In a high-drama spacewalk on Monday, a pair of NASA astronauts overcame an issue with a loose jetpack to make crucial repairs to the International Space Station. The jetpacks are designed to whisk astronauts back to safety should they float away from the ISS and into space. But once Mike Fossum had helped his partner Piers Sellers secure the jetpack, the two completed their work preparing the ISS for the expansion planned during future shuttle missions.The astronauts replaced a key system that sends power and commands to a railcar attached to the station's truss. The truss acts like a backbone to the station and supports its power-generating solar arrays.The station's robot arm moves on the railcar to access hard-to-reach areas, making the railcar critical for the installation of more solar arrays and truss segments."If we didn't get this successfully changed and checked out, then we couldn't proceed with the next mission, which is right on our heels," says ISS lead flight director Rick LaBrode. The next shuttle is currently scheduled for a lift-off on 28 August.In December 2005, a cable was inadvertently cut on one of two systems and send commands to the railcar and power it. The device can operate with just one system, but NASA prefers to move it only when both systems are working. On the mission's first spacewalk on Saturday, Sellers and Fossum installed a "blade-blocker" to ensure that the other system's cable cannot be inadvertently cut.But during the spacewalk on Monday, the latches attaching Sellers' jetpack to his spacesuit became loose. First, the astronauts noticed that the left hook had come unlocked, prompting Fossum to tie the jetpack to Sellers' spacesuit with a tether. Later, Discovery pilot Mark Kelly radioed from inside Discovery that it appeared Sellers' right latch had come loose as well.
View: Full Article | Source: New Scientist Space
