Lisa Pathfinder, Europe goes in search of gravitational waves – Sciences et Avenir

EINSTEIN . Predicted by Albert Einstein in the framework of general relativity, gravitational waves, these wrinkles in space-time, remain undetectable despite several research programs conducted since ground-based observatories. That is why Europe has decided to continue this quest in space with Elisa mission, a constellation of three satellites in heliocentric orbit, whose launch is expected after 2030. Before switching this ambitious project, the agency European Space (ESA) will place on the night of 2 to 3 December, 2015, a satellite in high orbit to test some of the technologies that will be used for ELISA.

and LISA gravitational waves. CNES.

cubes incredible stability

The demonstrator Lisa Pathfinder will be launched from the spaceport in Europe, Kourou, French Guiana with Vega rocket. It will be dropped on a low orbit, then using its own engines Lisa depart by stages to reach Earth Lagrange point 1-1500000 kilometers from Earth, in the month of January. In this position, where solar attraction and the Earth are compensated, Lisa Pathfinder will be ideally positioned to perform its assessment mission. This involves estimating the distance between two cubes of gold and platinum it contains. They are positioned in levitation in remote cavities 38 centimeters and a laser system will measure minute variations in this distance, between 1 and 100 billionths of a millimeter! To ensure they are fully a permanently stable, a micro-thruster system will allow the probe to offset the possible effects of the solar wind.

Lisa Pathfinder mission does not aim to detect gravitational waves. The distance between the two cubes is much too low to record their passage. They are there to validate the measurement method. If the experiment is successful, the mission will then Elisa engaged. The three satellites that make up the remote will be several million kilometers and they will be able to record the passage of a gravitational wave should rule out each other about a tenth of a millionth of a millimeter.

LISA Pathfinder advances towards its launch pad, November 18. ESA-Manuel Pedoussaut, 2015.

FALSE JOY . Gravitational waves are produced by the most violent phenomena in the Universe, such as supernova or collisions between two black holes or two neutron stars. They appear as tiny wrinkles that spread on the fabric of space-time and through the universe almost undisturbed, unlike light waves. Their existence has been indirectly confirmed through the observation of binary systems composed of two stars. In March 2013, a team in charge of BICEP 2 Telescope announced the detection of primordial gravitational waves produced during the first moments of the universe during the inflation phase. But a few months later, the enthusiasm had fallen: dust had distorted the measures and no gravitational wave has never been detected.