Galileo pathfinder GIOVE-A still working well after 5 years in space

WASHINGTON - The first prototype satellite of Europe’s Galileo satellite navigation system-ESA’s GIOVE-A-is still working well after five years in space.

Soyuz rocket from Baikonur in Kazakhstan launched the first ‘Galileo In-Orbit Validation Element’, GIOVE-A, on 28th December 2005, carrying a prototype rubidium atomic clock designed for the Galileo constellation.

It was joined on 27 April 2008 by GIOVE-B, equipped with an ultra-precise passive hydrogen maser design as well as a second rubidium clock. Operational Galileo satellites will carry both clock designs for maximum reliability.

“Both satellites had a design lifetime of 27 months each,” said Valter Alpe, managing GIOVE activities for ESA.

“It is a pleasant surprise, therefore, to have GIOVE-A still fully operational after 60 months in orbit. GIOVE-B, meanwhile, is showing no sign of problems after 33 months in space.

“Part of their long lifespans can be put down to design margins, though luck comes into it as well. The satellites have been orbiting through an exceptionally quiet time in the 11-year solar cycle, meaning they have accumulated lower radiation doses than originally anticipated,” said Alpe.

The results from GIOVE-A and -B have proved promising. Both atomic clock designs have proved resistant to radiation effects, with GIOVE-B’s passive hydrogen maser - designed to lose less than one second every three million years - running so well that errors cannot be spotted easily over the general measurement system noise.

With the Galileo IOV satellites on the way, GIOVE-A has already made room for them.

“Both GIOVEs will continue to have an important role,” said Stefano Binda, Systems Performance Engineer for GIOVE.

“We can experiment with them in a way we won’t be able to with the operational Galileo constellation, which will be serving users on a 24/7 basis.

“And we want to see how their performance changes over time, especially now the solar cycle is becoming more active.

“While the GIOVE platforms are not really equivalent to Galileo, their payloads are broadly comparable. So considering that Galileo satellites are designed for 12-yearlives, we are very interested in seeing how the GIOVE payloads start to show their age,” he said. (ANI)