杏吧原创

NASA engineers seemed to have cured nagging problems with the International
Space Station鈥檚 robot arm last week, but not before it had banged the side of
the station鈥攁pparently of its own accord. The Canadarm2 sprang free from
its fixing and struck the station during testing. Astronauts did not report any
damage. They had been hoping to locate an earlier fault, which stopped the arm鈥檚
shoulder joint working properly. 鈥淭he dilemma is do you have a perfectly healthy
arm, or a problem that just hasn鈥檛 shown itself in a couple of weeks?鈥� says Kyle
Herring of NASA鈥檚 Johnson Space Center in Houston.