This is the 8926th most frequent Japanese word.
毎秒
"Every second."
Here, '毎秒' is used to indicate the repetitive frequency of the machine's action per second.
この機械は毎秒100回動きます。
This machine operates 100 times per second.
In this sentence, '毎秒' describes the constant speed of the spacecraft in terms of distance covered per second.
宇宙船は毎秒13キロメートルの速度で移動しています。
The spacecraft is traveling at a speed of 13 kilometers per second.
The use of '毎秒' here expresses the measure of distance the light travels within one second.