Gui Haichao wore glasses on board the Shenzhou spacecraft! What should you pay attention to when wearing glasses in space? Learn more →

At 9:31 am Beijing time on May 30, the launch of the Shenzhou 16 manned spacecraft was a complete success.

Image source: CCTV News

Among the three astronauts on this mission, one is a little special. He is the one on the far left in the picture below. If you look closely, you will find that he is wearing glasses. But don’t astronauts have very high vision requirements? Didn’t the previous astronauts wear glasses?

This matter is actually not that simple. Let me talk to you about it.

01

Can astronauts wear glasses?

Let me first tell you the answer: Yes.

Some friends may wonder why all the astronauts we saw before did not wear glasses? The reason is actually very simple, because all the previous astronauts came from the Chinese People's Liberation Army Astronaut Group, and the members of this group were selected from experienced fighter pilots. To be able to become a fighter pilot, the eyesight is naturally quite good.

The bespectacled astronaut who is about to go into space to carry out the mission is named Gui Haichao. He is a payload expert for this mission, not a space pilot. His mission is to perform scientific research tasks in space, not to fly a spacecraft, so the vision standards are more relaxed.

So the question is, if the astronauts' eyesight deteriorates and they need to wear glasses, can they still perform their missions?

Since training astronauts is a long and difficult process, and accumulating experience in space missions is not easy, many senior astronauts can still be active in space missions even if their eyesight is not as good as before due to their age. For example, Chinese astronaut Zhai Zhigang once wore reading glasses to perform missions. In many videos of foreign astronauts, we can often see people wearing glasses while working.

Since people who wear glasses can go into space, will wearing glasses be different in space? What should people who wear glasses pay attention to?

02

Don't lose your glasses!

We often see in movies and TV shows that when characters wearing glasses think, they often push the frames of their glasses. This is because on Earth, glasses are affected by gravity and usually "hang" on people's faces through the temples and nose pads.

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In the microgravity environment of space, glasses can only be "clamped" to the head and fixed by friction. Although in theory, the design of swimming goggles/sports glasses is more secure, we can see from a lot of video materials that many foreign astronauts wear ordinary frame glasses, so it seems that they don't need to be very tight to wear glasses. In addition, when we sleep, we can safely put our glasses on the bedside table. If we don't fix our glasses before going to bed in space, they are likely to float away when we wake up...

However, this microgravity environment also brings benefits, because the glasses will no longer press on the bridge of the nose!

03

Don't break your glasses!

We know that when a rocket is launched and the return capsule re-enters the atmosphere, there will be violent vibrations. In this case, glasses may become a hidden danger - if the glasses fall and bump, the lenses will break and fly everywhere, which may injure the equipment and astronauts. When we usually take a plane and make an emergency landing, we are advised to take off our glasses. Based on this, it is reasonable to infer that at least during the launch and re-entry phases, astronauts should not wear frame glasses.

Judging from the live footage of the launch, no one was wearing frame glasses.

04

Don't drop your glasses!

If your glasses fall off on Earth, just pick them up and put them on. In some space missions, the consequences of glasses falling off can be serious. For example, when astronauts are fully armed and walking outside the cabin, if their glasses accidentally fall off, they cannot reach them because of the helmet. The glasses will float around in the helmet, which is not only a safety hazard but also blocks the vision. For similar reasons, a small sponge is often designed in the helmet of the space suit used for extravehicular activities. The purpose is to rub the itchy part of the face without having to scratch it with hands (which can't be scratched).

05

Can I wear contact lenses?

Since traditional frame glasses are a bit troublesome in space, can contact lenses be used? The answer is yes, as Canadian astronaut Marc Garneau once confirmed in an interview. However, in order to make contact lenses more comfortable to wear, a little "black technology" may be needed. This is because in a microgravity environment, the performance of gases and liquids is different from that on Earth. For example, tears cannot flow down smoothly, which may affect the cleanliness and hygiene of contact lenses. Therefore, some manufacturers have cooperated with aerospace agencies to conduct some experiments in space and developed contact lenses that are more suitable for use in the microgravity environment of space.

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Finally, let me summarize. As the saying goes, everything is difficult at the beginning. Our previous generations of astronauts undertook the arduous mission of exploring the path of China's manned space program. They used their fearless courage and hard training to achieve success and experience in mission after mission. Due to the high risk of the mission, these astronauts were selected from the best and the strongest. It is precisely because of their efforts that manned space technology continues to mature. I believe that in the near future, when recruiting astronauts, not only vision, but also various other standards will be appropriately relaxed, and more ordinary people will have the opportunity to enter space to perform missions.

Author: Qu Jiong popular science author; Ding Zong popular science author

Review｜Liu Yong, Researcher at the National Space Science Center, Chinese Academy of Sciences

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