Astronaut Karen Nyberg helps Chris Cassidy (left) and Luca Parmitano suit up for their spacewalk on July 9, 2013. Credit: NASA
Want a “you are there” view of today’s EVA that took place outside the International Space Station? Take a look at this great video of astronaut Chris Cassidy getting a ride on the station’s Canadarm-2 to make repairs and prepare for a new Russian laboratory. There are several great “over the shoulder” views during this short highlight video.
During their 6-hour and 7-minute spacewalk, Cassidy of NASA and Luca Parmitano of the European Space Agency worked on replacing a failed communications receiver, relocating grapple bars for future spacewalks and stringing cables for the when the Russian laboratory module arrives later this year.
The Ku-band communications receiver replaces one that failed last December. There was already a redundant backup system now in use, and this new one will become the backup.
The new Russian lab, called Nauka, will replace the Pirs airlock. It is scheduled to launch on a Proton rocket booster late this year, although the flight could be delayed a bit until early next year as because of assembly delays in Russia.
This spacewalk was the first of two in as many weeks for the duo. They will again venture outside the Quest airlock on July 16 for more upgrades and repairs. This was Parmitano’s first spacewalk, and he has now become the first Italian astronaut to walk in space. Old pro Cassidy has now been on five spacewalks, and this was the 170th spacewalk in support of space station assembly and maintenance.
A view of Aleksandr Misurkin during the spacewalk to prepare the International Space Station for a new Russian lab. Image via astronaut Karen Nyberg/NASA.
On Monday, two Russian cosmonauts conducted a 6-hour, 34-minute spacewalk to prepare for a new Russian module that will be launched later this year. Expedition 36 Flight Engineers Fyodor Yurchikhin and Alexander Misurkin also work on the first module ever launched for the ISS – the Zarya module which has been in space since 1998 – replacing an aging control panels located on the exterior.
The new lab will be a combination research facility, airlock and docking port, and is planned to launch late this year on a Proton rocket.
Watch video highlights of the EVA below:
This was the second of up to six Russian spacewalks planned for this year to prepare for the lab. Two U.S. spacewalks by NASA’s Chris Cassidy and Luca Parmitano of the European Space Agency are scheduled in July.
While Yurchikhin and Misurkin worked outside the ISS, the crew inside the ISS were separated and isolated from each other. Cassidy and station commander Pavel Vinogradov were sequestered in their Soyuz TMA-08M spacecraft that is attached to the Poisk module on the Russian segment due to the closure of hatches to the other passageways on the Russian side of the station which would have made the Soyuz inaccessible if there was an emergency. Parmitano and US astronaut Karen Nyberg were inside the U.S. segment of the station, and were free to move around since entry to their Soyuz vehicle (TMA-09M) was not blocked by hatch closures, since it is docked to the Rassvet module that is attached to the Zarya module.
NASA said the spacewalk was the 169th in support of space station assembly and maintenance, the sixth for Yurchikhin and the first for Misurkin.
Astronaut Tom Marshburn looks toward Earth during a spacewalk on May 11, 2013 to fix a leaking coolant system. Credit: NASA.
The image above could go down as an iconic shot of space exploration. Taken during the ’emergency’ spacewalk last Saturday to fix the leaking ammonia coolant in the pump and flow control system for the International Space Station’s power-supplying solar arrays, visible is astronaut Tom Marshburn taking a look at planet Earth. He shared the picture today on Twitter, saying, “Leaving is bittersweet. It’s been an unbelievable ride. Can’t wait to see what’s next!”
Marshburn is scheduled to return back to Earth later today along with ISS commander Chris Hadfield and cosmonaut Roman Romanenko.
Below are more great shots from Saturday’s EVA that were just released by NASA today. See here for earlier images of the spacewalk from Chris Hadfield via Twitter.
Astronaut Chris Cassidy during the May 11, 2013 spacewalk at the ISS. Credit: NASA
Expedition 35 Flight Engineers Chris Cassidy (left) and Tom Marshburn on a spacewalk on May 11 to inspect and replace a pump controller box on the International Space Station’s far port truss (P6) leaking ammonia coolant. Credit: NASA.Astronaut Chris Cassidy takes a self-portrait during the May 11, 2013 EVA at the ISS. Credit: NASA.Chris Cassidy with Earth as a backdrop during the EVA on May 11, 2013. Credit: NASA.Expedition 35 Flight Engineers Chris Cassidy (left) and Tom Marshburn completed a the 5-hour, 30-minute spacewalk on May 11 to inspect and replace a pump controller box on the International Space Station’s far port truss (P6) leaking ammonia coolant. Credit: NASA
Chris Cassidy and Tom Marshburn take a minute with visors open to have their picture taken by Chris Hadfield, inside the ISS. Credit: NASA/CSA/Chris Hadfield.
The spacewalk outside the International Space Station was captured on film by the tweeting, Facebooking, social media maven and space station commander Chris Hadfield. “Amazing day,” he said. “EVA went off without a hitch. Great crew, phenomenal ground support and a supportive audience. Who could ask for anything more?”
How ’bout a picturesque view? We’ve got that too! See a collection of great images from the EVA, which — for the moment — appears to have been a success in fixing the leaking ammonia coolant system.
Cassidy and Marshburn work outside the ISS in the ‘approaching orbital sunset, the harshest of light, a blackness like endless velvet,’ said Hadfield. Credit: NASA/CSA/Chris Hadfield.Chris Cassidy and Tom Marshburn turn on their helmet lights ‘doing their best to light the universe on the dark side of the Earth,’ said Chris Hadfield. Credit: NASA/CSA/Chris Hadfield‘Climbing out of the airlock, quite the commute to work!’ said Chris Hadfield via Twitter.Chris Cassidy, Navy SEAL and lead spacewalker Saturday. Credit: NASA/CSA/Chris Hadfield.Dr. Tom Marshburn, well-dressed for a day’s work outdoors. Credit: NASA/CSA/Chris Hadfield.
A slide showing the P6 Truss, the location of the coolant leak on the International Space Station. Credit: NASA.
Astronauts on the International Space Station are preparing for a potential emergency spacewalk to fix an ammonia coolant leak outside the station. On Thursday, the ISS crew spotted small white flakes floating away from an area of the Station’s P6 truss structure, and noticed pressure drops in the control panel of the pump and flow control system for the power-supplying solar arrays.
UPDATE: At a press briefing on Friday afternoon, NASA officials announced that the ISS crew will perform a spacewalk starting early Saturday to address the ammonia leak.
“Suddenly very busy!” tweeted astronaut Tom Marshburn, who along with Chris Cassidy is preparing for the contingency EVA. “Ammonia leak on the outside of station means that Cassidy and I will be doing a spacewalk tomorrow to try and repair it.”
Mission Control teams worked overnight to understand and sort through the problem and find potential fixes or work-arounds for the electricity systems. The Mission Management team met this morning to identify any issues or latent hazards of the spacewalk, and they are seeking input from all the international partners. The crew is expecting a final go or no go by later today on whether the spacewalk will take place. There will be an update on NASA TV at 20:00 UTC, 4 pm EDT.
“The whole team is ticking like clockwork, readying for tomorrow. I am so proud to be Commander of this crew. Such great, capable, fun people,” said ISS Commander Chris Hadfield via Twitter. Yesterday, he called the leak “serious” but that the situation was stable.
NASA has said that while the coolant is vital to the operation of the ISS for the electricity-supplying systems, the crew is not in any danger. The ammonia cools the 2B power channel, one of eight power channels that control the all the various power-using systems at the ISS. All the systems that use power from the 2B channel, the problem area, are being transferred throughout the day to another channel. The 2B channel will eventually shut down when the coolant is depleted, and the power is being diverted in order to keep everything up and running on the station.
Cassidy and Marshburn are now preparing for the spacewalk in the Quest airlock, arranging their spacesuits and gathering the specialized tools they will need to do the work outside the station. These two are the perfect people to conduct this spacewalk, as both are veterans of three spacewalks, two of which they performed together on the STS-127 space shuttle mission to the ISS, and they went to this exact same area on the P6 truss to replace batteries. They have also trained for this particular spacewalk already, as this spacewalk task does fall under the “Big 12” of contingency spacewalks of possible serious issues that may occur. All astronauts train for these in case an unexpected event requires a quick response.
While Cassidy and Marshburn prepare in space, Astronauts at NASA’s Johnson Space Center are using the Neutral Buoyancy lab – a 12- meter (40 ft.) deep swimming pool with mockups of the space station that simulates the zero-gravity conditions in space – going through the entire expected EVA. ESA astronaut Samantha Cristoferretti and NASA’s Terry Virts are walking through and choreographing the procedures to make sure the tasks could be done in a reasonable time as well as looking for potential hazards. They will confer with the ISS astronauts to share their experiences.
This video shows information about the potential spacewalk, as well as footage of the ammonia leak captured by the crew.
While NASA does not know for certain the exact location of the leak, they are focusing on the pump and flow control system, the suspected source. That exact same area and system was the location of a minor leak, first identified in 2007 – thought to have been caused perhaps by a micrometeorite impact — and in November 2012 two astronauts went on a spacewalk to fix the problem. They rewired some coolant lines and installed a spare radiator, and it appeared the problem had been fixed.
That first leak was not visible during the EVA, but this new leak is quite noticeable, as the crew wwas able to see the leak from inside the station.
One of the driving factors for getting the spacewalk underway as quickly as possible is that the location of the leak and the potential fix are not exactly known. The hope is that it is still leaking by the time they get out there on Saturday morning, so that they can easily identify the source of the leak. The first task will be identifying the source, then possibly replacing the current pump and flow control system with one of the spares, located handily out at the P6 truss. If that is not the source of the leak, they will look through the area to try and identify the source. NASA said the leak could potentially be located in the internal plumbing of the system, which would be harder to see immediately.
At the briefing, NASA officials said the spacewalk and ammonia leak won’t affect the scheduled departure of Hadfield, Marshburn and Russian cosmonaut Roman Romanenko, set for Monday May 13 at 7:08 p.m. EDT. Three crew members, Cassidy and Russian cosmonauts Alexander Misurkin and Pavel Vinogradov, will remain on the space station.
NASA astronaut Shane Kimbrough works outside the International Space Station in 2008. Credit: NASA
Think about your typical construction worker — there’s a lot of reaching, bending, stretching, lifting. How do you accomplish those tasks without gravity, as astronauts do on the International Space Station?
According to astronaut Shane Kimbrough — who should know, as he spent more than 12 hours “outside” doing station work and repairs during shuttle mission STS-126 in 2008 — instead of using your feet, you transfer most of the work to your hands. Your feet are basically used to brace yourself.
“You’re moving around, kind of walking with your hands, and pulling yourself in between the handholds and the rails,” he said to Universe Today, expanding on comments he made publicly at a conference last week.
Astronauts train for hours in a large pool known as the Neutral Buoyancy Laboratory, which includes a full-size model of the station modules inside. “You build up the [hand] strength in the NBL,” Kimbrough said, “with your hands fighting against the pressure of the spacesuit. If you didn’t do that, your hands would be fatigued [during a spacewalk.]”
It’s not a perfect training environment, though. “The big difference in the water is the drag it produces. You don’t realize you are floating, at times. If you’re moving along and walking with your hands down the rail, and you stop, you will immediately stop. In space, the mass of your spacesuit keeps going even if you stop. Your body will keep moving back and forth a few times, and using more energy when you need.”
Shane Kimbrough spent more than 12 hours outside the International Space Station during one mission. Credit: NASA
During the shuttle era, astronauts tended to specialize in different areas of spaceflight — robotics and extra-vehicular activity (spacewalks) being some of the fields. The station, however, demands that astronauts be versed in both, Kimbrough said. Any crew could be called upon to do a repair on short notice, or to haul in a robotic spacecraft (like SpaceX’s Dragon) that arrives at station.
This means there’s a huge demand within NASA now for spacewalking expertise. Before stepping into the NBL, the astronauts run through the procedures in the classroom, and will get a look at the tools to make sure they understand their functions. Occasionally, a crew might pop on scuba suits to do a rough run of an expected spacewalk at the station, rehearsing where they should be and how they should position themselves.
A spacesuit really limits the astronaut’s range of motion, making the hours of training crucial. “For people like myself, with short arms, our work envelope is very small,” said Kimbrough, who is hoping for another flight assignment.
“It’s really out in front, not very far, in a circular motion. If you put your hand out in front, a small circle, that’s my work envelope. If I want to get something higher or lower, I can’t get there by reaching based on the way the [spacesuit] shoulder and arm operates. You maybe have to go sideways or upside down.”
November 3, 2007 – Canadarm2 played a big role in helping astronauts fix a torn solar array. The arm’s reach was extended by the Orbiter Boom Sensor System, and here, allowing astronaut Scott Parazynski analyses the solar panel while anchored to the boom. Credit: NASA
Spacewalking is inherently a dangerous business. Many people remember a daring station-era spacewalk in 2007, when Scott Parazynski dangled on the end of a Canadarm2 extension to stitch together a torn — and live — solar array. For this spacewalk, a lot of procedures were put together on the fly.
NASA also has a computer program that can roughly simulate how the astronauts can get into various areas of the station, and this was extensively used before Parazynski’s spacewalk, Kimbrough said.
Kimbrough’s crew had a more messy problem as they worked to repair the broken solar array rotary joint (that controlled one of the station’s solar panel arrays) and do other station work. The grease guns the crew used in that mission periodically squirted way too much grease and covered everything. The work area, the spacesuits, the tools.
“It had to do with the thermal properties,” Kimbrough said. “It would go in between pretty hard, to not being so hard. So sometimes, the grease guns that were designed at the time leaked … they have been redesigned, a few modifications, and they’ve worked well since then.”
Kimbrough himself ran into a minor, but still surprising situation when at the end of a lengthy tether. It turned out that tether had a bit of zing to it. “I was working way out on the end of the truss, and it was nighttime and I felt somebody pulling me back and almost spinning me around. The force of it surprised me the most.”
Other astronauts had warned him about that ahead of time, Kimbrough said, but he didn’t realize how vehement the pull could be. “I was a believer after that,” he joked.
Our very own International Space Station is in the cosmic crosshairs.
As cosmonauts are to begin Extra Vehicular Activity (EVA) this morning to perform routine maintenance, an article reminding us of the hazards of such activity came to us via NASA’s Orbital Debris Quarterly Newsletter.
The problem is Micrometeoroid and Orbital Debris (MMOD) impacts. These are nothing new. Pits and tiny cratering has been observed during post-flight inspections of space shuttle orbiters. But this is the first time we’d seen talk of damage caused by tiny impacts on the exterior of the International Space Station.
The handrails are a particularly sensitive area of concern.
The study examined damage incurred on handrails exposed to the environment of space for years on end. These present a hazard to spacewalking astronauts who rely on the handles to move about. These craters often become spalled, presenting a sharp metal rim raised from the surface of the handle.
Close-up of a micro-meteoroid impact on a handrail. (Credit: NASA/JSC Image & Science Analysis Group).
Of course, these razor sharp rims present a problem, especially to space suit gloves. One 34.8 centimeter long handrail returned on the final Space Shuttle mission STS-135 had six impact craters along its length. The handrail had been in service and exposed to the vacuum of space for 8.7 years.
Craters as large as 1.85 millimetres (mm) in diameter with raised lips of 0.33mm have been observed on post-inspection. In studies conducted by NASA engineers, craters with lip heights as little as 0.25mm have been sufficient to snag and tear spacesuit gloves.
There have also been reported incidents of glove tears during EVAs conducted from the ISS over the years. For example, the report cites a tear noticed by astronaut Rick Mastracchio during STS-118 that cut the EVA short.
Analysis of an impact seen on STS-122. (Credit: NASA/JSC Image & Science Analysis Group).
To protect astronauts and cosmonauts during EVAs, the following measures have been instituted:
– Toughening space suit gloves by adding reinforcement to areas exposed to potential MMOD damage.
– Monitoring and analyzing MMOD impacts along handrails and maintaining a database of problem areas.
– Equipping spacewalkers with the ability to cover and/or repair hazardous MMOD areas during spacewalks.
The studies were carried out by the Johnson Space Center Hypervelocity Impact Technology Group in conjunction with a test facility at White Sands, New Mexico. Astronaut Rick Mastracchio can also be seen talking about the hazards of spacewalking on this video.
Today’s 6 hour EVA by cosmonauts Vinogradov & Romanenko begins at 14:06 UT 10:06AM EDT.
This will be the 32nd Russian EVA from the International Space Station and will use the Pirs hatch on Zvezda.
Tasks include retrieving and installing experiment packages and replacing a defective retro-reflector device on the station’s exterior. The device is a navigational aid necessary for the Albert Einstein ATV-4 mission headed to the ISS on June 5th.
Progress 51P is also scheduled to launch towards the ISS next week on April 24 for docking on April 26th.
Debris in Low Earth Orbit is becoming an increasing concern. The Chinese anti-satellite test in 2007 and the collision of Kosmos 2251 and Iridium 33 in 2009 have increased hazards to the ISS. Many fear that a tipping point, known as an ablation cascade, could eventually occur with one collision showering LEO with debris that in turn trigger many more. The ISS was only finished in 2011, and it would be a tragic loss to see it abandoned due to a catastrophic collision only years after completion.
More than once, ISS crew members have sat out a debris conjunction that was too close to call in their Soyuz life boats, ready to evacuate the station if necessary. DAMs (Debris Avoidance Maneuvers) are now common for the ISS throughout the year.
Several ideas have been proposed to deal with space debris. In the past year, NanoSail-2D demonstrated the ability to deploy a solar sail from a satellite for reentry at the end of a spacecraft’s life span. Such technology may be standard equipment on future satellites.
Expect reentries to increase as we near the solar maximum for cycle #24 in late 2013 & early 2014. This occurs because the exosphere of Earth “puffs out” due to increased solar activity and increases drag on satellites in low Earth orbit.
All food for thought as we watch today’s EVA… space travel is never routine!
The April 2013 edition of the Orbital Debris Quarterly News is available for free online.
Bruce McCandless testing out the ultimate jetpack during STS-41B in February 1984. Credit: NASA
The official name is “extra-vehicular activity,” (EVA) but most of us like to call it a spacewalk. However, when you think about it, you don’t really walk in space. You float.
Or more properly speaking, clutch on to handlebars as you make your way from spot to spot on your spacecraft as you race against the clock to finish your repair or whatever outdoor tasks you were assigned. But hey, the view more than makes up for the hard work.
Some astronauts actually got to fly during their time “outside.” During STS-41B 29 years ago this month, Bruce McCandless was the first one to strap on a jetpack and, in science fiction style, float a little distance away from the shuttle.
He called his test of the manned maneuvering unit “a heck of a big leap”. Nearly 30 years after the fact, it still looks like a gutsy move.
What other memorable floating NASA spacewalks have we seen during the space age? Here are some examples:
The first American one
Ed White did the first American spacewalk in 1965. Credit: NASA
The pictures for Ed White’s spacewalk on Gemini 4 still look amazing, nearly 48 years after the fact. The astronaut tumbled and spun during his 23-minute walk in space, and even tested out a small rocket gun until the gas ran out. When commander Jim McDivitt ordered him back inside, the astronaut said it was the saddest moment in his life.
The dancing-with-exhaustion one
Eugene Cernan during his spacewalk on Gemini 9. Credit: NASA
On Gemini 9, which took place the year after Gemini 4, Eugene Cernan was tasked with a spacewalk that was supposed to test out a backpack to let him move independently of the spacecraft.
Cernan, however, faced a lack of handholds and physical supports as he clambered outside towards the backpack. Putting it on took almost all the strength out of him, as he had nowhere to hold on to counterbalance himself.
“Lord, I was tired. My heart was motoring at about 155 beats per minute, I was sweating like a pig, the pickle was a pest, and I had yet to begin any real work,” Cernan wrote in his memoir, Last Man on the Moon, about the experience.
The situation worsened as his visor fogged up and Cernan struggled unsuccessfully to use the backpack. Cernan was so exhausted that he could barely get inside the spacecraft. “I was as weary as I had ever been in my life,” he wrote.
The three-astronauts-outside one
Three astronauts grab the Intelsat VI satellite during the STS-49 mission. Credit: NASA
Spacewalks traditionally (at least, in the shuttle and station era) happen in pairs, so that if one person runs into trouble there’s another to help him or her out. However, two astronauts working outside during STS-49 couldn’t get enough of a grip on the free-flying Intelsat VI satellite they were trying to fix. So NASA elected to do another spacewalk with a third man.
Pierre Thuot hung on the Canadarm while Richard Hieb and Thomas Akers attached their bodies to the payload bay. Having three men hanging on to the satellite provided enough purchase for the astronauts inside the shuttle to maneuver Endeavour to a spot where Intelsat VI could be attached to the payload bay.
The facing-electrical-shock one
Scott Parazynski repaired a damaged solar panel on the space station. Credit: NASA
In 2007, the astronauts of STS-120 unfolded a solar array on the International Space Station and saw — to everyone’s horror — that some panels were torn. Veteran spacewalker Scott Parazynski was dispatched to the rescue. He rode on the end of the Canadarm2, dangling above a live set of electrified panels, and carefully threaded in a repair.
In an interview with Parazynski that I did several years ago, I asked how he used his medical training while doing the repair. Parazynski quipped something along the lines of, “Well, the top thing in my mind was ‘First do no harm.’ ”
The International Space Station construction ones
Sunita Williams appears to touch the sun during this spacewalk on Expedition 35, which took place on the completed International Space Station. Credit: NASA
Spacewalks used to be something extra-special, something that only happened every missions or, on long-duration ones, maybe once. Building the International Space Station was different. The astronauts brought the pieces up in the shuttle and installed them themselves.
The station made spacewalking routine, or as routine such a dangerous endeavour can be. For that reason, an honorary mention goes to every mission that built the ISS.
What are your favorite EVAs? Feel free to add yours to the comments.
International Space Station Commander Gennady Padalka and Flight Engineer Yuri Malenchenko completed the first spacewalk of the Expedition 32 mission on Monday, Aug. 20, and successfully completed several tasks, including the installation of micrometeoroid debris shields on the exterior of the Zvezda service module and the deployment of a small science satellite.
Graphic showing the Debris Panel Installation Sites. Credit: NASA
The primary task during the five-hour, 51-minute EVA was to move the Strela-2 cargo boom from the Pirs docking compartment to the Zarya module. The move was another step in preparing Pirs for its eventual undocking and disposal, which will make room for the docking of the new Russian multipurpose laboratory module to the Zvezda nadir port.
This was the 163rd in support of station assembly and maintenance.
A second Expedition 32 spacewalk, scheduled for Aug. 30, will be conducted by NASA Flight Engineer Sunita Williams and Japan Aerospace Exploration Agency Flight Engineer Akihiko Hoshide. This will be the first U.S.-based spacewalk in over a year, since July 2011. During the planned 6.5-hour EVA, the astronauts will replace a faulty power relay unit on the station’s truss, rig power cables for the arrival late next year of a Russian laboratory module, replace a failing robotic arm camera and install a thermal cover on a docking port.
With space shuttle Atlantis docked to the space station for the STS-135 mission, the final EVA of the shuttle era took place on July 12, 2011. Here, Ron Garan is secured on a restraint on the space station remote manipulator system's robotic arm or Canadarm2, carrying a faulty pump module will be retuned to Earth by the shuttle. Credit: NASA
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It’s the end of an era: the final spacewalk during the space shuttle era was conducted by astronauts on July 12, 2011 during the final shuttle mission, STS-135. This is the 160th spacewalk supporting assembly and maintenance of the space station and the 249th EVA conducted by U.S. astronauts. The two spacwalkers were actually from the International Space Station crew, Expedition 28’s Mike Fossum and Ron Garan, but were assisted by the shuttle crew. Shuttle Pilot Doug Hurley and Mission Specialist Sandy Magnus operated operate the station’s 58-foot-long Canadarm 2 to maneuver the spacewalkers around during the spacewalk.
Here are more images from the EVA:
Astronaut Ron Garan egresses the Quest airlock on the International Space Station as he prepares to join crewmate Mike Fossum for the spacewalk. Credit: NASA
Mike Fossum works outside the ISS during the six and a half hour spacewalk, the final of the shuttle era. Credit: NASA.No, this isn't a picture of an astronaut carrying a freezer outside the space station. With his feet secured on a restraint on the space station remote manipulator system's robotic arm Canadarm2, Mike Fossum holds the Robotics Refueling Mission payload, an experiment which will test in-flight refueling with the DEXTRE robot. Fossum and Ron Garan installed the experiment during the July 12 EVA. Credit: NASASuspended in a very unique position on the end of Canadarm2, Mike Fossum takes a picture during a July 12 spacewalk. Credit: NASASpace shuttle Atlantis makes a cameo in this image as Mike Fossum takes a picture during the spacewalk while on a foot restraint on the Canadarm 2. Credit: NASARon Garan during the spacewalk: "I almost had 1 foot in day and 1 foot in night Orbital sunset," said Garan via Twitter of this picture. Credit: NASAA view of the Cupola on the ISS, and if you look closely, you can see faces of several of the Atlantis STS-135 and Expediton 28 crewmembers looking out the windows. Credit: NASAAnother view of Mike Fossum during the spacewalk. Credit: NASAA close-up view of Mike Fossum during the final EVA of the shuttle era. Credit: NASAWith his feet secured on a restraint on Canadarm2, Mike Fossum holds the Robotics Refueling Mission payload. The failed pump module is with DEXTRE in the upper left corner of the photo. The blue color on the space station module is a reflection from the blue of planet Earth. Credit: NASA"Knocking on the door to come back in from space after yesterday's spacewalk," said Ron Garan via Twitter. Credit: NASAFollowing the six-hour, 31-minute EVA, spacewalkers Ron Garan (top left) and Mike Fossum (top right), pose in the ISS’s Quest airlock with Chris Ferguson, STS-135 commander, Doug Hurley, pilot, and Rex Walheim, mission specialist. Credit: NASAHere’s how astronauts train for their EVAs, in the Neutral Buoyancy Laboratory (NBL) near NASA's Johnson Space Center. Here astronauts Rex Walheim and Sandy Magnus (mostly obscured), are raised from the waters of the N as a spacewalk training session comes to a close. Divers were in the water to assist Magnus and Walheim in their rehearsal. Credit: NASA
