Oh, nice!
好球
They need to figure out how far
他们要根据
the ball needs to travel depending on where the receiver is.
外接球手的位置判断球应当扔多远
How fast the receiver's running in that direction.
还要考虑外接球手的移动速度
Most quarterbacks don't sit down and calculate that on paper.
四分卫可没时间坐下来拿纸算
Set, go!
准备 开始
It's all done in their head
他们不用多想
instinctively without thinking about it.
而是下意识地做出动作
For spacecraft,
对航天器而言
we do it on paper, or these days, on computers.
我们就得用纸算了 现在是计算机算
The other thing a quarterback does
四分卫还要干的一件事
is put spin on the ball.
就是让球旋转
Spiral so that the ball flies in the correct trajectory.
旋转使球保持正确的飞行轨道
So we also are spinning our spacecraft,
我们同样也会让航天器旋转
so it maintains its attitude...
这样它才能保持姿态
and so that we can point the solar rays back at the Sun
使太阳能板朝向太阳
and communicate back to the Earth.
并与地球保持通讯
And so, the actual rotation of the ball
所以其实橄榄球的旋转
is similar to the rotation of the spacecraft.
和航天器的旋转很相似
They make it sound simple,
听起来很简单
but firing a spacecraft across the solar system
但是让一个航天器在太阳系中穿梭
involves some really complex ballistic calculations.
涉及到极其复杂的弹道学计算

重点解释：

1.figure out 算出；想出

例句：The boy can't figure out the algebra problems.
这个男孩做不出这道代数题。

2.sit down 坐下

例句：Move your stern, I want to sit down.
你把屁股挪一挪，我想坐下。

3.similar to 跟 ... 类似的

例句：A plantain is similar to a banana.
大蕉类似于香蕉。