For other uses for the acronym see LISA

The LISA is the Laser Interferometer Space Antenna. It will be launched in 2012 or earlier.

LISA is supposed to measure gravitational waves by using laser interferometry over astronomical distances. It uses 3 spacecrafts, each containing a freely floating mass, two optical setups and very precise thrusters to keep it all at the right place. When a gravitational wave disturbes the space-time field between two of the spacecrafts, a very small difference in the distance between the two masses should be measurable. The thrusters are supposed to be delicate enough to correct minor external disturbances like the pressure of sunlight. Also the whole setup has a triangle form consisting of 3 identical spacecrafts so (if all is well) every measurement is done with triple redundancy. The distance between any two of the spacecrafts is about 5 million kilometers.

Basically LISA will be a huge space borne Michelson interferometer calibrated by free-floating test masses measuring space itself — or actually 3 spaceborne Michelson interferometers.

The mission is sponsered jointly between NASA and the European Space Agency under the Beyond Einstein program.

External links

• LISA (http://lisa.jpl.nasa.gov/)

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