Leaks, failures, fires...what should we do if we encounter distress in space?

Recently, two Russian astronauts on the International Space Station were a little depressed: they were first forced to postpone their extravehicular walks due to a malfunction in their space suits, and then encountered an abnormal leak in the Soyuz MS-22 spacecraft. Not only was their extravehicular mission further postponed, but they were also not sure whether they could return home safely on this spacecraft in March next year. Looking back at the history of manned space flight, what dangers have astronauts experienced in space? What preventive measures and response plans have researchers and astronauts developed for this?

Spacecraft leaks are dangerous

Spacecraft are running at high speed in low-Earth orbit, and sealing measures that meet relevant standards must be taken. After all, the temperature, humidity, pressure, and radiation conditions of the vacuum environment of the universe do not allow direct exposure to the human body. When a manned spacecraft returns to the ground, it needs to pass through the Earth's atmosphere at high speed. The harsh external environment also requires the spacecraft to maintain good sealing. Therefore, any signs of spacecraft leakage will arouse high attention and prompt disposal to avoid tragedies.

Russia's Soyuz MS-22 spacecraft has an abnormal leak

The recent Soyuz spacecraft leak was detected in time because the astronauts found that the pressure sensor reading in the cooling circuit was abnormally low before leaving the cabin. Soon after, the camera on the robotic arm captured a large amount of coolant flying into space through the small hole. Experts from Russia, the United States and other countries are analyzing the cause of the accident, focusing on whether the spacecraft can complete the landing and return mission without coolant. If not, Russia will launch a rescue spacecraft in time.

In fact, over the past half century, foreign manned spacecraft have encountered many leakage incidents, which have endangered the lives of astronauts.

In August 2018, the Russian Flight Control Center detected a small amount of gas leakage in the cabin of the International Space Station, and the pressure sensor in the space station also sounded an alarm. Six astronauts found that there was a 1.5 mm diameter hole on the wall of the Soyuz spacecraft orbital module docked with the space station. If it is not handled in time, the oxygen in the space station may be exhausted within 18 days, causing fatal consequences. After the astronauts used special materials to urgently seal the small hole, Russian experts ruled out the possibility of the hole being caused by impacts of space debris or tiny celestial bodies after research, and then suspected that American astronauts drilled holes to damage the Russian spacecraft, which caused an uproar, and the two countries have different opinions to this day. If the abnormal leakage of the spacecraft occurs in the return capsule, the situation will undoubtedly be more dangerous.

In 1971, three astronauts died during the return of the Soviet Union's Soyuz 11 spacecraft to Earth. Investigations showed that the pressure valve of the spacecraft's return capsule malfunctioned, causing rapid leakage of air in the small return capsule. Before the astronauts could react, the cabin was severely depressurized, causing the astronauts to suffer from acute hypoxia and suffocation. That tragedy showed that the early interior design of the spacecraft was unreasonable. The Soviet space agency quickly improved the safety indicators of the Soyuz spacecraft, added a life support system, and stipulated that astronauts must wear special space suits during the ascent and return phases. The crew was reduced from three to two at one time until various improvement measures brought the safety of the spacecraft to a new level. In addition, the tragedy of the two US space shuttles was also caused by improper sealing.

Shortly after the Challenger space shuttle was launched in 1986, the seal failed and the hot gas from the solid booster abnormally impacted the external fuel tank, triggering a chain reaction and ultimately an explosion.

In 2003, the insulation foam on the external fuel tank of the Columbia space shuttle fell off and hit the leading edge of the left wing, posing a hidden danger. When the space shuttle re-entered the atmosphere, it had lost its sealing, and high-temperature gases entered the wing and caused hydraulic and control system failures, leading to disintegration. After the tragedy, NASA increased the inspection of thermal insulation tiles, so that the space shuttle needs to fly around the International Space Station before returning so that the astronauts stationed on the station can carefully check whether its external thermal insulation tiles are damaged.

Space suits repaired and expected to be replaced

In space, any minor anomaly can lead to a major accident, and this is true for the space suits that astronauts must wear when they go out of the spacecraft. In January 2016, American astronaut Coppella encountered a helmet leak during an extravehicular mission, which was classified as a "potential life-threatening incident" by NASA.

Astronauts on the International Space Station return to the cabin to remove water

Italian astronaut Parmitano also had a helmet leak, and the amount of water leaked was four times that of Koppella. In the weightless environment, the water once completely covered Parmitano's facial features, making it difficult for him to breathe and unable to hear the emergency radio communication information. If his colleagues had not received emergency rescue training and assisted him to return to the airlock in time, it would have likely caused serious consequences.

The accident investigation showed that inorganic materials in the water separator caused the drum hole to be blocked, and water droplets were forced to overflow and enter the ventilation loop, and a large amount of water was suspended inside the helmet. In response to the relevant defects, NASA improved the water separator of the extravehicular space suit to avoid blockage as much as possible, and added an absorbent pad inside the helmet and inserted a spare breathing tube.

Later, another astronaut encountered a water leak, but it also proved that these improvements had worked. In addition to water leaks, there was also a more dangerous puncture accident of the space suit outside the cabin.

In April 1991, American astronaut Apted accidentally punctured his space suit during an extravehicular activity, causing abnormal decompression, but fortunately he was not seriously injured.

Earlier in 1965, Soviet astronaut Leonov conducted the first spacewalk, but the early extravehicular space suit was not designed properly and expanded abnormally, so Leonov could not return to the spacecraft. However, Leonov was skilled and brave, and took the initiative to open the valve, risking the pressure of the extravehicular space suit, and finally returned safely.

In 2001, when American astronauts were connecting the cooling lines of the International Space Station, they encountered a valve failure, which caused ammonia to leak onto their extravehicular space suits. Because ammonia is toxic, astronauts must remove the remaining ammonia crystals when returning to the airlock, so they have to continue "sunbathing" in space, trying to evaporate them with the help of sunlight. After entering the airlock, astronauts wear oxygen masks for at least 20 minutes. After careful inspection, they are sure that ammonia has not leaked into the airlock before they can safely complete the mission. Looking at many accidents, it is not difficult to find that extravehicular space suits are called clothes, but they are actually miniature spacecrafts with complex internal structures and harsh working environments. It is inevitable that problems will occur. As time goes by, the classic models of extravehicular space suits developed by the United States and Russia in the early years have gradually become "old and frail", and they can only be barely maintained in use after frequent repairs. It is necessary to use new technologies, new materials, and new processes to launch a new generation of "space suits."

Don't panic if there's a fire in space

Foreign manned spaceflight has paid a heavy price due to fires. In 1967, the Apollo 1 crew of the United States encountered a fire during ground testing, and three astronauts died. Today, it is difficult for ordinary people to imagine that dangerous fires have occurred in space, so much so that a while ago, Russian astronauts conducted a fire drill on the International Space Station, which became a big news.

Russia's Mir space station once encountered a fire hazard

In fact, in 1997, the Russian Mir space station encountered a high-risk fire. At that time, the lithium perchlorate storage device used to generate oxygen leaked, and the raging fire caused the metal of the cabin wall and cables to melt. High-temperature droplets splashed on the cabin wall like ignited fireworks. The astronauts were worried about the cabin wall being punctured and depressurized. In the end, the astronauts put on breathing masks, endured the high temperature and smoke, took out the fire extinguisher, put out the open fire, and overcame the lack of oxygen in the small space. They tried hard to contact the ground team and finally turned the danger into safety under the guidance of experts.

This accident also put forward higher standards for the safe operation of the space station, such as the need to use materials with better high-temperature insulation to replace cheap but flammable aluminum alloys, and not to pile up objects in a messy manner, and to retain fire safety passages. The International Space Station is independently equipped with a Russian water foam fire extinguishing system and an American carbon dioxide fire extinguishing system. Astronauts conduct safety drills regularly so that they can deal with fires quickly and correctly, almost like a conditioned reflex. In addition, the newly designed manned spacecraft of various countries try to ensure that the interior is clean as much as possible, which not only helps to maintain the physical and mental health of astronauts, but is also an inevitable requirement for controlling fires. On spacecraft or space shuttles with smaller internal spaces, fires cannot be ignored.

In 1983, the Columbia Space Shuttle had a fuel leak when it returned to Earth. The fuel in the auxiliary power unit exploded, destroyed the valve, and burned nearby wires. NASA found that the fuel had actually leaked when the shuttle entered orbit, but it was frozen in low-Earth orbit and reignited due to intense friction and heating when it re-entered the atmosphere. The fire was considered a near miss, and NASA quickly improved the auxiliary power unit. Unfortunately, the space shuttle system was complex, and more hidden dangers were not detected in time, leading to the subsequent tragedy.

In short, manned space flight is a complex project full of risks. Researchers and astronauts have devoted great efforts and even risked their lives to eliminate hidden dangers. I believe that successors will continue to learn from the valuable experience passed down by their predecessors and make greater achievements.