spacetoday.net: Cygnus launch delayed for ISS repair spacewalks

Posted: Wed, Dec 18, 2013, 6:43 AM ET (1143 GMT)
ISS during STS-135 mission (NASA)

NASA announced late Tuesday that it has scheduled three spacewalks over the next week to replace a faulty coolant pump on the International Space Station, a decision that will delay the launch of a commercial cargo spacecraft until next month. NASA ISS astronauts Rick Mastracchio and Mike Hopkins will perform the spacewalks, planned for December 21, 23, and 25, to remove a pump module that suffered a valve failure last week and replace it with a spare module. The valve problem shut down one of two coolant loops on the station last Wednesday, disrupting some science operations but posing no immediate threat to the station and its six-person crew. Because of the spacewalks, NASA has delayed the launch of a Cygnus cargo spacecraft on Orbital Sciences' Antares rocket that was scheduled for Thursday night. That mission, the first of eight cargo missions by Cygnus spacecraft to the station under Orbital's current contract with NASA, has been postponed to mid-January.