Paving The Way To
Test Einstein With LISA Pathfinder
(19 June 2007) A mission which will
ultimately test Einstein's Theory of General Relatively and provide us with a
detailed insight into the behaviour of some of the most exotic objects in the
Universe, supermassive black holes, moved a step closer today with a formal
agreement being signed between NASA and the European Space Agency for the
technology demonstrator mission, Laser Interferometer Space Antenna (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,
CEO 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. With LTP we will
achieve inertial purity of test body motion better by many orders of magnitude
compared with the current state-of-the-art."
Professor Tim Sumner, a UK
LISA Pathfinder collaborator and member of the LISA International Science Team,
from Imperial College London said," LISA Pathfinder is a major stepping stone
towards the LISA project. The UK has been working hard on this mission for the
last 15 years because of the prospects of verifying one of the central
predictions of general relativity and of making such fundamentally different
observations of objects throughout the Universe which provides an enormously
rich new discovery opportunity."
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
The Science and Technology Facilities Council ensures the UK
retains its leading place on the world stage by delivering world-class science;
accessing and hosting international facilities; developing innovative
technologies; and increasing the socio-economic impact of its research through
effective knowledge-exchange partnerships.
The Council has a broad
science portfolio including Astronomy, Particle Physics, Particle Astrophysics,
Nuclear Physics, Space Science, Synchrotron Radiation, Neutron Sources and High
Power Lasers. In addition the Council manages and operates three
internationally renowned laboratories:
The Council gives researchers access to
world-class facilities and funds the UK membership of international bodies such
as the European Laboratory for Particle Physics (CERN), the Institute Laue
Langevin (ILL), European Synchrotron Radiation Facility (ESRF), the European
organisation for Astronomical Research in the Southern Hemisphere (ESO) and the
European Space Agency (ESA). It also contributes money for the UK telescopes
overseas on La Palma, Hawaii, Australia and in Chile, and the MERLIN/VLBI
National Facility, which includes the Lovell Telescope at Jodrell Bank
Observatory.
The Science and Technology Facilities Council is a partner
in the UK space programme, co-ordinated by the British National Space
Centre.
(source: Particle Physics and Astronomy Research
Council)