Earlier this year, scientists announced the detection of gravitational waves—Einstein’s ripples in spacetime—for the first time on Earth. Those ripples are now reverberating through NASA, nudging the agency to mend fences with the European Space Agency (ESA) and rejoin an ambitious mission, called the Laser Interferometry Space Antenna (LISA), to study gravitational waves from space.
This week, at the 11th LISA symposium in Zürich, Switzerland, a NASA official said he was ready to rejoin the LISA mission, which the agency left in 2011. Meanwhile, ESA says it is trying to move the launch of the mission up several years from 2034. “This is a very important meeting,” says David Shoemaker, a gravitational wave physicist at the Massachusetts Institute of Technology in Cambridge. “It feels like a turning point.”
Plans for LISA date back more than 2 decades. Three separate spacecraft, flying millions of kilometers apart from each other at the vertices of a giant triangle, would precisely measure their mutual separations using sensitive lasers, and thus be capable of detecting low-frequency ripples in spacetime. The objects causing these low-frequency ripples—such as orbiting supermassive black holes at the centers of distant galaxies—would be different from the higher frequency ripples, emitted by collisions of much smaller black holes, that have so far been detected on Earth.