宇航员在太空中飞行时,都身穿不漏气的密封服,头戴盔形帽。这套宇宙服对宇航员来说,是非常重要的。我们知道,离地面越高,空气就越少,气压就越低。当高度为10千米时,气压是地面的四分之一,高度为200千米时,气压为地面的六万亿分之一。当气压很低时,人体内的血管会突然破裂。另外在空气稀薄的高空,受阳面和背阴面的温度差异很 Astronauts wearing airtight, uniformed, helmet-shaped caps while flying in space. This cosmic service is very important to astronauts. We know that the higher the ground level, the less air and the lower the barometric pressure. When the altitude is 10 kilometers, the pressure is one quarter of the ground, and the altitude is 200 kilometers, the pressure is one of the six trillionth of the ground. When the pressure is low, the body's blood vessels will suddenly burst. In addition, the thin air at high altitude, the temperature difference between the sun and the shade is very