Nasa is deciding today whether it needed another spacewalk to make shuttle Discoverysafe for its return to Earth as its crew finished transferring cargo to and from the International Space Station.
The astronauts were loading up the station with as much food, water and other supplies as they could. Discoverywas the first shuttle to visit since before the 2003 Columbiadisaster, and another may not come for some time.
Nasa has grounded the shuttle fleet until it figures out how to stop insulation foam from the spacecraft's external fuel tank from coming loose at launch. Loose tank foam was blamed for the break up of Columbiaover Texas in 2003 and was spotted again when Discoverytook off.
Astronauts Steve Robinson and Soichi Noguchi have performed three spacewalks, including a landmark walk yesterday to remove loose cloth strips protruding from Discovery's belly.
Nasa feared the strips, which fill gaps between the ship's heat-resistant tiles, could cause dangerous heat damage when the shuttle lands on Monday.
Nasa is deciding whether to send the spacewalkers out again on Saturday to repair a tear in an insulating blanket that protects tiles near the commander's window.
There is a worry that a small piece of the blanket could tear off and strike the spacecraft when Discoveryreenters the atmosphere, possibly causing damage.