GIOVE-B Going, Going… GREAT!

The successful launch of the European Space Agency’s second Galileo In-Orbit Validation Element (GIOVE-B) occurred on April 27th from the Baikonur cosmodrome in Kazakhstan aboard a Soyuz/Fregat rocket at 04:16 local time. The Fregat upper stage performed a series of maneuvers to reach a circular orbit at an altitude of about 23,200 km, inclined at 56° to the Equator, before safely delivering the satellite into orbit some 3 hours and 45 minutes later. The two solar panels that generate electricity to power the spacecraft deployed correctly and were fully operational by 05:28 CEST. The 500 kg satellite was built by a European industrial team led by Astrium GmbH, with Thales Alenia Space performing integration and testing in Rome. Two years after the highly successful GIOVE-A mission, this latest satellite will continue the demonstration of critical technologies for the navigation payload of future operational Galileo satellites.

Like its predecessor, GIOVE-B carries two redundant, small-size rubidium atomic clocks. Each clock has a stability of 10 nanoseconds per day. But it also features an even more accurate payload: the Passive Hydrogen Maser (PHM), with stability better than 1 nanosecond per day. The first of its kind ever to be launched into space, this is now the most stable clock operating in earth orbit. Two PHMs will be used as primary clocks onboard operational Galileo satellites, with two rubidium clocks serving as back-up. GIOVE-B also incorporates a radiation-monitoring payload to characterise the space environment at the altitude of the Galileo constellation, as well as a laser retroreflector for high-accuracy laser ranging. Signal generation units will provide representative Galileo signals on three separate frequencies broadcast via an L-band phase array antenna designed to entirely cover the visible earth below the satellite. The satellite is now under the control of Telespazio‘s spacecraft operations centre in Fucino, Italy, and in-orbit checking-out of the satellite has begun.