Gravitational wave detectors measure gravitational waves directly. [excerpt]Oh?
Oh?
Elaborate.
http://en.wikipedia.org/wiki/Gravitational_wave_detector
Do they work in free-fall?
Yes. From the article:
"Space-based interferometers, such as LISA and DECIGO, are also being developed. LISA's design calls for three test masses forming an equilateral triangle, with lasers from each spacecraft to each other spacecraft forming two independent interferometers."