ultradrive n.

He’s a financier, or something like that. He put up the money to finance Threlkeld’s investigation of the ultra-drive for UN.

He grew aware of the thrum and quiver which meant he was aboard a spaceship running on ultra[-]drive.

A lot of time had rushed past into darkness. Russell had no idea now how long the four of them had been plunging toward the red-rimmed sun that never seemed to get any nearer. When the ultra-drive had gone crazy the four of them had blanked out and nobody could say now how long an interim that had been. Nobody knew what happened to a man who suffered a space-time warping like that.

The ship had only been provisioned to go to Alpha Centauri, scout the system without landing on any of the planets, and return. At ten lights, top speed for the ultradrive, it would take better than three months to get back.

Four hundred years ago, this had been Man’s earliest foothold on the stars—earliest, and, as it developed, only. The passage time had been worked down from ten years to five and a half, toward the end, but that was the best they could do. They were tinkering with an ultradrive just before the Invaders hit Earth. They still were, but it was too late for the Solar System.

The wreck had no ultradrive capability; it was truly a Slow Zone design.

He kicked into ultradrive again and was soon passing close to the next moon in line, several million miles away.