Sticky bolts proved too much for a pair of spacewalking astronauts.
Two spacewalking astronauts tried for hours Thursday to install a new power-switching box outside the International Space Station, but they had to call it quits because of stubborn bolts.
NASA's Sunita Williams and Japan's Akihiko Hoshide used all sorts of tools and tactics as they tried to bolt the new unit down, but nothing worked. With time running out, Mission Control told the astronauts to tie down the box and go back inside. The work will be left for a future spacewalk.
The power-switching unit is one of four. The other three are working fine. Nonetheless, the power system will need to be reconfigured at the space station given Thursday's failed effort.