Getting Ready for a Space Walk

Photo Credit: Nikolai Budarin,
ISS Expedition 6 Flight Engineer


     In the sci-fi movies, astronauts can quickly don their spacesuits and in short order, be out the door into the vacuum of space. They're always in a hurry to chase bad guys, alien monsters, or look for holes in the hull spewing out precious atmosphere," says ISS science officer Don Pettit.

     In real life it doesn't work that way.

     "Nothing happens fast," says Pettit. "It takes several days to prepare for a space walk." The airlock has to be cleaned out. The suits must be assembled--with exquisite care--from a suitcase full of parts. The checklist is long: charging batteries, regenerating the carbon dioxide scrubbers, topping off the water tanks, checking for leaks. "Small details are important," he says. For example: "We clean our visors and spread a thin layer of anti-fog on the inside surface. If there is too much anti-fog it can make your eyes sting and water; too little and it will fog up. It has to be just right if you want to see anything."

     "You also check out your SAFER, a compressed nitrogen
thruster backpack that we can use to fly back to the ISS. When we do a space walk without the presence of a docked Space Shuttle, drifting away would be a fatal mistake."

     "You review your script. It's like being an actor on a Broadway play. You think, you plan, you rehearse. In your sleep, you dream about your part. You know where every bolt and pin is located, what direction it is oriented, and how much torque is required to turn it. The Universe is a tough
critic, and the reviews will not be good if you have slacked in your preparations."

     "On space walk day, you start off with an exercise period on a stationary bicycle while breathing 100% oxygen through a facemask. After that, the task of suiting up begins. You rely on help from an extra crew member who tugs on sleeves, straightens out wrinkles, locks connectors.... It reminds me of a squire in the Middle Ages helping his knight suit up for battle."

     "It takes about six hours from the time you start in the morning until you are ready to open the hatch. After all of this preparation, you will not take lightly to a hatch that does not want to open.

     That's what happened to us before our spacewalk earlier this year. The hatch dogs were partly released and allowed the hatch to crack open only 3/8th of an inch. A shaft of brilliant sunlight came through the crack, as if teasing us to come out and play."

    "Fortunately, experience gained by owning an old pickup
truck with cantankerous doors came in handy. With a little jockeying on the handle and some soft-spoken words, the hatch came open and we started our day."

     "If we were chasing bad guys, I am afraid they would be well into hyperspace by now."

    Editor's Note: This story is based on Don Pettit's Space Chronicles #14, where you can read a fuller account of his preparations for the January 15, 2003 spacewalk. Pettit is conducting his 2nd spacewalk today.

Courtesy: NASA