New satellite to test Albert Einstein's theories

Next January, a new satellite aiming to test General Relativity Theory will be launched from the Kourou -French Guyana- on board the brand new European designed Vega rocket. It will be indeed Vega's maiden flight. This satellite, called LARES (Laser Relativity Satellite) has been developed by the Italian Space Agency and it is completely passive -it has no sensors inside. It is a tungsten sphere covered with 92 retroreflectors, which are used to measure the time light needs reach the Earth again with an awesome accuracy and with the help of the laser stations located around the globe belonging to the International Laser Ranging Service. Though the ball's diameter is only 36 centimetres long, it weighs nearly 400 kg. This program was also intended to measure the braneworld DGP model as well as to get an orders-of-magnitude improvement of the current limits in the equivalence principle. Unfortunately, these goals were later dismissed due to their complexity.

The measure of the Lense-Thirring effect (also known as frame dragging) describes the distortion caused by the rotation of a body -here, the Earth. Previous tests to measure this effect were launched in 1976 and 1972. Called LAGEOS and LAGEOS 2 they were made of alluminium in order to reduce the effect of the Earth's Magnetic Field by an italoamerican colaboration and they are still today working. These satellites provided an accuracy of a 10% and according to the designer of the LARES, his satellite will get an accuracy of a 1%, but this has been harshly called into question.

Via: ASI

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