2021-04-28

What is the experience of mankind’s first tetherless spacewalk?

By yqqlm yqqlm

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Spacewalking in the earth orbit is a very difficult process. Astronauts need to wear stiff and heavy clothes. The space suit works in a deadly vacuum environment for 6 hours, which is also a physical and mental challenge, and the premise is that everything goes well. On February 7, 1984, when astronauts Bob Stewart and Bruce McCandless left the “Challenger” space shuttle, they tested the NASA Space Manned Maneuver Unit (MMU) during the STS-41B mission “Jetpack”, I don’t know how bad a spacewalk will be…

What is the experience of mankind’s first tetherless spacewalk?

What they didn’t expect was that when they opened the door to leave the shuttle, trouble appeared. When the air was discharged from the shuttle’s airlock, Stewart followed Standard operating procedure, yawning to balance the pressure between the middle ear and the atmosphere of the spacesuit. The pressure here averages 1.95 kg per square inch, but this simple action broke the chin strap of the fixed communication tool on your chin. open.

Stewart recalled that the chin pad on the chin strap was floating in front of my eyes…this was probably the worst situation. I pursed my lips and breathed out hard, and then the chin strap was on my The nose bounced back and forth between the surface of the helmet, and when the chin strap slid over my mouth, I tried to catch it with my tongue and then tuck it into the helmet neck ring to prevent it from blocking my vision.

While Stewart tried to catch the chin strap with his tongue, he did not realize that his aerospace helmet was tilted up. Normally, the aerospace helmet is very comfortable to wear, but when this happens, it is fixed before The position of the microphone and headset also shifted. He said: “This is the first time I felt pressure on my earlobe during a spacewalk. When I lifted my head, the microphone had deviated to the position of my nose. I used my head. The head hits the back pad of the brain back to prevent the communication device from falling off.”

What is the experience of mankind’s first tetherless spacewalk?(1)

At the time, he had greater concerns. He didn’t want the ground control center to know about this issue because they might cancel the extravehicular activity. When the Challenger space shuttle and the ground control center got out of control, Stewart told the astronaut companion McCandless and space shuttle commander Vance Brand what happened. We discussed it, and in the end Stewart decided to continue this time. During the spacewalk, Brand said: “Okay, let’s continue!” When Stewart and McCandless walked out of the airlock, Stewart’s head was stuck on the back pad of his brain to prevent the communication device he was wearing from falling off.

Stewart clearly knows that it is not an interesting thing to stick an aerospace helmet close to the back of his head to perform a spacewalk, but he was a US Army test pilot and a veteran of hundreds of Vietnamese armed helicopter missions. , Stewart thinks he can make it through!

When McCandless was wearing a space maneuver for the first time “tetherless” spacewalk, Stewart began to work in the payload bay, he said: “I will start the spacewalk mission, At the same time, I found that my foot could not be put into the space ankle ring. I could put my toe into the ankle ring, but when the heel was locked, I couldn’t turn the heel. I couldn’t see the specific situation, but the situation was that the outer fabric of the space boot was already I slipped through the heel bolt, which meant that I had to fix my body with my left hand. At the time I was holding half of the tool in my left hand, I had to act on all the torque, not only through the arms, but also the feet. It was unbearable at that time. My arm is cramping…” When he was asked about the level of frustration at that time, Stewart said: “Oh my God, if the limit of frustration is 10 points, then my frustration level is 9.5 points!”

At the same time, the staff of the ground control center had a radio call with McCandless of “free flight”. He was describing the spectacular space scene seen high above the capsule, and then the ground The control center turned to Stewart, another space partner, and the ground control center called in the radio device: “McCandlis, we have finished the call with you, Stewart, are you in good condition?” At this time, Stewart’s voice control The microphone has shifted to the eyeball position, so Stewart shouted hoarsely: “Oh, I’m fine, let’s communicate later!” In fact, Stewart’s real idea at the time was that there was something wrong with this spacesuit, and I was dealing with it. Don’t contact me for now.

What is the experience of mankind’s first tetherless spacewalk?(2)

And ground control The staff at the center did not understand Stewart’s hint. Stewart’s throat was almost dry when he was breathing dry and pure oxygen in the helmet, but he still didn’t dare to move his chin to drink from the straw on the neck ring. He said: ” If I move my head to drink water, I may lose the communication carrier, after all, the chin strap of the fixed communication tool is broken.”

McCandlis continued on his magic carpet journey , While floating in space 100 meters above the “Challenger” space shuttle, Stewart faced a new problem. The sublimator in his aerospace flight backpack cooled the circulating water in the cooling suit pipes close to his skin. Blocked by ice water, according to the mission memorandum, the temperature of the spacesuit needs to be adjusted to the minimum when this happens. He explained that this is equivalent to placing the maximum amount of ice water around the human body, thereby using body heat to melt the sublimator But when I adjusted the temperature of the spacesuit to the lowest, it was like jumping into the Arctic Ocean. I couldn’t make the spacesuit heat up quickly.

At present, since there are not too many suggestions on the mission memo, Stewart believes that he can remove the ice water blockage by turning off the spacesuit’s fan and water pump, cut off the water flow, and finally the ice condensed in the spacesuit can be sublimated However, when the fan of the spacesuit was turned off, the carbon dioxide content in the helmet rose rapidly. When Stewart felt that his breathing was getting deeper and deeper, he turned on the fan again. During the next spacewalk, he experienced six such freezing phenomena. The last time he discovered the phenomenon when he returned to the airlock.

Stewart said lightly: “It is undeniable that it was a very frustrating extravehicular activity.” Two days later, the Challenger astronauts needed to take another spacewalk, this time Stewart He piloted a space manned mobile device. When he put on protective clothing, he tied the head communication tool with medical tape to the helmet for better control, but he still could not use the ankle ring to fix his feet .

Stewart said that driving a space manned maneuvering device is a test pilot’s dream. I have achieved the highest level of control of a space jetpack. This is a space flight device that I recognize very much. It is easier for astronauts. The only way to control the flight is to connect it with your own brain, so that as long as the astronaut’s consciousness performs a certain action, the space jetpack can achieve it. It is a pleasant machine…

In an interview with reporters, Stewart recalled the real feelings of spacewalking. He said: “When I look at the orbiter and the earth, I am thinking: What is it like to be the only person in the universe? So I turned the space manned mobile device to a place where I could not see the earth, the moon or the sun. Here I could only see the darkness of space. I only held on for about 15 seconds. Then I thought: Okay, let’s look back. Look, make sure everything is still there. It’s an interesting feeling I’ve never experienced before.”

Although this is the worst spacewalk that a space shuttle astronaut has ever experienced, this experience is The most precious life experience of an astronaut. (Ye Qingcheng)