Johnson space center, Houston (AP) Two spacewalking astronauts have completed the fourth of five excursions planned for the current shuttle mission to the international space station.
In the latest outing, they tested a caulking system designed to repair damaged heat tiles. Those are the thousands of protective plates that shield a shuttle from the intense heat that builds up during re-entry.
Astronaut Michael Foreman, knicknamed “Mr. Goo” for the walk, used a special caulk gun device to dispense a kind of high-tech silly putty onto some sample tiles to see how it reacts in space.
The repair could be crucial in case there's any damage to the heat tiles on next summer's repair mission to the Hubble space telescope. It's the only one of the 11 remaining shuttle missions that won't include a rendezvous with the space station, which could provide a safe haven in an emergency.