Adequate protection for the astronauts means repulsing the very numerous cosmic-ray protons with two billion electron volts (the standard unit of energy used in particle physics).

• 要提供太空人足够的保护，意谓著要推开密密麻麻、能量达20亿电子伏特（粒子物理学的能量标准单位）的宇宙射线质子。