STS-134 mission specialists Drew Feustel and Mike Fincke are outside the International Space Station, beginning the second of four spacewalks scheduled for space shuttle Endeavour's final mission.

The two astronauts switched their spacesuits to internal (battery) power at 1:05 a.m. CDT on Sunday, marking the start of their planned six and a half hour excursion.

"Alright guys, here we go," said spacewalk choreographer Greg Chamitoff from inside Endeavour. "This is an important one for the longevity of the station, for the power and cooling, so let's get started."


The 246th spacewalk made by U.S. astronauts and the 157th in support of station assembly and maintenance, this is the fifth for Feustel and the seventh for Fincke.

"Welcome to your first U.S.-based EVA from the U.S. airlock," Chamitoff radioed Fincke, whose earlier spacewalks were all out of Russian station airlocks.

"Drew, welcome back outside, man," said Fincke a few minutes later. "It is an honor to be spacewalking with a Hubble spacewalker."

Prior to this flight, Feustel made three spacewalks during the final Hubble Space Telescope servicing mission, STS-125, in May 2009.

"It is an honor to be [space]walking with the man with the most U.S. time in space," Feustel said to Fincke, who on Flight Day 12 will surpass 376 days in space, the most for any American astronaut.

Feustel and Fincke will work on two major projects: refilling one of the station’s cooling loops with ammonia, and lubricating one of the station’s massive Solar Alpha Rotary Joints (SARJs).

They will also install a camera cover and lubricate an end effector on the Special Purpose Dexterous Manipulator (SPDM) Dextre two-armed robot, and install two radiator grapple bar stowage beams.

To help identify them in video and photos, Feustel, as lead spacewalker, is wearing a spacesuit with solid red stripes. Fincke's suit is unmarked.

The two spacewalkers, their shuttle crewmates and station crew member Ron Garan woke at 8:27 p.m. Saturday to "Il Mio Pensiero" performed by Ligabue for European Space Agency astronaut Roberto Vittori.

Astronauts working early Sunday morning outside the International Space Station (ISS) ran into problems with bolts and washers popping free, causing Mission Control to revise the spacewalkers' plan for greasing a joint that rotates the orbiting laboratory's power-providing solar arrays.

Shuttle Endeavour astronauts Andrew Feustel and Mike Fincke ventured outside the station tasked with topping off the complex's slowly-leaking coolant system and lubricating the left-side solar arrays' rotary joint.

Work on the earlier proceeded smoothly but it wasn't long before the bolts began flying on the latter.

"Mike, the status of bolt 1, [do] you have it?" asked Greg Chamitoff, the spacewalk's choreographer, to Fincke, who was working to free thermal covers covering the joint's mechanism.

"No, it went to heaven," replied Fincke.

Feustel, working nearby on the coolant system refill, spotted the bolt as it slowly floated toward the left side of the station. Astronauts working inside the space station were able to photograph the bolt and send the images to Mission Control.

At least four other bolts came free from the thermal covers, but Fincke was able to catch them before they floated away.


As viewed from his helmet cam, Fincke holds a rotary joint cover and its bolt.
"[Fincke] was doing a great job at being gentle. Again he gets the golden glove award for another catch. That was fantastic," said Mission Control. "We really don't have a good answer for why that is happening."

The retaining washers that were designed to hold the bolts in place were either missing or bent, reported Fincke. One of the washers that was still present came free and was also lost.

As a result, Mission Control decided to have the spacewalkers open only four of the six covers that were originally planned and take extra caution while doing so.

"We're going to minimize the number of covers we're going to take off," said spacecraft communicator Steven Swanson from on Mission Control in Houston. "We'd like though, as [Fincke] takes them off, to go to seven turns [with a power tool] and then if possible, use his hands to gently turn the next two turns until [the bolt] pops up."

"I'd like to be even more methodical than usual on these. We'll get the job done and be even more careful," said Fincke.

That method seemed to work, as no other bolts or washers were lost and the astronauts were able to move ahead with using grease guns to apply lubrication to the rotary joint.

In 2007, the joint's right-side counterpart was found to be grinding against itself, depositing metal fragments in the mechanism, slowing its rotation. A 2008 space shuttle Endeavour mission had spacewalkers apply grease to the joints, resolving the problem.

The waterwheel-like joints now need to be periodically greased, which is what Fincke and Feustel was working to do today.

With the coolant system refilled and the rotary joint partially lubed, the spacewalkers were scheduled to install two stowage beams for a radiator and add a camera cover and lubricate the hand of the Canadian-built two armed robot, Dextre.

Meanwhile, as they do that work, Mission Control will remotely command the station's left-side Solar Alpha Rotary Joint to rotate so the grease applied by the astronauts will be spread evenly around the ring. If time allows at the end of the spacewalk, Fincke and Feustel will return to the rotary joint to apply even more lubrication and then reinstall the covers they removed earlier.

Drew Feustel and Mike Fincke completed the second of four spacewalks scheduled for Endeavour's STS-134 mission. The eight hour and seven minute outing ended at 9:12 a.m. CDT Sunday with the repressurization of the International Space Station's Quest airlock.

The spacewalk ran about an hour and half longer than originally planned due to loose bolts and washers coming free — with one of each floating away — as Fincke worked to remove thermal covers from the station's port, or left, side Solar Alpha Rotary Joint (SARJ), a waterwheel-like gear that turns the outboard solar arrays so that they always face the sun.

Despite that initial trouble, the two spacewalkers completed all the tasks set out for them, including lubricating the rotary joint with a layer of fresh grease, refilling the station's ammonia coolant system, outfitting the robot Dextre with a new camera cover and lubricating its hands, and installing two grapple bar stowage beams necessary if a radiator ever needed to be replaced.

"Great job guys, you got it all done. Outstanding work!" Greg Chamitoff, the spacewalk's choreographer, said to the two spacewalkers. "You guys earned your pay for the day."

"Do we get paid?" asked Feustel. "I think our pay was just being out here looking at the Earth spinning by. It's beautiful."

This was the 246th spacewalk made by U.S. astronauts, and the 157th in support of space station assembly and maintenance, increasing the total time spent working outside the ISS to 988 hours and 19 minutes.

This spacewalk was a fifth for Feustel and the seventh for Fincke. Both are scheduled to perform the next spacewalk on Wednesday (Flight Day 10).

At eight hours and seven minutes, today's spacewalk ranked as the sixth longest in history. The longest, made in 2007, was 49 minutes longer.

At 10:31 a.m. CDT Sunday, Roscosmos cosmonaut Dmitry Kondratyev, who has been the commander of Expedition 27 aboard the International Space Station, conducted a ceremonial change of command with Andrey Borisenko, who will command Expedition 28.

Kondratyev, European Space Agency flight engineer Paolo Nespoli, and NASA astronaut Cady Coleman will return to Earth Monday night inside their Soyuz TMA-20 spacecraft that launched to the station on Dec. 15.

Expedition 28 will officially begin at the moment of Soyuz undocking.