It is said that astronauts have three fears! So what are these three fears?

Astronauts have "three fears". Astronauts are a group of brave people, but after working and living in a distant space station for more than a year, there will be many concerns. Astronauts on the International Space Station have "three fears": one is afraid of fire, the other is afraid of collision, and the third is afraid of lack of oxygen.

The space station is a small enclosed space. Although it has been continuously built and expanded for more than 20 years, the pressurized volume available for survival of the International Space Station is only 9 15.6 cubic meters, which is also filled with a large number of instruments and equipment, and the space available for human activities is very small. 1In February 1997, a fire broke out in the equipment of the Mir space station in the former Soviet Union. It took 14 minutes to put out the fire, and the cabin was full of toxic smoke. Similar hidden dangers are not uncommon in the International Space Station.

Due to the frequent launch of spacecraft into space in recent decades, coupled with space weapon experiments and accidental collisions of satellites, billions of large and small debris wander in low-earth orbit. These fragments are not static, they all revolve around the earth at a speed of more than 7.5 kilometers per second. At the same time, there are countless dust particles in space, some as big as fists and some as thin as needles, but their speeds are all above 1 1 km/s without exception. Once these things collide with the space station head-on, the harm caused is unimaginable.

External impact may lead to pressure loss of the space station, and internal failure may also lead to air leakage. There have also been several air circulation system failures on the International Space Station, which suffocated astronauts.

When an emergency requires evacuation, astronauts need to return to the spacecraft docked with the space station and start emergency procedures to leave the space station and return to the ground. A friend asked, why can't astronauts parachute back directly from the space station?

Where is the limit of skydiving? Since the invention of parachutes, there have been warriors constantly challenging the limits of skydiving, including ultra-low altitude skydiving, ultra-high speed skydiving and ultra-high altitude skydiving.

In 20 14, alan eustace, an American computer scientist in silicon valley, jumped from a helium balloon with a height of 41425m. After four and a half minutes of free fall, he opened his parachute and successfully returned to the ground, setting a record for human skydiving.