Anticlimactically, all this sophisticated equipment will not actually be able to sense gravitational waves itself. As the craft’s name suggests, it is indeed a pathfinder, designed to prove that such sensitive technology can work in space. If it does, the way will be clear for the next phase of the project, known as Evolved LISA. This is a far bigger experiment. It will employ a trio of spacecraft flying in formation in the shape of an equilateral triangle that has sides 1m kilometres long, with lasers shining between the craft.