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News Release from: Saft Batteries | Subject: Hubble application
Edited by the Engineeringtalk Editorial Team on 22 March 2002

Saft's lithium powers Hubble servicing

NASA astronauts servicing the Hubble telescope relied on lithium batteries supplied by Saft - and the batteries are now standard on power tools used on Shuttle missions.

Working with their American partners, Saft's engineers at the battery company's Maryland plant developed and qualified the lithium batteries for the power-ratchet tool (PRT) used by NASA astronauts in performing service work on the Hubble telescope The space mission has grabbed headlines around the world, as the upgrade substantially expands the telescope's capabilities to peer deep into space

Saft and its partners - the Goddard Space Flight Centre in Maryland, the Johnson Space Centre in Texas and Orbital Science in Maryland - began the process of qualifying the lithium battery technology for Shuttle missions four years ago.

An Orbital Science engineer stationed at mission control in Houston reported: "A - lithium-ion battery was used successfully today in the PRT during installation of the new advanced camera for surveys (ACS) into the Hubble Telescope".

He added, "The fourth of five space walks to rejuvenate Hubble featured installation of the ACS, which will see far beyond the reach of current instruments.

The faint object camera was the last of original science instruments remaining on the telescope and was removed to make room for the advanced system".

The PRT with Saft's lithium-ion battery providing 0.5s 8A pulses was used to remove the old camera and replace it with the ACS.

Saft's lithium-ion batteries powered the tools that mission specialists Jim Newman and Mike Massimino used as they "untorqued" fasteners on the old camera and "torqued" the ASC camera in place.

The astronauts completed their mission by adding the phone-booth-size camera to the four-story orbiting Hubble Telescope on Thursday 7th March 2002.

Saft's lithium batteries operate safely and effectively in extreme temperatures - yet temperature extremes are just one part of the technical hurdles that the batteries had to overcome.

The development and qualification program that Saft undertook with its partners included testing the lithium-ion batteries' performance in conditions of shock, vibration and thermal vacuum.

A major concern during qualification and acceptance testing was to ensure that the cells would not leak electrolyte.

Testing procedures were rigorous and redundant.

The batteries are now approved as standard for Shuttle missions that will follow this Hubble servicing performed by the Columbia crew.

The batteries' lithium-ion cells each weigh just 40 grams and are packaged in a robust metal battery case that connects to the PRT with an umbilical electrical cable.

In all, three Saft lithium-ion rechargeable batteries - each containing eighteen 18650 cells - flew with the Columbia astronauts on the Hubble servicing mission.

The Saft lithium technology replaces the earlier silver-zinc batteries that flew on Shuttle missions.

Saft batteries were on a Shuttle flight last year for preliminary testing purposes.

The high-power cells that comprise the battery are Saft's 18650s, which measure just 18 x 6 x 50mm.

Although they are easily rechargeable in normal use (yielding up to 500 or more charging cycles), the recharging for Shuttle missions is performed on the ground rather than in space.

Astronomers and others investigating the far reaches of the universe will benefit enormously from the Hubble's new capabilities.

One Maryland professor of astronomy put it this way: "If two fireflies were less than 2m apart in Tokyo, Hubble's view with the advanced camera for surveys [installed on the March mission] would be so sharp that, with the telescope placed in Washington, an observer would be able to see whether it was two fireflies or just one".

The astronauts performed five space walks on five consecutive days to service the Hubble telescope, using the power tools with Saft's lithium batteries in walk four.

The Hubble orbits 600km above the earth pointing out into space to capture its images.

Dr Robert Staniewicz, a Saft Maryland-based scientist, comments: "The rigorous qualification process to enable our lithium-ion technology batteries to fly on the Shuttle was an opportunity for us at Saft to demonstrate our advanced technology capabilities, not just in terms of research and design, but also in manufacturing.

We are pleased to work alongside such prestigious space partners as NASA and Orbital Sciences, and look forward to further participation in mission-critical power assignments for space applications.

Our lithium batteries have already been selected for deployment on commercial spacecraft being built for Eutelsaft by Astrium.

Lighter weight and improved performance from Li-ion batteries are critical factors for orbital or other space missions, and Saft is unique in our ability to deliver batteries to customers from our specialised facilities either in the USA or those in Europe". Request a free brochure from Saft Batteries ...

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