NASA's much-delayed Lockheed Martin-built Gravity Probe B satellite, designed to test Albert Einstein's theory of general relativity, has arrived at Vandenberg AFB, California, for its late 2003 launch aboard a Boeing Delta II booster. Once in polar Earth orbit the satellite will slowly roll about the line of sight to a guide star viewed by a ground-based reference telescope. Data from four onboard gyroscopes, cooled with liquid helium, will be compared with data from the telescope to an accuracy of 0.1 milliarcseconds.

Source: Flight International