Why Spacewalking Is All About The Hands

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
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
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.

How Micrometeoroid Impacts Pose a Danger for Today’s Spacewalk



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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).
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
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.

 

What are the Most Memorable NASA Spacewalks?

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
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
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
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 space station
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 on the completed International Space Station. Credit: NASA
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.

Shields Up! ISS Spacewalkers Install New Micrometeorite Shields

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.

Historic Images of Final Spacewalk of Shuttle Era

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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: NASA
Suspended in a very unique position on the end of Canadarm2, Mike Fossum takes a picture during a July 12 spacewalk. Credit: NASA
Space 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: NASA
Ron 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: NASA
A 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: NASA
Another view of Mike Fossum during the spacewalk. Credit: NASA
A close-up view of Mike Fossum during the final EVA of the shuttle era. Credit: NASA
With 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: NASA
Following 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: NASA
Here’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

For larger versions of any of these images, and to see more images from the STS-135 mission, see NASA’s Human Spaceflight website’s mission gallery.

Spacewalking: Through an Astronaut’s Eyes

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What is it really like to go on a spacewalk? Some astronauts have said there are no words to describe the experience, but we talked with astronaut Chris Hadfield – the same guy who gave the best description ever of going to the bathroom in space – and asked him to convey his thoughts about his EVA experiences. Hadfield has done it again, and has now given the best description ever of a spacewalk.

UT: Chris, you were part of the STS-100 space shuttle crew that flew to the ISS 2001, and you had the opportunity to do a couple of spacewalks to help in the construction of the station. I once heard you describe one of your spacewalks where you said you were holding on to the side of the space station with one hand with your face into the wind as it were, and you were looking out at the rest of the entire Universe. For all of us that wish we could experience it, what is it really like to do a spacewalk?

Chris Hadfield during an EVA in 2001. Also in the image is the Canadarm2 robotic arm on the ISS. Credit: NASA

Chris Hadfield: Gosh, I’m not sure how to describe it. I was there for the birth of all three of my children. I did the first F-18 intercept of a Bear bomber off the coast of Canada. I represented Canada in a bunch of different levels, including as a fighter pilot. I was a test pilot doing all sorts of very fascinating, challenging, brand new work. I went to Mir, I went to the ISS. But nothing compares to going outside for a spacewalk. Nothing compares to being alone in the Universe; to that moment of opening the hatch and pulling yourself outside into the Universe.

Sometimes you’re driving on a mountain road, it’s slippery and you’re doing a bunch of curves and you don’t really see anything because you have a cliff falling away on one side and another cliff up on the other. But suddenly you come around a corner and you say, “Oh wow!” And there you’ve got the whole valley in front of you, or they make one of those nice pullovers where you can stop and look out, and you do, and you stop and you get out of your car and walk over to the edge and you see where you are, where all those little myopic turns have taken you.

A spacewalk is very much like that in that the opening of the hatch is probably step 750 of the day. And steps 1 through 749 were all boring and minuscule and each one was on a checklist and you had to do every one right, so you were very painstaking. But suddenly you do this one step, and suddenly you are in a place that you hadn’t conceived how beautiful this could be. How stupefying this could be. And by stupefying I mean, it stops your thought.

You’ve probably heard me say this before, but I knew I couldn’t keep notes up there and I would forget stuff so I sorta resolved to myself that I would verbalize and attempt to, as eloquently as I could, express what I was feeling and what I was seeing so that later I could listen to the recordings of it and remember, and not have missed such an amazing experience. And yet when I listen to the transcripts of what I said, most of it was just, “Wow!” It was so pathetic! But the experience was just overwhelming!

Chris Hadfield during an EVA in 2001. Credit: NASA

It is like coming around a corner and seeing the most magnificent sunset of your life, from one horizon to the other where it looks like the whole sky is on fire and there are all those colors, and the sun’s rays look like some great painting up over your head. You just want to open your eyes wide and try to look around at the image, and just try and soak it up. It’s like that all the time. Or maybe the most beautiful music just filling your soul. Or seeing an absolutely gorgeous person where you can’t just help but stare. It’s like that all the time.

So, it’s an extremely distracting place to work. But it also really puts yourself into perspective because this human creation is right next to you and its inherently, massively beautiful, like the prow of the Titanic or something, where you feel this great human achievement of building this great structure that takes us to a place we’ve never been. But then you notice that even though it is huge and capable, it’s just a speck between everything which is on your left and all the colors and textures of our planet that are just pouring next to you on the right. And you are this little peephole of a microcosm in between those two things, both physically and historically. And you’re very much aware of that the whole time. I’m sort of gushing, but that’s what a spacewalk feels like. It is infinitely worth all the thousands of steps it takes to get there. It’s a great, great thing – I recommend it very highly.

You can hear Chris Hadfield give his description of a spacewalk, as well as talk about NASA’s current situation and his views on the International Space Station on the March 11, 2010 edition of the 365 Days of Astronomy podcast.

Hadfield on the flight deck of the Endeavour orbiter during the STS-100 mission. Credi: NASA

Incredible! Watch Time-Lapse of EVA-1/Tranquility Node Berthing

This is so cool! Normally spacewalks, or EVAs take 6-7 hours. But here you can watch the first EVA of the STS-130 mission in just one minute and 45 seconds! And that even includes watching the astronauts put on their spacesuits. Ron Smith has created a time-lapse video of EVA-1, so you can watch all the action of the new Tranquility Node being berthed to the ISS. This is especially great since the EVA took place during the night-time hours here in the US, when most of us were supposed to be sleeping. Some of us tried to stay awake to watch the spacewalk, and now I can quickly see what I missed when I nodded off…

Hat tip to @avgjanecrafter on Twitter!