David P Cadogan. American Scientist. Volume 103, Issue 5. Sep/Oct 2015.
For the past 50 years, space suits have played a part in several defining historical moments. From the Cold War race to establish dominance in space, to the Moon landings, to the establishment of a continuous human presence in Low Earth Orbit on the International Space Station (ISS), space suits have enabled incredible achievements. Until recently, their iconic appearance has been driven by an adage of design-form follows function. They appear simple at first glance, but there is a level of complexity beneath a space suit’s surface layer that matches human motion and protects its occupant from the harsh environment of space.
The National Aeronautics and Space Administration (NASA) has led the United States manned space exploration missions since 1958. Achievements from the Mercury (first American in space), Gemini (first American spacewalk), Apollo (first Moon landing), and Skylab (first American space station) programs captivated the attention of the world. Even though these programs were packed with tremendous scientific and engineering breakthroughs, the space suit became arguably the most recognizable piece of equipment in NASA’s inventory. As mankind reached beyond the confines of the Earth, space suits protected the men and women who were laying their lives on the line and represented the human element in space exploration.
The past few decades of human space exploration have witnessed the transition of missions to space from extraordinary to almost commonplace. The Space Shuttle program demonstrated reusable launch vehicles that provided regular access to space, and people have lived continuously on the International Space Station since November 2, 2000. Hundreds of spacewalks have been conducted since the beginning of human space exploration, including those on the surface of the Moon, from the Space Shuttle, and from the ISS. Over the past 50 years, more than 2,877 hours of spacewalks have been conducted in U.S. space suits, and the number will rise again soon.
Space suit development and manufacture has been performed internationally for as long as the U.S. program and also continues to advance today. The Soviet Union was a dominant power in early space suit work as they developed suits for the launch of Yuri Gagarin, the first man in space, in 1961 and the first spacewalk by Alexy Leonov from Voskhod 2 in 1965. The Russian company Zvezda led the early development of Soviet space suits and has produced all Russian suits, including the ones used today on the Russian-led spacewalks on the International Space Station. As with the efforts in the U.S., their design team created and tested many variations of space suits over the decades. The two types of suits that have seen the widest use in space are the Sokol and Orlan Series suits. The Sokol was introduced in 1973 to be worn during launch and landing and is still used today on all flights of the Soyuz spacecraft. The Orlan was introduced in 1977 for use during spacewalks from the Salyut space stations, was then used on the Mir space station, and is now used on the International Space Station along with the U.S. suit. The Russian suits follow a slightly different design mentality from U.S. suits. They are very robust and built to get the job done without frills. The U.S. suits, by contrast, use the latest materials and technologies to provide the highest levels of comfort and performance. A simple analogy might be driving a Jeep versus a sports car. Both get the job done effectively but the ride is a little different. In recent years the Russians worked with the Chinese to assist them in starting their manned space program. The Chinese have produced their own suits that are derivatives of the Sokol and Orlan space suits for launch, entry and spacewalk use. India is also developing its own suits for its young space program.
Currently, human space exploration is undergoing a transition into its next phase, which will consist of commercial space exploration as well as NASA led efforts. As space tourism grows and more people travel to space, new space suits will be required to meet the needs of this type of traveler. Conversely, as NASA structures missions to asteroids, the Moon, or Mars, advanced space suits will be required to accommodate travel to these environments. These two categories of suits are dramatically different, because a commercial suit is used primarily for emergency protection during launch and landing and thus can be very simple, whereas the kind used in spacewalks must meet much more stringent protection standards and performance needs. The focus here will be on suits that are used in spacewalks, or high-performance emergency suits used when performance needs, such as piloting the spacecraft, are critical.
The creation of an effective space suit begins with a fundamental understanding of the environments in which the suit will be used and the capabilities the suit will need. This information is used to develop a set of requirements that guide engineers and technicians in the selection of materials, design of components, test protocols, and overall configuration of the space suit system.
Space suits are typically thought of as being used in environments such as Low Earth Orbit and the surface of the Moon. However, they are often designed to operate also during numerous mission phases beyond spacewalks, or Extravehicular Activity (EVA), including launch, abort, landing, and emergency operations, which further increase their complexity. In Low Earth Orbit, the astronaut must be protected from and operate in the vacuum of space, as well as thermal extremes ranging from +120 degrees Celsius to -150 degrees, microgravity, rapid changes from intense sunlight to absolute darkness as the Earth is orbited every 90 minutes, and micrometeoroids and orbital debris traveling at speeds ranging from 8 to 16 kilometers per second. In other words, it is a very dangerous and difficult place to live and work, so a space suit has to function flawlessly.
The environmental challenges increase on the Moon or planetary bodies. In addition to the same threats encountered in Low Earth Orbit, the Moon has one-sixth the gravity .of Earth, which alters human motion, and it is covered with fine particles of lunar dust that are sharp-edged and abrasive. The dust, if not managed correctly, can quickly degrade materials and clog bearing joints, rendering a suit ineffective. Mars, on the other hand, has 3/8th the gravity of Earth, has a slight atmosphere, and appears to have more forgiving soil that has been worn down by wind so it is not sharp-edged, but in some cases may include chemical oxidants that can degrade polymeric materials.
In addition to knowing the environments, the design team must fully understand how the suit will be used. Typical EVA work includes construction, repair, maintenance, and setting up or monitoring experiments. The suit needs to be able to mirror every human motion involved in these activities and do so in a way that limits fatigue on the wearer. Moving from point to point in microgravity requires excellent shoulder, arm, and hand mobility, because astronauts move by gripping handholds and connecting and disconnecting tether hooks. Once at the work location, foot restraints can be used to anchor the body and free the hands to work. Mobility requirements are entirely different on the limar or Mars surfaces, where the limited gravitational field greatly alters normal human motion, but the legs and waist are used constantly to traverse distances and therefore require excel- lent mobility. No matter what the mission, the gloves always need to have the greatest mobility, tactility, and dexterity possible because they are critical to most work being conducted.
EVAs usually last between 6 to 8 hours, so the suit must accommodate all physiological needs, including hydration and waste functions. Components provide oxygen for breathing, remove carbon dioxide produced by exhalation, absorb moisture created by sweat, and apply pressure to all body surfaces to prevent the body’s fluids from evolving into gases. The suit also needs to provide impact protection for the wearer and itself dining both normal use and minor accidents such as collisions with equipment or falls.
All components of the space suit must last for their storage and use life. The storage life for all textiles and polymeric materials is eight years, and for metals is 20 years. All suit components must be able to withstand hundreds of hours of pressurized time and typically more than 100,000 cycles for each motion, such as flexion and extension of the elbow, that represent the suit’s use in 25 spacewalks. This requirement is one of the more challenging ones of space suit design because materials and seams can degrade with the stresses involved in long-term use. In addition to the loads on the suit from pressurization, the suit must also withstand ones that the person wearing the suit can induce into the suit during use. For instance, when fitting a suit to an astronaut, the torso length should be undersized by a small amount, while also accounting for spinal elongation in microgravity, so the wearer doesn’t float inside the suit. This maintains contact with the suit’s inner surfaces, so the wearer has spatial awareness along with the ability to react to loads while performing work. However, when the suit is sized this way, the astronaut can then stretch inside the suit while working and generate a load of several hundred pounds on the suit itself in various locations. The ways the suit can be stressed don’t stop there. If an astronaut is in foot restraints attached to the Space Shuttle or BS and grabs a massive object such as a satellite while it is moving away, the inertial load of the satellite can be transmitted through the suit to the foot restraints. And of course, all these loads could potentially be applied concurrently, so the suit must be very strong with high factors of safety.
Another challenging requirement for space suits is interchangeable components that can be swapped in orbit, so new suits don’t have to be flown in with every new crew. The U.S. astronaut population can range in size from the 1st percentile female to the 99th percentile male, a wide variation in anthropometric measurements with low correlation between local measurements from person to person. The challenge is to achieve this goal without an excessive number of sizes-mass and storage space are both highly valuable commodities in a space launch. Gloves used for EVA are usually custom fit to the astronaut. Nonetheless, during the Apollo missions, each astronaut wore a custom fit suit for all mission phases, and it’s possible that future missions could return to this paradigm.
As if providing all the protection and functionality required in a space suit for optimal mission performance wasn’t difficult enough, it all has to happen in a highly dynamic environment, and the wearer must maintain a good level of comfort. For example, the solar load on the suit can change quickly depending on where the astronaut is working, and the astronaut’s level of physical exertion on a task can also change quickly. The space suit and life support system are constantly adapting to these variable conditions to manage the astronaut’s thermal comfort, and stay within safe physiological limits. Other physical comfort issues such as “hot-spots,” abrasions, or constrictions are also very important to consider, as they can have a profound effect on fatigue and mission performance. Consider how distracting a pebble in your shoe can be over a short period of time, especially if you are working hard and sweating a lot. Such a circumstance is not desirable for an astronaut who is performing complex tasks in a life-threatening environment.
As with most protective equipment, the requirements are at odds. A strong suit is needed to withstand all the loads and environmental stresses, but at the same time the wearer does not want to feel like he or she is wearing a space suit. The ability to perform dexterous work flawlessly is essential. This conjunction is where the challenge in design lies.
Space Suit Components
Space suits are really single-occupant spacecraft. They consist of an articulated anthropomorphic pressure vessel that conforms to the wearer, known as the space suit assembly, and a portable life support system that typically looks like a backpack. Together, the suit and the life support equipment are called an Extravehicular Mobility Unit (EMU) in NASA terms. Much of the surface area of the space suit is made from softgoods, layers of textiles and flexible membranes (See figure above). They are sewn and thermally bonded together tp make an airtight vessel that is pressurized with pure oxygen to 29.7 kilopascals. The result is similar in composition to a football or basketball. The suit consists of three major layers: the bladder that contains the oxygen, the restraint that provides the structure, and the thermal and micrometeoroid layer that provides protection from the environments. Each of these assemblies performs specific functions and operates independently, but they must collectively function as a single unit to help maintain the breathing atmosphere, pressure, and temperature necessary to protect the astronauts from the space environment. Together, a total thickness of less than one-tenth of an inch protects the astronaut from space.
Before putting on a space suit, the astronaut dons something along the lines of high-tech long underwear, followed by what’s called the Liquid Cooling and Ventilation Garment, a form-fitting elastic bodysuit that has plastic tubing threaded into it. Chilled water is passed through the tubing to remove body heat and keep the astronaut comfortable. The two layers wick perspiration from the body, which is then evaporated by airflow from the portable life-support system.
Next come the bladder and restraint layers. The bladder layer consists of thermally bonded, impermeable polyurethane-coated nylon to contain the pressurized oxygen in the space suit and prevent moisture transmission to the vacuum-exposed side of the suit, where it would cause uncontrollable cooling via evaporation. The bladder and restraint are specially designed to include highly flexible joints that provide the astronaut as much mobility as possible. The materials are formulated to withstand the rigors of constant flexing while pressurized, and abrasion from the relative motion of the layers of the suit. The restraint layer also withstands the stress of pressurization and other types of loading, maintains the human form, and keeps the bladder from ballooning. It is assembled from sewn patterns just like everyday clothing and is manufactured from polyester fabric.
The outer assembly of the space suit, the thermal and micrometeoroid layer, protects the astronaut from small, hyperfast particle impacts and the thermal effects of solar radiation (or lack thereof). It is made from orthofabric, which is three dimensionally woven to have white Gore-tex on the exterior and fire-retarding fibers with a ballistic-rated polymer ripstop on the interior. The Gore-tex is slippery to prevent friction between parts of the suit during movement and to facilitate mobility. Its color also limits the absorption of solar energy. Aluminized polymer insulation layers maintain a comfortable thermal environment for the astronaut by reflecting the Sun’s energy out when in sunlight and the astronaut’s body heat in the suit when in shade. The orthofabric also is designed to break up the hypervelodty particles, and turns them into gas jets that are absorbed by a coating on the nylon layer.
In addition to the softgoods, the suit has a number of metal and composite components that aid mobility and attachment of various parts of the suit. Ball bearings are located at the arm, shoulder, wrist, and waist. Metal rings with locking mechanisms called disconnects are used at the neck to attach the helmet, the wrist to attach the gloves, and at the waist to allow the astronaut to get in and out of the suit.
A Brief History of Space Suits
The first U.S. space suit that was developed specifically for use in spacewalks was the Apollo space suit first used in 1968 on Apollo 7. Spacewalks were conducted during Project Gemini, but the space suits used were modified high altitude flight suits that were attached to the capsule by an umbilical and had limited mobility. Suits were worn during Project Mercury flights but were only required for protection against capsule depressurization. The Apollo space suit went through several versions but the most well known was the A7LB, which was used for the lunar landings and on the Skylab space station. This suit was worn during all mission phases (launch, EVA, landing), and was custom made for each astronaut. It had an active life of just one mission. It was designed to have good upper body mobility, and to facilitate walking on the lunar surface and driving of the lunar rover.
The Space Shuttle EMU was developed specifically for EVA from the Space Shuttle in microgravity, and assembled from sized components for each astronaut. The first EMU EVA was performed in 1983 from the maiden flight of the Space Shuttle Challenger. This suit was designed to have excellent upper body mobility so the astronaut could move around easily in the Shuttle bay and perform work while in foot restraints. Upgraded during the 1990s to facilitate operations on the International Space Station, this suit is still in service today.
However, this extended use was not the original plan. As the Space Station was being designed, new space suits were developed that could operate at higher pressures of 57.2 kilopascals, which eliminates the need for astronauts to pre-breathe oxygen for four hours before an EVA. The pre-breathing purged the body of nitrogen that could cause the bends (bubbles in body tissues) while operating at suddenly lowered atmospheric pressures. With hundreds of hours of EVA planned, the four-hour pre-breathe could become logistically costly for NASA. The prototype suits, called MKIII and AX-5, performed well, but NASA elected to modify the Space Shuttle suit instead, because of decades of experience and a proven track record in performance.
Around 2000, when NASA was gearing up for new programs that would return humans to the surface of the Moon or possibly Mars, our team began developing an advanced model called an I-Suit, designed to have improved mobility, facilitate walking in a gravitational environment, and interface with rovers. The versions had rear-entry hatches for rapid donning and doffing in the spacecraft or through a suit port that attached the suits to the exterior of the spacecraft. The I-Suit technology became the basis for the current EVA space suits under development, including the suit used in the record-setting StratEx high-altitude parachute jump from a height of 41,419 meters in 2014. Others under development are the Z-Suits and the Constellation Space Suit, both of which are designed to shorten preparation time, increase flexibility, and potentially be used on extended planetary missions.
Behind the Scenes
It takes hundreds of incredibly skilled people, including project managers, engineers, and technicians, to design and manufacture space suits. Much of the team responsible for the EVA space suit currently used on the ISS has been together for decades, with their knowledge base rooted in learning from the Apollo space suit team. Like many engineered products, much of the knowhow required to realize the product is embedded in people rather titan books or journals. Decades of testing components and assemblies of a wide range of designs and materials has created a database of knowledge that informs the team about what will and won’t work as the technology evolves over time. This information has enabled decades of spacewalks without any anomalies that have led to loss of life.
A wide variety of materials and manufacturing processes are used to fabricate space suits. For the softgoods portions alone (gloves, arms, legs, and other parts), fabricators use sewing, thermal welding, radio-frequency welding, bonding, dipping, and taping, to name a few. For the rigid components (bearings, helmets, boot soles, and so forth), fabricators machine, blow-mold, injection mold, and compression mold, among many other techniques. The equipment used is calibrated and constantly monitored to maintain precision. The steps to make every component are detailed in work instructions for uniformity, and the parts being manufactured are inspected at numerous points during their manufacturing cycle. Everything is controlled and monitored throughout the entire process, all the way back to the machines used to make the materials that are part of the space suit.
However, none of the machines or process controls would matter without the dedication and skill of the operators. Astronaut Scott Parazynski visited the manufacturing floor where the sewing occurs prior to his first of five Space Shuttle flights, to thank the team that was making his suit. As he shook the hand of one sewer, she said, “When I do the work, I just imagine I am making this for my son, so it has to be perfect.” Going to space, perhaps one of the most technology-laden endeavors we undertake, still remains a very human affair.
Some parts of the suit are manufactured with long-established techniques, and others use state-of-the-art equipment and processes. Gloves are critical to an astronaut’s performance and are the most challenging part of the suit to design. The process to produce the gloves used on the ISS is as high-tech as it gets in protective equipment. First a laser scanner is used to create a 3D image of an astronaut’s hand. The data are loaded into Computer Aided Design (CAD) software. The data are manipulated with special algorithms to provide the needed easements between the hand and inner wall of the glove in all positions, as local circumferences change when muscles flex. Restraint patterns are then created directly from the CAD model. Parts are cut using the patterns and then stitched together using sewing machines; or by hand for light-tolerance components. Then, stereolithography—a type of 3D printing that builds up a model layer by layer by curing a resin with an ultraviolet laser-is used to create a physical model of (he CAD glove form. The model is painted and dipped in a flexible polymer to manufacture the bladder of the glove.
After manufacture, the components of the space suit are inspected and rigorously tested at the factory before being accepted for flight. One of the more critical exams is the “leak-proof-leak” test, where the component is first pressurized to operational pressure and its leakage recorded. All components have an acceptable value that is typically only a few standard cubic centimeters per minute. Then the component is pressurized to one and a half times its maximum operational pressure, to test its structural performance at a point that will not compromise it structurally. The leakage is assessed again at operational pressure. If the leakage remains consistent and all other inspection parameters are acceptable, the component is sent to NASA Johnson Space Center for processing before it heads to ISS on one of several launch vehicles.
When component designs are developed anew or modified, or a new material is swapped in for their construction, they are put through a battery of tests before they are certified for manufacturing. For the final step in this certification, there’s no substitute* for human use. Space suit components perform differently when they are simply bent and stretched by machine. So, suit subjects are put in a full suit in a lab and perform hundreds of thousands of motions to test the durability of the pressurized component to simulate what it will see in its lifetime. This is when the fun, and physical exhaustion, begins for the suit subjects.
Wearing a space suit is an incredible experience because it provides an appreciation for what the astronauts experience, and for how much work it is. Operationally, wearing a space suit in Earth’s gravity is very different than in microgravity because the body isn’t floating in the suit and you can use gravity to your advantage. However, you do get a feeling of how claustrophobic it is, how you have to learn to move in a certain way to work with the suit, how quickly your body makes heat during work, and where all the pressure points are.
During testing the subjects wear the same Liquid Cooling and Ventilation Garment that astronauts wear. Chilled water is pumped around to remove heat from the body and it becomes your best friend when working hard in a suit. Air (or oxygen when in space) is pumped into the suit from a pressurized chamber at the back of the helmet and washes over the face to remove exhaled carbon dioxide from the helmet. The air then flows over the body to the extremities, picking up moisture from sweat along the way, and then enters tubes on the ventilation garment, where it is removed from the suit.
The space suit has a number of mobility joints and bearings that enable it to mirror human motion. However, even though the suit can be positioned to match the range of motion of a person, the path to move the suit to that position isn’t as straightforward as human motion is. This effect is called programming and is most observable in the arms and shoulders. Rather than just reaching straight forward and forcing the suit to follow your motion, you can rotate your shoulder and then arm to get to the point you were reaching for with less energy. It sounds complicated, but it becomes second nature after a few minutes in the suit. The suit contacts your body at various locations as you move. The weight of the suit and the torque it takes to move the joints affect these contact points. So, when you move one part of the suit in gravity, the weight redistributes and the suit pushes on you in various locations. For example, when you bend forward at the waist and reach for something on a table you will feel stronger contact on the backs of your knees and at the back of the shoulders as the suit redistributes its weight onto your body. A close example is what it feels like to move around while wearing a large full backpack, but the forces push on your body in different places. Again, you get used to it quickly and it becomes second nature. lire trick is to learn how it works and not fight it because you will become fatigued quickly.
One of the hardest things to get used to in a space suit is the small helmet. The “bubble” is directly attached to the torso and doesn’t have mobility like your neck does. Therefore, when you walk, your torso shifts inside the torso of the suit and the helmet bumps your head. It may sound difficult but wearing the suit is really quite comfortable and gives you a high level of mobility given that it is an articulated spacecraft that has to withstand the environments of space, have multiple structural redundancies, and last for many EVAs.
What makes all this possible is high performance mobility joints, and creating them isn’t as easy as it looks. Imagine trying to bend a football in half; space suit joints do this with virtually no resistance. The guiding principle in pressure suit joint design is to make the joint have a constant volume throughout its motion, so you are not doing work by compressing the inflation gas. Single axis joints such as the elbow or knee are more straightforward and easier to create than omnidirectional joints such as the shoulder and hip. There are several basic technologies that are used, which allow the material to gather, fold, and slide on itself so its axial length can change. The wrinkles in the skin over a person’s knuckles demonstrate this concept well. It takes clever design and patterning to create mobility joints that can have low torque and a high range of motion to match human mobility. But that is only the first part of the challenge. The bar is raised significantly in trying to make that joint meet all the requirements of a space suit concurrently without compromise in performance. Miss just one of the requirements-in poor materials selection, inadequate design, or lack of proper analysis and test-and a multimillion dollar mission could be compromised or worse, a life could be lost.
The Next Generation
Future space suit designs will be defined by the missions they support, economics, and the technologies available. Operation of the International Space Station will continue for several decades and will use the current EMU with planned upgrades. The more revolutionary paths of space suit development will come with new missions to explore our Solar System over the next several decades, including going to the Moon, Mars, the surface of an asteroid, perhaps one day to Europe. Commercial activities in Low Earth Orbit are also developing, such as tourism, space hotels, and satellite repair, to name a few. In the distant future, as technology advances are made that facilitate efficient energy production and compact life support systems, we could eventually see colonization of the Moon or Mars. Achieving these goals will require space suits able to support activities ranging from tourism to heavy construction, to the more dexterous operations associated with maintenance and repair of a wide range of equipment cm these missions.
In construction or other heavy work, strength augmentation will be of benefit. Future space suits might incorporate powered exoskeletons for superhuman strength or simply fatigue reduction. Some pioneering work was conducted in this area in the 1990s for space suit gloves, where the feasibility of integrating robotics and softgoods space suit components was demonstrated. Other actuation technologies that use flexible materials in the place of rigid robotic elements are also under study. These include biomimetically inspired inflatable cells to morph the shape of the suit, or externally applied electroactive polymers that constrict like muscles when electrified. Consider-‘ able advancements are being made in robotics, prosthetics, and soft robots that will help shape a path to realizing space suits with powered exoskeletons that move the suit for the wearer and enhance strength. However, these advances will be difficult to realize until the problem of creating small, portable power units is solved and astronauts will not have to carry tens of pounds of batteries with them to make the suit function.
Another path of study being considered in future suits is eliminating the pressurized envelope around the body and replacing it with a mechanical counter-pressure layer that would apply the correct pressure over the skin to keep body fluids from evolving into gas. Research began in this area in the 1970s, but such suits were found to be limited in comfort and mobility. Future incarnations under study now propose to use electroactive polymers or some other smart tensioning system to track the body’s movements and adapt pressure application, as well as allow the suit material to elongate and provide joint mobility.
Instant access to information regarding the local environment, the mission, and human physiology will be critical to operational efficiency and safety in future missions as we travel farther from Earth in greater numbers. Smart structures and wearable electronics technologies have already been demonstrated in space suits and these technologies are advancing every day in medical and consumer products. Soon space suits will have distributed wireless sensors that monitor the environment, the suit itself, and the wearer while at the same time processing the data with distributed onsuit computation, and adapting as necessary or alerting the wearer through voice or visual displays.
Performance enhancements will only be part of the equation for creating better space suits. Logistical enhancements that reduce mission cost by requiring fewer and longer-lived components will be paramount, and a more likely near-term development target as budget pressures increase. Launching and operating spacecraft is expensive, and every measure will need to be taken to address the major mission cost factors, including those centered on space suits. Costs are difficult to accurately identify, but estimates of the cost to launch one kilogram into Low Earth Orbit is on the order of tens of thousands of dollars, and crew time there is on the order of thousands of dollars per minute. These numbers will escalate significantly for planetary or deep space missions. Therefore, future space suits need minimal mass and require as low logistical support as practical including minimization of maintenance, fitting a broad population with interchangeable components, and having the longest useful life possible.
Advances are already being made in materials to address logistical needs of long-term space flight by eliminating the time it takes the crew to clean suits between uses or replace worn components. Among the more advanced are anti-microbial and selfhealing materials. Anti-microbial agents are added to the materials used in the space suit that are in contact with the occupant (inside the bladder layer) to kill bacteria or viruses that are expelled during respiration or sweating. These agents reduce odor, improve hygiene, and enhance medical safety, in addition to reducing the logistics burden on the mission. These materials work well but require support from other mechanisms for full efficacy in creation of a fully selfcleaning suit. Concepts are being developed for internal illumination of the suit with ultraviolet light, or inflation with vaporized hydrogen peroxide, in order to sterilize it.
Self-healing materials have been developed and tested in the suit’s bladder layer to demonstrate the ability to seal a hole from wear or puncture. These materials work in seconds without the aid of power or any action by the crew. The next generation of highly durable textiles and polymeric coatings are also being developed to increase material’s durability in flex fatigue and abrasion, which will dramatically increase the life of the suit. So, when an astronaut exploring Mars in 2055 puts on her suit for the 250th time to repair the power generation system outside, it will be as strong and smell as fresh as when it left the factory, and it will passively seal the hole in the suit created when the robotic rover accidentally runs into her.
In addition to the space suit development work being conducted at the companies that have been building space suits for decades, numerous programs are underway at small companies and universities to advance technologies used in space suits or in new designs altogether. Small technology companies such as Nanosonic, Aspen Aerogels, NEI Corporation, and others are developing new materials based on nanotechnology and advanced processing techniques to advance the performance of various layers or components of space suits. These include technologies such as structural health monitoring systems, improved insulation, and self-healing materials. Several universities, including the Massachusetts Institute of Technology, the University of Maryland, the University of Delaware, and others have been developing advanced space suit concepts for several years. The university efforts include mechanical counter-pressure suits, powered exoskeletons, and advanced composite structures. Many of the studies are small, but infusion of these concepts and technologies into the NASA program usually works best when small businesses and universities team with the suit manufacturing companies. Good things happen when you combine experience with ideas.
Aesthetics are also becoming increasingly important in space suit design. With the introduction of commercial activities comes a need for companies to brand their offerings. It won’t be enough to allow form to follow function as has happened in the past with white EVA suits that provided thermal comfort in Low Earth Orbit, or orange flight suits that provided the best visual contrast in emergency smoke or water landings; now image matters too. Even NASA has embraced the drive for a new look for EVA space suits in their latest Z-2 program. A crowd-sourcing event was held where NASA invited the public to select the design for the outer layer.
Future versions of space suits will most certainly benefit from technology advancements in other industries. However, the converse is true as well, and just as space suit technology spin-offs have been used in numerous ways, such as treating bum victims or for racecar driver thermal regulation, technology from the next generation of space suits will be used to benefit society in some way. It is difficult to tell exactly what form space suits of the future will take but one thing is sure: They will be inspiring and iconic.