That was one fine evening; when I switched on our TV I saw a movie explaining about the space exploration. I got astonishment when I saw the astronaut’s costume. Even I never had a thought that, ill be studying about the textiles in future. During my B.Tech time I had a dream to write about the space textiles, many people said textiles fits every where and textiles are in part with many basic activities, but no one clarified my doubts, of course except my teacher Dr A Mukhopadhyay. Recently I got an idea to share my thoughts about textiles. Even I have uploaded about the thermal garments. In that series, here I would like to write about the space garments, however her I have given you the main idea and little bit literature, the space garment design is information is vast and in a single blog. So here I have described its principles, know how, etc. However at present the space garments reached the third stage as researchers are trying to send man to mars. Let us come to the topic.
As we know NASAs space explorers are called as “astronauts”, so for the convenience I will mention in the same manner. When they traveling through space they meet complex environment nature, from the basic science one can know that the Earth’s gravitational attraction holds a dense atmosphere of nitrogen, oxygen, carbon dioxide, and water vapor in a thick manner surrounding Earth’s entire surface. The weight of this atmosphere exerts pressure, and its movements distribute heat from the Sun to balance global temperatures. Earth atmosphere protects us from these various factors. When Earth astronauts leave the surface of our planet and travel into space, they must be ready to meet the environment which is available there. The astronauts travel to the space with the help of spacecraft, which is designed with high performance metal, glass, plastic and composites. What will be the design of the dress wore by the astronauts. Before discussing the design of the suit, I would like to discuss the atmospheric condition of the space.
Outer space is like a void, through this, environment radiation and objects can pass freely. An unprotected human or other living being placed in the outer space environment would perish in a few moments. The environment of outer space is the vacuum or nearly total absence of gas molecules. The gravitational attraction of large bodies in space, such as planets and stars, pulls gas molecules close to their surfaces leaving the space between virtually empty. Some stray gas molecules are found between these bodies, but their density is so low that they can be thought of as practically non existent. On Earth, the atmosphere exerts pressure in all directions.
In space, the pressure is nearly zero. With virtually no pressure from the outside, air inside an unprotected human’s lungs would immediately rush out in the vacuum of space. Dissolved gases in body fluids would expand, pushing solids and liquids apart. The skin would expand much like an inflating balloon. Bubbles would form in the bloodstream and render blood ineffective as a transporter of oxygen and nutrients to the body’s cells. Furthermore, the sudden absence of external pressure balancing the internal pressure of body fluids and gases would rupture fragile tissues such as eardrums and capillaries. The net effect on the body would be swelling, tissue damage, and a deprivation of oxygen to the brain that would result in unconsciousness in less than 15 seconds.
The temperature range found in outer space provides a second major obstacle. The sunlit side of objects in space at Earth’s distance from the Sun can climb to over 120° Celsius while the shaded side can plummet to lower than minus 100° Celsius. Maintaining a comfortable temperature range becomes a significant problem, so the sit should be of thermal insulation as well as thermal resistant.
Other environmental factors encountered in outer space include: microgravity, radiation of electrically charged particles from the Sun, ultraviolet radiation, and meteoroids. Meteoroids are very small bits of rock and metal left over from the formation of the solar system and from the collisions of comets and asteroids. Though usually small in mass, these particles travel at very high velocities and can easily penetrate human skin and thin metal. Equally dangerous is debris from previous space missions. A tiny paint chip traveling at thousands of kilometers per hour can do substantial damage, so the armor should capable of higher impact resistance.
NASA’s spacesuit engineers developed a reusable Extravehicular Mobility Unit (EMU). The Shuttle EMU has 14 layers to protect astronauts. It contains layers of structures to perform thermal insulation, resistance, moisture vapor absorbing layer, etc. The inner layers comprise the liquid-cooling and ventilation garment. First a liner fabric made up of Nylon tricot (knitted) over which a layer of spandex fabric laced with plastic tubing. Next the pressure bladder layer of urethane-coated nylon and fabric layer of pressure re straining Dacron. Above the bladder and restraint layer is a liner of Neoprene coated Nylon Rip stop. This is followed by a seven layer thermal micro meteoroid garment of aluminized Mylar, laminated with Dacron scrim. The outer layer of the suit is made of Ortho-Fabric which consists of a blend of Gore-tex, Kevlar, and Nomex materials. The design of the body armour is shown in figure. However I haven’t discussed much in detail but those who are beginner, can able to understand the basic idea of space suites.
Source: NASA’s Beginners Guide