To match the protection offered by Earth's atmosphere takes the same one kilogram of shielding material per square centimeter, although astronauts could comfortably make do with 500 grams, which is equivalent to the air mass above an altitude of 5,500 met
To match the protection offered by Earth's atmosphere takes the same one kilogram of shielding material per square centimeter, although astronauts could comfortably make do with 500 grams, which is equivalent to the air mass above an altitude of 5,500 met
要相当于地球大气层所提供的保护，需要每平方公分一公斤重的屏蔽物质，不过500公克（相当于海拔5500公尺处的大气）对太空人已经足适。