NASA Decides to do Spacewalks to Fix Coolant Problem, Cygnus Launch Delayed – UPDATE

NASA Decides to do Spacewalks to Fix Coolant Problem, Cygnus Launch Delayed – UPDATE

UPDATED December 17, 2013, 5:25 pm ET with more details throughout and link to NASA press release.

ORIGINAL STORY December 17, 2013, 4:51 pm ET.   NASA decided today to conduct a series of spacewalks to fix a coolant problem on the International Space Station (ISS), including one on Christmas Day.  Consequently, it delayed the launch of Orbital Sciences Corporation’s Cygnus cargo spacecraft to January.  It had been scheduled for this Thursday.  NASA will hold a press briefing about its decision tomorrow, December 18, at 3:00 pm ET, at Johnson Space Center, TX.

Engineers began troubleshooting the coolant problem last week.  A flow control valve is not working properly and the ammonia used as coolant in that loop — one of two on the ISS — therefore is not being maintained at the proper temperature.  The affected loop was shut down and all critical ISS systems transferred to the functioning loop.  The ISS could remain in that situation for a while, but with reduced scientific experiments and less redundancy.   They were trying to find a workaround to avoid spacewalks, but decided today that they needed to move forward with fixing the problem.

Three spacewalks are needed and are scheduled for December 21, 23 and 25.  

Orbital was planning to launch Cygnus on its first operational cargo flight to ISS on December 19, but that now will wait until January.  The Orb-1 mission is Orbital’s first under the Commercial Resupply Services (CRS) contract.   The company successfully completed a demonstration mission in September/October 2013.

NASA announced the decision to conduct the spacewalks and delay the Cygnus launch in a tweet from Johnson Space Center (@NASA-Johnson):

A press release was later distributed announcing a press briefing that will be held at Johnson Space Center at 3:00 pm ET tomorrow (2:00 pm Central Time), December 18, on NASA TV.   Participants include ISS Program Manager Mike Suffredini, ISS flight director Dina Contella, and lead spacewalk officer Allison Bolinger.

Each of the three spacewalks will begin at 7:10 am ET, with NASA coverage beginning at 6:15 am ET.   All of them are expected to last six and a half hours. 

A date for the Cygnus launch was not announced.  The press release says only that it will take place no earlier than January. 

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