A joint ESA/NASA mission to test technology for detecting gravitational waves which will be used in the subsequent Laser Interferometer Space Antenna (LISA) mission. The launch of LISA Pathfinder is planned for 2013. It will be placed at the L1*Lagrangian point of the Earth's orbit.
http://sci.esa.int/science-e/www/area/index.cfm?fareaid=40/ ESA mission website.
Subjects: Astronomy and Astrophysics.