The International Space Station (ISS) has been welcoming astronauts on missions for 25 years. Everyone knows that staying in space also comes with danger. Here are the 3 worst situations that can happen to astronauts, as told by Thomas Pesquet.
A 450-ton house has been orbiting the Earth for 25 years. This house is the International Space Station (ISS). NASA party in November 2023, the anniversary of putting this large space laboratory into orbit. Astronauts follow one another to conduct experiments in the space environment. This was the case for Frenchman Thomas Pesquet, twice in 2016 and then in 2020.
This workplace is like no other. Its extreme environment requires you to be ready to face the worst and to know from within what the right responses are in case of a problem. In his book My life without gravityThomas Pesquet says this was the first thing he learned when he arrived at NASA during his training (which lasted from 2010 to 2016). In life-size modules of the station, the astronaut carries out simulations of the most dangerous situations that are likely to occur on the ISS. “ There are three extremely serious situations: », writes Thomas Pesquet. These are the ones.
Fire, public enemy in the space station
One of the worst disasters on board the station would be a fire. Even if everything in the ISS is fireproof, the risk is never reduced to zero. It has happened before that a fire broke out on board a station, the French astronaut recalls. “ One of the research modules at the MIR station caught fire in 1997. The crew extinguished it within a minute and a half. Great achievement, even though this minute must have seemed very long to them in the midst of the smoke that filled the module. »
So it is essential to know what to do. In this case, astronauts learn to shut off ventilation to prevent the fire from spreading to other modules, or learn to use the fire extinguishers and masks at their disposal.
Beware of depressurization in the room
The pressure on board the ISS must not decrease on board. Lowering the pressure is therefore another very urgent situation. This can happen when a hole appears in the station’s hull due to a collision with space debris or a mechanical incident. “ Because any space object is launched at lightning speed, a collision could be catastrophic. The ISS is protected by armor that can withstand debris of up to one centimeter, no more », underlines Thomas Pesquet.
This is why losing tools is one of astronauts’ worst nightmares during an extravehicular outing. No astronaut wants to be responsible for depressurizing the station when his screwdriver comes back to hit it.
The station cannot tell astronauts where the problem is occurring, but it does inform them that the pressure is decreasing. “ The crew may be able to feel it in their ears, such as in a tunnel or in an airplane.indicates Thomas Pesquet. In fact, the control center sees the bends and warns us immediately. All action: the astronauts immediately started looking for the cause of the problem. We calculate how quickly the pressure is dropping and determine whether we have three hours or twelve minutes to save ourselves and the station (in that order). »
The astronauts are then instructed to stay close to their capsule and isolate the other modules to determine the cause of the problem. Suction cups or resins can then be used to seal the breach, if it is identified.
The risk of a toxic atmosphere
Finally, astronauts may also be at risk of poisoning themselves on board the ISS in case of a toxic atmosphere. “ It could be a harmful product that we use for a scientific experiment, which escapes us and then spreads in weightlessness. It could be the urine in combination with the treatment product, which is very acidic. » — a product for which precautions must also be taken when astronaut toilets need to be repaired.
A big fear concerns ammonia (the toxic gas from ammonia, sometimes used in kitchens and bathrooms). Ammonia circulates in liquid form in the ISS’s external radiators to cool it. In the event of an ammonia leak on the ISS, this liquid would quickly turn into gas and become very dangerous to inhale. “ In the face of such a disaster, there is no other option than to put on a mask and join the Soyuz [ndlr : la capsule russe]close behind yourself and remove soiled clothing if necessary. » It is then time to assess the situation and determine whether the station can be saved or not.
Living in space is a dream that has been fulfilled by many astronauts on the ISS for 25 years. But it can quickly turn into a nightmare within seconds. Therefore, crews must be prepared for any eventuality.
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