Spaceflight Now




Astronauts struggle to release tight bolt
BY WILLIAM HARWOOD
STORY WRITTEN FOR CBS NEWS "SPACE PLACE" & USED WITH PERMISSION
Posted: September 13, 2006;
Updated after status briefing

Astronauts Dan Burbank and Steve MacLean, using their combined muscle power, a big wrench and lots of grunts and groans, finally freed an overly tight bolt today that threatened to prevent a massive rotating joint from operating properly.

"What a great day," station flight director John McCullough said when the work was done. "Today we had numerous battles with the hardware, but that's the reason we have people in space. And today it took a couple of strong folks to get the job done.

"I know it's not a very good analogy, but it was almost like giving birth today, the fighting that we had to go through and the labor pains. I hate to use that analogy because it's nothing like that. But you get the idea."

The spacewalk began at 5:05 a.m. and ended seven hours and 11 minutes later at 12:16 p.m. It was the 71st space station assembly or maintenance spacewalk, pushing total EVA time to 431 hours and 54 minutes since construction began in December 1998.

The bolt in question secured one of six large launch restraints on the 2,500-pound solar alpha rotary joint at the heart of the new port 3 truss that was attached to the space station Tuesday. The SARJ was launched with 16 launch locks on the main gear assembly and larger launch restraints, all of which had to be removed to permit rotation of the new solar array making up the outboard P4 truss.

MacLean and Burbank successfully removed the smaller launch locks, although one of the bolts used to secure a thermal blanket broke free. Astronaut Joe Tanner ran into similar trouble during a spacewalk Tuesday, prompting concern about potential debris inside the SARJ mechanism. But flight controllers said Tuesday and again today that they were not concerned.

"I didn't see this as a real big deal," said John Haensly, lead spacewalk flight director at the Johnson Space Center.

Earlier today, MacLean ran into problems freeing a bolt holding a large launch restraint in place. After breaking a socket trying to free the bolt, he and Burbank, with advice and guidance from Tanner, used a larger wrench and put their combined muscle power into the effort.

Despite concern they might snap the head off the bolt, McCullough said there was never any chance of that and in any case, Burbank and MacLean eventually succeeded, much to everyone's relief.

"Yoo hoo!" one of the astronauts yelled.

"All right!" another said.

"OK, that one's free," MacLean confirmed, prompting another astronaut to observe "now there was much rejoicing."

"You guys didn't spend enough time at the gym," someone joked.

"Whoa," Burbank said. "Yeah, Steve broke one of your tools because he didn't spend enough time at the gym."

"I hope they don't take it out of my wages, you know," MacLean said.

A few moments later, astronaut Pam Melroy called from mission control in Houston, saying "we appreciate your answering that age-old question for MCC: how many astronauts does it take to unscrew a bolt? And apparently it takes three, two outside and one inside. We're very pleased, you guys did an awesome job and that was great teamwork."

"Yeah, this was an amazing effort you guys," Tanner added. "You wouldn't have imagined the drama inside here and I'm sure the drama on the ground right now, a few minutes ago."

"It would be a show stopper for rotation and (solar array) deploy," agreed Burbank.

"You betcha."

Flight controllers, meanwhile, are gearing up to begin test and checkout of the SARJ prior to ordering a full 360-degree rotation later today. The still-stowed P4 solar arrays must be rotated 180 degrees before they are deployed Thursday and after the SARJ completes its 360-degree turn, it will reverse and move back 180 degrees.

A second SARJ will be attached to the right side of the space station's solar array truss next February and engineers are anxious to check out the operation of the one in P3.

"This is a component we haven't flown yet, this is the first one we're doing," spacewalker Heidemarie Stefanyshyn-PiperPiper said in a pre-launch interview. "So that's probably one of the big unknowns, how is that joint going to react in space? If it doesn't work, then your arrays are going to be parked where they are, you're not going to be able to track the sun."

For readers interested in a bit more technical detail, here's a description of the joint from Boeing, the prime contractor:

"P3 consists of the Solar Alpha Rotary Joint (SARJ), which continuously rotates to keep the solar array wings on P4 and P6 oriented towards the sun as the station orbits the earth. Located between P3 and P4, the SARJ is a 10 foot diameter rotary joint that tracks the sun in the alpha axis that turns the entire P4 module (and eventually the P6 module when it is relocated). The SARJ weighs approximately 2,500 pounds.

"The SARJ can spin 360 degrees using bearing assemblies and a servo control system to turn. All of the power will flow through the Utility Transfer Assembly (UTA) in the SARJ. Roll ring assemblies allow transmission of data and power across the rotating interface so it never has to unwind. Under contract to Boeing, the SARJ was designed, built and tested by Lockheed Martin in Sunnyvale, Calif.

"The solar array wings are also oriented by the Beta Gimbal Assembly (BGA), which can change the pitch of the wings by spinning the solar array. The BGA measures 3 x 3 x 3 feet and provides a structural link between the Integrated Equipment Assembly (IEA). The BGA's most visual functions are to deploy and retract the SAW and rotate it about its longitudinal axis.

"Both the SARJ and BGA are pointing mechanisms and they can follow an angle target and rotate to that target. On-orbit controllers continuously update those targets so it keeps moving continuously as the station orbits the Earth every 90 minutes, maintaining contact with the sun at the same orbital rate. The SARJ mechanism will move much more than the BGA. The BGA will move about four or five degrees per day, whereas the SARJ will rotate 360 degrees every orbit or about 4 degrees per minute.

"The SARJ will be the first one to be installed on station and it is unique because it rotates the entire truss element, allowing it to rotate in the alpha axis rotation. The station has been using the P6 BGA to move as an alpha joint. Eventually, the SARJ will provide primary rotation with BGA doing minor movements and will be tested on this flight, but won't be activated until assembly mission 12A.1."

That mission, by the shuttle Discovery, is scheduled for launch Dec. 14. During the flight, the left wing of the P6 array, currently mounted on the Z1 truss atop the Unity module, will be retracted. That will clear the area needed for the new P4 arrays to rotate as designed.

The right wing of the P6 array will be retracted during the next shuttle flight in February. If all goes well, the arrays will be attached to a spacer next to P4 next August.

Spaceflight Now Plus
Additional coverage for subscribers:
VIDEO: STEP-BY-STEP PREVIEW OF SPACEWALK NO. 2 PLAY
VIDEO: POST-EVA 1 STATUS BRIEFING DIAL-UP | BROADBAND
VIDEO: TANNER LOSES BOLT DURING ROTARY JOINT WORK PLAY
VIDEO: PIPER UNFOLDS SOLAR BLANKET BOXES SHORT | FULL
VIDEO: SECOND WING'S STRUCTURE DEPLOYED BY PIPER PLAY
VIDEO: FIRST SOLAR WING'S STRUCTURE DEPLOYED BY TANNER PLAY
VIDEO: STEP-BY-STEP PREVIEW OF SPACEWALK NO. 1 PLAY
VIDEO: TRUSS HANDED FROM SHUTTLE ARM TO STATION ARM PLAY
VIDEO: ARM MANEUVERS TRUSS OVER SHUTTLE WING PLAY
VIDEO: TRUSS SLOWLY LIFTED OUT OF PAYLOAD BAY PLAY
VIDEO: ATLANTIS' ARM GRAPPLES THE TRUSS PLAY
VIDEO: MONDAY'S MISSION STATUS BRIEFING DIAL-UP | BROADBAND
VIDEO: ATLANTIS WELCOMED ABOARD THE STATION PLAY
VIDEO: DOCKING REPLAY FROM CAMERA ON SHUTTLE ARM PLAY
VIDEO: SHUTTLE ATLANTIS DOCKS TO THE STATION PLAY
VIDEO: ATLANTIS' BREATH-TAKING FLIP MANEUVER PLAY
VIDEO: CREW'S CAMCORDER FOOTAGE OF EXTERNAL TANK PLAY
VIDEO: NARRATED ANIMATION PREVIEWING TRUSS UNBERTHING PLAY
VIDEO: NARRATED ANIMATION PREVIEWING THE DOCKING PLAY
VIDEO: NARRATED ANIMATION OF PAYLOAD BAY CONFIGURATION PLAY
MORE: STS-115 VIDEO COVERAGE
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VIDEO: BRIEFING ON TANK'S PERFORMANCE DIAL-UP | BROADBAND
VIDEO: TANK'S ONBOARD CAMERA LIFTOFF TO SEPARATION PLAY
VIDEO: FLIGHT DIRECTOR EXPLAINS INSPECTIONS PLAY
VIDEO: SUNDAY'S MISSION STATUS BRIEFING DIAL-UP | BROADBAND

VIDEO: LAUNCH OF ATLANTIS! PLAY
VIDEO: SHEDDING FOAM MAY HAVE HIT ATLANTIS PLAY
VIDEO: ONBOARD VIEW OF EXTERNAL TANK SEPARATION PLAY
VIDEO: INSIDE MISSION CONTROL DURING LAUNCH PLAY
VIDEO: STATION CREW TOLD VISITORS EN ROUTE PLAY
VIDEO: HOUSTON RADIOS DEBRIS REPORT TO CREW PLAY
VIDEO: POST-LAUNCH NEWS CONFERENCE DIAL-UP | BROADBAND
VIDEO: QUICK-LOOK BRIEFING ON DEBRIS DIAL-UP | BROADBAND

LAUNCH REPLAYS:
VIDEO: BEACH MOUND TRACKER PLAY
VIDEO: CAMERA IN FRONT OF PAD PLAY
VIDEO: BANANA CREEK VIEWING SITE PLAY
VIDEO: VEHICLE ASSEMBLY BUILDING ROOF PLAY
VIDEO: PAD 39B SIDE PERIMETER PLAY
VIDEO: PLAYALINDA BEACH TRACKER PLAY
VIDEO: PLAYALINDA BEACH ZOOM PLAY
VIDEO: UCS 23 TRACKER PLAY
VIDEO: UCS 11 TRACKER PLAY

VIDEO: MISSION SPECIALIST 4 STEVE MACLEAN BOARDS ATLANTIS PLAY
VIDEO: MISSION SPECIALIST 3 HEIDE PIPER BOARDS PLAY
VIDEO: MISSION SPECIALIST 2 DAN BURBANK BOARDS PLAY
VIDEO: MISSION SPECIALIST 1 JOE TANNER BOARDS PLAY
VIDEO: PILOT CHRIS FERGUSON BOARDS PLAY
VIDEO: COMMANDER BRENT JETT BOARDS PLAY

VIDEO: ASTRONAUTS EMERGE FROM CREW QUARTERS PLAY
VIDEO: CREW SUITS UP FOR LAUNCH TO SPACE PLAY
VIDEO: FINAL INSPECTION TEAM CHECKS ATLANTIS PLAY
VIDEO: ASTRONAUTS READY FOR SECOND LAUNCH TRY PLAY
MORE: STS-115 VIDEO COVERAGE
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