"X-21 reporting," he said almost naturally. "We are well past Hawaii and approaching the continent. Altitude...."
He was halfway through when green solid ground with very few clouds lay directly below, and the Rocky Mountains were a little way ahead. He could not quite detect their height, but the pattern of the soil was distinctive. McCauley flipped on his own throat-mike and said:
"I interrupt. Here is the situation. My fuel tanks read...." He snapped off the readings. "I'm going to swing the ship end for end and burn my remaining rocket fuel to kill velocity. Then I'll adopt such skip-stop practices as the situation requires. I doubt it will require them. We were lucky enough to get a nearly circular orbit. In consequence our velocity is lower than if we'd had to make an eccentric one. We saved fuel unexpectedly in getting into space, and I'm going to use it getting out. Over."
He cut off and made his preparations. His figuring was extremely close. But there had necessarily been a slight margin of fuel. A circular orbit does not require nearly the fuel expenditure that an elliptical one does. But McCauley had made the most efficient possible use of fuel at the beginning. He'd used one long blast, a two-second blast, and a one-second rocket thrust to get into nearly a perfect space trail. He meant to collect for that partly accidental expertness. But he meant to collect much more for an observation.
The observation was that a one-second blast was not a thousandth the ordeal that a sixty-second blast was. No man could survive a long-continued twenty-gravity acceleration. But most men could take a one-second push—and not only once, but many times. With time for recovery in between, and a rocket engine that fired infallibly when it was turned on....
He set the rocket timer.
"This," he said over his shoulder, "may be our last chance to exchange compliments, Furness. But I think you're the same kind of idiot as I am. I'd have come on this trip with my insides hanging out rather than stay behind. So would you. Very nearly, you did. It's nice to have known you. I hope we survive."
Steam-jets spouted at the ends of the X-21's rear fins. In emptiness, the ship spun halfway about until the swiftly moving solidity below ceased to move toward the pointed nose. It fled away. The ship traveled backward where there was no air.
"And here we go," said McCauley.
The rocket timer was set. He pressed the blast button. A second later he came out of near-unconsciousness and set it again. There was another rocket blast. He almost recovered from the effect of it before he set the timer for a third.