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Batteries Digest Newsletter and Website are Copyright 1996-2007 by Teksym Corporation
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 (May 2007)   NASA reports on cause of disappearance  of Mars Global Surveyor in 2006.  Evidently, an uploaded command to update positioning in the High Gain Antenna’s position for  contingency operations had information sent  to the wrong memory address in the Mars Global Surveyor’s onboard computer.  The corrupted upload happened because two previous updates conflicted with the upload. The error caused problems with the solar array, causing the craft to go into contingency mode, exposing batteries to direct sunlight  which resulted in  overheating and depletion . A second parameter error caused the antenna to rotate away from the Earth resulting in blocked communications with the craft.

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 (April 2004) Saft’s Lithium-ion batteries are the first to be operated in a geostationary earth orbit (GEO). Saft was the pioneer supplier of this battery to W3A’s prime contractor EADS Astrium.   The March 16th launch of Eutelsat’s W3A by a Proton rocket was the beginning of a new system in GEO satellite power.

Previous satellites have used Nickel-hydrogen batteries, but this is the first time a GEO satellite will benefit from the lower-weight, smaller-volume Lithium-ion batteries.  

As GEO satellites fly in an orbit 36,000 km (about 21,000) miles above the Earth, launch weight and mass are critical factors.  By reducing battery weight and space on EADS Astrium’s Eurostar E3000 platform, the Lithium-ion batteries enable Eutelsat to add more revenue-gathering transponders to the payload.

W3A’s battery is made of Saft’s Lithium-ion VES 140 cells.  These batteries, as the payload itself, are designed to perform throughout the 15-year service lifetime of the satellite.  Like other satellites, the W3A will use its batteries only when it is hidden from the Sun by the Earth.  The rest of the time, it will rely on solar panels
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