Footfall

Space will be colonized-although possibly not by us. If we lose our nerve, there are plenty of other people on this planet. The construction crews may speak Chinese or Russian — Swahili or Portuguese. It does not take “good old American know-how” to build a city in space. The laws of physics work just as well for others as they do for us.

—Robert A. Heinlein

COUNTDOWN: H MINUS TWO DAYS

The meeting was called for 0900, but they were still straggling in at a quarter past. Some had hangovers. All had stayed up too late.

Too bad, Jenny thought. They’ll have to get used to military hours. She had a strong urge to giggle. Suppose they didn’t? Maybe they’d make Cheyenne Mountain adapt to the hours science fiction writers kept…

They took their places in the lecture room, but they tended to sit for a moment, then get up and gather in clumps. Most of them talked at once. Working with the science-fiction people was an educational experience. They had no reverence for anything or anyone, except possibly for Mr. Anson, and they argued with him; they just didn’t call him names.

They’d spent the past days learning about U.S. and Soviet weapons. Now it was time to examine what was known about the aliens.

Not that there’s anything to know. Our best photos don’t show details. Just that it’s damned big.

One of the men, the one with the heavy mustache, began before she could. “Major Crichton, I assume that the government has been no more successful in communicating with the aliens than all the private attempts were?”

“Correct. We’ve tried every means of communication we can think of.”

“And a few no one would have thought of,” Sherry Atkinson added. They all laughed, remembering that the mayor of San Diego had persuaded the citizens of his city to blink their lights on and off while they were in the alien ship’s view.

“With no result,” Jenny said. “Our best prediction is that the alien ship will arrive day after tomorrow. Sometime day after tomorrow. We can’t predict it closer than that, because the ship has begun random acceleration and deceleration.”

“As if it didn’t want us to know the precise ETA,” Curtis said.

“ETA?” Atkinson asked.

“Estimated Time of Arrival” Jenny said. “And yes, we’ve thought of that.”

“It might be their engines aren’t working properly.” Atkinson looked thoughtful. “Or that the concepts of time and regularity don’t mean much to them.”

“Bat puckey,” Curtis said. “If they’re space travelers, they have to have clocks.”

“Doesn’t mean they use them,” someone said.

Jenny spoke through rising voices. “Lieutenant Sherrad will review what we know.” The chatter stopped.

Sherrad was a Regular Navy man hoping for his bad foot to heat so that he could go back to sea. Jenny wasn’t quite sure how he’d been assigned to Colorado Springs, but she did know the Admiral thought well of him. His father had been a classmate.

The Navy seemed to have even more of that sort of thing than the Army. He ran new blowups of films taken by the Mauna Kea telescopes as far back as the late l970s. A few showed a flickering star that must have been the alien ship, although at the time no one had realized it.

Sherrad showed each film in sequence. Then again. He brought the lights up and waited, as if teasing the audience.

“Son of a bitch.”

“What, Joe?”

“It dropped something.”

Sherrad nodded. “It does look that way.”

It took me four hours to see that, Jenny thought. Maybe there is a good reason to have these birds here-.

“Our best guess is that it came from the southern region of the Centaur, dropped something heavy, rounded the sun, and went to Saturn,” Lieutenant Sherrad said. “Decelerating all the way.”

“They knew where they were going, then.”

“Well, Dr. Curtis, it does seem so.”

Jenny nodded approval. Sherrad had memorized the doctorates.

Voices arose from one of the clumps. “Okay, they refueled at Saturn—”

“Why not Jupiter?”

“It takes less delta-V to slow down for Saturn. Jesus, but they must have been going on the last teacup of fuel for that to matter!”

“Jupiter could have been around on the other side—”

“Could we see it again?” Anson asked.

Sherrad waited until they were quiet. “Certainly. We also have the computer simulation.”

The room darkened again.

Black dots speckled a white field: a negative of the night sky. Astronomers generally preferred to use negatives; it was easier to see the spots that were stars. The scene jumped minutely every few seconds. The stars stayed where they were-the photographs had been superimposed-but one dot jumped too, and grew Larger.

“These were taken from Mauna Kea observatory. Notice the point that jumps. When we realized what we had, we made same graphs—”