Space Chronicles on Ice #14
by Don Pettit
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The Scott Tent
Dec 20, 2006:
We are living in tents patterned after the tent that Robert Scott designed for his fated 1910-13 South Pole expedition. They are a four-sided pyramid that stands about 9 feet tall and are 8 feet square at the base. They have withstood 200 kilometer per hour katabatic winds, a necessary trait if you want to have shelter in the Antarctic interior. The walls are double with the outside wall being wind proof and the inner wall being porous to water vapor. Like thermal pane windows, the double wall adds some measure that helps keeps the inside warm; however, the real genius to the double wall is not increased insulation. Scott knew from previous Antarctic expeditions that water vapor generated from human activity would condense on the inside, freeze, and then when the wind flexed the fabric, come drizzling down on the occupants as a continuous man-made snow storm.
Two tent walls circumvented this nuisance by having the inner wall made from porous fabric that would allow the water vapor to pass through and freeze on the outer wall. Then when the ever constant katabatic winds flexed the fabric, the snow would simply flake off in between the tent walls and thus, not rain down on bare heads. The timeless nature of this elegant design is apparent 100 years later.
By design, the floor is a separate piece. The main reason is to allow the tent to blow away without taking the occupants along for a half-fly, half-roll that would make bungee jumping pale as a comparable thrill. Secondary benefits to this design allow the tent to be quickly set up over rather uneven sastrugi snow, and then leveled from inside where you are out of the wind. Perhaps the most useful aspects of the separate floor, one that took us awhile to discover, is that when breaking down the tent, one does not need to tediously pass all the gear through the rather smallish and awkwardly designed door. Simply pull up stakes and tip the tent over, exposing all your gear where you can simply haul it to the waiting Nansen sledge.
The door is probably the most ill-designed feature of this tent. It works exceptionally well in keeping the cold out and thus, the heat in; however, it is not the best when taking human dynamics into consideration. The door is circular in design with a billowy fabric tunnel that closes with a draw string, something like an iris diaphragm in a camera lens. In concept this is a slick design, however the door is not large enough in diameter to pass both head and feet at the same time. So one has to either worm out head first or worm out feet first, either way depositing you into a pile of wind blown sastrugi, patiently waiting to slither down the neck, boots, or sleeves, whichever it can find. To complicate matters, there are two identical doors in series, one for the inside layer and one for the outside layer, that need to be negotiated. And add to that the puffy down parkas, pile pants, head gear, and mittens, one is panting for breath simply from exiting the tent. With the door being like an iris diaphragm, the simple act of passing out the tent truly makes one feel like he has been born again.
The inside is rather roomy, with sufficient floor space for two bed rolls, a stove, food and lots of gear. There is head room to stand up, a nice feature for donning bulky clothing. With the stove lit, the floor level of the tent stays around -10 degrees C (it typically runs -20 degrees C outside with wind chill, -40 degrees C). The upper part, which acts as a chimney, runs around 15 degrees C, making a great place to dry clothes. The chimney area, like scuba diving through kelp, is swimming with damp socks, mitts, bibs, gaiters, bunny boots, and perhaps, a favorite bottle of ketchup or hot sauce. For Christmas and New Years, there is sufficient room to pack all eight of us in for holiday celebrations. To capture this on film is definitely a fisheye lens moment.
Around the inside wall are sewn in pockets, very handy places to tuck away small goodies and keep them from being lost. Speaking of which, swimming in this virtual sea of loose gear, it is so easy to lose small items. They can be misplaced sometimes for a day or more, only to be discovered under your foam mat or clinging to the seat of your pile pants by a Velcro tab.
There are similarities to tent life and living in space. Both have rather cramped quarters, and both are buried in a sea of gear. Finding items in your spacecraft can be a real Easter egg hunt, sometimes taking an hour to locate a few small but essential pieces of gear. Losing items is a daily way of life. You place your glasses in some safe corner only to have them float off. You search in vain, but it is difficult, of course, to locate your glasses without first having glasses. A day or two goes by and they mysteriously appear in front of you, floating by your nose like some hound dog returning home from a running spree, as if nothing extraordinary had happened.
Yes, tent life has a lot of parallels to space life, with one glaring exception. The weightlessness of orbit allows one to fully utilize small volumes in ways impossible in an Earth-bound tent. If our Scott tents were in orbit instead of staked to the surface of Antarctica, our sleeping bag would not be confined to the floor. We could tie them to a wall, or curl them up near the chimney area where it is warm. Any direction has no bearing to up and down so we could stretch out our legs without gravitational boundaries. Playing our game of Scrabble would be a challenge, unless each piece had a spot of Velcro to keep it from floating away.
In weightlessness, it’s the small items that give you the most troubles. However, with time comes the skill to manipulate diminutive objects. On Space Station, we dismantled and repaired one of our watches. The resulting video demonstrated that one is not necessarily a bull in the china closet simply because of weightlessness. Humans have this uncanny ability to adapt to any environment presented before them.