Even before the first gravitational waves were observed, plans were in place for the generation that would follow the successful LIGO detectors. The new hardware is expected to operate in space and sense gravitational waves that we have little-to-no chance of detecting using Earth-based observatories.
Of course, no one wants to launch a very expensive system into space without some assurance that it will work. Hence, the ESA developed a pathfinder mission that tests the technology. The latest report from the pathfinder mission is not just positive, it is what-did-I-just-snort positive.
Illuminating stretchy space
Gravitational waves are detected by sensing very tiny shifts in the distance between two mirrors, which changes as a gravitational wave passes through and the very fabric of spacetime stretches and contracts. If we can count the number of wavelengths that fit between two mirrors, we can sense the change in distance. LIGO (laser interferometer gravitational wave observatory), for instance, uses this approach to spot changes of about 10-19 meters between mirrors that are separated by four kilometers.
Source: FS – All – Science – News
LISA pathfinder mission a glorious success