Spacewalking plumbers make Tranquility cooler
BY WILLIAM HARWOOD
STORY WRITTEN FOR CBS NEWS "SPACE PLACE" & USED WITH PERMISSION
Posted: February 14, 2010
After successfully hooking up ammonia coolant lines to the new Tranquility module, astronauts Robert Behnken and Nicholas Patrick returned to the space station's Quest airlock to check for contamination while flight controllers finished powering up the module's electrical systems.
Despite the release of a small amount of ammonia early in the mission, Patrick's suit was not contaminated and Flight Director Bob Dempsey said engineers successfully powered up the new module, a major milestone for the shuttle Endeavour's mission.
"It was an extremely exciting and successful day on the International Space Station, one that I'm very proud of," Dempsey said. "The team has been working for over two years to make today happen. And it did, and it was extremely successful and I'm very pleased with the way it has gone.
"Everything was accomplished as we had planned," he said. "The main objective, of course, was hooking up the ammonia lines. The ammonia lines provide cooling to the electronics and systems of the node 3 (Tranquility) module and integrates it into the cooling system of the space station. That was performed today, which allowed us to begin actually powering up the module for the first time."
As planned, only one of the two ammonia coolant loops was activated. The second loop will be activated during a spacewalk overnight Tuesday. But with one loop circulating coolant to and from the new module, flight controllers were able to complete the power-up sequence, activating lights, ventilation, computer systems and air conditioning.
The only problem occurred early in the spacewalk when Patrick was sprayed by a small amount of ammonia when he uncapped a line prior to connecting a jumper hose.
The spacewalk proceeded smoothly through its initial stages, but Patrick reported getting sprayed with a small amount of ammonia around 11 p.m. when he uncapped a connector on the Unity module before plugging in a jumper hose.
"And, OK, I have a small spray of ammonia coming out from under the cap," Patrick said. "I've backed away, I do have... ammonia did come in my direction. No more is coming out. I would estimate the total amount to be on the order of 1 cc."
"I saw some small pieces that just looked like snow, no continuous stream, just flakes is what I saw," Behnken said.
"Yep, I do not see any that's adhered to me," Patrick said. "It came out in the general direction of my right glove and my visor, but I see none adhering. I believe no more is coming out."
"And again, nothing visible currently on your helmet?" Robinson asked a few moments later.
"Nothing at all. It was about the kind of quantity of stuff that you would expect if you didn't empty the straw at the end of your drink bag."
"If you were drinking ammonia," Robinson said.
"If you were drinking ammonia," Patrick laughed.
A few moments later, Patrick pressed ahead with uncapping the line.
"I can confirm the pressure behind it is now released," he said. "My working hypothesis is it was a small leak and I'll go and continue this here. ... There's no more ammonia coming out."
"Outstanding. So this was the case we were briefed about that's happened several times before," Robinson said.
The astronauts continued the spacewalk as planned, but they returned to the airlock early and worked through a procedure to make sure no toxic ammonia made it into the station.
Patrick did not believe any ammonia had adhered to his spacesuit and a test showed none was present. The astronauts then were cleared to re-enter the station.
"This is something we've seen before, it's not unexpected necessarily, and we had prepared for it," Dempsey said. "We did go through some decontamination procedures during the EVA, just sort of inspecting and timing what we call a 'bake out.' We did come in a little bit early to make sure we had enough consumables to complete all our other decontamination procedures, which we did. No ammonia was detected, everything was fine."
The spacewalk already was officially over by that point, ending at 3:14 a.m. EST for a duration of five hours and 54 minutes. Over two spacewalks, Behnken and Patrick have logged 12 hours and 26 minutes of EVA time, pushing the station total to 867 hours and 28 minutes over 139 spacewalks.
Connecting the ammonia lines was one of the top priorities of Endeavour's mission.
"You'll be pleased to know that cooling is flowing through node 3 and our temperatures are dropping and we're continuing with the node 3 activation," Hal Getzelman radioed from mission control.
"Outstanding!" Stephen Robinson replied from the shuttle Endeavour's flight deck. "Outstanding, that's great. We're so happy our feet are off the floor."
Behnken and Patrick had no problems deploying a long sheet of multi-layer insulation and the four long ammonia hoses needed to connect Tranquility to the station's cooling system. The astronauts then had to wrap the hoses in the insulation.
"I am enjoying watching you," shuttle commander George Zamka said at one point "You are making this look very easy despite how hard we thought it was going to be."
"All those practice runs in the pool seem to be helping," Patrick said.
"Yeah, they sure do. I mean, you guys are making it look like regular duct work up there."
"Actually getting a chance to go to Huntsville (Ala.) and see the hardware makes a difference," Behnken said.
"Oh yeah, this is the second time, at least, that you all are seeing this, which must help a lot," Zamka said.
While the spacewalk was going on, station commander Jeffrey Williams continued troubleshooting an interference issue that has prevented the crew from installing a protective cover over the hatch mechanism of Tranquility's outboard port where a multi-window cupola currently is attached.
The astronauts need to move the cupola from the outboard hatch to Tranquility's Earth-facing port, but the move is on hold pending resolution of the interference issue.
Williams removed two protruding bolts that were contributing to the interference and while that appeared to resolve the matter in theory, clearances remained very tight and Dempsey said engineers were not comfortable with proceeding.
"It does fit," Dempsey said of the protective cover. "Unfortunately, it doesn't appear we have the clearance that we were hoping to get. We thought we would have about (two tenths of an inch) clearance and it looks like it's very thin, maybe 1/32nd of an inch. Therefore, we're not sure yet that we are comfortable in relocating the cupola with this potential interference. So the teams are continuing to look at options."
Dempsey said the space station's repaired urine recycling equipment appears to be working well, but another part of the water processing system is operating in a degraded mode, putting out less water than expected. Dempsey said the system's output is stable, but engineers are continuing to evaluate its performance.