Stillsuit/DE

A stillsuit was a Fremen garment which allows desert survival by cooling the wearer and by preventing water loss. These slick, gray bodysuits were the second skins of Fremen — and of all those with good sense who had occasion to venture into the Arrakeen desert.

An unprotected human, without access to a staggeringly large water supply, could last no more than a day on the sands; one wearing a stillsuit of Fremen manufacture, however, could keep water loss under 15 mL per day. The less efficient versions of the suits produced in village factories by the Arrakeen peons were greatly inferior and offered no such level of protection.  

History

Stillsuits were an invention-of-necessity developed after the Zensunni nomads were transported to Arrakis. Not even on Ishia, an earlier stop in the Zensunni's migrations, had water conservation been so essential that permitting any bodily moisture to escape could be fatal. Practices which had made life possible on that arid planet (though far less arid than Arrakis) were simply too inefficient for the new environment, and the stillsuit was one of the first adaptations made.

Design

The invention of the stillsuit was a tribute to the Fremen's ability to "cross-use" technology. The Zensunni were used as laborers of many different types during their generations of wandering and retained the knowledge of the various kinds of devices and machinery they had operated. One such machine, a cryogenic separator, was used on a number of worlds for drawing oxygen and other gases from a planet's atmosphere. The Fremen remembered the technique and applied it to the manufacture of stillcloth. The fabric itself made the suits effective.

The fabric, a micro-sandwich in its completed form, is produced in layers. The innermost layer consists of a porous membrane allowing the free passage of perspiration, exhaled moisture, and other bodily secretions. It is also an efficient insulator, protecting the suit's wearer from evaporative chill. The next two layers accomplish the separation of reusable water, and a complex system of fine tubes permeate the fabric. They are equipped with checkvalves at various points in order to keep the system's contents from reversing directions. The tubes contain air at the beginning of the suit's cycle; air pressure is built up by the pumping action of the wearer's breathing and by heel pumps located within the soles of the suit.

At a pre-set pressure (which varies with the atmospheric conditions under which the suit is worn), air is released into a holding chamber located within the suit's hood. This sudden release cools the air by the Joule-Thompson effect, and the cooled air is drawn back into the system and again run through the suit, dropping the temperature of the separating layers. The build-up, release, return cycle continues until the temperature drops sufficiently in order to liquefy the ammonia produced when the suit's thigh-pads filter the wearer's urine. Once the ammonia is liquefied, air is automatically retained in the hood chamber, and the ammonia is pumped into the tubing system, keeping the temperature down until it is converted back to a gas by acquired heat, at which point the air cycle was triggered again.

Passing through this chilled area returns the trapped water vapor — which is protected from ammonia contamination by the airtight nature of the tubing system — to liquid form. This water is forced through the separating layers by both pumping pressure and osmosis and is subsequently trapped in the fourth layer. Here, another tubing system routes the reclaimed water (from which salt precipitators, also located in the second and third layers, remove most of the salinity) to the suit's catchpocket. Any radiated body heat which makes it through the separating layers then passes through the fifth, outermost layer along with unreclaimed gases.

Components

Catchpocket

A catchpocket is a compartment for holding distilled water waiting to be consumed or measured. Most catchpockets are used in stillsuits. A series of two and sometimes three catchpockets are interconnected so that overflow from the primary is not wasted. The heel pump, besides aiding in the distilling process, moves distilled water to appropriate carrying points where the catchpockets are built into the stillsuit. The wearer sucks on an attached catchtube to drink the water from the primary reservoir.

Valves are rarely used in catchpocket system of the stillsuit, but a few contain a capillary-type, flapped suction valve on the primary pocket. Suits developed by non-Fremen in the villages first used these valves. These usually serve as a back-up precaution, behind the catchtube plug, in order to prevent accidental spillage. The use of the valve largely skipped over the sietches closest to the villages, but caught on in the deep desert settlements fairly late in the Dune era.

The capacity of catchpockets vary between 0.25 and 0.5 L (combined capacity). (It is unlikely that a conscientious user would ever need that much storage). Stilltents have been found with total capacities approaching two liters, but most can store only about one liter. Variations on the fundamental catchpocket have been used as waiting basins on portable deathstills and, temporarily, in connection with windtraps.

Filtplug

A filtplug is small, tubular device used on Arrakis to help prevent loss of body moisture. Many examples have been uncovered in different sietches. All are made of a spice-based compound, with silicon and orthatan added in varying proportions. There is a high correlation between the proportions of additives and the locations where the plugs were found. Differences in composition appear to have been a matter of local preference.

Most filtplugs are about 25 mm long, with each branch of the Y-shaped device between 5 and 7 mm in diameter. The single outlet at the bottom fits the upper end of a stillsuit's primary catchtube. Each upper branch of the Y slips into one nostril. The outside surface of the fitted ends is roughened slightly so that the seal is snug. The roughness can cause sores at first and may eventually leave calluses around the nostrils of constant users. The filtplug directs all the air exhaled from the lungs, along with its moisture, into the stillsuit's recovery system.

Filtplugs have screen filters of moderate mesh built into each of the Y branches. These capture significant particulates, keeping them from fouling the distillation apparatus. If one filter clogged, the wearer can still exhale through one nostril. Filtplugs can be cleared in the field by pulling them from the nose and the catchtube and blowing backwards through the air passage. Usually, however, both filter cleaning and the substitution of a new filtplug for a used one are carried out before leaving or after returning to the sietch.

Other components

• Breathing mask (also called a "filter mask" or "moisture mask")
• Gloves
• Recath (presumably similar to today's catheters)
• Stillsuit cap
• Stillsuit hood

Significance

The stillsuit was considered an unattractive but essential garment by most non-Fremen, and its manufacture brought a steady income to a number of sietch factories. On Arrakis, any man who valued his life would not venture into the desert without a well-maintained stillsuit of Fremen manufacture; its importance can be seen not only in the survival of the Fremen themselves, but in the death rate among Harkonnen servitors, to whom the tribes adamantly refused to sell their wares.

After Paul Muad'Dib Atreides became emperor, an interesting phenomenon took place: recognizing that the true source of the emperor's power lay in his Fremen, and wishing to advance themselves at Court, some sycophants adopted a custom of wearing stillsuits beneath their courtier's clothing. That these individuals had taken to wearing the garments where they were not needed amused the emperor and his Fedaykin tremendously. When it was discovered that all of the fashionable stillsuits were non-functional replicas, their wearers were made the objects of such derision that they abandoned the practice.

The fashion was revived, however, during the rule of Leto II, although the stillsuits worn by his Museum Fremen were also useless. The irony did not escape the God Emperor, and a number of his Journal entries refer to the Museum Fremen as "sand dandies, at whose dress a true Fremen would laugh until no laughter remained." Leto kept a small number of stillsuits, manufactured in the old style, at his Citadel, for use by persons he wished to accompany him into the Sareer.

See also

• Fremen
• Stilltent
• Windtrap
• Deathstill

Further references

• Janet Oslo, Fremen: Lives and Legends (Salusa Secundus: Morgan and Sharak).