A few hours ago ESA’s LISA Pathfinder space probe was successfully launched atop a Vega rocket from the Kourou space center in French Guiana. After about an hour and 45 minutes it separated from the rocket’s upper stage and activated to begin its long journey thanks to its propulsion module.
LISA Pathfinder entered an elliptical orbit where it will make a series of maneuvers that within a few weeks will take it to the area called L1, where the gravity of the Earth and the Sun get balanced with the other forces acting on the probe. The propulsion module will be disconnected after exhausting its function and the probe will remain in the L1 area, about 1.5 million kilometers (about 900,000 miles) from Earth.
The LISA (Laser Interferometer Space Antenna) Pathfinder mission, originally called Small Missions for Advanced Research in Technology-2 (SMART-2), is designed to test the possibility to detect gravitational waves, for years one of the major objectives in the field of physics. The technologies tested, developed mainly by the Italian Space Agency, will be used for a future mission called for now Evolved Laser Interferometer Space Antenna (ELISA).
The LISA Pathfinder space probe contains two test masses, two gold-platinum cubes of 46 mm side, which will be placed in a state of nearly perfect free fall at a distance of 40 cm from each other. Their relative motion will be measured with unprecedented accuracy. The ion micro-thrusters allow to keep the probe centered about the test masses.
The aim is to isolate the two cubes from all forces except the gravitational one. This way, it will be possibility to try to detect the gravitational waves predicted by Albert Einstein’s general theory of relativity. Thanks to a system of lasers it will be possible to measure any movement of the cubes with extraordinary precision since it can detect displacements of 10 picometers, ten millionths of millionths of a meter.
If the maneuvers and the subsequent testing will give no problems, in March 2016 the LISA Pathfinder spacecraft will begin its mission. It’s expected to continue for at least six months in order to enable ESA to carry out all the tests of the equipment needed to develop the next mission.