ESA's LISA Pathfinder experiment launches to explore Einstein’s General Theory of Relativity
ESA's LISA Pathfinderexperiment has successfully launched atop a Vega rocket from theagency's spaceport in Kourou, French Guiana, and completed initial maneuvers required to place the probe in a low, stable orbit. Theexperiment will seek to observe tiny ripples in space known asgravitational waves, which were first predicted by Albert Einstein inhis General Theory of Relativity.
Over the next twoweeks, the spacecraft will perform six critical burns, the last ofwhich will establish the probe at its operational location known asLagrange point 1 (L1). L1 is a point in space located roughly 1.5million km from Earth, at which the spacecraft would hold itsposition relative to our planet and the Sun, leaving it well suitedto the study of gravitational waves.
Gravitational waves, asenvisioned by the great Albert Einstein, are minute ripples in thefabric of spacetime caused by the movement of very massive objectssuch as black holes. However, the disturbances caused by even thesemonsters would be very difficult to detect, creating a ripple theequivalent of an atom in a million-km stretch of space.
LISA Pathfinder isessentially an attempt by ESA to validate technologies that could beused in the construction of a future full-scale observatory, thatwould be designed to take incredibly accurate readings of the elusivephenomena.
Once in its operationalorbit at L1, the probe will release the mechanical holding mechanismsconnecting two cubes, each of which are contained within a vacuumchamber in the core of the probe. The gold-platinum cubes will attheir release be placed 38 cm (15 inches) apart in the mostperfect free-fall ever achieved, with only the minute disturbancescaused by gravity to affect their relative distance.
In order to ensure thatthe spacecraft does not come in to contact with the cubes owing to aforce other than gravity, such as the pressure exerted on an objectby sunlight, tiny thrusters will fire roughly 10 times a second tomaintain the probe's position in relation to its cargo. The probe isexpected to reach its final orbit roughly 10 weeks after launch.
During LISAPathfinder's operational life, a highly complex laser interferometerwill take detailed readings of the gravity inducedmovement of the cubes up to within a billionth of a millimeter. Suchdetailed readings have never before been achieved in an experiment.
"After many years of development and testing onthe ground, we are looking forward to the ultimate test, which canonly be run in space," states Paul McNamara, project scientist forthe LISA Pathfinder mission. "In a few weeks, we will be exploringthe very nature of gravity in space, gaining the confidence to builda full-scale space observatory to study the gravitational Universe inthe future."