One experiment has been running since the autumn of 2004 with the satellite Gravity Probe B. The aim is to examine the influence of the Earth's gravitation on the orientation of gyroscopes in space.

Four rotating balls with the size of tennis balls are sent on a polar route in an orbit around the Earth. In comparison with the fix star heaven one measures the changes of direction of the rotation axes of the balls. Theoretically one expects a change of 6 arcseconds per year due to the de Sitter precession and only 0,04 per year due to the Lense-Thirring effect. The latter effect was described as early as 1918, but could so far not be tested, because of its tinyness. First results are expected in 2006.