body who had also been among the first people to receive them on Ganymede?
And that was another point-Hunt had spent a lot of time on Ganyniede, and he still had many close friends among the UNSA personnel there with the Jupiter Four and Jupiter Five missions. Jupiter was a long, long way from the vicinity of Earth, which meant that no receivers anywhere near Earth would ever know anything about a beam aimed toward Jupiter from the fringe of the solar system, whether the beam diverged appreciably or not. And, of course, the J4 and J5 command ships were linked permanently to Earth by laser channels . . . which Caidwell and Naycomms just happened to control. It couldn’t possibly be all just a coincidence, he decided.
Hunt looked up at Caldwell, held his eye for a second, then turned his head to gaze at the two people from Washington. “You want to set up a private wire to Gistar via Jupiter to arrange a landing here, without any more messing around, before the Soviets get around to doing something,” he told them. “And you want to know if I can come up with an idea for telling the people at Jupiter what we want them to do, without the risk of any Thuriens who might be bugging the laser link finding out about it. Is that right?” He turned his eyes back toward Caidwell and inclined his head. “What do I get, Gregg?”
Heller and Pacey exchanged glances that said they were impressed.
“Ten out of ten,” Caldwell told him.
“Nine,” Heller said. Hunt looked at her curiously. There was a hint of laughter in her expression. “If you can come up with something, we’ll need all the help we can get handling whatever comes afterward,” she explained. “The UN might have decided to try going it alone without their Ganymean experts, but the U.S. hasn’t.”
“In other words, welcome to the team,” Norman Pacey completed.
chapter four
Joseph B. Shannon, Mission Director of Jupiter Five, orbiting two thousand miles above the surface of Ganymede, stood in an instrumentation bay near one end of the mile-and-a-quarter-long ship’s command center. He was watching a large mural display screen from behind a knot of spellbound ship’s officers and UNSA scientists. The screen showed an undulating landscape of oranges, yellows, and browns as it lay cringing beneath a black sky made hazy by a steady incandescent drizzle falling from somewhere above, while in the far distance half the skyline was erupting in a boiling column of colors that exploded upward off the top of the picture.
It had been fifty-two years before-the year that Shannon was born-when other scientists at the Jet Propulsion Laboratory in Pasadena had marveled at the first close-ups of lo to be sent back by the Voyager I and II probes, and dubbed the extraordinary disk of mottled orange “the great pizza in the sky.” But Shannon had never heard of any pizza being cooked in the way this one had.
Orbiting through a plasma flux of mean particle energies corresponding to 100,0000 Kelvin sustained by Jupiter’s magnetic field, the satellite acted as an enormous Faraday generator and supported internal circulating currents of five million amperes with a power dissipation of a thousand billion watts. And as much energy again was released inside it as heat from tidal friction, resulting from orbital perturbations induced as Europa and Ganymede lifted lo resonantly up and down through Jupiter’s gravity. This amount of electrically and gravitationally produced heat maintained large reservoirs of molten sulfur and sulfur compounds below the moon’s surface, which eventually penetrated upward through faults to explode into the virtually zero-pressure of the outside. The result was a regular succession of spectacular volcanoes of solidifying sulfur and sulfur-dioxide frost that ejected at
velocities of up to a thousand meters per second, and sometimes reached heights of 300 kilometers or more.
Shannon was looking at a view of one of those volcanoes now, sent back from a probe on b’s surface. It had taken the mission’s engineers and scientists more than a year of back-to-the-drawing-board experiences to devise an instrumentation package and shielding method that would function reliably under Jupiter’s incessant bombardment of radiation, electrons, and ions, and Shannon had felt an obligation to be present in person to observe the results of their eventual success. Far from being the chore he had expected, the occasion had turned out an exhilaration and served as a reminder of how easy it was for supreme commanders of anything to allow themselves to become remote and lose touch with what was happening in the trenches. In future, he thought to himself, he would make a point of keeping more up to date on the progress of the mission’s scientific projects.