Astronauts Garrett Reisman and Stephen Bowen carried out an extended seven-hour 25-minute spacewalk Monday, moving a backup Ku-band antenna to the International Space Station along with an equipment mounting platform. They also loosened bolts holding six new solar array batteries to a cargo pallet as get-ahead work for two upcoming spacewalks.

An illustration of the spacewalkers working on the station's new communications antenna next to the original one. Credit: NASA

"The EVA was pretty much a raging success," said Lisa Shore, the lead spacewalk officer for Atlantis' mission at the Johnson Space Center. "We met every one of our major objectives. These EVAs were a challenge to train because we could not complete them end to end in (ground facilities). Until we actually performed them, we weren't sure how the timing was going to come out. And the crew just did a fantastic job."

The spacewalkers had to contend with a space station computer glitch during the excursion, struggled with a balky electrical connector and were unable to completely tighten down the new dish antenna on its eight-foot-tall support mast.

Engineers are considering whether the bolts in question should be re-tightened at some point down he road to close up a 1-millimeter gap in the dish-boom interface. Because the current configuration has never been analyzed in terms of its response to structural loads, the astronauts were told to re-engage the antenna's steering system launch locks and to tether the antenna to the truss as a safety precaution.

Even so, mission managers said they considered the spacewalk and the progress of the Atlantis mission to this point to be an overall success.

"We couldn't be more pleased with how the mission is going so far," said LeRoy Cain, chairman of NASA's Mission Management Team. "We've had a few glitches here and there, but they're not significant in the grand scheme of the kinds of things we're trying to accomplish on this docked mission."

The computer glitch occurred as Reisman, anchored to the end of the station's robot arm, was in the process of getting the dish antenna from a cargo pallet before moving it up to the Z1 truss for installation. One of the station's three primary command-and-control computers, or C&C machines, dropped off line and handed operations over to a backup.

That, in turn, shut down the station's video system and the lab's robot arm. The robot arm was re-enabled after a brief interruption and the spacewalk proceeded.

Flight Director Emily Nelson said engineers believe the glitch may have been triggered when Bowen removed caps from electrical connectors in preparation for installation of the new Ku-band antenna.

"When the cap was removed, what we suspect is that that broke continuity in one of our data buses and that confused our C&C, our command and control computer, such that it suspected a failure," she said. "And in case the failure is with that computer, it goes off line and allows its backup to come up.

"All of the critical functions that that computer provides are handed over immediately to the backup machine. So we maintained communications via S-band, the (robot) arm safed itself because of that transition of its controller. But all of our other functions within the machine were handed over from one to the next."

The space station currently is operating with two C&C machines, a primary and a backup, pending a review of telemetry to make sure the problem with C&C No. 3 is fully understood.

Monday's spacewalk was the 144th devoted to station assembly and maintenance since construction began in 1998, the eighth so far this year and the first of three planned by the shuttle Atlantis' crew. Total EVA time now stands at 900 hours and 58 minutes, or 37.5 days. Bowen's EVA time through four spacewalks is 27 hours and 21 minutes while Reisman's total through two EVAs stands at 14 hours and 26 minutes.

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Additional coverage for subscribers:
VIDEO: MONDAY'S MISSION STATUS BRIEFING PLAY
VIDEO: AN ADDITION TO DEXTRE ROBOT PLAY
VIDEO: TORQUING ANTENNA ASSEMBLY INTO PLACE PLAY
VIDEO: FETCHING 6-FOOT-DIAMETER ANTENNA DISH PLAY
VIDEO: BOLTING BOOM ATOP STATION'S Z1 TRUSS PLAY
VIDEO: SPACEWALKERS HANDOFF ANTENNA BOOM PLAY
VIDEO: UNPACKING ANTENNA BOOM FROM CARRIER PLAY
VIDEO: SPACEWALK NO. 1 BEGINS PLAY
VIDEO: STEP-BY-STEP WALKTHROUGH OF EVA NO. 1 PLAY
VIDEO: PREVIEW OF FLIGHT DAY 4 ACTIVITIES PLAY
VIDEO: MONDAY MORNING'S FLIGHT DIRECTOR INTERVIEW PLAY

VIDEO: FLIGHT DAY 3 HIGHLIGHTS MOVIE PLAY
VIDEO: MISSION MANAGEMENT TEAM CHAIRMAN UPDATE PLAY
VIDEO: CARRIER ATTACHED TO STATION'S RAILCAR PLAY
VIDEO: CARGO PALLET LIFTED FROM SHUTTLE BAY PLAY
VIDEO: SUNDAY'S MISSION STATUS BRIEFING PLAY
VIDEO: WELCOMING CEREMONY FOR SHUTTLE CREW PLAY
VIDEO: ATLANTIS DOCKS TO INTERNATIONAL SPACE STATION PLAY
VIDEO: SHUTTLE ATLANTIS PERFORMS BACKFLIP MANEUVER PLAY
VIDEO: BEAUTIFUL VIEWS OF SHUTTLE ATLANTIS APPROACHING PLAY
VIDEO: ANIMATED PREVIEW OF FLIGHT DAY 3 ACTIVITIES PLAY

VIDEO: FLIGHT DAY 2 HIGHLIGHTS MOVIE PLAY
VIDEO: CREW'S HOME MOVIES FOR FLIGHT DAY 2 PLAY
VIDEO: MISSION MANAGEMENT TEAM CHAIRMAN UPDATE PLAY
VIDEO: SATURDAY'S MISSION STATUS BRIEFING PLAY

VIDEO: FLIGHT DAY 1 HIGHLIGHTS MOVIE PLAY
VIDEO: SHUTTLE ATLANTIS BLASTS OFF! PLAY | HI-DEF
VIDEO: GO INSIDE MISSION CONTROL DURING LAUNCH PLAY
VIDEO: POST-LAUNCH NEWS CONFERENCE PLAY

VIDEO: LAUNCH REPLAY: VAB ROOF PLAY | HI-DEF
VIDEO: LAUNCH REPLAY: PRESS SITE PLAY | HI-DEF
VIDEO: LAUNCH REPLAY: PATRICK AFB PLAY | HI-DEF
VIDEO: LAUNCH REPLAY: PAD PERIMETER PLAY | HI-DEF
VIDEO: LAUNCH REPLAY: BEACH TRACKER PLAY | HI-DEF
VIDEO: LAUNCH REPLAY: PAD CAMERA 070 PLAY | HI-DEF
VIDEO: LAUNCH REPLAY: PAD CAMERA 071 PLAY | HI-DEF
VIDEO: LAUNCH REPLAY: PLAYALINDA BEACH PLAY | HI-DEF
VIDEO: LAUNCH REPLAY: PAD FRONT CAMERA PLAY | HI-DEF

VIDEO: CREW ARRIVES AT LAUNCH PAD 39A PLAY | HI-DEF
VIDEO: ASTRONAUTS LEAVE CREW QUARTERS PLAY | HI-DEF
VIDEO: CREW FINISHES GETTING SUITED UP PLAY | HI-DEF
VIDEO: ASTRONAUTS WEARING TUXEDOS LAUNCH DAY PLAY | HI-DEF

VIDEO: NARRATED REVIEW OF SHUTTLE'S PREPARATIONS PLAY | HI-DEF
VIDEO: NARRATED REVIEW OF PAYLOADS' PREPARATIONS PLAY | HI-DEF

VIDEO: ATLANTIS ON EVE OF FINAL PLANNED LAUNCH PLAY | HI-DEF
VIDEO: LAUNCH PAD'S SERVICE TOWER RETRACTED PLAY | HI-DEF
VIDEO: PAYLOAD BAY DOORS CLOSED FOR LAUNCH PLAY | HI-DEF
VIDEO: ASTRONAUTS INSPECT THE PAYLOAD BAY PLAY | HI-DEF

VIDEO: JERRY ROSS' LAUNCH ON MISSION STS-61B PLAY
VIDEO: MAIDEN LAUNCH OF ATLANTIS AS SEEN LIVE IN 1985 PLAY
VIDEO: ATLANTIS' FIRST MISSION ENDS WITH LAKEBED LANDING PLAY
VIDEO: AN ASTRONAUT'S TRIBUTE TO SHUTTLE ATLANTIS PLAY

VIDEO: COUNTDOWN STATUS AND WEATHER FORECAST PLAY
VIDEO: WATCH NASA'S PRE-LAUNCH NEWS CONFERENCE PLAY
VIDEO: GET BRIEFED ON THE LAUNCH COUNTDOWN PLAY
VIDEO: HEAR FROM THE COMMANDER AT THE RUNWAY PLAY | HI-DEF
VIDEO: ASTRONAUTS ARRIVE IN FLORIDA FOR LAUNCH PLAY | HI-DEF

VIDEO: PRE-LAUNCH INTERVIEW WITH KEN HAM PLAY
VIDEO: PRE-LAUNCH INTERVIEW WITH TONY ANTONELLI PLAY
VIDEO: PRE-LAUNCH INTERVIEW WITH GARRETT REISMAN PLAY
VIDEO: PRE-LAUNCH INTERVIEW WITH MIKE GOOD PLAY
VIDEO: PRE-LAUNCH INTERVIEW WITH STEVE BOWEN PLAY
VIDEO: PRE-LAUNCH INTERVIEW WITH PIERS SELLERS PLAY

VIDEO: STS-132 MISSION PREVIEW MOVIE PLAY | HI-DEF

VIDEO: FULL FLIGHT READINESS REVIEW NEWS BRIEFING PLAY
VIDEO: RECAP OF THE FLIGHT READINESS REVIEW PLAY | HI-DEF
VIDEO: MANAGERS ASSESS ISSUES BEFORE FLIGHT PLAY | HI-DEF
VIDEO: UPDATE ON PRE-LAUNCH PREPS AT PAD 39A PLAY | HI-DEF

VIDEO: PROGRAM BRIEFING BY SHUTTLE AND STATION CHIEFS PLAY
VIDEO: THE STS-132 MISSION OVERVIEW PRESENTATIONS PLAY
VIDEO: PREVIEW BRIEFING ON MISSION'S SPACEWALKS PLAY
VIDEO: THE ASTRONAUTS' PRE-FLIGHT NEWS BRIEFING PLAY

VIDEO: SHUTTLE EVACUATION PRACTICE PLAY | HI-DEF
VIDEO: ASTRONAUTS BOARD ATLANTIS PLAY | HI-DEF
VIDEO: LAUNCH DAY REHEARSAL BEGINS PLAY | HI-DEF
VIDEO: CREW BRIEFED ON EMERGENCY PROCEDURES PLAY | HI-DEF
VIDEO: TEST-DRIVING AN EMERGENCY ARMORED TANK PLAY | HI-DEF
VIDEO: CREW'S CHAT WITH REPORTERS AT PAD 39A PLAY
VIDEO: ASTRONAUTS AT KENNEDY SPACE CENTER RUNWAY PLAY | HI-DEF
VIDEO: CREW ARRIVES FOR PRACTICE COUNTDOWN PLAY | HI-DEF

VIDEO: GANTRY PLACED AROUND ATLANTIS PLAY | HI-DEF
VIDEO: SHUTTLE ATLANTIS REACHES PAD 39A PLAY | HI-DEF
VIDEO: CROWDS AND THE CREW CHEER ON ATLANTIS PLAY | HI-DEF
VIDEO: OVERNIGHT ROLLOUT TO THE PAD BEGINS PLAY | HI-DEF

VIDEO: SHUTTLE HOISTED FOR ATTACHMENT TO TANK PLAY | HI-DEF
VIDEO: CRANE ROTATES THE ORBITER VERTICALLY PLAY | HI-DEF
VIDEO: ATLANTIS RISES OFF THE TRANSPORTER PLAY | HI-DEF
VIDEO: ORBITER EMERGES FROM ITS HANGAR PLAY | HI-DEF
VIDEO: BUTTONING UP RUDDER/SPEED BRAKE PLAY | HI-DEF
VIDEO: DOME SHIELDS AROUND MAIN ENGINES PLAY | HI-DEF
VIDEO: EXTERNAL TANK ATTACHED TO BOOSTERS PLAY | HI-DEF

VIDEO: PAYLOADS HEAD FOR LAUNCH PAD PLAY | HI-DEF
VIDEO: RASSVET PLACED INTO THE TRANSPORTER PLAY | HI-DEF
VIDEO: PALLET LOADED WITH MISSION'S CARGO PLAY | HI-DEF
VIDEO: RUSSIAN RASSVET MODULE ON DISPLAY PLAY | HI-DEF
VIDEO: RUSSIAN ENGINEERS DISCUSS THEIR RASSVET MODULE PLAY
VIDEO: RASSVET HATCH CLOSED FOR FLIGHT PLAY | HI-DEF
VIDEO: FILLING MODULE WITH NASA SUPPLIES PLAY | HI-DEF

VIDEO: ASTRONAUTS VISIT THEIR SPACECRAFT PLAY | HI-DEF
VIDEO: CREW INSPECTS RASSVET MODULE PLAY | HI-DEF
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