part 8 of a series on the ISS-
"...the sirens and warning tones went off... and my heart was in my throat. It was the beginning of a very long night and three weeks of the greatest physical and mental challenge of my life..... We scrambled and worked through the night as the Space Station was slowly dying."-US Astronaut Doug Wheelock was part of a six person international crew living aboard the International Space Station in six month intervals. This is the 8th on a series about the life of my old friend and NASA Astronaut Doug Wheelock, a post in which I'll share his thoughts about the emergency they recently experienced on the ISS which required some unexpected spacewalks -- Doug's 4th spacewalk and Tracy Caldwell Dyson's first. Here's Doug, describing the night of Saturday, July 31, 2010.
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I hadn't quite made it to bed yet that night, we were enjoying a relatively calm and quiet weekend getting rested for our spacewalk that was originally scheduled for Thursday, August 5th.
I had just finished running on the treadmill and was in the US Lab shutting down the treadmill power, when the alarms came. The 'Caution & Warning Panel' (kind of like your car's dashboard 'Check Engine' or 'Maintenance Required' lights) lit up like the 4th of July ... the sirens and warning tones went off.... and my heart was in my throat. It was the beginning of a very long night and three weeks of the greatest physical and mental challenge of my life..... We scrambled and worked through the night as the Space Station was slowly dying. We powered down a lot of equipment including the Columbus (European) and Kibo (Japanese) Laboratories.
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The Space Station has two cooling loops to reject heat to space through radiators out on the truss. The medium outside is anhydrous ammonia, some pretty nasty stuff, and inside the medium is water. Simply put, the water coolant lines flow through the Station, picking up heat from anything and everything that is operating on the Space Station, everything from laptop computers to life support systems that maintain pressure, temperature, and the oxygen that we breathe. That water is moved through the lines by pumps inside that carry the water through the hull of the spaceship to several heat exchangers on the outside of the Station. In these heat exchangers, the water transfers that heat through conduction to high-pressure liquid ammonia, which is moved through lines by pumps outside on the truss to radiators where the heat is rejected to space.
There are two of these ammonia pumps outside, and at about 11:00 pm GMT on July 31st, the Loop A pump seized due to an electrical short and the Space Station began to die. It's hard to describe how that feels when you're inside, but let's just say that both loops of my adrenaline pump are working just fine."
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The rest of the story is chronicled in history now and is becoming a fading memory. Three very challenging spacewalks, totaling 22 hours and 49 minutes, of slugging it out with high pressure ammonia lines and stubborn mechanisms. I thank God every day of my life for delivering us through that time. I've always ascribed to the adage "
if you're not living life on the edge... you're taking up way too much space." Those 22 hours and 49 minutes teetering on the edge turned out to be one of NASA's finest hours, and I feel so fortunate to have been a witness to the power of faith, teamwork, and perseverance, with a dash of good old creative ingenuity, and all covered with God's grace.
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Prior to each spacewalk, we go into an oxygen pre-breathe and low-pressure 'campout' in the airlock. We pressure breath 100% pure oxygen for 70 minutes, and then depressurize the airlock to a reduced pressure (10.2 psi), oxygen enriched (24%) environment to purge nitrogen from our bodies prior to suiting up. It is a restful and peaceful night of sleep in the airlock. A healthy set of nerves is ever-present, but that keeps us at the top of our game. Here is a shot of Tracy Caldwell Dyson and me getting ready to seal the hatch for our campout:
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-"during EVA (spacewalk) 2, declaring victory over my 'giant' (the M3 connector):
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"...during EVA 3, working on the new pump module....
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We were able to get the new Pump Module up and running and bring the Space Station back to life. It was an incredible adventure, and I look forward to re-telling the tall tales and remembering when . . ."
-I am so grateful to Doug for sharing his experience and I think he has an excellent ability to write. I do want to add a note about how NASA engineers in Houston respond to an emergency situation such as this.
After the engineers and scientists determine the strategy required to do the repair, they have a "dress rehearsal" of the spacewalks in the Neutral Buoyancy Lab. This is where there is a replica of the Space Station in a huge tank of water, creating an environment very closely to that of the Space Station in outerspace, of which I have a photo and some description in
this previous post . They acted the spacewalks out in this lab prior to sending Wheelock and Caldwell Dyson out on the actual spacewalk, and thus they were able to anticipate any problems and better guide them on the spacewalk.
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In an interview with KILT radio, Doug recalled waiting to hear from NASA as to how he would repair a ripped solar panel on the ISS during a spacewalk a few years ago:
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I remember during those first hours when we didn't hear much from Houston and we weren't sure what we were going to do about this torn solar ray. I knew this was going to be really, really magical what these sharp, creative minds come up with and you know, it was crazy at first. They said, 'We're going to send you out there and you're going to make these sutures and essentially sew up this solar ray.' And we thought
'What a crazy, crazy idea,' but it worked and was just a real testament to team work, faith in your team and the ability for NASA to pull together. This moment of desperation really became one of NASA's finest hours. It was a real privilege being a part of that."
-In an interview with BBC, Doug made this comment about spacewalks: "
It's a real eye-opening experience. It takes a little time to get your mind around it. The most encouraging part is knowing you have a team of people behind you and you can hear them in the headset - that's very, very comforting."
-Doug's Bio
Beautiful Pictures from space on
Doug's Twitter
My first ISS post.
My second ISS post: Change of Command
My third ISS post. To Infinity & Beyond: A Young Boy's Dream?
My fourth ISS post. ISS: Home Away From Home
My fifth ISS post. One Big Science Lab
My 2nd fifth ISS post. No Vacancy
My sixth ISS post. In Which Doug has a Screw Loose, I mean a Loose Screw
My seventh ISS post. Personal note from Doug about working with the Russians.
My eighth ISS post. Doug talks about the emergency on the ISS
My ninth ISS post. Everyday Life on the ISS
My tenth ISS post. Heading Home
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