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I've enjoyed the first two books in Jean Johnson's "Theirs not to reason why" series.

The science seems relatively well thought out to me.

The emergency pressure suits were described as being a certain way to prevent the pores in your skin 'inverting' due to decompression. I was curious if that would that really happen. Ie would the pores in your skin turn inside out if you were vented to space?

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Short Answer

  • It is unclear why the writer believes the skin of a normal human would suddenly have its pores explode when exposed to space but that is not a true statement. The USAF Flight Surgeon's Guide does not list exploding skin pores as one of the potential threat of sudden explosive decompression.

  • A person is more likely to have their lungs distend or possible even rupture if they were to hold their breath in a zero atmosphere environment. Intestinal gasses could also be a problem by distending the bowel regions and reducing space within the body cavity, making breathing difficult or even compressing the heart. In this case, it is certainly a safety consideration regarding bowel gasses with the expression "better out, than in."

  • Holding one's breath could cause a rupture in the soft lung tissues and such a rupture could send bubbles into the bloodstream potentially causing an embolism or stroke, resulting in death.**

Longer Answer:

Your pores are neither filled with any gasses nor have any pressure beneath them which would be trying to escape due to a sudden reduction in atmospheric pressure such as a decompressed environment. The goal of a space suit is to prevent your internal pressures from trying to escape explosively from your body when under the zero pressure environment of space. Here is a cross-section of a skin/pore region. Your skin has no gases trapped beneath it to worry about exploding into space.

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In The USAF Flight Surgeon's Guide, Fischer lists the following effects due to mechanical expansion of gases during decompression.

Gastrointestinal Tract During Rapid Decompression.

  • One of the potential dangers during a rapid decompression is the expansion of gases within body cavities. The abdominal distress during rapid decompression is usually no more severe than that which might occur during slower decompression.

  • Nevertheless, abdominal distention, when it does occur, may have several important effects. The diaphragm is displaced upward by the expansion of trapped gas in the stomach, which can retard respiratory movements. Distention of these abdominal organs may also stimulate the abdominal branches of the vagus nerve, resulting in cardiovascular depression, and if severe enough, cause a reduction in blood pressure, unconsciousness, and shock. Usually, abdominal distress can be relieved after a rapid decompression by the passage of excess gas.

The Lungs During Rapid Decompression.

  • Because of the relatively large volume of air normally contained in the lungs, the delicate nature of the pulmonary tissue, and the intricate system of alveolar airways for ventilation, it is recognized that the lungs are potentially the most vulnerable part of the body during a rapid decompression.

  • Whenever a rapid decompression is faster than the inherent capability of the lungs to decompress (vent), a transient positive pressure will temporarily build up in the lungs. If the escape of air from the lungs is blocked or seriously impeded during a sudden drop in the cabin pressure, it is possible for a dangerously high pressure to build up and to overdistend the lungs and thorax. No serious injuries have resulted from rapid decompressions with open airways, even while wearing an oxygen mask, but disastrous, or fatal, consequences can result if the pulmonary passages are blocked, such as forceful breath-holding with the lungs full of air.

  • Under this condition, when none of the air in the lungs can escape during a decompression, the lungs and thorax becomes over-expanded by the excessively high intrapulmonic pressure, causing actual tearing and rupture of the lung tissues and capillaries. The trapped air is forced through the lungs into the thoracic cage, and air can be injected directly into the general circulation by way of the ruptured blood vessels, with massive air bubbles moving throughout the body and lodging in vital organs such as the heart and brain.

  • The movement of these air bubbles is similar to the air embolism that can occur in SCUBA diving and submarine escape when an individual ascends from underwater to the surface with breath-holding. Because of lung construction, momentary breath-holding, such as swallowing or yawning, will not cause sufficient pressure in the lungs to exceed their tensile strength. -- U.S. Naval Hospital Flight surgeon Manual, 3rd Edition 1989 (see also 2nd edition, 1998).

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