Astronauts from the space shuttle Endeavour have completed their first space walk, while NASA mission controllers on the ground made plans to check the shuttle’s damaged heat shield. Rick Mastracchio and Dave Williams made a planned six hour spacewalk. Their main job was to bolt a three and a half metre aluminium extension beam onto the space station’s backbone. The beam weighs two tonnes on Earth; in zero gravity though the job was fairly straightforward. The astronauts took with them all the tools needed. The final piece of the station’s spine will be carried up late next year.
NASA engineers at mission control meanwhile were finalising plans to inspect the shuttle’s heat shield. A small but possibly deep gash was spotted as Endeavour arrived in orbit. The ship’s skin is covered in ceramic tiles and carbon panels to protect it during re-entry, when temperatures can reach more than a thousand degrees Celsius. Repair work, if necessary, can be carried out in orbit, in which case NASA will schedule an extra spacewalk.