太空是一个与地面完全不同的环境,其重要特征就是微重力和高真空。在地面上,人们无法得到无重力环境,而到了空间飞行器上,尽管重力的影响不会完全消失,但和地面相比就到了可以忽略的程度。由于重力消失了,物理规律可能出现不同的表现,这让人们得以进行许多在地球上无法开展的科学实验,这些实验有着地面实验所无法比拟的价值。 Space is a completely different environment with the ground, its important feature is the microgravity and high vacuum. On the ground, people can not get the environment without gravity, and to the spacecraft, although the impact of gravity will not disappear completely, but compared with the ground to a negligible extent. Due to the disappearance of gravity, physical laws may show different manifestations, allowing people to carry out many scientific experiments that can not be done on Earth. These experiments have the value unmatched by the ground experiments.