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Astronauts are both familiar and mysterious to ordinary people. Before officially undertaking missions in the sky, they had to follow numerous extremely strict rules.
For ordinary folks, astronauts are only seen through TV screens. It's very difficult to know, interact with, or understand the true daily life of an astronaut, both before and during their 'space conquest' missions.
In reality, every astronaut has undergone rigorous technical and psychological training. Ultimately, going into space is no ordinary matter; if you leave Earth in space, you'll risk losing your precious life if you're not careful.
During a NASA astronaut recruitment for a Moon mission, they disclosed some rather stringent requirements such as:
Candidates must meet educational requirements, such as having at least a master's degree in STEM fields like biology, physics, computer science, or mathematics;
Professional flying experience is a must, with at least 1,000 hours as a captain for jet aircraft or 1,500 hours for commercial aircraft;
Exceptional physical fitness is required, including 20/20 vision, blood pressure not exceeding 140/90, completion of diving certification, and military-style survival training underwater...
These are just the initial selection criteria. Those who pass may undergo further training and screening to meet job requirements over the long term.
The space environment is extremely harsh, so astronauts undergo multiple rounds of selection and training, including a series of physical and mental tests.
One such requirement pertains to physical appearance, such as fingernails. Although currently, technological advancements have rendered this step unnecessary, in the past, all astronauts had to 'pull' their nails before venturing into space.
Some argue that this regulation stemmed from the difference in pressure between space and Earth, potentially causing astronauts' nails to not withstand the pressure during growth. Additionally, blood cannot cease flowing due to this, hence all nails are removed.
Moreover, some argue that living in outer space for extended periods causes their nails to grow longer. If nails grow too rapidly, they interfere with clothing and equipment, necessitating trimming. However, the trimmed nails also easily float around, potentially impacting spacecraft devices.
We all know that every operation in space requires meticulous calculations to ensure absolute precision. If nail clippings float around and land on delicate equipment, they could cause scratches or, worse, damage, leading to serious consequences. Hence, astronauts pluck all their nails before venturing into space.
Regarding this issue, scientists provide explanations revolving around the following reasons:
Firstly, to ensure maximum safety and health, astronauts undergo a series of air pressure tests before soaring into the sky, an environment they must endure.
Secondly, even if nails fall off directly, they will still grow back; some astronauts need to work continuously in space for over a year. If they keep worrying about spacecraft operations being affected by nail issues, it will impact their work.
Furthermore, space exploration is very serious, with no room for errors in many aspects, while also considering the safety of astronauts. Because the space environment is so different from Earth, not only nails but also hair grows rapidly in that environment.
If nails grow rapidly in space, under vacuum pressure, they will fall off, causing significant harm to astronauts.
Canadian astronaut Chris Hadfield once shared: 'They will fly everywhere instead of falling to the ground, so they can't be swept away. Sometimes they fly into the eyes or even into the airways.'
Indeed, the cut nails can become space debris, difficult to handle at that time. They freely move in the zero-gravity environment and can easily get stuck in crucial spacecraft equipment, potentially causing damage.
Sometimes, an accident caused by nails can also turn into a major disaster. In severe cases, it can even endanger the lives of astronauts.
Therefore, the first thing to do is to prevent excessive growth, which is why astronauts eventually pull their nails out.
Fortunately, with the advancement of science and technology, space travelers now have a new way to handle nails, no longer requiring nail trimming, and not as strict as the initial requirements.
Source: Huffpost
