It is set to be one of the major science projects of the 2030s.
The European Space Agency has just given the green light to the LISA mission to detect gravitational waves.
This will see lasers bounced between three identical satellites separated by 2.5 million km.
By looking for tiny perturbations in these light beams, the trio hope to catch the warping of space-time that is generated by cataclysmic events such as the merger of gargantuan black holes.
Ground-based laboratories in the US have recently begun detecting gravitational waves from coalescing objects that are 20-30 times the mass of our Sun.
But by sending an observatory into space, scientists would expect to discover sources that are millions of times bigger still, and to sense their activity all the way out to the edge of the observable Universe.
It should immeasurably advance our understanding of gravity and how it works; and perhaps even highlight some chinks in Einstein’s so-far flawless equations.
“We have no idea what we will discover, but perhaps we can get closer to the line that divides gravity from quantum physics. This may take us there,” said Esa’s director of science, Prof Alvaro Giménez Cañete.