Lisa Pathfinder: it works!
Just time for a quick post to pass on some impressive news from LISA Pathfinder (which is basically a technology demonstrator mission intended to establish the feasibility of a proposed space-based gravitational wave facility called LISA). LISA Pathfinder is ostensibly an extremely simple experiment, consisting of two metal cubes (made of a gold-platinum mixture) about 38cm apart. The question it tries to answer is how accurately these two cubes can be put an ideal “free-fall” state, i.e. when the only force acting on them is gravity.
Here’s a short explanatory video about the latest results:
The technical details are presented in a paper in Physical Review Letters, from which the key figure is this:
This shows very clearly that the performance of the LISA Pathfinder experiment (as shown by the red measurements) comfortably exceeds the requirements of the full LISA experiment (black curve). Indeed, these results, from only two months of science operations, show that the two cubes are in free-fall to a precision more than five times better than originally required.
So, not to put too fine a point on it, it works!