轨道速度

tā guǐ dào sù dù yī dìng shì zài měi miǎo jǐ bǎi mǐ

它轨道速度一定是在每秒几百米。

Its orbital speed must be a few hundred meters per second.

dì qiú tōng guò tài kōng de guǐ dào sù dù

地球通过太空的轨道速度

the orbital speed of the Earth through space