Bruce McCandless in an Extravehicular Mobiliy Unit
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In the evolution of space suits however older designs are not subject to obsolesce. The Gemini suits were used again but this time for the use of the space shuttle. In an effort to protect shuttle astronauts in contingency NASA derived from the Gemini suits the Advanced Crew Escape Suit or ACES. ACES was an emergency spacesuit worn by those traveling on the space shuttle and granted bailing capabilities at altitudes 30 kilometers or lower. As opposed to the Launch-Entry Suit which came before it, ACES had several significant improvements. Using the newly developed suits for jets called the S1035 on the SR-71 Blackbird, ACES included covering for the entire body as a full body pressure suit. The suit also carried integrated life support systems so that not only did the astronauts have a breathable oxygen supply but a completely isolated system so that shuttle depressurization or contamination would not affect the crew if sudden depressurization or leaking were to occur. In addition the ACES suit was more comfortable to wear than its Gemini predecessors as a layer of liquid cooling and improved ventilation systems were used for the frequent trips off and to Earth’s surface.
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Of the regularly active space suits none is more seen than the Extravehicular Mobility Unit or EMU. The EMU was the spacesuit used for EVA aboard the space shuttle and is still in use aboard the ISS. In many ways the EMU bears a striking resemblance to the Apollo mission suits. Of its many components, the EMU holds components nearly exactly like those on the Apollo mission like the HUT, PLSS, and a liquid cooling garment. The EMU did have significant additions however as it worked in conjunction to the ISS. An improved umbilical cord for the suit allowed for extended stays outside of the space shuttle and ISS as its connection to the Service and Cooling Umbilical attached to the PLSS added a lifeline. Another important addition to the EMU was the Simplified Aid for EVA Rescue jetpack or SAFER. SAFER was added to the PLSS pack to act as an emergency thruster device in the case that an astronaut was to become separated from his or her base of operation. SAFER uses a gas jet propellant to maneuver in empty space. Thankfully there have been no emergencies needed for SAFER to be used.
Though the EMU is the best spacesuit commercially available, complications are still present even after half a century of improvement. The process of putting on the suit often requires aid and an excess of half an hour. Even after that the pressure capacity of suit is not high enough to allow astronauts to move from a craft environment straight into space. An experience most often felt by divers called the bends is the reason for several hours of waiting for the astronaut to breathe pure oxygen before he or she can enter into space. The bends is a pressure effect which a body can experience if the rate of pressure change is too great. In the case of rapid depressurization, like if a diver swims up too fast or an astronaut goes into space without proper preparation, nitrogen in the person’s blood will boil throughout the body causing immense pain and possible long term damage to the body. Also despite constant improvements the EMU and other pressurized suit require a great deal of strength to move in due to the balloon effect. As one moves within the suit the suit will always pull back to the position with largest volume and least restrictive force. A problem often encountered by EVA astronauts is exhaustion and bruising due to the forces required to move and hold positions in space.
Though the EMU is the best spacesuit commercially available, complications are still present even after half a century of improvement. The process of putting on the suit often requires aid and an excess of half an hour. Even after that the pressure capacity of suit is not high enough to allow astronauts to move from a craft environment straight into space. An experience most often felt by divers called the bends is the reason for several hours of waiting for the astronaut to breathe pure oxygen before he or she can enter into space. The bends is a pressure effect which a body can experience if the rate of pressure change is too great. In the case of rapid depressurization, like if a diver swims up too fast or an astronaut goes into space without proper preparation, nitrogen in the person’s blood will boil throughout the body causing immense pain and possible long term damage to the body. Also despite constant improvements the EMU and other pressurized suit require a great deal of strength to move in due to the balloon effect. As one moves within the suit the suit will always pull back to the position with largest volume and least restrictive force. A problem often encountered by EVA astronauts is exhaustion and bruising due to the forces required to move and hold positions in space.