At any moment, he would have some action for Earth.

Dad, you've done more for Earth than everyone in the government put together.

That would probably mean even more serious trouble for Earth.

The other changed course at the last moment and headed for Earth.

I don't care if the only way we have of setting course for Earth is having you go outside and push!

I am telling you one last time: set your ship's course for Earth.

Were they trying to build a space elevator for Earth?

And now he's come along with me in this search for Earth, though he must know it's dangerous.

They arrived back in port a couple of days after you left for Earth.

Meanwhile, he wanted the best possible look at whatever was headed for Earth.