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Space-walking astronauts have repaired a new segment of the International Space Station that could leak ammonia, according to a report by news service Reuters.
Before it was launched on board Space Shuttle Atlantis, workers at NASA reported that they had discovered that the truss segment, some 14 m (45 ft) long, would leak ammonia once in space and attached to the Space Station. The ammonia is used in a type of air conditioning system for the station, and carries away heat from laboratories and other modules to radiators on the truss.
Rather than make repairs on the ground, which might have delayed the launch, the space agency decided to use astronauts to make them while the Shuttle was in orbit.
According to the report, they were required to install about 24 clamps, or Spool Positioning Devices, to connections on the ammonia lines. The clamps, rather than acting as tourniquets, actually allow small amounts of ammonia to bleed into space so an explosive pressure does not build up between dual seals. The job was to work on the truss, which will grow into the longest part of the orbiting station, stretching more than 100 m, and forming what NASA refers to as the 'backbone' of the station.
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Figure 4. Rolling the expanded PTFE onto itself is judged to improve its gasketing properties. Samples of 2.1 mm diameter gasket made using 14:1 expanded microporous PTFE sheet gave a longitudinal strength of 39 050 \_+ 834 KPa, and a modulus of 403 700 \_+ 42 510 KPa. A sheet of the same PTFE mate
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