Transfer work will be going on in- and outside of the International Space Station today, as the crew performs the first and only spacewalk of the STS-135 mission.

Space shuttle Atlantis' crew awoke at 1:59 a.m. CDT to the song "More" by Matthew West. It was played for mission specialist Rex Walheim.


Walheim today will be choreographing from inside the space station the spacewalk being performed outside by ISS Expedition 28 flight engineers Mike Fossum and Ron Garan. Fossum and Garan will be packing a pump module that failed in 2010 into the shuttle's cargo bay. It was moved into a temporary storage location on an external stowage platform during the STS-133 mission earlier this year.

Returning the pump module to Earth will allow engineers to look into what caused its failure and then refurbish it for use as a spare.

Fossum and Garan will also be installing the Robotic Refueling Mission experiment on a platform used by Dextre, the Special Purpose Dexterous Manipulator, to hold spare parts. The robotic experiment will demonstrate and test the tools, technologies and techniques needed to fuel and repair satellites in space.

The spacewalk is scheduled to begin at 7:44 a.m., and last six and a half hours.

Meanwhile, inside the space station, every member of the shuttle crew and many of the station crew will be working to unload the newly installed Raffaello multipurpose logistics module. It's packed with 9,400 pounds of cargo, all of which must be unloaded and replaced with 5,700 pounds of trash and used equipment to return home.

Each day that the final space shuttle mission is in flight, collectSPACE plans to highlight milestones and events from the space shuttle's history that also occurred on the same day over the past three decades. "Today in Space Shuttle History" will also note "lasts" being set by the STS-135 mission.

STS-135 Flight Day 5, July 12

1985
Space shuttle Challenger's first attempt at launching the STS-51F mission ends at T-3 seconds with a pad abort. A malfunction with the No. 2 Space Shuttle Main Engine (SSME) coolant valve caused a shutdown of all three main engines.

2001
Space shuttle Atlantis launches the STS-104 mission to deliver and install the Quest airlock for the International Space Station (ISS). The launch marked the first flight of upgraded "Block II" space shuttle main engines (SSME).

2006
Piers Sellers and Mike Fossum perform the third and final spacewalk of shuttle Discovery's STS-121 mission. The spacewalkers spent seven hours and 11 minutes working outside the International Space Station, testing techniques to inspect and repair damage to a shuttle's heat shield.

2011
International Space Station flight engineers Ron Garan and Mike Fossum perform the final spacewalk during the space shuttle era.

July 12: Challenger's STS-51F abort in 1985 (left); Atlantis launches STS-104 in 2001. Credit: NASA

The first and only spacewalk during the STS-135 mission — and the last to be performed during the space shuttle program — began at 8:22 a.m. CDT Tuesday as International Space Station flight engineers Ron Garan and Mike Fossum switched their spacesuits to internal battery power.

The planned six-and-a-half hour extravehicular activity, or EVA, will see the two spacewalkers retrieve a failed coolant system pump module from an external stowage platform and stow it in Atlantis' cargo bay for return to Earth. They will also install a robotics refueling experiment, deploy part of a materials science experiment, troubleshoot a protruding wire from an arm attach point on the Russian Zarya module and install a thermal cover on a docking adapter.

This is Fossum's and Garan's fourth spacewalk together — they earlier paired for a trio of spacewalks during the 2008 STS-124 mission. This is Garan's fourth career spacewalk and Fossum's seventh.

As lead spacewalker, Fossum is wearing a spacesuit marked with a solid red stripe. Garan's suit is all white.

STS-135 was originally not intended to include a spacewalk; the desire to return the pump module that failed on the International Space Station in 2010 for study on the ground made one necessary, and over time other tasks were added to it as well.

With only four people however, the STS-135 crew was too small to do the spacewalk on top of all of their other work. So members of the Expedition 28 crew were recruited for the job, though the shuttle crew members will still support the spacewalk from inside the space station.

The last spacewalk to be performed by space shuttle crew members took place on STS-134, the final flight of space shuttle Endeavour.

Fossum and Garan prepared for this EVA using a new practice tried out for the first time during STS-134. Aimed at cutting down the amount of oxygen used in spacewalk preparations, Fossum and Garan waited until this morning to begin getting ready, rather than spending the night inside the Quest airlock at a lower air pressure, as they would have otherwise done.

Earlier today they breathed pure oxygen through air masks for an hour as the air pressure inside Quest was lowered to 10.2 psi. After that, they donned their spacesuits and performed light exercise (moving their legs inside of their spacesuits) for 50 minutes to raise their metabolic rate and purge nitrogen from their bloodstream.

Two hours and 12 minutes into today's spacewalk, astronauts Ron Garan and Mike Fossum completed their first task, transferring a failed space station coolant system pump module from a temporary storage platform on the station's truss to space shuttle Atlantis' payload bay.


Returning the 1,400 pound pump module, which failure last year disabled half of the station's cooling system — is a key objective of the STS-135 mission.

Engineers will diagnose what caused the failure so they can take steps to mitigate future pump module problems.


Next, Fossum will trade places with Garan and climb onto the end of the space station's Canadarm2 robotic arm. Fossum will retrieve the Robotic Refueling Mission (RRM) experiment from Atlantis' bay and ride the arm to Dextre, the Special Purpose Dexterous Manipulator.

The spacewalkers will dock the RRM to a platform on Dextre that holds equipment for the robot to use.

The RRM experiment will demonstrate and test tools, technologies, and techniques that could be used to robotically refuel and repair satellites in space. Data from the tests could help reduce the cost and risk of future robotic refueling missions.

Three hours and 15 minutes into today's spacewalk, International Space Station flight engineers Mike Fossum and Ron Garan finished installing the Robotic Refueling Mission experiment onto a platform on Dextre, the Canadian-built robot, or Special Purpose Dexterous Manipulator.


The task's completion marked the last time astronauts worked in a space shuttle's payload bay, the two having retrieved the RRM experiment from Atlantis' cargo hold. As it happened, Garan was the last man out.

"Take a look around Ronnie, you are the last EVA person in the payload bay of the shuttle," advised Fossum.

"As I leave for the last time, I want to tell you how much I appreciate all the thousands of people who worked on this vehicle. It is really beautiful back here," said Garan, who previously flew as a space shuttle astronaut aboard Discovery's STS-124 mission.

"Yes, it's an amazing vehicle, isn't it," responded Rex Walheim, STS-135 mission specialist and today's spacewalk choreographer.

The spacewalkers will next work to deploy the Optical Reflector Materials Experiment, part of the Materials International Space Station Experiment (MISSE) 8 that was installed on the External Logistics Carrier 2 during STS-134. They will also take photos of the material samples. MISSE 8 will be retrieved late next year.

The final spacewalk of the space shuttle era ended at 2:53 p.m. CDT on Tuesday, six hours and 31 minutes after it began.

International Space Station flight engineers Mike Fossum and Ron Garan completed all the tasks set out for them on this extravehicular activity, or EVA, which included the last visits by spacewalkers into a space shuttle payload bay.

"You guys did an outstanding job today. You got everything done plus one bonus task and you're finishing perfectly on time," said Rex Walheim who choreographed today's spacewalk from inside Atlantis.

The two astronauts retrieved a failed coolant system pump module from an external stowage platform and stored it in Atlantis' cargo bay for return to Earth. They also installed a robotics refueling experiment, deployed a materials science experiment, tucked in a protruding wire from a robotic arm attachment outside a Russian module, and installed a thermal cover on a docking adapter.

This was the 160th spacewalk supporting the assembly and maintenance of the International Space Station and the 249th excursion conducted by U.S. astronauts.

This was Ron Garan's fourth career spacewalk, bringing his total time to 27 hours and three minutes. Today was Fossum's seventh EVA, raising his total time to 48 hours and 32 minutes and ranking him seventh on the all-time list of world spacewalkers.

Inside the shuttle-station complex, transfer of payload from the Raffaello multipurpose logistics module has begun.

The work to unload the more than 9,400 pounds of supplies and spare equipment brought up by Raffaello and then repack it with 5,700 pounds of equipment, supplies and trash to return home will continue for much of Atlantis' stay at the station.

The astronauts retired for the day at 5:29 p.m. CDT.