In the space shuttle era of NASA, the ability of extravehicular activity was very developed. Astronauts ride robotic arms, float in the air by manipulating jet packs, control satellites with their hands, and build the International Space Station (ISS). The spacesuits they wore were designed according to the design first developed for the Apollo mission in the 1960s.
Each suit is a humanoid spaceship, featuring a backpack and a main life support system; A layered pressurized jacket to protect astronauts from the space environment; There is also a kind of "Long John" underwear, which can circulate frozen water through pipes to prevent astronauts' spacesuits from getting too hot.
When 1974 designed these "next generation" spacesuits, NASA chose a modular "tuxedo" mode, in which various components (upper body, lower body, helmet, arms and gloves) can be mixed and matched to suit each astronaut. Spacesuit has five sizes, from extra large to extra large, mainly depending on men's size. Women are not eligible to participate in NASA's astronaut program before 1978.
Forty-seven years later, kimbrough and peske wore the same spacesuit while working on the International Space Station, although the design life of the spacesuit was only 15 years.
Nowadays, NASA's spacesuits are no longer customized, but more like the surplus of discount shopping malls; The original 18 suits produced by the next generation project are now only four complete suits. Four people died in the disasters of Challenger and Columbia. Some of them have finished their working lives and no one has succeeded them.
This means that in order to be selected for spacewalking on the International Space Station, astronauts must meet one of two optional sizes: male medium size or male large size. The first all-female extravehicular spacesuit originally scheduled for March 2065438+2009 had to be postponed because there was only one medium-sized spacesuit to choose from. On October 20/91June 0/8, astronauts Christina Koch and Jessica Mayer successfully completed their groundbreaking spacewalk.
Most extravehicular activities are carried out in groups of two, and flight controllers will carefully arrange the activities of each astronaut in advance to minimize the "idle" time and complete the task as efficiently as possible.
Each EVA participant receives 65,438+00 hours of training every hour. In a water pool with a depth of 65,438+02 meters, astronauts practiced all aspects of spacewalking using the physical model of the International Space Station.
During the actual extravehicular activity, the mission controllers on the ground pay close attention to the progress of the astronauts, and the astronauts can communicate with the ground controllers, extravehicular activity partners and the astronauts of the International Space Station as needed.
Space is a harsh environment. Spacesuit can protect against radiation, extreme temperature (from -270℃ to+120℃), small particles and debris. In order to prevent the risk of being hit by "space junk", EVA is arranged in a low-risk period, which is based on the tracking of known objects.
Astronauts must also take measures to avoid decompression sickness or "decompression sickness". Just as scuba divers rise rapidly from deep water, astronauts who quickly transfer from pressurized space stations to low-pressure spacesuits may be affected, and may even form deadly nitrogen bubbles in their blood. Before carrying out extravehicular activities, astronauts will "camp" in the airlock of the International Space Station for one night under reduced pressure to help them adapt to the environment, and then put on spacesuits.
No one died in extravehicular activities, but there were a few lucky escapes. 1965, Soviet astronaut Alexei leonov made the first spacewalk. The expansion of his spacesuit in the space vacuum almost prevented him from re-entering the Voskod space capsule, which almost ended in disaster.
On July 6th, 20 13, Luca Pamitano went down in history with two firsts: the first Italian who walked in space and the first man who almost drowned in space. A week before his extravehicular activity, a water pipe in his spacesuit burst. But this information did not reach the command system, and the task controller authorized him to start EVA.
In less than an hour, Luca's helmet was filled with nearly two liters of water, making it difficult to breathe. Luca said that he could not look out through the mask, nor could he communicate with his colleagues. He could only navigate back to the safe airlock room with a tether.
There is no doubt that he and other astronauts will be keen to wear NASA's latest "xEMU" spacesuit, which is currently being developed for NASA's long-awaited moon landing program -Artemis.
It is hoped that Al themis will have more choices when wearing spacesuits on the moon, which means that astronauts can be selected to perform tasks because they have the right materials and are limited by the right size.