Running about an hour behind schedule, the Atlantis astronauts successfully bolted a new 36,000-pound solar array truss and rotary joint to the international space station today, setting the stage for a spacewalk by Jim Reilly and Danny Olivas to activate and outfit the new equipment.

Danny Olivas makes his way along the space station truss with shuttle Atlantis in the background. Credit: NASA TV/Spaceflight Now

Shuttle pilot Lee Archambault, operating the space station's Canadian-built robot arm, eased the huge truss segment into place for an initial capture around 2:27 p.m. A large claw on the outboard end of the existing S1 truss then rotated and locked onto a capture bar in the S3 segment.

As the claw pulled the S3/S4 segments in tight, alignment guides ensured four motorized bolts lined up properly. By 3:11 p.m., three of the bolts had been successfully driven home - a requirement for pressing ahead with today's spacewalk - and a few minutes later, Archambault, operating the robot arm, released the now-firmly-attached truss. The fourth bolt was in place by 3:38 p.m.

The work ran about an hour behind schedule after the space station's control moment gyroscopes became "saturated," losing their ability to maintain the station's orientation. This is a routine issue with gyroscope systems and after using the shuttle's thrusters to maintain control, the station gyros were reset and able to resume control.

Reilly and Olivas (prono: oh-LEE-vus) switched their spacesuits to internal battery power at 4:02 p.m. to officially begin a planned six-and-a-half-hour spacewalk. The goal of the excursion is to electrically connect a newly attached solar array truss segment to the station's power system and to remove a variety of launch locks and restraints so the huge blankets can be unfurled Tuesday.

This is the 84th spacewalk devoted to station assembly and maintenance since construction began in 1998, the seventh so far this year and the first of at least three EVAs by the Atlantis astronauts. It is the first spacewalk for Olivas and the third for Reilly.

"It's beautiful out here," Olivas marveled as he floated out of the Quest airlock module.

Reilly and Olivas began today's spacewalk an hour and six minutes late because of work needed to reset the space station's control moment gyroscopes earlier in the truss attachment sequence.

Here is an estimated timeline of today's activities based on the actual start time of the EVA (in EDT and elapsed time; subject to change):

EDT........HH...MM...EVENT

04:02 PM...00...00...Spacesuits to battery power
04:12 PM...00...10...Airlock egress
04:27 PM...00...25...Reilly: Connect S1-S3 nadir electrical cables
04:47 PM...00...45...Olivas: Release solar array blanket box restraints
05:02 PM...01...00...Reilly: S3 computer shroud removal
05:32 PM...01...30...Reilly: Connect S1-S3 zenith electrical cables
06:02 PM...02...00...Reilly: Keel pin rotate
06:32 PM...02...30...Reilly: Release solar panel gimbal assembly
06:47 PM...02...45...Olivas: Release radiator locks
07:12 PM...03...10...Reilly: Unstow forward solar array blanket box
07:17 PM...03...15...Olivas: Unstow aft solar array blanket box
07:32 PM...03...30...Reilly: Install rotary joint drive motor (1 of 2)
07:37 PM...03...35...Olivas: Remove unneeded insulation blankets
08:07 PM...04...05...Olivas: Rigidize internal truss braces
08:32 PM...04...30...Reilly: Remove rotary joint launch locks
08:47 PM...04...45...Olivas: Remove rotary joint launch locks
09:47 PM...05...45...Cleanup and ingress
10:27 PM...06...25...Airlock repressurization

Additional coverage for subscribers:
VIDEO: SUNDAY'S MISSION STATUS BRIEFING PLAY
VIDEO: SHUTTLE CREW WELCOMED ABOARD STATION PLAY
VIDEO: ATLANTIS DOCKS WITH THE SPACE STATION PLAY
VIDEO: WATCH THE RENDEZVOUS BACKFLIP MANUEVER PLAY
VIDEO: FLIGHT DAY 2 HIGHLIGHTS MOVIE PLAY
VIDEO: SATURDAY'S MISSION STATUS BRIEFING PLAY
VIDEO: FLIGHT DAY 1 HIGHLIGHTS MOVIE PLAY
VIDEO: INSIDE MISSION CONTROL DURING LAUNCH PLAY
VIDEO: LAUNCH REPLAY: VIEW FROM COMPLEX 41 PLAY
VIDEO: LAUNCH REPLAY: PAD PERIMETER PLAY
VIDEO: LAUNCH REPLAY: THE VAB ROOF PLAY
VIDEO: LAUNCH REPLAY: THE PRESS SITE PLAY
VIDEO: LAUNCH REPLAY: UCS-23 TRACKER PLAY
VIDEO: LAUNCH REPLAY: PAD FRONT CAMERA PLAY
VIDEO: LAUNCH REPLAY: CAMERA AT THE BEACH PLAY

VIDEO: LAUNCH OF ATLANTIS! PLAY
VIDEO: FULL LENGTH MOVIE OF ASCENT TO ORBIT PLAY
VIDEO: EXTERNAL TANK ONBOARD VIDEO CAMERA PLAY
VIDEO: POST-LAUNCH PRESS CONFERENCE PLAY

VIDEO: ASTRONAUTS DEPART QUARTERS FOR THE PAD PLAY
VIDEO: PAD'S ROTATING SERVICE STRUCTURE RETRACTED PLAY
VIDEO: HIGHLIGHTS FROM ATLANTIS' LAUNCH CAMPAIGN PLAY
VIDEO: HIGHLIGHTS OF THE PAYLOAD'S LAUNCH CAMPAIGN PLAY

MORE: STS-117 VIDEO COVERAGE
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