Apollo PLSS [ edit ] The interior of the Apollo PLSS Diagram of the A7L PLSS and OPS, with interfaces to the astronaut and the Lunar Module cabin His fellow astronaut was equally unfazed. “I decided that this was the easiest thing I had ever flown,” says Stewart, a former test pilot. “The only way you could make it easier would be to wire it directly to your brain.”

The portable life support system used in the Apollo lunar landing missions used lithium hydroxide to remove the carbon dioxide from the breathing air, and circulated water in an open loop through a liquid-cooled garment, expelling the water into space, where it turned to ice crystals. Some of the water was also used to remove excess heat from the astronaut's breathing air, and collected for dumping into the spacecraft's wastewater tank after an EVA. The PLSS also contained a radio transceiver and antenna for communications, which were relayed through the spacecraft's communication system to Earth. PLSS controls were provided in the Remote Control Unit (RCU) mounted on the astronaut's chest. Oxygen and water were rechargeable for multiple EVAs from the spacecraft's environmental control system.The MMU did prove itself as a satellite-rescue tool in November 1985, when astronauts Joe Allen and Dale Gardner piloted it to retrieve a pair of errant communications satellites. What would you bring to space if you were going to orbit the earth for a week? Just remember that your big adventure would take place in zero gravity. So, that bag of chips should probably stay at home. Although, chasing pieces of Pringle around a space cabin sounds pretty fun. We aren't sure if NASA would allow that. Would you let us know if you find out? McCandless tested this MMU, marked with the serial number 3, on a February 7, 1984, spacewalk from the Challenger. Underneath the spacesuit, astronauts wear a Liquid Cooling and Ventilation Garment. Tubes are woven into this tight-fitting piece of clothing that covers the entire body except for the head, hands and feet. Water flows through these tubes to keep the astronaut cool during the spacewalk. The spacesuit consists of several pieces. The Hard Upper Torso covers the astronaut’s chest. The arm assembly covers the arms and connects to the gloves. The helmet and Extravehicular Visor Assembly are designed to protect the astronaut’s head while still allowing him or her to see as much as possible. The Lower Torso Assembly covers the astronaut’s legs and feet. The flexible parts of the suit are made from several layers of material. The layers perform different functions, from keeping oxygen within the spacesuit to protecting from space dust impacts.

Life support device for a space suit A portable life support system from the Apollo A7L suit, with its outer cover removed NASA’s first spacewalks took place during the Gemini program. The suits used for Gemini were more advanced than the Mercury suits. But the Gemini suits were simpler than today’s spacesuits. These suits did not contain their own life support. Instead, they connected to life support systems on the Gemini spacecraft with a cord called the umbilical.Cooling and recirculating oxygen through the pressure garment, and water through a Liquid Cooling and Ventilation Garment or Liquid Cooling Garment. The operating pressure of the space suit is maintained at 4.3 psi (30 kPa) (0.3 atm ~ one third of Earth atmospheric pressure) during extravehicular operations, and 0.7psi (4.8kPa) relative to external pressure while in intravehicular mode ( i.e., inside the pressurized spacecraft). The air handling function of a PLSS is similar to that of a diving rebreather, in that exhaled gases are recycled into the breathing gas in a closed loop. But after the Challenger disaster in 1986, NASA re-evaluated shuttle missions, including spacewalks, and the MMU was deemed unnecessary. “It became pretty obvious that you didn’t need it,” explains Nelson. “The shuttle had such an amazing capability to fly right up to something, and it made more sense to just reach out and grab it, either with the [robotic] arm or just with a person, that the MMU became a really cool piece of technology that didn’t quite have a purpose.”

Lunar surface EVA times for the first four missions (Apollo 11 through 14) were limited to 4 hours, with oxygen stored at 1,020 pounds per square inch (7.0MPa), 3.0 pounds (1.4kg) of lithium hydroxide, 8.5 pounds (3.9 liters) of cooling water, and a 279 watt-hour battery. For the extended missions of Apollo 15 through 17, the EVA stay time was doubled to 8 hours by increasing oxygen to 1,430 pounds per square inch (9.9MPa), lithium hydroxide to 3.12 pounds (1.42kg), cooling water to 11.5 pounds (5.2 liters), and battery capacity to 390 watt-hours. [1] In space, however, it didn’t turn out that way. The MMU flew perfectly, but the capture device would not grab on. (The failure was later traced to a small protrusion next to the trunnion pin that wasn’t in the blueprints.) Running low on fuel, a frustrated Nelson returned to Challenger. Oxygen (O 2), carbon dioxide (CO 2) and water vapor are drawn from the extremities of the suit by the liquid cooling and ventilation garment or LCVG, which sends the gas to the PLSS. When gas enters the PLSS, activated charcoal removes odors and lithium hydroxide (LiOH) removes carbon dioxide. Next, the gas passes through a fan which maintains a flow rate of about six cubic feet per minute. A sublimator then condenses water vapor, which is removed by a "slurper" and a rotary separator. The removed water is stored and used to supplement the water supply used in the LCVG. The sublimator also cools the remaining oxygen to about 55°F (13°C). A flow sensor monitors the flow rate.A couple of months after McCandless and Stewart took the MMU for its first spin, astronauts put the invention to work. A satellite called Solar Max had suffered a malfunction. Whitsett and McCandless helped convince NASA to mount a rescue mission, launched in April 1984. In addition to the EMU, NASA astronauts wear other suits today. The Advanced Crew Escape Suit is the orange suit that astronauts wear during launch and landing of the space shuttle. This suit cannot be worn during spacewalks. Sometimes, NASA astronauts will wear the Russian Orlan spacesuit. This suit is the Russian version of the EMU and is used for spacewalks. Another Russian suit is the Sokol. Like the Advanced Crew Escape Suit, the Sokol is designed only to be used inside a spacecraft. It is used on the Russian Soyuz spacecraft. More About Spacesuits