Overnight International Space Station and Space Shuttle mission managers agreed there is no need for a fourth spacewalk to replace the nitrogen tank assembly that has a jammed valve. Station ground teams have determined the station can operate for an extended period of time in the current configuration. The team is continuing to troubleshoot the stuck valve and is looking at options for future replacement of the nitrogen tank assembly should that be necessary.
Discovery’s crew was told about the decision on space-to-ground communications shortly after wake up at 12:21 a.m. EDT.
The stuck valve is in a nitrogen tank assembly needed to pressurize a new ammonia tank installed on the station during this mission’s three spacewalks. It keeps ammonia circulating through radiators that dissipate the heat generated by the station’s electronic systems.