Saft to supply Li-ion batteries for GALILEO satellites

Citation

(2006), "Saft to supply Li-ion batteries for GALILEO satellites", Aircraft Engineering and Aerospace Technology, Vol. 78 No. 6. https://doi.org/10.1108/aeat.2006.12778faf.006

Saft to supply Li-ion batteries for GALILEO satellites

Saft to supply Li-ion batteries for GALILEO satellites

Keywords: Aerospace industry, Spacecraft navigation

Galileo Industries and the European Space Agency (ESA) have selected Saft lithium-ion (Li-ion) battery modules to provide the on-board power for the four satellites that will comprise the in orbit validation (IOV) phase of GALILEO, Europe's contribution to the Global Navigation Satellite System (GNSS). The GALILEO Programme is jointly funded by the European Commission and ESA and the project will see Saft's high-energy, flight-proven Li-ion batteries, which are already well established as the first-choice for geosynchronous earth orbit (GEO) communications satellites, breaking new ground in the world's first application of rechargeable Li-ion battery technology for a permanent constellation of medium earth orbit (MEO) satellites.

This latest development follows Saft's successful delivery in May 2005 of the Li-ion battery modules for the GIOVE second pathfinder (technology validation) satellite for the GALILEO programme. This satellite, manufactured by Alcatel Alenia Space on a Proteus LEO platform and due for launch late 2006, will perform in-orbit testing and characterisation of critical payload elements and the Galileo navigation signal and receivers.

“Saft has been leading the way in space batteries for over 40 years. So we are especially pleased to be making yet another important breakthrough by working with Galileo Industries to pioneer the application of Li-ion batteries for a MEO satellite constellation.” said John Searle, Saft CEO. “What makes it even more exciting, is that as well as working at the very fore-font of technology, in GALILEO we have a significant involvement from the start of a massive, high-profile European project that promises to have a direct impact on the lives of people throughout the world by taking satellite-based navigation systems to new levels of accuracy, reliability and signal availability.”

GALILEO is scheduled to be fully operational before the end of the decade, with overall costs estimated at 3.7 billion. It is seen as an independent but complementary system to the US GPS and Russia's Glonass. GALILEO is being designed around the needs of civilian users with the objective to make the already existing and future satellite- based navigation systems inter- operational and compatible.

GALILEO will comprise 30 satellites in a “Walker” constellation, with three orbital planes at 56º nominal inclination and an MEO altitude of 23,222km. Each plane will contain nine operational satellites, equally spaced at 408 plus one inactive spare satellite that can be manoeuvred quickly into position in case of failures. This configuration results in a constellation repeat cycle of ten days, during which each satellite will have completed 17 revolutions.

The VES180S cells will be manufactured in Saft's industrial factory in Bordeaux, France and integrated into the satellite modules and tested at Saft's facility in Poitiers, France. The qualification and flight model batteries will be delivered to Alcatel Alenia Space, the company responsible for integration of the GALILEO satellite. Saft will deliver the batteries for the four satellites according to a planned schedule between November 2007 and April 2008.

The first four GALILEO IOV satellites will be launched by two separate rockets, with two satellites placed into each of the first two orbital planes. Together with the ground stations currently under development, they will be used to validate the entire GALILEO system, using advanced system simulators. The next two satellites will then be launched into the third orbital plane.

In normal operation, the solar panels on the GALILEO IOV satellites will supply all the power required for the on- board electronic systems. There will be a minimum of 170 times a year when the panels are “eclipsed” by the earth, with no direct sunlight for periods of up to 80min. During these periods, the on- board batteries will have to provide around 1.5kW of power to ensure the satellite's continued, uninterrupted operation, throughout a 12-year mission.

Saft has developed a specialised high energy battery module for the GALILEO IOV project, comprising nine Li-ion battery packs connected in series, each pack comprising three VES180S cells in parallel. The VES180S is a new, up-rated cell derived from the VES140S cells established as the standard for GEO satellite applications. It has a specific energy of 170Wh/kg, a 25 per cent improvement on the VES140S, providing a significant weight saving and improved payload capacity.

Saft has 40 years of experience in supplying batteries for satellites and launch vehicles, based on a variety of electrochemistries including Ni-Cd, nickel-hydrogen (Ni-H2) and now Li- ion. Li-ion batteries can store the same amount of energy as Ni-H2 in a smaller package, delivering a weight saving of around 50 per cent. It is expected that the GALILEO satellites will be delivered into orbit by Ariane 5 launch vehicles. Saft has signed an agreement with EADS Space Transportation to provide all the in-flight batteries systems – including Ni-Cd and silver oxide-zinc (AgOZn) – for the Ariane 5 programme through to 2010.