The Nothing Equation — Tom Godwin

The cruiser vanished back into hyperspace and he was alone in the observation bubble, ten thousand lightyears beyond the galaxy's outermost sun. He looked out the windows at the gigantic sea of emptiness around him and wondered again what the danger had been that had so terrified the men before him.

Of one thing he was already certain; he would find that nothing was waiting outside the bubble to kill him. The first bubble attendant had committed suicide and the second was a mindless maniac on the Earthbound cruiser but it must have been something inside the bubble that had caused it. Or else they had imagined it all.

He wasn't afraid. Oh no, not him. He was the third man on the match, but that didn't scare him, not at all.