Microgravity Primer

 

On the International Space Station the key words that control living in space are "apparent weightlessness." There will be many surprises in an existence where you can push away from a solid object with a finger and appear to be floating. Look in the mirror above the wash basin. Your eyes will seem smaller because your face has grown fuller. This results from the shift of much blood normally in the lower part of your body to the upper part. If you had wrinkles or a double chin on Earth, they will have disappeared. As a result of the blood shift, your waistline has shrunk 2.5 to 5 centimeters (one to two inches), and you must tighten the bands of your pants. Your leather boots have also become too loose, and you will have to tighten the laces.

As for your body, you will measure 2.5 cm to 5 cm (one to two in) taller, for the discs between the vertebrae of your backbone no longer have the downward pressure of gravity upon them. To handle your new height, the flight jacket was made with elasticized pleats that run up each side of the back and over the shoulders.

Your posture, too, will be different, but not for the better. Joints go to their midpoint in microgravity so that your hips and knees will be bent into a slight crouch. Your arms will tend to float in front of you unless you consciously hold them down. When you sit at a work bench, you will, of course, have to strap yourself in place. Even so, your seated . posture will be to lean back.

The way you handled the most ordinary tasks on Earth must be replaced by new techniques to offset the effects of microgravity. Eating is a prime example. Forks and spoons will drift off unless they are anchored. When you broke a slice of rye bread at home, you knew the crumbs would drop to your plate. In space, crumbs float, presenting a menace if you inhale them or if they get inside equipment. As a result, bread has to be soft so it will not crumble. Table salt sprinkled toward your meat will scatter instead into the air. Spilled water does not drip down, but moves outward to form fairly stationary, suspended balls. Should these globules hit a solid object, however, they will spread like pancake batter, sticking stubbornly to the surface and be extremely difficult to wipe away.

On Earth, you depended on the reaching force of friction to help you do many jobs. In microgravity, you must do all the work yourself, with extra steps that consume much energy. Take the simple problem of opening a hinged floor plate in the mid-deck. If the orbiter were on Earth, you would merely bend down and pull it open. But if you bent down to do this in space, you would continue into endless somersaults until you managed to stop yourself. Instead, you go to storage for a portable handhold with suction cups. Then you position your body in a floating headstand, reach down, and press the handhold against the floor. With your free hand, you pinch the opposing springloaded fasteners on the floor plate together; when you succeed, the plate will come open.

 

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