How's this thing powered? Are solar or big RTGs enough? I would think power requirements for these scale lasers, detectors, and transmissions would be pretty large. Isn't it an extraordinary amount of data that needs to be constantly sent back to Earth? I thought LIGO was generating a crazy amount of data per day beyond what I'd think would be possible to stream live back to Earth from so far away.<p>Also, how can the test masses remain in free fall, while each satellite is undergoing course corrections? Or are corrections infrequent enough for satellites in this earth-following orbit that it wouldn't cause any real amount of downtime? Of course Earth is free-falling.