At last an answer came back, “White Sands to Spaceship-go ahead.”
“Give us a series of radar checks, time, distance, and bearing.”
A new voice cut in, “White Sands to Spaceship-we have been tracking you, but the figures are not reasonable. What is your destination?”
Traub glanced at Barnes, then answered, “Luna, to White Sands-destination: Moon.”
“Repeat? Repeat?”
“Our destination is the Moon!”.
There was a silence. The same voice replied, “Destination: Moon’ — Good luck, Spaceship .Luna!”
Bowles spoke up suddenly. “Hey! Come look!” He had unstrapped and was floating by the sunward port.
“Later,” Barnes answered. “I need this tracking report first.”
“Well, come look until they call back. This is once in a lifetime.”
Corley joined Bowles. Barnes hesitated; he wanted very badly to see, but he was ashamed to leave Traub working. “Wait,” he called out. “I’ll turn ship and we can all see.”
Mounted at the centerline of the ship was a flywheel. Barnes studied his orientation readings, then clutched the ship to the flywheel. Slowly the ship turned, without affecting its motion along its course. “How’s that?”
“Wrong way!”
“Sorry.” Barnes tried again; the stars marched past in the opposite direction; Earth swung into view. He caught sight of it and almost forgot to check the swing.
Power had cut off a trifle more than eight hundred miles up. The Luna had gone free at seven miles per second; in the last few minutes they had been steadily coasting upwards and were now three thousand miles above Southern California. Below-opposite them, from their viewpoint-was darkness. The seaboard cities stretched across the port likeChristmas lights. East of them, sunrise cut across the Grand Canyon and shone on Lake Mead. Further east the prairies were in daylight, dun and green ‘broken by blinding cloud. The plains dropped away into curved skyline.
So fast were they rising that the picture was moving, shrinking, and the globe drew into itself as a ball. Barnes watched from across the compartment. “Can you see all right, Mannie?” he asked. —
“Yeah,”, answered Traub. “Yeah,” he repeated softly~ “Say, that’s real, isn’t it?”
Barnes said, “Hey, Red, Doc-heads down. You’re not transparent.”
Traub looked at Barnes. “Go ahead, skipper.”
“No, I’ll stick with you.”
“Don’t be a chump. I’ll look later.”
“Well — ” Barnes grinned suddenly. “Thanks, Mannie.” He gave a shove and moved across to the port.
Mannie continued to stare. Later the radio claimed his attention. “White Sands, calling Spaceship-ready with radar report.”
The first reports, plus a further series continued as long as White Sands and Muroc were able to track them, confirmed Barnes’ suspicion. They were tracking “high,” ahead of their predicted positions and at speeds greater than those called for by Hastings’ finicky calculations. The difference was small; on the autopilot displays it was hardly the thickness of a line between the calculated path and the true path.
But the difference would increase.
“Escape speeds” for rockets are very critical Hastings had calculated the classical hundred-hour orbit and the Luna had been aimedjo reach the place where the Moon would be four days later. But initial speed is critical. A difference of less than one percent in ship speed at cutoff can halve-or double-the transit time from Earth to Moon. The Luna was running — very slightly ahead of schedule-but when it reached the orbit of the Moon, the Moon would not be there.
Doctor Corley tugged at his thinning hair. “Sure, the cutoff was mushy, but I-was expecting it and I noted the mass readings. It’s not enough to account for the boost. Here-take a look.”
Corley was hunched at the log desk, a little shelf built wto the space between the acceleration bunks. He was strapped to a stool fixed to the deck in front of it. Barnes floated at his shoulder; he took the calculation and scanned it. “I don’t follow you,” Barnes said presently; “your expended mass is considerably higher than Hastings calculated.”
“You’re looking at the wrong figure,” Corley pointed out. “You forgot the mass of water you used up in that — test. Subtract that from the total mass expended to get the effective figure for blast off-this figure here. Then you apply that — ” Corley hesitated, his expression changed from annoyance to dismay. “Oh, my God!”