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Textiles in space

January 8th, 2016 / By: / Feature

Engineers and technicians at NASA’s Johnson Space Center in Houston are testing the spacesuit astronauts will wear on trips to deep Space. Named the Modified Advanced Crew Escape Suit, it will contain all the necessary functions to support life and enable spacewalks. Photo: NASA/ Bill Stafford
Engineers and technicians at NASA’s Johnson Space Center in Houston are testing the spacesuit astronauts will wear on trips to deep Space. Named the Modified Advanced Crew Escape Suit, it will contain all the necessary functions to support life and enable spacewalks. Photo: NASA/ Bill Stafford

The textile industry is called upon to help NASA prepare for its manned mission to Mars.

Since the start of human spaceflight, the U.S. space program has faced many challenges in clothing astronauts. Survival inside a spacecraft needed to be addressed first. Historically, human space exploration started with modifications of high-altitude pressure suits, which were the result of 30 years of research and development for the U.S. Army.

Clothing in the Mercury and Gemini capsules consisted of a pressure suit with added fire and thermal protection. In the Mercury project (1958–1963), with a maximum flight duration of 3 hours and 20 minutes, astronauts wore cotton long underwear under the pressure suit. In later flights the underwear was modified with Trilok waffle-weave patches for ventilation. In the Gemini project (1961–1966), flight durations increased and new features were added for thermal comfort and waste management. The long underwear was also modified with bio-instrumentation and communication devices and given the name Constant-Wear Garment.

Coveralls and the pressure garment were worn over the constant-wear garment. Research and development of these early spacesuits were done under government contracts from the U.S. Army Air Service Medical Research Laboratory using textiles and other materials available at that time; consequently, the Project Mercury suit was made of coated and uncoated nylon fabrics.

Engaging the industry

During Project Gemini, spacesuits gradually became more complex as the astronauts needed protection for intravehicular and extravehicular activities. The engagement of the textile industry in human space exploration started with the Gemini spacesuit.

In the context of the Cold War, NASA’s Manned Spacecraft Center awarded contracts to the aerospace and defense products division of the B.F. Goodrich Co. and the David Clark Co. to design, develop and fabricate Gemini spacesuit prototypes. Under these contracts, novel fabrics and suit layers were developed, including custom aluminized mylar films with thin nonwoven polyester fabrics developed for thermal insulation in the vacuum of space.

Chromel R, a nickel chromium alloy fiber developed by Hoskins Mfg. Co. in the mid-1960s, was used in the form of a woven-metal fabric to protect the astronauts’ legs from hot gases produced by the astronauts’ maneuvering unit. These materials would also be used in the subsequent Apollo program.

Responding to tragedy

The 1967 tragedy in the Apollo program led to major breakthroughs in textile science and engineering. The cabin fire that killed Gus Grissom, Edward White and Roger Chaffee during a launch pad test directly led to the development of the Beta glass fiber by Owens Corning Fiberglas Corp.

The company had been experimenting with an ultrafine glass fiber when NASA’s Johnson Space Center contracted it to further the development of ultrafine fibers. The result of this work was the development of a glass fiber with a 4.8 micron diameter that became known as Beta fiber in the aerospace community. Both NASA and Owens Corning invested in this development.

Owens Corning built a full-scale production plant after the successful development of the finest glass fiber ever made. Beta glass fiber was used extensively in the Apollo spacesuit and many other applications through the Apollo and space shuttle programs. The production plant operated until the mid-1990s when it was dismantled. Aerospace agencies had been the only customers for Beta glass fiber over the decades, and the consumption of the fiber was insufficient for the company to sustain the operation of the plant.

New fiber development

Driven by fire concerns during the Cold War and the Apollo program, other flame retardant fibers were developed for the Department of Defense and NASA. Polybenzimidazole (PBI), developed by the Celanese Corp. of America, was the first inherently flame-retardant polymer fiber that had physical and mechanical properties suitable for replacing cotton in crew cabin clothing and sleeping bags.

Other companies contracted by NASA focused on the development of flame retardant treatments. Monsanto Co. developed a flame retardant treatment for meta-aramid fibers that included halogenation and heat. The treated aramid products were given the trademark Durette® in 1969. This trademark expired in 1992.

Similarly, cotton fabrics used in spacecraft were treated with flame retardant compounds developed for NASA by Cotton Inc. All these flame-retardant products were used in multiple NASA applications, and some are still used in the International Space Station (ISS) program.

The ISS is a microgravity laboratory with an atmosphere similar to that inside a building on Earth. Consequently, clothes made of fibers that char rather than melt-and-drip in ambient conditions can be used on ISS. Cotton has been the material most used for crew clothing; however, its lint creates problems with the onboard air filters so yarns made of multifilament fibers are preferable. This is one reason PBI multifilament yarns were developed and used in previous programs. Unfortunately, they are no longer manufactured; NASA was essentially the only customer.

Other existing fibers, such as P84 polyimide from Lenzing AG, could be used but are not available in linear densities and types of yarns desirable for astronauts’ apparel. For the trip to Mars in the 2030s, NASA needs previously available yarns as well as new types of yarns.

While some NASA engineers and contractors are developing the Orion spacecraft to support human exploration missions in deep space, others are defining the logistics of such missions. It has been determined that with minimal resupply opportunity in long-duration missions, the amount of logistics needed for four astronauts will be unprecedented if supplies are provided similarly as they are now. Clothing is one of these logistical elements that must be addressed differently than it has been for the ISS program, where garments are trashed after they have been worn so many times until they are no longer acceptable.

Crew clothing

Currently, crew clothing can be divided into two categories: the spacesuit system for outside activities and the cabin clothes for work, exercise, sleep and special occasions such as public appearances. The spacesuit assembly is a modular system: it has an upper torso, lower torso, limbs, gloves, helmet and boots.

Some suits are returned to the manufacturer, ILC Dover, Frederica, Del., after the completion of missions with space walks, where they are inspected for damage and the nature and possible causes of damage are analyzed. Repairs are made if there is minor damage that does not affect vital functions of the spacesuit. Otherwise, a new module is assembled for use with the undamaged modules of the suit. On a three-year journey to Mars, these repairs are neither practical nor logistically feasible. Astronauts will need to learn to inspect and repair their suits and have spare modules for such long-duration missions with limited resupply.

Similarly, everyday clothes must last three years with little or no laundering capability. Typical crew apparel includes work and exercise clothes, underwear and nightwear, and special garments for public appearances. On a multiyear trip in deep space, everyday clothing must be functional, attractive and logistically sound. This means that type, mass, volume and maintenance of clothing must be carefully engineered for deep space travel.

The approach taken for the ISS crew clothing represents a mass and volume burden to manned missions beyond Low Earth Orbit (LEO). As a result, several clothing studies have been conducted at the Johnson Space Center to address both the length of wear of garments and the perception associated with repeated use of a given garment without laundering. These studies were performed with different groups of participants, some of them including astronauts and cosmonauts. In addition, fiber and fabric properties that could affect length of wear without cleaning were evaluated in laboratory studies.

Seeking support

Fifty years ago the textile industry produced exclusively for NASA fibers and fabrics specifically needed to go to the moon. Today, NASA needs fabrics for living in the Orion capsule and for residing on the Martian surface. While the motives for sending humans in space are different today from those in the 1960s, NASA still needs support from the textile industry. Some companies in the textile industry supported NASA to the extent of building plants to produce fibers for the space program while hoping to open other markets.

The growth of W. L. Gore and Assoc., Newark, Del., after having developed the expanded polytetrafluroethylene (e-PTFE) fiber used in the shuttle spacesuit, is one of the few success stories about performance fibers because they found a wider market. PBI, however, is only available as a staple fiber.

Fibers like the Beta glass have disappeared because they were not needed for industrial or apparel applications. The Beta fiber developed for a one-time-use protective outer layer of the Apollo spacesuit was too expensive for use in the market of protective fabrics.

Today, with the commercialization of space and the beginning of space tourism, a new industry is growing and needs the same materials NASA is using. This will give better incentives to the textile industry to invest in supporting the U.S. space program and in finding new markets for its products.

Evelyne Orndoff is with the Textiles and Non-Metallic Materials, Crew and Thermal Systems Division, at NASA’s Johnson Space Center in Houston, Texas.