Recently, three astronauts on the International Space Station ended their isolation in the Russian module. As a result of the previously discovered gas leak in the U.S. segment, they concentrated on the Russian segment on August 21 to cooperate with the Flight Management Center to conduct closed-cabin pressure checks to find the source of the leak. Although the final quarantine period was extended by one day, as of press time, the relevant parties did not announce the finding of gas leak points.
Yang Yuguang, a researcher at the Second Academy of China Aerospace Science and Technology Group and vice chairman of the IAF’s Space Transport Committee, told Science and Technology Daily that the gas leak would not threaten the safety of astronauts. For this subtle gas leakage phenomenon, although easy to detect, but to find the source, there is no particularly simple and effective means.
Moderate gas leakage contributes to harmful gas emissions.
Yang Yuguang said that whether it is the space station or manned spacecraft, in fact, allowing a certain rate of air leakage, which helps to remove harmful gases. It’s just that spacecraft from different countries and at different times have different standards for leakage rates.
On manned spacecraft, he said, the CYS is used to sustain astronauts’ lives, including atmospheric control, water control, and other pollutant control.
Early U.S. manned spacecraft used a pure oxygen atmosphere with low atmospheric density and lower air pressure to make the spacecraft’s casing thinner. The Soviet Union began by mixing the atmosphere with nitrogen and oxygen. Today, nitrogen-oxygen-mixed atmospheres are standard for manned spaceflight in all countries.
Therefore, the CYS system mainly includes nitrogen, oxygen and carbon dioxide in atmospheric control. All three are too many not to do, less not to be able to. In addition, the capsule will produce a variety of harmful substances, such as electronic equipment will break down to produce harmful gases, astronauts farts also contain hydrogen sulfide. These harmful gases build up if they are not controlled, so proper air leakage rates can be helpful in reducing the accumulation of pollutants.
It is estimated that the International Space Station is leaking about 220 grams of air per day. Mr Yang said the leak rate did not exceed the ISS’s safety threshold. According to a statement issued by NASA and the Russian Federal Space Agency, the air leakage rate in the capsule is only “slightly above standard.”
Typically, an astronaut needs about 6 to 10 kg of air a day, compared with more than 200 grams of air. Perhaps that’s why NASA has been leaking gas from the space station since September 2019, only to start finding it a year later.
However, while there is no risk to the safety of the space station, unplanned air leakage has also caused some waste. After all, the leaking gas always has to be replenished, and supplies can only be transported from the ground.
Yang yuguang said the International Space Station has always maintained pressure of nearly one atmosphere, with air consumption, daily oxygen and nitrogen needs to be replenished, these supplies need to be transported from the ground. But the cost of such resupply transportation is very high, according to the cost of cargo ships, rockets and launch costs, each to the space station to transport a kilogram of material, the cost is much more expensive than the equivalent of gold.
For the other way, the International Space Station every day to cast more than 4 or two gold, you say distress?
The leak is equivalent to looking for pinholes in a large airliner.
In the end, NASA couldn’t sit back and see. On August 20th they announced that they would begin looking for the source of the leak.
According to the air leakage estimates, the cause of the leak may be a section of the shell has a diameter of about 0.1 mm small hole. Finding such a hole smaller than the tip of a needle in a huge space station is obviously not easy.
The International Space Station is jointly built by 16 countries, including the United States and Russia, and currently has more than a dozen pressurized segments. Yang Yuguang said that Russia has five segments, including the “Sugon” function module, “Star” service module are 20 tons.
The U.S. segment is partially connected to Russia via the Unity node module. These include the Destiny experimental module of the United States, the node module of the Serenity, the observation module of the Dome, and the multi-function logistics module of the Leonardo. The United States “harmony” node module, and connected to Europe’s “Columbus” experimental module, as well as Japan’s “hope” experimental module … These segments are connected like a section of lotus, with trunks and branches, and are quite complex. Yang Yuguang said the international space station has a total weight of more than 400 tons and more internal space than a large passenger plane.
As a result of the preliminary determination that the source of the leak was in the United States, as of 21 August, all three astronauts stationed on the space station entered the Russian segment and closed the doors of the various segments of the United States in order to check for the leaky segment. It is reasonable to say that the space station has a wide variety of sensors, and it is not difficult to do so.
However, Yang Yuguang believes that even if the air leakage section is found, it is difficult to find further air leakage points, ultrasound and other means are not applicable under any circumstances, many times also rely on astronauts lying on the wall bit by bit to find. But on the one hand, the space station module is equipped with organic cabinets, which are non-sealed equipment, and there are several layers of structure, if the leak point is behind the cabinet, unless the cabinet is removed, it can neither be seen nor touched. On the other hand, small holes 0.1 mm in diameter are difficult to discern with the naked eye and are difficult to detect quickly, either in or out of the cabin.
So even if there is a financial cost, the ISS may have to keep leaking for a while if it’s not.
This is not the first time the space station has leaked gas.
In any case, the leak was not serious and was not the first time it had occurred on the space station.
Gas leaks have also been detected on the International Space Station in 2018. After examination, crews found a hole about 2 mm in diameter on the Soyuz MS-09 spacecraft docked with the International Space Station. The hole, though small, caused the cabin air pressure to drop. The astronauts then used tape and special glue to plug the hole and safely drive the spacecraft back to the ground.
In 2004, a leak in the vacuum-span cable used to balance window air pressure on the International Space Station was broken, so that the damage was not severe, and the astronauts replaced the new cable to solve the problem.
By contrast, the 1997 collision between the Russian Mir space station and the Progress M-34 cargo ship caused more serious gas leaks. It was on the night of June 24 that the spacecraft separated from the Mir space station’s Quantum 2 module and, after pulling away at a distance, attempted to re-dock with the station to test its new Toru docking control system. However, the system is not as reliable as one might expect. When the spacecraft approached the space station at a relative speed of 17.5 kilometers per hour, the “rate abort control” component failed, so it ignored the astronaut’s instructions and flew forward along the station’s long axis, crashing straight into the solar panels of the Spectral module, causing the Spectral main module to deflect in. Before confirming the damage, the astronauts on the space station had clearly felt the change in air pressure. Fortunately, after emergency disposal, the space station personnel out of danger, “in trouble” spacecraft is back under control, but the damaged section is permanently out of pressure, no longer suitable for habitation.
The worst tragedy caused by the air leak occurred in 1971 when the Soviet Soyuz 11 spacecraft returned to Earth. On June 6, 1971, astronauts Georgi Dobrowolski, Viktor Pachaev and Vladislav Volkov successfully docked with the world’s first real space station, Salute 1, and set a record of 23 days, 18 hours and 22 minutes on the station. But on June 30th, when the people who greeted the hero opened the capsule and returned to the capsule, they saw the remains of three astronauts.
After investigation, when the spacecraft re-entered the atmosphere, the return module separated from the orbital module, the pressure valve of the return module was shaken open, the cabin air leakage quickly. At the same time, the Soyuz capsule space is so narrow that the Soviet space agency put them at risk by letting them take off their spacesuits in order to accommodate three astronauts. As a result, three astronauts died of acute hypoxia asphyxia and boiling body fluids before they could react too much.
Later, it took the Soviet Union more than two years to design a second-generation Soyuz spacecraft, focusing on improving safety, while changing the membership from three to two and requiring astronauts to wear spacesuits during the liftoff and return phases. This is the lesson of the three astronauts’ life in return.
Yang Yuguang said there are several levels of accidents caused by air leaks. Minor cases can be repaired with emergency disposal, segments may need to be closed if the leak is serious, and emergency evacuations of astronauts may be organized if they are severe, such as residential cabin loss of pressure and no longer living conditions.
And the soyuz 11 tragedy, I hope never happen again.