ballast

This means that teams with KERS have less ballast to move around the car and hence have less freedom to vary their car’s weight distribution.

这就是说使用KERS的车队使用了更少的压舱物来移动赛车，因此有较少的自由来改变他们的车的重量分配。

But small satellites, including shoebox-sized “cubesats”, are often used in place of the ballast carried by rockets to improve their weight distribution.

不过小型卫星（包括鞋盒大小的“立方体卫星”），常用来代替火箭携带的压舱物，以改善其重量分布。