The giant ships that would fly on the fifth manned mission to Jupiter had been under construction in Lunar orbit for over a year. Besides the command ship, six freighters, each capable of carrying thirty thousand tons, gradually took shape high above the surface of the Moon. During the final two months before departure, the floating jumble of machinery, materials, containers, vehicles, tanks, crates, drums, and a thousand other items of assorted engineering that hung around the ships like Christmas tree ornaments were slowly absorbed inside. The Vega surface shuttles, deep space cruisers, and other craft also destined for the mission began moving in to join their respective mother ships. At intervals throughout the last week, the freighters lifted out of Lunar orbit and set course for Jupiter. By the time its passengers and final crew complement were being ferried up from the Lunar surface, only the command ship was left, hanging alone in the void. As H-hour approached, its gaggle of attendant service craft and satellites withdrew, and a flock of escorts converged to stand a few miles off, cameras transmitting live via Luna to the World Grid.
As the final minutes ticked by, a million screens showed the mile-and-quarter-long shape drifting almost imperceptibly against the background of stars, its serenity seeming to forewarn somehow of the awesome power waiting to be unleashed. Exactly on schedule, the flight-control computers completed their final countdown checkout, obtained "Go" acknowledgment from ground control, and activated the main thermonuclear drives in a flash clearly visible from Earth.
The Jupiter Five mission was under way.
For the next fifteen minutes the ship gained speed and altitude through successively higher orbits. Then, shrugging off the restraining pull of Luna with effortless ease, Jupiter Five soared out and away to begin overhauling and marshaling together its flock of freighters, by this time strung out across a million miles of space. After a while the escorts turned back toward Luna, while news screens on Earth showed a steadily diminishing point of light being tracked by the orbiting telescopes. Soon even that vanished, and only the long-range radars and laser links were left to continue their electronic exchanges across the widening gulf.
Aboard the command ship, Hunt and the other UNSA scientists watched on the wall screen in mess twenty-four as Luna contracted into a full disk partly eclipsing that of Earth beyond. In the days that followed, the two globes waned and fused into a single blob of brilliance standing out in the heavens to signpost the way they had come. As days turned into weeks, even this shrank to become just another grain of dust among millions, until, after about a month, they could pick it out only with difficulty.
Hunt found that it took time to adjust to the idea of living as part of a tiny, man-made world, with the cosmos stretching away to infinity on every side and the distance between them and everything that was familiar increasing at more than ten miles every second. Now they depended for survival utterly on the skills of those who had designed and built the ship. The green hills and blue skies of Earth were no longer factors of survival and seemed to shed some of their tangible attributes, almost like the aftermath of a dream that had seemed real. Hunt came to think of reality as a relative quantity-not something that can be left for a while and returned to. The ship became the only reality; the things left behind ceased, temporarily, to exist.
He spent hours in the viewing domes along the outer hull, slowly coming to terms with the new dimension being added to his existence, gazing out at the only thing left that was familiar: the Sun. He found reassurance in the Sun's eternal presence, with its limitless flood of life-giving warmth and light. He thought of the first sailors, who had never ventured out of sight of land; they too had needed something familiar to cling to. Before long, men would turn their prows to toward the open gulf and plunge into the voids between the stars-and one day, maybe, even the galaxies. There would be no Sun to reassure them then; the galaxies themselves would become just scattered spots.
What strange new continents, he wondered, were waiting on the other sides of those gulfs.