We may be able to pick up an ion trail, then.

The human ships following the ion trail were now far beyond any friendly system.

She didn't quite recall having asked for a spectrographic analysis of the ion trail.

Paris followed the ion trail more closely than he seemed to be following the conversation.

"So why is it a problem if our ion trail was disrupted?"

No, but we have been able to trace its ion trail until it left the system.

An ion trail meant that a ship had been there.

Almost immediately, he added, "I've got a huge ion trail in the lower atmosphere."

"Then we will have to rely on our ability to identify and track their ion trail."

"I have isolated another ion trail," he told the captain.