Question: Why are u building a spacebourne gravitational wave observatory?.

Christian Killow answered on 16 Mar 2016:

Once you realise that ‘seeing’ gravitational waves is a great thing, then you start looking at all the different things happening in the Universe that cause them. You then quickly realise that many of these things happen quite slowly, giving signals that vary once every thousand seconds or so (low frequency). On earth there are lots of things that move around on this kind of time scale, so our detectors here aren’t very sensitive at low frequency as they just see all the things moving about down here.

So, we go far away from the moving things – into space!