NASA managers are still determining whether to launch Cygnus Thursday at 9:19 p.m. EDT or begin a series of spacewalks to replace a cooling pump module as soon as Friday or Saturday. Meanwhile, the Antares rocket carrying Orbital Sciences’ Cygnus commercial resupply craft rolled out to its launch pad Tuesday morning at the Wallops Flight Facility in Virginia.
Support personnel completed loading station gear inside the Cygnus on Sunday. If Cygnus launches on time Thursday, the automated spacecraft would arrive Sunday morning at the International Space Station and be grappled by the Canadarm2 at 4:52 a.m. for berthing to the Harmony node.
Flight controllers have reported some progress manipulating an isolation valve in the faulty pump module on the station’s Starboard 1 truss. They also began work to integrate the Destiny laboratory’s heat exchanger with a cooling loop to properly reject heat generated from station hardware.
NASA astronauts Rick Mastracchio and Mike Hopkins continued with more spacesuit preparations, tool checks and procedure reviews. Japanese astronaut Koichi Wakata trained for his work as robotic arm operator should the spacewalks become necessary.
Mastracchio, who has conducted six spacewalks for a total 38 hours and 30 minutes, would be the lead spacewalker. This would be Hopkins first spacewalk. Wakata, who has never conducted a spacewalk, has operated the Canadarm2 during previous spacewalks.
Flight Engineer and veteran cosmonaut Mikhail Tyurin began Tuesday testing new tools and procedures to detect pressure leaks for the long-running BAR experiment. He later performed maintenance work on the Elektron oxygen generator and audited Russian gear for the station’s inventory management system.