Realtime Coverage of U.S. EVA-17
1:50 PM EDT: Spacewalk ends
Astronauts Tracy Caldwell Dyson and Douglas Wheelock began repressurizing the Quest airlock module at 1:40 p.m., officially ending a seven-hour 20-minute space station repair spacewalk.
It was the third spacewalk by Wheelock and Caldwell Dyson to replace an ammonia cooling pump, a complex job that ended up requiring 22 hours and 49 minutes of EVA time to complete.
Wheelock's total through six career spacewalks now stands at 43 hours and 30 minutes, moving him up to 10th on the list of most experienced spacewalkers. Total EVA time for station assembly and maintenance now stands at 944 hours and 24 minutes - 39.4 days - through 150 spacewalks.
A wrapup story will be posted shortly.
1:20 PM EDT: Cable installation deferred; crew told to wrap up EVA
With their spacewalk running a bit longer than planned, flight controllers told astronauts Douglas Wheelock and Tracy Caldwell Dyson to skip the planned installation of a power cable between the Quest airlock and the Unity module and to head back to the airlock to wrap up the excursion.
The primary goal of the spacewalk -- installation of a spare ammonia pump module as part of a complex coolant system repair -- was successful. The extension cable installation will be deferred to a future spacewalk.
1:10 PM EDT: Controllers assess time needed for cable installation
Astronauts Douglas Wheelock and Tracy Caldwell Dyson have completed work to collect and inventory the tools and equipment they used to install a replacement ammonia cooling system pump.
The only task remaining on today's agenda is to install an extension cord between the Quest airlock and the International Space Station's central Unity module that is needed before the attachment of a cargo module during the next shuttle visit in November.
But the time needed to pack up tools and equipment used for the installation of the spare ammonia pump ran a bit longer than expected and it's not yet clear whether the astronauts will have time to fully install the cable before heading back to the Quest airlock to end the spacewalk.
11:15 AM EDT: Coolant lines connected to replacement pump
Astronaut Douglas Wheelock successfully connected four ammonia lines to a replacement pump module, wrapping up work to replace a faulty pump that knocked one of the International Space Station's two coolant loops out of action July 31.
The fourth ammonia line was connected at 10:41 a.m. and after installing positioning devices, Wheelock opened quick-disconnect valves in the lines to permit the normal flow of ammonia coolant into and out of the new pump module.
To the relief of flight controllers, no ammonia leaks were spotted.
"And Wheels, just to confirm, we did not see any ammonia come out today, amazingly," Oscar Koehler said from mission control. "So if you can confirm you saw no ammonia during any of the QD ops we are go with no ammonia tests at the end of the EVA."
"OK. I did not, Oscar," Wheelock replied. "I did at one time, though, saw what I thought were just a couple of little snowflakes. But I'm not able to confirm that. There was no leak or anything."
A few moments later, Wheelock showed off a cue card on his spacesuit's left wrist that thanked flight controllers and ended with the words "Game over!"
While no one suspected a leak, flight controllers decided the spacewalkers would be in direct sunlight long enough during the remainder of the spacewalk to bake out any ammonia ice that might have been present before Wheelock and Caldwell Dyson return to the Quest airlock at the end of the excursion.
The pump installation capped a complex three-spacewalk repair job that was required in the wake of a July 31 pump failure that took down half the space station's cooling, triggering a widespread power down to keep critical equipment from overheating.
(Photo: NASA TV)
ammonia lines in place with valves opened. (Photo: NASA TV)
Flight controllers earlier verified the electrical health of the replacement pump and now will carry out a complex series of steps to reactivate coolant loop A, work that is expected to take several days to complete.
Wheelock and Caldwell Dyson, meanwhile, planned to clean up the worksite on the S1 truss, putting insulation blankets back in place and rounding up their tools and equipment.
The only remaining task is to run an extension cord from the Quest airlock to the Earth-facing side of the Unity module that needs to be in place before attachment of a cargo module during a shuttle visit in November.
Wheelock and Caldwell Dyson had planned to install that cable during a spacewalk Aug. 5, but that excursion was canceled in the wake of the loop A pump failure.
9:30 AM EDT: Spare ammonia pump installed in S1 truss
Astronaut Douglas Wheelock, anchored to the end of the space station's robot arm, manhandled a 780-pound ammonia pump into the starboard one, or S1, truss segment, replacing a faulty pump that was removed during a spacewalk last week.
"Like butta," Wheelock said as the module slid into the truss.
"Like butta," Caldwell Dyson agreed.
"OK, I think we're in there," Wheelock reported a moment later.
"Outstanding," replied robot arm operator Shannon Walker.
"Good job, guys," Oscar Koehler called from mission control in Houston.
ammonia pump into place during orbital darkness. A faulty pump
removed earlier can be seen in the background. (Photo: NASA TV)
While Wheelock bolted the new pump in place, Caldwell Dyson connected five electrical and data cables, completing the work at 9:04 a.m. A few minutes later, flight controllers powered up the pump module, the oldest of four spares aboard the station, to verify electrical continuity and to spin up the pump's drive shaft for a brief test.
"The bump test has been successful," Koehler called from Houston.
"Oh, sweet! That's awesome news," Wheelock replied.
Wheelock then pressed ahead with work to re-connect ammonia coolant lines and to disconnect a pressure-regulating "jumper box" that was installed earlier.
connectors on a replacement pump being moved into place in the
S1 truss. (Photo: NASA TV)