Engineers study options for replacing lost grease guns
BY WILLIAM HARWOOD
STORY WRITTEN FOR CBS NEWS "SPACE PLACE" & USED WITH PERMISSION
Posted: November 18, 2008
NASA planners are studying options for replacing, or doing without, two grease guns lost overboard from the international space station today when spacewalker Heidemarie Stefanyshyn-Piper, struggling to clean up after an unexpected grease gun leak, somehow let a 30-pound tool bag get away.
The incident occurred as Stefanyshyn-Piper and fellow spacewalker Stephen Bowen were preparing to begin work cleaning and lubricating a damaged solar array rotary joint on the right side of the station. Video from Stefanyshyn-Piper's helmet cam showed her struggling to clean up after the leak. Apparently thinking the bag was still tethered, she moved it to one side and briefly turned away. The bag immediately began floating away. She made an attempt to catch it, but the bag was beyond her reach.
It was one of the most significant tool losses in recent memory and Stefanyshyn-Piper's chagrined "oh no" as the bag eluded her grasp and floated away summed up her feelings.
"We were running well ahead of time going into the beginning of the SARJ (solar alpha rotary joint) work," said spacewalk officer John Ray. "That was where things got kind of interesting. When Heide got out there and opened up the bag with the tools and spare bearings and things that we had packed to go out to the SARJ, we found that one of the grease guns had, the word Heide used was, 'exploded.'
"What it appeared on the downlink video was that one of the guns had leaked a fairly significant amount of grease out into the inside of the bag. We could see that there was grease on a lot of the tools inside the bag. Then as Heide was trying to clean that up, we could see some of that grease getting onto her gloves and she was cleaning it off her gloves as she went."
In the process, "one of our crew lock bags, which contains one set of tools that we were using to clean the SARJ with, that became untethered and separated from the bag and was lost," Ray said. "So we had to perform our SARJ cleaning with one set of tools, just sharing those between Steve and Heide. It turned out, with the additional time we had going into the EVA, they were able to work together very effectively, we still got all of our objectives done for the SARJ. Everything went really well with the SARJ cleaning."
Three more spacewalks are planned Thursday, Saturday and next Monday and all three involve more SARJ clean and lubrication.
"We've got spares of everything we can replace for the other EVAs except for the grease guns," Ray said. "But we've got some options we're looking into and some folks are working on that right now."
One option would be to use or modify one of two similar grease guns on the shuttle Endeavour as part of a wing leading edge repair kit. A heat-resistant material known as NOAX is on board to repair small cracks or blemishes in the leading edge panels and Ray said the applicators are roughly similar to one of the lost grease guns.
"We're also looking to see if we can just replan these EVAs to do them with one set of guns and just sharing them," he added. "That went fairly well on today's EVA."
Praising Stefanyshyn-Piper's work today, Ray said "all it takes is one small mistake for a tether just not to be hooked up quite correctly or to slip off where it's supposed to be engaged. And that's what happened here."
"Heide did a great job for the rest of the EVA and she showed real character and great discipline in recovering and doing a great job for the rest of the EVA," he said.
An analysis of the lost bag's departure trajectory indicates it poses no threat to the space station. An hour after the spacewalk ended, the bag was roughly 2.5 miles ahead and 650 feet below the station, moving steadily away.
While the spacewalk was going on outside the station, the rest of the combined station-shuttle crew was busy moving racks and other equipment from a storage module carried up aboard Endeavour and attached to the lab complex Monday.
"We had a great day today, both inside and outside the space station," said lead flight director Ginger Kerrick. "We had a lot of rack transfers scheduled for today. The crew has completed all of them and is a quarter of the way through the rack transfers for tomorrow. So we've been having a hard time keeping up with them."
After getting ahead of schedule Monday, the astronauts moved two 1,700-pound water recycling racks into the Destiny lab module. They also transferred combustion research gear and other rack-mounted experiment hardware, a new toilet and crew sleep stations intended to give station astronauts a bit of privacy.
The water recycling gear, which will convert condensate and urine into pure water for drinking food preparation, hygiene and oxygen generation, is crucial for NASA's plans to boost the station's crew size to six next year. Kerrick said the astronauts hoped to hook up the two water processing racks Wednesday and to begin pumping stored urine into the system Thursday.
Water samples will be returned to Earth aboard Endeavour for detailed chemical analysis. A full three months of testing is planned in orbit, with additional ground tests after the next shuttle visit in February, before any astronauts are allowed to sample the recycled water.
Going into Endeavour's mission, flight controllers were holding open the option of extending the flight one day to give the crew enough time to set up and activate a potable water dispenser. The goal is to collect samples of water from the processing racks and from the dispenser, which is tied into a common potable water bus.
The crew's fast work Monday and today "puts us in an excellent position to obtain the additional PWD, potable water dispenser, samples we had intended to go after only if we had the plus-one day added to the mission," Kerrick said.
"But now, we believe that we are so far ahead that we will be able to accomplish that within the context of our planned mission. So we expect to get the water samples from the water processor assembly that was originally planned, we get those on flight day 11 (Monday) and we expect to have the potable water bus and the potable water dispenser all set up to be able to take samples from those on either flight day 12 (Tuesday) or flight day 13 (Wednesday). So it's been great going inside."