Paving the way to test Einstein with LISA Pathfinder

The ESA-initiated mission, which is currently due for launch to the L1 Lagrange point between Earth and the Sun in early 2010, is aimed at demonstrating the technologies needed for a planned future joint ESA-NASA mission, LISA, to detect gravitational waves in space and test Einstein's theory. Einstein predicted that ripples in space time criss-cross the Universe and by detecting these ripples LISA will open a completely new field of astronomy.
For LISA to work properly scientists must be able to guarantee that a mass can float freely in space completely undisturbed and they will have to control the spacecraft position with an accuracy of a few millionths of a millimetre. These are the technologies to be tested in the LISA Technology Package (LTP) onboard LISA Pathfinder.

Professor Keith Mason, Chief Executive of the UK Science and Technology Facilities Council (STFC) said, "LISA is an ambitious mission which relies on technologies that have never been built before. By collaborating on demonstrator missions such as LISA Pathfinder these new technologies can be developed and tested in space – the only place where they can be truly verified."

UK scientists from Imperial College London, University of Birmingham, University of Glasgow are LISA Pathfinder collaborators, alongside UK industry including Astrium (UK) who are the spacecraft main contractor and SciSys Ltd as software architect.

Dr Harry Ward from Glasgow University, the UK representative on the ESA LISA Pathfinder Science Team, said "LISA Pathfinder gives us a unique opportunity to push major technology boundaries. LISA - and many other extreme precision gravitational investigations - require test bodies that are extremely well shielded from external, non-gravitational, disturbances."

Image Credit: Astrium

LISA Pathfinder will pave the way for the LISA mission by testing in flight the very concept of the gravitational wave detection.

It will put two test masses in a near-perfect gravitational free-fall and control and measure their motion with unprecedented accuracy. This is achieved through state-of-the-art technology comprising the inertial sensors, the laser metrology system, the drag-free control system and an ultra-precise micro-propulsion system.

According to today's agreement, which was signed by ESA's Director General Jean-Jacques Dordain and NASA's Administrator Michael Griffin at Le Bourget Air Show in Paris, ESA will design, develop, launch and operate the LISA Pathfinder spacecraft. A consortium of European scientific institutes will provide the LTP, consisting of two test-masses in a nearly perfect gravitational free-fall and a sophisticated system to measure and control their motion with unprecedented accuracy.

NASA will provide the Disturbance Reduction System Package (or DRS). The DRS, that will make use of the LTP sensors and metrology capability, is designed to test the drag-free attitude control as well. The inclusion of both the LTP and DRS packages on board will make it possible to compare and assess the performance of the two types of actuators and relevant software, in preparation for LISA.

The UK is providing three major subsystems for LTP. The University of Glasgow is building the ultra-stable interferometer that is used to monitor the test-mass motion, the University of Birmingham is providing the measurement readout electronics, and Imperial College is supplying a charge management system that prevents build-up of electrostatic charge on the test masses.

Science and Technology Facilities Council News Release