From the archives of the Enzmann Starship notes ca 1980s:

The need for improved spacesuits

Starship crews should be able to perform a wide range of difficult functions more efficiently than permitted by today’s spacesuits and to survive indefinitely despite ominous hazards

a. One-way tickets for some voyagers, colonists for whom, because of time dilation or for other reasons, return to the Earth would be impossible or impractical. Therefore seek to improve chances of survival and success in interstellar space and on landfalls.

b. The primary importance of people, appropriate clothing does not merely make the man, it may save him

d. To understand the changes in spacesuits needed to make them appropriate for star flight, we need to briefly consider the development of spacesuits and their present characteristics. First, examine how space-suited crew members could safely leave and enter a starship and vehicles in which they could be communally transported.

Prerequisites for using spacesuits

a. Airlocks. When leaving or entering a starship, one must conserve air by preventing it from leaving the ship. Present-day methods are from the Stone Age, not sufficiently effective for starships. Four new methods: Air pump (pump air in locks back into airlock supply; waffle-board locks about the spacesuit (tight-fitting connection to prevent air leakage); glove docks (almost no air leakage); gangplank airtight tubes frame cranes.

b. Lifeboats, Like life rafts, to transport space-suited workers or serve as preservative cosmic lifeboats for survival in disasters.

c. Mini lifeboat. Has its own Amoeba-lock. Enter it in spacesuit lying on back, carries one or two crew members and supplies, including spheres that blow up like balloons with a diameter of about eight feet. Has a sheath or hull over it, so it blows up on its own; a ship leaves it behind as part of the bubble and can later dock with it.

d. Larger lifeboat, about 20 feet long, carries more crew members and supplies, including flame sprayers and spheres that, when expanded, would be large enough to enclose a small asteroid, thereby permitting mining.

e. Two larger lifeboats, one of which can carry 25 people, the other 250 people, also serve as quarters.

f. Life-preserver unit (for attachment to spacesuit).

Gracile spacesuits

a. Technology feasible to construct comfortable, tight-fitting, yet expandable, full-pressure spacesuits that would dwarf today’s suits in potential size, complexity, and life-sustaining capability.

b. Powered suits recycling everything would be equipped with numerous instruments for life support and life enhancement.

c. Can be made of fine tungsten, stainless steel alloyed, and vanadium, augmented by stainless steel, with a diamond-finished surface (extremely hard, strong surface).

d. Comfortable to wear and attractive, handcrafted and decorated

e. Yet too bright to behold. A windshield effect – solar scintillation – just as one can be overcome by the inescapable bright reflections of the sun’s light by cars parked at various angles, so any nearby star could cause the rounded diamonds on the surface of a spacesuit to radiate blinding light. Dulling the diamonds colorfully, to protect against this shiny specularism; need to darken or color the diamond coating. Shading the eyes: in addition, install in spacesuits specular spot-filter eye-protecting visors.

f. Basically standardized, with replicable parts, but somewhat personalized, especially distinctive male and female versions adjusted for urogenital differences; also, variations in the size of suits.

g. Lead time: estimated twenty years, which could be reduced to ten; no major technological breakthrough required, though recycling feces is an exacting task.

h. Cost: We’re worth it. Expensive, individual production: estimated $10 million per suit. Mass production: between $500,000 and $2 million per suit. Requires machinery and skilled persons to produce. To discourage suit theft, use chips tuning the suit to owners. An Echo Lance must be able to repair and produce gracile space suits, though the first few trips could be made with the ability to produce a somewhat lower-grade suit.

Gracile spacesuits as miniaturized starships

a. Like long-lived turtles are protected by their shells, so a group of stranded crew members could survive comfortably with close social contact for years on an isolated, barren asteroid.

b. Like starships, they would be equipped with life support systems, communication devices, libraries, shielding from hostile environments, and their own sources of propulsion.

Indefinitely long-life support

a. Occupant able to live indefinitely in a suit, the main hazard being a major accident that would penetrate the puncture-resistant material, thereby causing death.

b. Precise regulation of pressure and temperature.

d. Full recovery of oxygen to produce breathable air from exhaled CO2. Air recycling. CO2 scrubbing, volatiles, filtering humidity.

e. Continually renewable food and water supply from safe recycling of wastes.

e. Washed the body, ensuring cleanliness, avoiding itching with dirt, submariners’ dirty eye-lines

f. Perpetually satisfies all the body’s basic physical needs.

Propulsion and strength from power plants
a. Even without the use of its power supply, the comfortable suit allows smooth movement.

b. Power plants using small conformal radio-isotope plutonium packs safely implanted in the suit’s arms and legs provide the wearer with both a source of propulsion via mini-Lance drives and enhanced power for such tasks as lifting boulders or tearing metal apart with claws.

c. Uses a quadrupole accelerator: the nuclear part generates electrical energy which the other part – the beam of the lance – uses to accelerate particles.

d. The packs, which also power other functions of the suit, constitute a virtually inexhaustible source of energy.

e. Position or orienting oneself is accomplished by using inertial reaction back and side wheels, or alternatively by liquid pumping.

A panoply of additional functions

a. many instruments and tools contained within the suits a host of corresponding functions; hammer, saws, torch, pliers, drill.

b. Communication via conformal antennas built into the suits

c. Navigational equipment projected on helmet plate; beacons.

d. Lights, visible, infra-red, radar

e. Instruction: a computerized library available for prolonged study, photography, recording, project on helmet plate

f. Entertainment: extensive, varied entertainment in solid-state storage, print, diagrams, movies, music voice, interactive voice, helmet screen, thoracic screen.

g. Kinetic pellet gun, beam laser for defense but also for drilling, can be directed by eye for one or multiple targets.

Suited for expansion and co-habitation

a. Thoracic expansion: from the waist upward, may be enlarged into a small room, four conjoined to another suit. Mobility of arms allows tending a baby, made possible by “origami shoulder” – fold arms in draw arms into spacesuit.

b. Can turn the expandable thorax into a back porch that does not interfere with arm movement by means of two O-rings.

c. Blowing bubbles within bubbles: blow several Mylar bubbles, one inside of another for added protection. Padding them with Aerogel (Aerogel is especially strong, rigid, and resilient), and flame spray nickel-iron steel on their walls, forming a room perhaps as large as 25 feet in diameter, size limited by air supply weight. Use of roll-top extender.

d. Coupling together: can join (egress) with another suited person at a conjunction port (intersect junction), permitting that person to enter the room; can join others at six ports, but the others cannot enter the room while a visitor is there. Going from one suit to another involves the use of double-turning O-rings, which are as wide as the shoulders.

e. Enables a space-suited individual to enjoy close social contacts, combats loneliness, and facilitates sharing with others.

f. bubbles can be made transparent: glass, plastic beads, and slots; light pipes, pipe screens.

g. Also the expanded bubble makes possible aerobic exercise to combat bone and cardiovascular deterioration. Artificial gravity could be generated by using the power pack to spin the bubble, though this would not be very good. A shortcut continuous running track, a raceway, can be constructed around the interior of a bubble. A bicycle-like apparatus can be rolled around it.

Who gets what type of spacesuit to use, how and when

Gracile suites will be made available to all passengers who can afford them. Those who cannot, will be supplied with minimal containment suits that would give them the opportunity to reach lifeboats in case of catastrophe.

a. acceleration-deceleration suits: worn to increase tolerance to G-force while accelerating, decelerating, or undergoing a gradient plunge in a starship, this making possible rapid acceleration or deceleration which otherwise would have been ruled out by human inability to tolerate such levels. Everyone gets one and must wear them at appropriate times.

b. Living sleepsuits: for hibernation. High speeds of the Echo Lance could make hibernation unnecessary for trips within the Milky Way Galaxy.

c. Minimum pressure suits, priced at perhaps $250,000 each, may be made available for certain passengers in Torch ships, perhaps to leaders of passengers, or perhaps only to passengers who are willing to assist the crew in large-scale tasks such as refueling.

d. Liquid breathing suits: (to be discussed subsequently)

e. Gracile suits: supplied only to crew members, but each has at least two (use is considered in the next section)

Occasions when worn 

a. Drills in the Echo Lance

b. Solar Gradient plunges

c. If a starship becomes punctured by a collision

d. To repair the ship from outside while in space

e. Transfers to other ships

f. Landing on the surface of a landfall that lacks a breathable atmosphere.

g. Initially exploring the surface of a new landfall regardless of atmosphere. The danger of rebellion within the ship.

h. Encounter with aliens; the danger of contamination or war, the danger of giving away information, finding Earth’s location.

i. Castaways marooned on a landfall without food or drink, even for generations.

j. Ceremonies.

k. Sometimes, while working in a fusion Torch ship.

Prospect of liquid breathing suits

a. While this document, unlike typical treatments of star flight, centers attention on what is currently technologically feasible, or on what requires only minor expected breakthroughs to become feasible, occasionally mentions a possible breakthrough so revolutionary that it should not be ignored.

b. Experiments suggest that humans may be able to breathe certain liquids safely.

c. If lungs are filled with saline or oxyfluoride compounds, humans can apparently tolerate much more g-force, perhaps as much as 20 to 50 Gs or even higher.

d. If everyone in an Echo Lance was totally immersed in liquid, each inside a special small compartment, a starship could reach near light speed in a few days and decelerate in a similar period. Otherwise, much of the time in star flight would be consumed in one or the other.

e. The crew would need to be in the eyeballs out position – lying down and looking up in the direction of motion.

f. The problem of getting nutrients into the bodies and extracting wastes would have to be solved; no trouble, take a rest period.

g. Tightly compartment the ship; most of the air in the ship would have to be pumped into containers because of the Pogo effect.