Astronauts on the U.S. space shuttle Endeavour are conducting a spacewalk Saturday to add new components to the International Space Station (ISS).
This is the fourth and final spacewalk for the Endeavour mission. After it is complete, the shuttle and ISS crews will bid each other goodbye, then seal off the hatches to begin preparations for Endeavour's possible early departure from the orbital outpost.
The U.S. space agency NASA has been considering having the shuttle return to earth earlier than its scheduled Wednesday arrival, to escape the effects of a powerful hurricane on NASA's manned-spaceflight operations center in Houston, Texas.
U.S. forecasters say Hurricane Dean, traveling west through the Caribbean, could arrive in the Gulf of Mexico in the next few days. If it veers toward Houston, the agency would be forced to move its operations to the Kennedy Space Center in Florida.
Earlier this week, Endeavour's crew cut short a third spacewalk when astronaut Rick Mastracchio found a small hole in his glove. Officials said he was in no danger, but flight controllers ended the spacewalk as a precaution.
Meanwhile, Endeavor commander Scott Kelly says the crew agreed "absolutely 100 percent" with NASA's decision not to repair a small gouge on the orbiter's exterior heat shield.
The damage occurred when either foam or ice fell off the shuttle's external fuel tank during last week's launch and struck the shield.
After nearly a week of analysis, flight managers announced Thursday that the gouge is not a threat to the spaceship or its crew, and is unlikely to cause further damage. Commander Kelly says the crew shared NASA's concern that a repair spacewalk could potentially cause even more damage.
Some information for this report was provided by AFP, AP and Reuters.