Linenger's Letters to his Son

May 2, 1997
Let me tell you about my Orlan M spacewalking suit"

Dear John:

I have a great picture of you hanging on the bulkhead.

You are dressed in overalls, looking at the ground inquisitively, as if you had just spotted your first grasshopper and are unsure whether to touch it or to run. You look like a little man, perhaps a farmer, in those overalls.

Maybe you caught a look at me in my spacesuit the other day, and thought: “boy, is Dad ever dressing strangely these days; I should lend him a pair of my overalls.” Let me tell you about my Orlan M spacewalking suit--and maybe then you’ll understand why overalls just won’t do.

It is the latest fashion, a brand new model, never used in space before. The people at the Zvesda (meaning “star” in Russian) company in Moscow designed the suit. They built the first space walking suit ever used back in the sixties.

It comes in one color--off white--and weighs about 175 pounds. You climb into it through a “backdoor” that can be closed by pulling a wire that is attached to the door and winds around the exterior of the left side of the spacesuit. You grab the wire by the fastening ring on its end, pull firmly until the door behind you swings shut, and then hook the ring to a hook located on the (reachable) front chest section of the suit. This loosely closes the door. Loose isn’t good enough in a pressure suit.

The door is snugged up tightly (air tight!) and locked shut by pulling up on a metal lever on the right hip section. Because of this rigging, unlike you, John, I can get dressed by myself--though, in actuality, we help each other. It is better to make sure that nothing is caught in the sealing ring when you close the door.

When unpressurized, your head strikes the top; so that you are hunched over, stuffed uncomfortably, into the suit. You feel like a sardine--packed in nice and tight.

Once the door is closed, you need air, air conditioning, a way to keep the moisture down (to prevent fogging of the visor), and cooling. The suit comes equipped with two oxygen tanks (prime and reserve--the reserve being used only if the prime tank is exhausted, or if the prime malfunctions), a carbon dioxide scrubber, and a moisture gatherer with separator. The oxygen within the suit is circulated by a fan (prime, with a backup).

Cooling is provided by circulating fluid around your body through tubes that are sewn into an inner garment that you wear over your cotton undergarment. Inlet and outlet fittings from these inner garment tubes are mated to the suit itself. Two pumps (prime and reserve) circulate the water. The fluid inside the tubes passes through a heat exchanger, which in turn is cooled by evaporating (actually, sublimating, which means it goes “poof” and “boils” away as would most fluids, including your own blood, when subjected to vacuum) water into the vacuum of space.

Power supplied by battery. Radio for communications (we piped in some music from the space station while we were waiting (20-30 minutes periods every hour or so), in darkness, for sunrise). EKG and body temperature sensors probe and send their information via telemetry to the ground.

Suit pressure gages, oxygen pressure gages, control panels, and a caution and warning panel are all located on the upper chest area where they can be seen. We kept a close watch on all parameters throughout the spacewalk, and except for a master alarm that went off inside the space station itself during the spacewalk (which was heard by us via the radio, and which turned out to be minor), the emergency indicators on the spacesuit remained quiet and unlit. (When I heard the alarm, I immediately scanned suit pressure and oxygen level--the two most critical elements for survival--and both were normal. And a few minutes later, I noticed that my pulse was back to normal also).

That’s what makes up the spacesuit, and that is why it looks so strange. An amazing piece of gear; essentially, an independent spacecraft that allows you to work on the exterior of the space station while protecting you from the harsh, life-threatening environment of space.

I still like your coveralls, John.

Goodnight. Be good, but adventurous (a little naughty is okay).



P.S. Grasshoppers won’t bite. Chase ’em next time.

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