Credit: NASA TV/Spaceflight Now

A 2,500-pound rotary joint seeing its first use aboard the international space station, successfully rotated a new set of still-stowed solar arrays today in a key test before array deployment early Thursday.

As installed on the left end of the station's main solar array truss Tuesday, the new panels were oriented so their cooling radiators would have extended straight up if deployed, contacting a set of operational arrays.

After checking out the new solar alpha rotary joint - SARJ - flight controllers sent commands to turn the joint, first 5 degrees and then a full 180 degrees, using one of two redundant motors. Space station flight director John McCullough said the initial checks went well and controllers will move the joint a full 360 degrees later today to test the other drive system.

"The really great news is the SARJ, the solar alpha rotary joint that we worked so hard on and talked about so much, it moved right before this briefing," McCullough told reporters. "I was pretty excited to see that. It was a great day and very visually enticing."

If all goes well, flight controllers will begin the solar array extension process late today, deploying each packed-up wing a bit more than a yard, the length of one bay of their motorized self-assembling masts. On Thursday, the Atlantis astronauts will send commands to extend the masts the rest of the way.

Once deployed, each 38-foot-wide solar array wing will stretch more than 115 feet in opposite directions. A detailed overview of solar array deployment will be posted here later today.

Additional coverage for subscribers:
VIDEO: PORT 3/PORT 4 TRUSS KEEL PIN REMOVED AND STOWED PLAY
VIDEO: HELMETCAM OF BURBANK REMOVING SARJ RESTRAINT PLAY
VIDEO: SPACEWALKERS PAUSE FOR PICTURE TIME PLAY
VIDEO: STEVE MACLEAN REPORTS LOST BOLT PLAY
VIDEO: ROTARY JOINT LOCK REMOVED BY SPACEWALKER PLAY
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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