"I can only get about half power from the impulse engines!"

He could only hope there was enough left of the impulse engines to get him in range.

Not enough, he said, to allow starting of the impulse engines.

How much had the impulse engines been able to slow them?

"We still have impulse engines, and I mean to use them."

Looks like they got their impulse engines back on line at the last second.

Running on impulse engines, their craft would not reach Earth for hours yet.

"But at least the impulse engines seem ta be working."

The design for the impulse engine is still giving us problems.

I cannot tell whether it is one impulse engine or two.