Second spacewalk completed by US astronauts

Second spacewalk completed by US astronautsIt has been reported that two US astronauts completed their 7-hour-26-minute spacewalk Sunday after struggling with a troublesome bolt that forced them to leave some of their work undone.

Rick Mastracchio and Clayton Anderson, who are visiting the International Space Station on the space shuttle Discovery mission, removed an empty ammonia tank and installed a new one. The tank is vital to keeping the station's cooling system working.

Their spacewalk was started by the astronauts ahead of schedule, at 1:30 am (1100 IST), and finished at 8:56 am.

The multi-step process of installing the new tank with the aid of the station's robotic arm requires three spacewalks, the first of which was Friday.

Tasks that were deferred from Sunday's spacewalk because of the problem included the fluid connections to the ammonia tank and retrieval of two micrometeoroid debris shields for return to Earth. (With Inputs from Agencies)