A European Space Agency (ESA) mission aimed at testing new technologies for understanding the universe has left Britain for final testing before being launched into space. The LISA Pathfinder mission's propulsion and science modules left Airbus Defence and Space for Industrie Anlagen Betriebs Gesellschaft (IABG) in Germany for final tests before shipment to the ESA launch site in Kourou, French Guiana, where they will be shot into low-Earth orbit atop a Vega rocket.

According to Airbus, LISA Pathfinder is the first British-led ESA mission since the 1985 Giotto probe. Its objective is to test a series of ultra-high precision technologies for the eLISA mission slated to launch in 2034, which will be composed of a constellation of three spacecraft that form a high precision Michelson interferometer floating in outer space with a baseline of one million km (620,000 miles). The interferometer, or gravitometer, works by detecting how the length of the baselines change in infinitesimal increments as the ripples of gravity stretch and compress space-time.

If successful, eLISA will provide new insights into Einstein's theory of relativity, dark matter, and the fundamental nature of the universe. However, the technologies it will use to study gravitational waves are so advanced that a major test mission needs to be sent up first.

This is where Laser Interferometric Space Antenna (LISA) Pathfinder gravitational wave observatory comes in. Its job is to test the concept of low-frequency gravitational wave detection and the station-keeping technology that the eLISA spacecraft will use to form the interferometer.

This involves two electrostatically-suspended 4.5 cm (1.7-in) gold-platinum test masses. These float without connection to the LISA science module and are constantly measured by a laser interferometer to within one billionth of a millimeter (one picometer). A micro-Newton microthruster system then recenters the masses by shifting the spacecraft, so it maintains its station with great precision.

Once at IABG, the LISA Pathfinder will undergo system-level tests, environmental tests to ensure that the modules can withstand being in space, and the installation of the LISA Test Package Core Assembly (LCA) built by a European consortium led by Airbus.

The LISA Pathfinder is scheduled to launch later this year. Airbus says that once it's in orbit, the propulsion module will push it 1.5 million km (932,000 miles) from Earth to the L1 Earth-Sun Lagrange point. There it will be freed from most magnetic and gravitational interference. After in-orbit testing and completing its commissioning phase, the spacecraft will be handed over to ESA’s science operations center (ESAC).

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