Short Fiction · The Snowbank Orbit (1/3)

The Snowbank Orbit

I

The pole stars of the other planets cluster around Polaris and Octans, but Uranus spins on a snobbishly different axis between Aldebaran and Antares. The Bull is her coronet and the Scorpion her footstool. Dear blowzy old bitch-planet, swollen and pale and cold, mad with your Shakespearean moons, white-mottled as death from Venerean Plague, spinning on your side like a poisoned pregnant cockroach, rolling around the sun like a fat drunken floozie with green hair rolling on the black floor of an infinite barroom, what a sweet last view of the Solar System you are for a cleancut young spaceman⁠ ⁠…

Grunfeld chopped off that train of thought short. He was young and the First Interstellar War had snatched him up and now it was going to pitch him and twenty other Joes out of the System on a fast curve breaking around Uranus⁠—and so what! He shivered to get a little heat and then applied himself to the occulted star he was tracking through Prospero’s bridge telescope. The star was a twentieth planetary diameter into Uranus, the crosslines showed⁠—a glint almost lost in pale green. That meant its light was bulleting 1600 miles deep through the seventh planet’s thick hydrogen atmosphere, unless he were seeing the star on a mirage trajectory⁠—and at least its depth agreed with the time since rim contact.

At 2000 miles he lost it. That should mean 2000 miles plus of hydrogen soup above the methane ocean, an America-wide layer of gaseous gunk for the captain to play the mad hero in with the fleet.

Grunfeld didn’t think the captain wanted to play the mad hero. The captain hadn’t gone space-simple in any obvious way like Croker and Ness. And he wasn’t, like Jackson, a telepathy-racked visionary entranced by the Enemy. Worry and responsibility had turned the captain’s face into a skull which floated in Grunfeld’s imagination when he wasn’t actually seeing it, but the tired eyes deep-sunk in the dark sockets were still cool and perhaps sane. But because of the worry the captain always wanted to have the last bit of fact bearing on the least likely maneuver, and two pieces of evidence were better than one. Grunfeld found the next sizable star due to occult. Five-six minutes to rim contact. He floated back a foot from the telescope, stretching out his thin body in the plane of the ecliptic⁠—strange how he automatically assumed that orientation in free fall! He blinked and blinked, then rested his eyes on the same planet he’d been straining them on.

The pale greenish bulk of Uranus was centered in the big bridge spaceshield against the black velvet dark and bayonet-bright stars, a water-splotched and faded chartreuse tennis ball on the diamond-spiked bed of night. At eight million miles she looked half the width of Luna seen from Earth. Her whitish equatorial bands went from bottom to top, where, Grunfeld knew, they were spinning out of sight at three miles a second⁠—a gelid waterfall that he imagined tugging at him with ghostly green gangrenous fingers and pulling him over into a hydrogen Niagara.

Half as wide as Luna. But in a day she’d overflow the port as they whipped past her on a near miss and in another day she’d be as small as this again, but behind them, sunward, having altered their outward course by some small and as yet unpredictable angle, but no more able to slow Prospero and her sister ships or turn them back at their 100 miles a second than the fleet’s solar jets could operate at this chilly distance from Sol. G’by, fleet. G’by, C.C.Y. spaceman.

Grunfeld looked for the pale planet’s moons. Miranda and Umbriel were too tiny to make disks, but he distinguished Ariel four diameters above the planet and Oberon a dozen below. Spectral sequins. If the fleet were going to get a radio signal from any of them, it would have to be Titania, occulted now by the planet and the noisy natural static of her roiling hydrogen air and seething methane seas⁠—but it had always been only a faint hope that there were survivors from the First Uranus Expedition.

Grunfeld relaxed his neck and let his gaze drift down across the curving star-bordered forward edge of Prospero’s huge mirror and the thin jutting beams of the port lattice arm to the dim red-lit gages below the spaceshield.

Forward Skin Temperature seven degrees Kelvin. Almost low enough for helium to crawl, if you had some helium. Prospero’s insulation, originally designed to hold out solar heat, was doing a fair job in reverse.

Aft (sunward) Skin Temperature 75 degrees Kelvin. Close to that of Uranus’ sunlit face. Check.

Cabin Temperature 43 degrees Fahrenheit. Brr! The Captain was a miser with the chem fuel remaining. And rightly⁠ ⁠… if it were right to drag out life as long as possible in the empty icebox beyond Uranus.

Gravities of Acceleration zero. Many other zeros.

The four telltales for the fleet unblinkingly glowed dimmest blue⁠—one each for Caliban, Snug, Moth, and Starveling, following Prospero in line astern on slave automatic⁠—though for months inertia had done all five ships’ piloting. Once the buttons had been green, but they’d wiped that color off the boards because of the Enemy.

The gages still showed their last maximums. Skin 793 Kelvin, Cabin 144 Fahrenheit, Gravs 3.2. All of them hit almost a year ago, when they’d been ace-ing past the sun. Grunfeld’s gaze edged back to the five bulbous pressure suits, once more rigidly upright in their braced racks, that they’d been wearing during that stretch of acceleration inside the orbit of Mercury. He started. For a moment he’d thought he saw the dark-circled eyes of the captain peering between two of the bulging black suits. Nerves! The captain had to be in his cabin, readying alternate piloting programs for Copperhead.

Suddenly Grunfeld jerked his face back toward the spaceshield⁠—so violently that his body began very slowly to spin in the opposite direction. This time he’d thought he saw the Enemy’s green flashing near the margin of the planet⁠—bright green, viridian, far vivider than that of Uranus herself. He drew himself to the telescope and feverishly studied the area. Nothing at all. Nerves again. If the Enemy were much nearer than a light-minute, Jackson would esp it and give warning. The next star was still three minutes from rim contact. Grunfeld’s mind retreated to the circumstances that had brought Prospero (then only Mercury One) out here.

II

When the First Interstellar War erupted, the pioneer fleets of Earth’s nations had barely pushed their explorations beyond the orbit of Saturn. Except for the vessels of the International Meteor Guard, spaceflight was still a military enterprise of America, Russia, England and the other mega-powers.

During the first months the advantage lay wholly with the slim black cruisers of the Enemy, who had an antigravity which allowed them to hover near planets without going into orbit; and a frightening degree of control over light itself. Indeed, their principal weapon was a tight beam of visible light, a dense photonic stiletto with an effective range of several Jupiter-diameters in vacuum. They also used visible light, in the green band, for communication as men use radio, sometimes broadcasting it and sometimes beaming it loosely in strange abstract pictures that seemed part of their language. Their gravity-immune ships moved by reaction to photonic jets the tightness of which rendered them invisible except near the sun, where they tended to ionize electronically dirty volumes of space. It was probably this effective invisibility, based on light-control, which allowed them to penetrate the Solar System as deep as Earth’s orbit undetected, rather than any power of travel in time or subspace, as was first assumed. Earthmen could only guess at the physical appearance of the Enemy, since no prisoners were taken on either side.

Despite his impressive maneuverability and armament, the Enemy was oddly timid about attacking live planets. He showed no fear of the big gas planets, in fact hovering very close to their turgid surfaces, as if having some way of fueling from them.

Near Terra the first tactic of the black cruisers, after destroying Lunostrovok and Circumluna, was to hover behind the moon, as though sharing its tide-lockedness⁠—a circumstance that led to a sortie by Earth’s Combined Fleet, England and Sweden excepted.

At the wholly disastrous Battle of the Far Side, which was visible in part to naked-eye viewers on Earth, the Combined Fleet was annihilated. No Enemy ship was captured, boarded, or seriously damaged⁠—except for one which, apparently by a fluke, was struck by a fission-headed anti-missile and proceeded after the blast to “burn,” meaning that it suffered a slow and puzzling disintegration, accompanied by a dazzling rainbow display of visible radiation. This was before the “stupidity” of the Enemy with regard to small atomic missiles was noted, or their allergy to certain radio wave bands, and also before Terran telepaths began to claim cloudy contact with Enemy minds.

Following Far Side, the Enemy burst into activity, harrying Terran spacecraft as far as Mercury and Saturn, though still showing great caution in maneuver and making no direct attacks on planets. It was as if a race of heavily armed marine creatures should sink all oceangoing ships or drive them to harbor, but make no assaults beyond the shore line. For a full year Earth, though her groundside and satellite rocketyards were furiously busy, had no vehicle in deep space⁠—with one exception.

At the onset of the War a fleet of five mobile bases of the U.S. Space Force were in Orbit to Mercury, where it was intended they take up satellite positions prior to the prospecting and mineral exploitation of the small sun-blasted planet. These five ships, each with a skeleton five-man crew, were essentially Ross-Smith space stations with a solar drive, assembled in space and intended solely for space-to-space flight inside Earth’s orbit. A huge paraboloid mirror, its diameter four times the length of the ship’s hull, superheated at its focus the hydrogen which was ejected as a plasma at high exhaust velocity. Each ship likewise mounted versatile radio-radar equipment on dual lattice arms and carried as ship’s launch a two-man chemical fuel rocket adaptable as a fusion-headed torpedo.

After Far Side, this “tin can” fleet was ordered to bypass Mercury and, tacking on the sun, shape an orbit for Uranus, chiefly because that remote planet, making its 84-year circuit of Sol, was currently on the opposite side of the sun to the four inner planets and the two nearer gas giants Jupiter and Saturn. In the empty regions of space the relatively defenseless fleet might escape the attention of the Enemy.

However, while still accelerating into the sun for maximum boost, the fleet received information that two Enemy cruisers were in pursuit. The five ships cracked on all possible speed, drawing on the solar drive’s high efficiency near the sun and expending all their hydrogen and most material capable of being vaporized, including some of the light-metal hydrogen storage tanks⁠—like an old steamer burning her cabin furniture and the cabins themselves to win a race. Gradually the curving course that would have taken years to reach the outer planet flattened into a hyperbola that would make the journey in 200 days.

In the asteroid belt the pursuing cruisers turned aside to join in the crucial Battle of the Trojans with Earth’s largely new-built, more heavily and wisely armed Combined Fleet⁠—a battle that proved to be only a prelude to the decisive Battle of Jupiter.

Meanwhile the five-ship fleet sped onward, its solar drive quite useless in this twilight region even if it could have scraped together the needed boilable ejectant mass to slow its flight. Weeks became months. The ships were renamed for the planet they were aimed at. At least the fleet’s trajectory had been truly set.

Almost on collision course it neared Uranus, a mystery-cored ball of frigid gas 32,000 miles wide coasting through space across the fleet’s course at a lazy four miles a second. At this time the fleet was traveling at 100 miles a second. Beyond Uranus lay only the interstellar night, into which the fleet would inevitably vanish⁠ ⁠…

Unless, Grunfeld told himself⁠ ⁠… unless the fleet shed its velocity by ramming the gaseous bulk of Uranus. This idea of atmospheric braking on a grand scale had sounded possible at first suggestion, half a year ago⁠—a little like a man falling off a mountain or from a plane and saving his life by dropping into a great thickness of feathery new-fallen snow.

Supposing her solar jet worked out here and she had the reaction mass, Prospero could have shed her present velocity in five hours, decelerating at a comfortable one G.

But allowing her 12,000 miles of straight-line travel through Uranus’ frigid soupy atmosphere⁠—and that might be dipping very close to the methane seas blanketing the planet’s hypothetical mineral core⁠—Prospero would have two minutes in which to shed her velocity.

Two minutes⁠—at 150 Gs.

Men had stood 40 and 50 Gs for a fractional second.

But for two minutes⁠ ⁠… Grunfeld told himself that the only surer way to die would be to run into a section of the Enemy fleet. According to one calculation the ship’s skin would melt by heat of friction in 90 seconds, despite the low temperature of the abrading atmosphere.

The star Grunfeld had been waiting for touched the hazy rim of Uranus. He drifted back to the eyepiece and began to follow it in as the pale planet’s hydrogen muted its diamond brilliance.