Space Shuttle Atlantis Set For Liftoff
NASA Apparently Solves Problem With Bent Radiator Hose On Space Shuttle
Special Tool Devised To Resolve Hose Woes
Better late than never, at least for Space Shuttle Atlantis, which now is set to lift off from Launch Pad 39A at Kennedy Space Center at 2:45 p.m. ET Thursday, two months and several false starts after its initial launch date.
That launch Thursday will occur, assuming that a new problem involving a bent shuttle coolant hose has been resolved by use of a special tool to fold it into place, and assuming that the old problem of glitches in sensor data lines from external fuel tank gauges don’t recur.
The critical test of whether a fix for the fuel tank sensor data lines is going to work will come just before launch time, when NASA technicians fill the gigantic Atlantis external fuel tank with liquid hydrogen and liquid oxygen. Bet on a successful fix.
Top NASA officials last week held a flight readiness review, going over those and other issues, and emerged to clear Atlantis for flight Thursday, assuming the radiator hose problem is resolved by use of the tool.
During an inspection of Atlantis before the meeting, one of four hoses that carry Freon to the shuttle radiators in the payload bay was found to be bent and not properly retracted in its storage box.
Other hoses were fully retracted into their storage boxes, as expected.
Bill Gerstenmaier, associate NASA administrator for space operations, and Wayne Hale, space shuttle program manager, briefing reporters after the flight readiness review, indicated that further study of the radiator hose issue might show that it’s safe to fly with the hose bent, at least for one mission.
Then, NASA experts and contractor workers devised a fix, a tool to help fold the hose into place as the giant Atlantis payload bay doors swing shut. Problem solved.
Even before the tool was created, Hale emphasized that the hose, even though bent, still works to carry Freon that moves between electronic components that must be kept cool, so they don’t overheat, and radiators in the space shuttle payload doors.
"Right now, that hose is operational," Hale said. "This hose … is not leaking, it’s just bent the wrong way." The radiator hose is designed to flex as the space shuttle payload doors open and shut.
"Hopefully, we will come to the conclusion that this is acceptable to fly, or manually straighten [the hose] out," Hale said.
Even in a worst-case scenario, if the hose had a problem while Atlantis was in orbit, the NASA leaders noted that if there were a problem with the cooling system in space, they could bypass the radiators and go to a backup water evaporation system, though they would prefer not to do that, wishing to conserve water.
Gerstenmaier and Hale also expressed a great deal of certainty that the fuel tank sensor fix is going to work, after experts and technicians labored for weeks to fathom what caused the glitch.
"They’ve got a good fix on it," Gerstenmaier said, because they were able to reproduce the problem in tests.
"This fix is a good fix," agreed Hale. "I have a high degree of confidence we have solved the problem." He expressed hope that "we’ll never have to talk about engine cutoff sensors" again.
The fuel gauge sensors detect when fuel in the external fuel tank is running low, which is important because if the tank runs dry and shuttle engines continue to run, there could be a disastrous explosion.
At this point, the shuttle can fly if three of the four sensors and sensor data lines are operating well.
Over the past two months, NASA engineers and experts have battled bedeviling glitches in lines that feed data from fuel gauges, sensors near the bottom of the Atlantis external fuel tank.
While there was a glass-smooth countdown to a planned Dec. 6 Atlantis launch, at the last minute the liftoff had to be scrubbed, because during fueling operations, sensors at the bottom of the liquid hydrogen portion of the tank appeared to malfunction.
It took exhaustive detective work to discover that it wasn’t the sensors at fault, but rather the wiring and pass-through connectors carrying data from the sensors through the side of the tank, to the outside and on to the orbiter vehicle. (Please see Space & Missile Defense Report, Monday, Jan. 14, 2008)
After experts determined that electrical pins in the connector failed to make contact, causing the faulty fuel sensor readings, technicians soldered parts in place, apparently resolving the problem.
Experts also are studying cracks in glass materials in the pass-through connector design. "There have been numerous cracks noted," Hale said. "We do not believe [the] cracks are a major issue," but will continue to examine them over the next two months or so.
The pass-through connector malfunction is just the latest example of launch-delaying problems that have afflicted the star-crossed space shuttle.
Atlantis last year was on the launch pad when a rogue thunderstorm rumbled along and hammered hail onto the shuttle, putting an enormous number of dings in the external fuel tank insulation that had to be repaired before the shuttle could fly. Months were lost from the flight manifest schedule.
Earlier, Atlantis was up for a mission when another thunderstorm hurled a lightning bolt that narrowly missed the spaceship, so technicians had to check myriad electrical circuits and computer parts to see whether they had been zapped. Then, a hurricane howled toward Atlantis, only to turn away before hitting Cape Canaveral.
Perhaps the latest problems with sensor data lines and the coolant hose, hopefully now solved, will prove that bad luck comes in sets of three, and Atlantis finally will break its Red Sox curse.
Now, if the bent coolant hose problem is resolved by using the custom-designed tool, perhaps Atlantis can head up to the blackness of space.
Even if all goes well and Atlantis flies Thursday, that still will leave NASA with a crowded shuttle flights manifest this year. Including Atlantis, NASA is aiming to perform five space shuttle missions this year, perhaps not a new record, but still a challenging pace.
At issue is completion of the International Space Station (ISS) before the mandated retirement of the space shuttle fleet, now set for Sept. 30, 2010. While the United States will develop a new spaceship system, the Orion crew exploration vehicle capsule for astronauts and the Ares rocket to lift Orion into orbit, that won’t be ready for manned flight until 2015. And when it does fly, even the cargo version of the new system won’t have anything like the size and muscle of a space shuttle. The shuttles are the only spacecraft capable of hauling huge, heavy structural components into orbit required for assembling the space station.
Both Gerstenmaier and Hale said that NASA won’t be pressured by flight schedule concerns, and won’t permit the shuttle to fly until it is safe.
For example, when Atlantis finally roars aloft on the 11-day STS-122 Mission, it will carry the Columbus European Space Agency laboratory module, a huge room-sized addition that will be fastened to the space station. The Columbus laboratory will expand space station research facilities and provide scientists around the world with the ability to conduct a variety of life, physical and materials science experiments.
In a closely choreographed, meticulously orchestrated orbital operation, Space Shuttle Endeavour will blast off on March 11, less than five weeks after the Atlantis liftoff, for the STS-123 Mission to carry a pressurized part of the Japanese Kibo laboratory to add to the space station.
Shuttles this year also will execute two more space station assembly missions, plus a mission to repair and upgrade the Hubble Space Telescope.
The Space Shuttle Atlantis STS-122 Mission will include three spacewalks, delivery of a new crew member to the station and return of another astronaut after nearly four months aboard the complex.
That astronaut, Dan Tani, flight engineer with the Expedition 16 space station crew, was in orbit when his mother died. He missed attending her funeral, and because of delays in the Space Shuttle Atlantis flight, he is still in orbit, still working hard, including taking a spacewalk to fix a problem on the space station.
The Atlantis space shuttle crew numbers seven personnel: Commander Steve Frick, Pilot Alan Poindexter and Mission Specialists Leland Melvin, Rex Walheim, Stanley Love and European Space Agency astronauts Hans Schlegel and Leopold Eyharts.
Eyharts will replace Tani, who has lived on the outpost since October. Eyharts will return to Earth on the Space Shuttle Endeavour next month.