thrilling return home
Beware of anhydrous hydrazine poisoning
Shenzhou 14 cold night return search and rescue drill
Shenzhou 14 group space business trip ends for 183 days, and will return to Dongfeng landing ground on a cold winter night. I wish the three space heroes safely! That being said, the "returning home" journey of astronaut is still thrilling. In addition to the familiar overload and wearing black barrier , there is another thing that everyone may not be familiar with - caution hydrazine poisoning ! Fortunately, our ground search and rescue system is fully prepared.
mentioned that anhydrous hydrazine poisoning is caused by many netizens: what is anhydrous hydrazine , what is used for, why is poisoning, and how to prevent and treat it. The editor will explain it to you one by one.
What is anhydrous hydrazine?
First talk about its power. After the 00 kilogram of anhydrous hydrazine explodes, it is equivalent to a small atomic bomb . But don't be scared by .
anhydrous hydrazine is a colorless transparent liquid fuel. It works together with an oxidant to form a space liquid propellant. This propellant has many advantages such as specific surge, stable combustion, multiple ignition, easy storage and adjustable thrust. It is used in return capsule of Shenzhou manned spacecraft.
Of course, the disadvantages of anhydrous hydrazine, a special fuel, are also obvious, is highly toxic, explosive, and flammable . Therefore, in Jiuquan Satellite Launch Center , anhydrous hydrazine is usually stored in the special fuel station. People in Aerospace City stay away from it. In the eyes of many people, this is like a crater that may erupt at any time.
What is the use of anhydrous hydrazine?
When the Shenzhou manned spacecraft returns to Earth, only the return capsule in the middle comes back, and the orbital compartment and propulsion compartment on both ends will temporarily remain in space.
Return cabin looks like a big bell, with one end having a round, a large blunt bottom and an inverted cone. When the astronauts return to Earth in a return capsule, some stages require adjustment of attitude, which requires a propulsion system to achieve. Where are they installed? Let’s see that there are two umbrella cabins at the end of the small head of the return capsule (that is, on the cone section), one is the main umbrella cabin and the other is the backup umbrella cabin. A propellant compartment is set up under the backup umbrella cabin, and a single-unit propulsion subsystem is installed here. The return capsule attitude control engine uses anhydrous hydrazine fuel. According to data, four anhydrous hydrazine tanks were installed in the return cabin, with a total refueling amount of 56 kg, and the use amount during the return process was about 52 kg, and the safety margin was 4 kg.
Why is poisoned?
Let’s talk about two cases first. In 1975, the United States Apollo and the Soviet Union flew together. When they returned to the atmosphere, the nitrous oxide fuel penetrated into the return capsule, and three of the American astronauts were poisoned and almost died. In 1983, the 9th flight test of the of the US space shuttle leaked during landing, and caught fire. Two of the three auxiliary propulsion devices exploded.
anhydrous hydrazine as a single-component propellant is often used in the propulsion system of spacecraft. Anhydrous hydrazine has the characteristics of white smoke coming out when wet, and may explode when wet, rust or oxidant. The so-called anhydrous hydrazine is not absolutely anhydrous, but only has extremely low water content or only trace content. Moreover, when anhydrous hydrazine comes into contact with an oxidant, an exothermic reaction will occur. Even if there is no oxidant, anhydrous hydrazine will decompose the exothermic heat. Under standard atmospheric pressure, anhydrous hydrazine is more likely to evaporate and catch fire at ambient temperature if it leaks in a space environment.
anhydrous hydrazine is not only flammable, but also highly toxic. Since the anhydrous hydrazine pipeline passes through from the return capsule, after the spacecraft returns, it must first use special instruments to detect leakage of the anhydrous hydrazine in the cabin to see if the standard exceeds the standard. If the standard exceeds the standard, it must be eliminated as soon as possible. If the astronauts show poisoning in the cabin, they must immediately undergo pre-cabin treatment.
Astronauts return to search and rescue drill
How to treat it?
When it comes to astronaut rescue, there may be two main injuries.The first familiar situation is trauma, such as emergency escape when the rocket takes the spacecraft ascends, or "impact overload" when the return capsule lands. Astronauts are inside like jumping off a building. If the situation is serious, it will cause damage to the internal organs and cervical spine.
The second type may not be familiar with. The leakage of harmful gases such as nitrous tetroxide, dimethylhydrazine, carbon monoxide, , and anhydrous hydrazine in rockets and spacecraft propellants, causing the toxic gases in the cabin to exceed the standard, resulting in astronauts poisoning. The most dangerous one is the leakage and poisoning of "anhydrous hydrazine".
When a large amount of anhydrous hydrazine enters the human body, it is easy to pass through the blood-brain barrier, compete with the vitamin B6 in the body, and even replace it. If it is lacking, it will increase the excitability of the central nervous system and paroxysmal ankylosing convulsions, which are similar to carbon monoxide poisoning, such as respiratory and cardiac arrest.
Astronauts return to search and rescue drill
When the door of the return capsule is opened, professionals first test the anhydrous hydrazine in the cabin. If the standard is found to exceed the standard and the astronauts have symptoms of anhydrous hydrazine poisoning, our medical treatment system has a mature precabin treatment plan.
① Before treatment, medical staff first wear complete protective equipment, wear gloves, protective suits and gas masks;
② Then open the window of the pressure suit in the astronaut's cabin and wear gas masks for the astronauts. Then quickly evacuate and return to the cabin site to quickly isolate it from the water-anhydrous hydrazine leaks, and keep the scene quiet, keep the astronauts warm and inhale oxygen. After transferring to a safe area, rinse the astronaut with clean water, then take off the pressure suit in the cabin. Then rinse the exposed mucosa such as the skin, eyes and other mucosa in a lot of water. If the astronauts experience convulsions and spasm and at this time, they must inject microorganism B6 in large doses. Some also need to undergo intravenous diuresis and promote ejaculation. In order to prevent suffocation caused by convulsions, airway protection and other measures must be taken.
Conclusion
Although our country has fully mastered the Shenzhou Spaceship return technology, and has also established a powerful and complete search and rescue and medical treatment system, forming various medical rescue plans for astronauts when they encounter danger. This is called "Everything is planned, and if it is not planned, it will be abandoned", but we still hope that the astronauts of our country will go home safely and smoothly, and like these heroes who are willing to contribute, selfless and fearless, and pray for them.
Reference materials, thank you very much!
1, "University Concept: Cognition and Practice"
2, "Harbin Institute of Technology"
3, "Soaring Space--China's Manned Space Road"
4, "Pilot of Aerospace Technology--Development and Achievement of Rocket and Spacecraft Technology in Beijing Institute of Space Mechanical and Electrical Research"
5, "Impact of Rocket Propellant Operation on Health and Sanitary Protection"
6, "The Explosion Danger of Anhydrous Hydrohydrazine and Methylhydrazine in Space Environment"
7, "Expert Consensus on Treatment of Astronauts in the Return Cabinet of Space Station Mission Landing Site"
#The Crew of God Fourteen Astronauts Will embark on a Journey Home #What you see is very scientific
