The Evolution of the Spacesuit
A spacesuit worn for high atmosphere travel or outer space visits, is more than a suit of clothing. In some cases it's an entire spaceship of its own. In the beginning of space technology, as far back as the 1930s when high altitude travel became possible for pilots, suits were needed to protect from the change of environment that high atmospheric travel requires. The suits have changed with technology over time but still share basic purposes starting with protection from pressure change. The suits also need to supply breathing and provide cover.
Early suits for high altitude travel were known as partial-pressure suits. They were flexible since they were made from movable fabric and provided protection in emergency situations. Pressure changes with a rise in altitude. The suits of early flights were meant to be worn tightly so as to support the skin and provide pressure to the body similar to that found at sea level.
The SK-series of suits is considered one of the first working full pressure suits. They were worn during Soviet space missions in the early 1960s. The SK-1 was developed for Yuri Gagarin and was the first suit worn by humans in space. The suits worn by the competing astronaut program in the United States were known as Navy-Mark IV's, worn during the US Mercury Project. These were built to protect astronauts in case of a forced evacuation from the space vehicles. They are made of loose fitting fabric and would inflate with air providing full pressure to the wearer to allow temporary protection in high altitude.
These early suits contained elements that suits of today share. They have attached hard material helmets for head protection and breathing apparatuses to allow for circulation of breathable oxygen. In some early cases, the tubes were tethered to planes or to hand held or backpack modules.
Long term or space vacuum travel requires full pressure suits with additional safety measures. Space suits are now built as EVA suits, for Extra-Vehicular Activity. These are full pressure suits with protection from space debris and radiation. EVA suits are the latest evolution of space gear and are the type we typically associate with space walks or the International Space Station. The units are self-contained and made to control temperature, breathing, and waste containment.
Space suits are manufactured by several different companies and approved for use by NASA. They continue to develop new modules for ease of use in space. NASA has also approved of academic research which is being studied by researchers at MIT.
Space suits are difficult to move in and can be uncomfortable. Micro meteors can tear into suits, breaking the pressure seal. Humans can survive for a short while in a vacuum but on extra planetary bodies or the International Space Station, suits need to be designed for efficiency and actual work so need to protect for periods of time and still allow for movement. Radiation is also a concern as is temperature changes and researchers have developed skin supporting suits which are meant to be worn tightly against the skin to provide pressure but still flex enough for movement.
A Space Activity Suit which allows for easy movement has been in the works from several inventors since the 1950s. Known as the SAS, it has been studied at length and resurrected in research several times by NASA. The latest evolution is MITs Bio-Suit. During development, the suit was made with components of both kevlar and spandex, both tight fitting fabrics. The study of biomechanics, or human movement, has led to some success in test models of the Bio-suit but hands and feet still require pressurized casing and helmets remain similar in design to previous versions.
Space also puts pressure on the human system as an organism, more than being just the recipient of physical space dangers. Space launches and landings can cause heart distress, motion sickness and even orthotic bone problems. Isolation and vertigo are two more issues space travelers face. The effort of physical work in a heavy space suit requires an athletically fit person.
Most astronauts pass a rather intense physical exam which includes requirements of height, weight and vision. Once chosen, astronauts train for two or more years both physically and mentally for the tasks that they will perform in space. Most receive training in a variety of disaster recovery efforts in a zero gravity environment. They also take courses in the work they'll be doing on the ISS like life support or payload deployments, space station maintenance and scientific and mechanical experiments.
All in all a trip to space is no picnic. But in the decades since humans began dealing with high altitude travel, both the gear used and the knowledge gained have created a better understanding of how humans can survive space travel. With MIT's Bio-suit work and the ongoing travel and work on ISS, hopes for a return to the Moon or a trip to Mars is not in the realm of science fiction any longer, but a much closer reality.