To enjoy the full Mail & Guardian online experience: please upgrade your browser
Liz Austin Peterson
31 Oct 2007 16:45
Nasa scrambled on Wednesday to deal with two power problems at the International Space Station that could delay future missions and make it even harder to finish building the orbiting outpost before the space shuttles must be retired.
Both issues competed for the precious little spacewalking time that’s left in Discovery‘s mission, which already was extended a day after the first problem cropped up last weekend. Spacewalks were scheduled for Thursday and Saturday.
Discovery commander Pamela Melroy said that her crew is ready to tackle whatever repairs are ordered—even if that means extending the mission and adding another spacewalk.
“I think we’re kind of in the groove right now, so if the ground decides that’s the right thing to do and they ask us to do it, we’ll be ready to support it,” Melroy said on Wednesday.
Astronauts Scott Parazynski and Douglas Wheelock were getting ready on Wednesday to spend the mission’s fourth spacewalk thoroughly inspecting a malfunctioning rotary joint that keeps the station’s solar panels turned toward the sun.
Spacewalkers may spend Discovery‘s fifth planned spacewalk repairing a giant solar wing that ripped as it was being unfurled on Tuesday.
The tear forced the space agency to halt the process before the wing was fully extended.
Until at least one of the problems is resolved, the station won’t be able to generate enough power to support new equipment, such as a European lab that is supposed to be delivered by Atlantis in December.
Delaying that mission would set back other deliveries, including the planned February installation of a new Japanese lab.
Nasa is up against a hard 2010 deadline for completing the space station and retiring the three remaining shuttles.
Space-station programme manager Mike Suffredini hinted on Tuesday that another two days could be added to the flight if the newest problem is deemed serious enough.
The solar panel ripped just after Parazynski and Wheelock finished a seven-hour spacewalk to install the beam that holds the wings. Deploying the damaged wing’s twin went off without a hitch.
Melroy said the crew did the best they could with the deployment, given the fact that the sun was shining directly into their cameras. “Of course we’re always going to second-guess ourselves ... but I think we certainly aborted as soon as we saw something that wasn’t right,” she said during a joint crew news conference.
Astronauts took pictures of the wing tear, but Nasa engineers couldn’t tell what caused the damage, space-station flight director Heather Rarick said late on Tuesday. “Until we know what we think the cause is, maybe until we get some better pictures, I don’t think we really have any solid leads on how to fix it yet,” Rarick said.
Astronaut Daniel Tani said he noticed a second, smaller tear near the 75cm rip while he was taking additional pictures on Wednesday.
Nasa also wasn’t sure about the cause of the rotary-joint problem. Steel shavings were found during a spacewalk over the weekend in the joint on the right side of the station. Until Nasa figures out what’s grinding inside the gears and fixes it, the right joint will remain in a parked position as much as possible, limiting power collection.
On Thursday, Parazynski and Wheelock plan to remove 21 protective covers from the joint and search for whatever’s causing the problem. They also may clean up some of the debris.
The fifth spacewalk is dedicated to preparing the newly installed Harmony module to be moved to its permanent space-station home.
Discovery delivered the new compartment last week and it was installed in a temporary location. The three-person space-station crew plans to move the module after Discovery leaves. Those tasks could be postponed if Nasa figures out a way for spacewalkers to repair the solar wing.
Wheelock planned to use a back-up spacesuit glove on Thursday after noticing a small hole in his right glove following Tuesday’s spacewalk. It was the third time in four shuttle missions that a spacewalker had noticed a cut in his glove.
The hole only penetrated the exterior part of Wheelock’s multilayered glove. If something penetrated the entire glove, the spacewalker’s suit could leak, putting him in danger if he couldn’t quickly get back inside the station.
Discovery currently is scheduled to undock from the station on Monday and land on November 7.—Sapa-AP
Create Account | Lost Your Password?