Spacesuits

Basic Biofilter

Tech level 1

Made of millimeter-thin carbo-polymer fabric, a biofilter is a whole-body protection system designed to isolate a humanoid body from any biological environment. Its purpose is to make the transit of virii, bacteria, prions, spores, and any other biological contaminants across the barrier impossible, while allowing gasses and fluids to transit unimpeded, thus accomplishing respiration, perspiration, etc.

Over most of the body, the fabric is skin-tight, using adaptive fibers to morph to the body's shape, eliminating wrinkles, sagging fabric, bunching, etc. The nano-fibers coordinate intelligently with one another, forming a dense matrix with nanometer-scale apertures for air and water molecules to pass, but nothing larger. At that scale, protein fragments and fungal spores are enormous, and virii and bacteria are truly collossal. They simply cannot transit through any given dozen layers of material, and there are millions of such layers.

To suit the humanoid form, a biofilter contains a mouthpiece, nasal adapter, and two eyepieces. The mouthpiece and nasal adapter are said to be mildly unpleasant to mount--one must inhale them, causing the extra-flexible material to conform to the inner surfaces of the mouth and nasal passage. While perspiration can slowly seep through the skin-adjacent layers, the passage of liquid through the mouthpiece is inconveniently slow. It is not recommended to injest fluid through a biofilter, although it can be done. No solid food can pass through it--in fact, only the smallest molecules (i.e. dissolved simple sugars) can pass through along with water. Generally, for longer-term missions, intraveneous nutrient packs are utilized.

While a powerful ward against biological intrusion and contamination, the biofilter is not a suit of armor, and fares poorly against the smallest amount of kinetic, thermal, or explosive damage. Thus, it is almost always paired with an exosuit and possibly armor, for the purposes of protecting the wearer. For the biofilter's main purposes of preventing contamination, given the possibility of puncture via weapons, shrapnel, or just environmental hazards, biofilters do not rely on external armor. They are designed to wrap around intrusive particles, entering the body with them, and continuing to separate the body from the outside environment.

A simple example: a knife is quite capable of overcoming the meager resistance a biofilter could pose, while threatening to nullify its mission with a single puncture. Instead, the biofilter conforms to the shape of the knife as it enters. Its carbon nanotubes are much stronger than tissue, so rather than being severed by the blade, they in fact transmit the blade's force. Whether the knife remains embedded or is removed, the fabric is not punctured. This does not prevent injury, but does prevent cross-contamination, which is the biofilter's main purpose after all.

This adaptation is best suited to kinetic damage--slashing and piercing weapons, blunt force trauma, shrapnel, etc. Biofilters do not fare well under extreme heat. Ordinary fire can melt them to the surface--a very painful process that, in small amounts, does not compromise the filter's effectiveness, but with enough thermal damage, the suit will lose its integrity.

Basic Exosuit

Tech level 1

Much thicker and more durable than a biofilter, but still not much thicker or constrictive than ordinary clothing, an exosuit is a whole-body system designed to protect the wearer from negative pressure (i.e. vacuum), thermal radiation, and minor damaging particles such as sandstorms. It is intended to protect from the hazards of space, and of those found on many uninhabitable worlds, but is not intended for a firefight, at least not without armor added on.

An exosuit is made of billions of layers of nano-woven carbon fibers, which are able to change their length, elasticity, flexibility, and cohesion according to electrical signals sent from a variety of tiny processors sown into the suit. As such, the fabric is slack when not in use, and quickly conforms to the body when donned. It is aware of the geometry and range of motion of humanoid bodies, enabling a skin-tight fight without appreciable resistance when bending, rotating, extending and contracting limbs, etc.

In response to negative pressure, the suit can adaptively tighten in a normal direction, applying even pressure throughout the body, almost as evenly as a gaseous atmosphere. The pressure is created through tension, so while it can recreate normal atmospheric pressure (or more, as needed by the wearer) in a vaccum, it cannot appreciably provide outward pressure, and is not suitable for underwater operation or in exotic gaseous atmospheres like a gas giant. Still, this crucial feature means not only is the suit much less restrictive and bulky than a gas-based pressure suit, it does not lose pressure when punctured.

The material is self-healing, adapting to small punctures with minimal loss of function, although enough damage will compromise its capabilities in the damaged region. It is meant to offer near-immunity to incidental damage such as micro-meteorites, orbital shrapnel, etc, but in a sustained firefight, it will be quickly overwhelmed without armor plating.

Generally speaking, the exosuit is paired with a helmet, simply because the exposed areas of the head--certainly the ears and eyes, but most crucially the upper respiratory tract--are best kept pressurized using gas, rather than tension. A solution such as that used in biofilters would not work, as tension alone cannot provide the outward pressure needed to brace the soft tissues of the respiratory tract. It is possible to use a flexible headpiece, although a humanoid wearer would require fluid-filled sacs fixed tightly to the orbitals to protect the eyes, and a full mask fixed over the nose and mouth (with vacuum-rated earplug) matched with a respirator. Helmets tend to be easier, especially modern helmets equipped with robotic systems to manage perspiration, extend external stimuli into the helmet for digital manipulation (i.e. scratching an itch), and the whole comfortable breathing thing.

The outer and inner layers of the exosuit are extremely reflective, rejecting 99% of thermal radiation, and granting the suit its characteristic metallic sheen. Without this feature, the fabric would provide only a few minutes of thermal protection from solar radiation in an inner solar system, and its dark side would radiate body heat quickly into space. With this adaptation, the wearer can survive for hours without power assistance, and days or more with a power source to actively manage heat. Similarly, the helmet's visor is equipped with light-speed reactive sensors to adapt to lighting conditions. It is safe to look directly at a star with these helmets, as they will reflect the vast majority of its light, but permit light outside the immediate corona to limit the star's blinding effect.

Typically, an exosuit is paired with a powered life support module, often worn as a backpack, which contains either pressurized gas, a fuel cell, or a solid state system to generate internal atmosphere (in increasing order of endurance) and scrub waste gases. Said modules can interface through ports in a biofilter (when present) to an intraveneous nutrient dispenser, to enable long-term endurance missions. Generally speaking, with adequate heat management, a humanoid in open space provides more than enough heat, and the power is actually used to radiate waste heat adaptively through the suit's dark side. However, an exosuit can provide warmth in certain cryogenic climates, although cold worlds with thick atmospheres and/or precipitation require more robust defense. Similarly, hot worlds with dense atmosphere require specialized life support modules--the planet Venus, for instance, would not be survivable for even a few seconds with a mere exosuit, or even most power armor.

While the suit is not "inflated" with gas, to prevent it from becoming rigid and inflexible, the internal atmosphere is pumped through channels in the suit's fabric to manage body heat, adapting to the body's natural proclivities on heat management. Sweat is an excellent cooling mechanism when the water can be quickly wicked away, but salinity becomes a problem. Biofilters can be configured to block saline, but would quickly become clogged if they did, and the long-term life support of the module would be reduced, as hyponatremia becomes a factor. While configurations exist that recycle water and salinity effectively, a simpler solution is desired for most basic needs. To that end, the exosuit pumps fluids cooled to carefully-calculated temperature to keep the contact area of the suit at an ideal thermal gradient for heat management to minimize perspiration. In other words, exosuits tend to feel cool, and unaccountably moist, without noticeable moisture buildup. Something like the feeling of stepping out of a shower into a cool breeze, or being submerged in a pool of water that isn't quite as warm as one would prefer, but one can "get used to it" after a few minutes. Also it somehow doesn't feel "wet", but the fabric still slides off the skin with almost zero friction, as water might do, but without the typical stickiness of water.

Altogether, exosuits are not as comfortable as ordinary clothing, but much more comfortable and capable than pressure suits (tech level 0), while being far easier to don and doff, simpler to maintain, more resilient to damage, and just plain stylish.

Exotic Environment Adaptation Systems

A wide variety of more robust, specialized exosuits exist--many of which are designed to fit over and incorporate a standard exosuit, and some of which replace them. Examples include:

• High pressure atmospheric gear: an exosuit is great from 0 to 1 atmospheres of pressure, but not much more than 1. Some of these suits go far past that.
• Low-Flux Thermal Gear: dense or fluid environments at cryogenic or superheated temperature require thick, highly-effective insulation, with minimal heat transfer. Such suits tend to be much more rigid than normal, trading in flexible, skin-tight joints for rigid, metallic ring, socket, or sleeve joints, allowing for thick thermal plating, usually ceramic/aerogel composite. Such gear can protect against cryogenic or superheated atmospheres for several hours passively, but inevitably, thermodynamics takes hold. Thus, they are typically powered, with excessive power loads compared to an ordinary exosuit. Heat pumps can ensure comfortable internal temperatures as long as the wearer remains within a designed temperature band, and as long as power remains available.
• Underwater Gear: depending on the environment, many fluid environments use the same thick, bulky Thermal Gear as are used in thick atmospheres, but in certain fluids--namely water--the liquid temperature range is actually not too far from the wearer's thermal preference, allowing the reduction of thermal insulation and the reintroduction of flexibility. Of course, it all depends on the intended pressure--particularly deep pressure gear often resembles bulky thermal gear, but built with denser, more robust materials. But when talking about one of the most common use cases, that being Earthlike oceans made of water within reasonable temperature limits (i.e. at or near freezing at coldest, at or near body temperature at highest), and within pressure limits comparable to Earth's oceans, there is a fairly standard approach for deep exploration: a flexible suit filled with fluid, which is fully infiltrated into the wearer's respiratory system. While unpleasant to integrate and deintegrate with, the system allows flexible, non-pressurized diving at depths far greater than traditional SCUBA gear, without lengthy depressurization after diving, as no pressurized gases were inhaled. The system is not biologically stable and requires robotic assistance for respiration, especially at high pressure, and different species have different tolerance for such respiration. At depth, these suits must provide additional thermal protection, and can be configured to resist some effects of pressure without bulky plating. Still, the depths reachable with such a suit, while far greater than air-based suits, are far less than what is possible with durable, rigid submarines.

Armor

Anything over and above the needs of a basic exosuit is generally considered armor. In short, armor is anything meant to deflect, absorb, redirect, or otherwise counter damage, especially from kinetic, thermal, explosive, or electromagnetic sources.

The simplest armor is just dumb matter that interposes between the wearer and whatever may damage them. Said matter's effectiveness is directly proportional to its mass, and many other factors, but most notably mass. An all-purpose suit of armor that adequately protects against all foreseeable danger tends to be prohibitively heavy, therefore bulky, restricting, and expensive. Thus, most uses of armor tend to be more minimalistic, and based on prediction of likely danger. Armor that specializes in a particular form of defense--such as reflective armor that deflects lasers, light, and radiation, or reactive armor that counters explosive blasts--tends to be much more effective at its specialty with a lower cost in bulk and raw expense, at the cost of being anywhere from useless to a liability when protecting against forms of damage it wasn't meant for.

• Basic armor: grants +Armor rating at the cost of minimum strength, or else slowdown, Dex penalties, disadvantage, etc
• Armor specializations:
  • Reactive armor creates shaped explosions that nullify incoming explosive damage
  • Reflective armor scatters light, rendering lasers useless
  • Ceramic armor is very effective at absorbing kinetic energy without transmitting it through.
  • Faraday armor is meant to block certain frequencies of EM radiation. This is not common for creatures which are generally not vulnerable to said radiation, but is sometimes used to protect sensitive electronics within armor, or to protect robots or cybernetic lifeforms. Microwaves are a common weapon employed against electronics, easily inducing currents and overloading systems. Thankfully for those who wish to defend against them, they can be defended against with a simple, passive shield of perforated metal (the same one in the window of a microwave oven).
• Ways to generally improve armor, at a cost:
  • Ablative armor sacrifices its outer layers to protect inner ones; not too specific to damage type, but limited in how many layers before it runs out
  • Liquid metal armor quickly flows mass to where its needed most, flexing its linear "sacs" of ferrofluid to create momentary patches of ultra-thick armor at the exact moment of impact, while overall being quite thin and light. Most effective against point damage (kinetic).