, it proved the laser interferometry technology required for the upcoming Laser Interferometer Space Antenna (LISA). LISA, slated for launch by the ESA in the 2030s, will use a massive triangle of three spacecraft to detect low-frequency gravitational waves from supermassive black holes.

The highly successful LISA Pathfinder mission concluded in 2017 after completing its final set of experiments. The mission operations team sent the final commands to permanently shut down the spacecraft. It had far exceeded its design requirements and operational lifespan expectations.