Arthur C Clarke's Venus Prime Omnibus

by Paul Preuss

  17

  The surface of the moon Phobos is hereby declared restricted, by authority of the Board of Space Control. Unauthorized parties landing on Phobos are subject to arrest.

  The announcement repeated itself automatically on the navigation advisory channel, a channel automatically monitored by every spacecraft in Mars space.

  It alternated with a second message: Mars Cricket to Mars Station unit, Board of Space Control: officer requires immediate assistance at Phobos Base. Code Yellow.

  The commander of the Doradus arrived on the bridge less than a minute after the first reception. He settled into the command couch behind the pilot and engineer, smoothing his thick gray hair along the sides of his patrician head. He had an air of distinction unusual for the captain of a space freighter, and his freshly scrubbed crew in their crisp white uniforms more nearly resembled the crew of a private yacht.

  The commander listened to the transmission. “You’ve jammed it, of course?”

  “Yes, sir. We instituted electronic countermeasures after the first transmission. We believe we successfully intercepted at least the second part of the transmission, the request for assistance. We have sent an ECM missile to substitute for the originating vessel’s transponder codes.”

  “Won’t they detect the missile?”

  “We don’t believe the originating vessel has the equipment to detect ECM.”

  “Who is the originating vessel?”

  “The Mars Cricket is a planetary shuttle, sir.”

  “Any response from Mars Station?”

  “No indication they received the message, sir.”

  “The shuttle’s trajectory?”

  “It is now closing on Phobos. Computer tracks its trajectory back to Labyrinth City.”

  “It came up from Mars.”

  “Yes sir. Doppler indicates that on its present course it will rendezvous with Phobos in approximately thirty minutes.”

  “Our estimated arrival time?”

  “Sir, we have been following our original flight plan. Our unpowered elliptical orbit—”

  “Yes, yes—”

  “—puts our near approach to Phobos in just under two hours.”

  “Abandon the plan. Proceed on a powered trajectory to Phobos rendezvous. If pressed by traffic control, reply that we thought we’d fixed our engine problems but were wrong. What’s the best estimate?”

  The pilot tapped briefly at the mounded keyboard of the navigational computer. The display was instantaneous. “With continuous acceleration and deceleration, forty-nine minutes to orbit—matching and rendezvous, sir.”

  “Execute the program.”

  “Yes sir.” The pilot hit the acceleration warning siren. Below the flight deck the other crewmembers scrambled for their couches.

  “As soon as ignition sequence is completed, I want you to retract the camouflage cowling.”

  “Yes, sir.”

  “Fire control is to arm two torpedoes.”

  Sparta was alone in the commandeered shuttle, calculating her own high-energy flight path directly from the instrument readings faster than the ship’s computers could do it for her. Through the shuttle’s narrow quartz windows she could already see the cratered black rock that was Phobos.

  Equally demanding of her attention was the blip of Doradus, bright on her navigation flatscreen, although in line of sight from Sparta’s point of view the freighter itself was still below the horizon of Mars. Mars Station had just sunk below the opposite horizon, but navigation satellites kept watch on Mars space and every object in it and automatically relayed positional data to all ships through Mars Station traffic control.

  To accomplish this, traffic control needed cooperation in the form of transponder beams—or without such cooperation, traffic control needed a target big enough for radar to see. The Mars Cricket and the freighter Doradus were too big to escape detection even without transponders.

  But Sparta knew that an object had landed on Phobos two weeks ago which had escaped detection. Penetrators weren’t big enough to be seen on wide-field radar, and they announced themselves only if they were programmed to do so.

  A penetrator—more formally, a solid-fuel penetrometer rocket—was meant to be fired from an orbiter or a marsplane into Mars, not out into space. Only a tiny portion of the dry planet had actually been visited by humans. In the huge remaining expanse the penetrometers served as remote sensing stations for regions not yet entered by explorers on the ground.

  The armored, arrowhead-shaped payload sections of the rockets were built to withstand the shock of driving deep into solid rock without destroying the sturdy instruments contained within them. The tail sections, equipped with wide fins like an arrow’s feathers, broke off when the heads slammed into the rock; the tail stayed on the surface, paying out a cable as the head dove into the ground and deploying a radio antenna to send telemetry to remote receivers. The transmitter conveyed seismic and geological data from the buried instruments.

  Rip the scientific instruments out of a penetrator and you had a cavity big enough to contain the Martian plaque. Fire the penetrator straight up, and you had enough energy to reach the orbit of Phobos.

  The friable carbonaceous stuff on that moon, struck head on, would have eagerly swallowed the rocket’s head. Program the tail section to send a coded signal, and you could locate your buried treasure at leisure.

  The Martian plaque had been sent off Mars the same night it was stolen. No radar, no navigational computer had even noticed its passing. The plaque had been waiting on Phobos for Doradus to pick it up ever since.

  Doradus had waited until Mars Station and Phobos, in their close but not matching orbits around Mars, had traveled almost to opposite sides of the planet. When at last the two bodies had glided into the right relative positions, a convenient engine failure upon launch allowed Doradus to drift in leisurely and quite innocent fashion to a near rendezvous with the little moon.

  No one would have noticed when a landing party left Doradus for a quick visit to the surface of Phobos. No one would have been suspicious when, soon after the party had returned to the ship, the freighter’s engine-control problem had been corrected and she blasted for the asteroids.

  Sparta reached to the command console of the Mars Cricket and hit switches. The shuttle’s maneuvering system rockets ignited like mortars. Through the windows, the stars wheeled as the winged craft rotated on its yaw axis. Another burst of mortar fire and the stars stopped turning.

  She punched the main engine triggers and shoved slowly on the throttles. In seconds Sparta’s weight went from nothing to six times normal, crushing her into the acceleration couch. The Mars Cricket was standing on its tail, rapidly decelerating to match orbits with Phobos.

  A few minutes now and she would be leaving the craft empty in space. She had received no acknowledgment of her call to Mars Station for assistance. She recalled Blake’s complaint about his too-much-used cover and wondered whether he was really the victim of incompetence. Had he been betrayed? She knew from experience that the Free Spirit could penetrate any government agency they wished to.

  She was not seriously concerned for her own safety, though; her loud and repeated public declaration, designating Phobos a restricted area and announcing a Space Board presence on the little moon, should deter Doradus. She had only to land on Phobos first and begin her search for the plaque.

  She would have seized Doradus and placed its crew in detention if she’d had a scrap of evidence. But she had only informed intuition. The Space Board could place Doradus under permanent surveillance later.

  The thing was to locate the plaque. Sparta had no doubt that if the crew of Doradus succeeded in getting to the plaque first, the precious object would be too well hidden by the time the freighter reached its Mainbelt destination for even the most thorough customs inspection to discover it.

  Worse, if the crew of the Doradus were resigned to losing the plaque forever, once under acceleration they might simply ejec
t it on a random trajectory that sooner or later would carry it into interstellar space.

  The roar of the Mars Cricket’s main engines was suddenly silenced, leaving her ears ringing. Outside the quartz windows the surface of Phobos had blacked out every star, filling the field of view. She entered station-keeping instructions into the computer, unstrapped, and climbed down into the crew airlock.

  Inside the cramped lock she sealed her helmet and pulled the hatch shut behind her, twisting its wheel to seal it. Warning lights shifted from green to yellow. She hit the buttons and pumps began to suck the air out of the lock.

  Her suit was the high-pressure kind, with mechanical joints that didn’t stiffen under atmospheric air pressure; it was made for emergency work in deep space when there was no time for the long prebreathing period needed to purge nitrogen from the bloodstream. Her compressed air tanks were full; her suit gauges showed she could survive on the surface of Phobos for six hours. Her backpack maneuvering unit was fully charged with gas.

  On the wall of the lock there was a bag of fine mesh, containing emergency tools: recoilless wrenches, tape, adhesive patches, gel sealant, wires, connectors, a laser welder with a charged power pack. She unclipped the tool kit and waited for the pumps to stop.

  The red warning sign came on: DANGER, VACUUM. She lifted the safety lock from the wheel of the outer hatch, twisted it, and pushed the thick round door outward. Half a kilometer below was a black sea of dust and craters. She got her boots on the lip of the hatch and pushed off gently. When she was well free of the Mars Cricket she used the suit’s maneuvering jets to descend slowly toward Phobos.

  She moved cautiously across the narrow strait of vacuum, listening over her short-range suitcomm as the Mars Cricket continued to broadcast her automated navigation warning and her call for help to all the vessels and satellites in near space. The shuttle was her commlink to Mars Station; as long as it was in her line of sight, it could relay her suitcomm channel to the satellites orbiting Mars.

  Why hadn’t Mars Station responded to her “officer needs assistance” message? She was beginning to wonder how much good the commlink through the shuttle would do her, if she needed it.

  Sparta’s boots touched down gently on the dusty surface of Phobos; she could feel the crunch of the meteorite-blasted dirt through her toes. Head up, she checked her position. The only light was the ocher radiance of Mars, looming above the nearby horizon, filling a third of the sky; the sun was below the horizon. But marslight was quite sufficient for her purposes, and she could see very well. She stood in the center of an irregular plain about two kilometers across, surrounded by groups of low hills over which she could leap rather easily if she wished. The hills were, in fact, crater rims. The highest of them, silhouetted against Mars, was the rim of Stickney, where the structures of Phobos Base stood more perfectly preserved than the graves of lost explorers in the Arctic ice.

  She moved off toward the base and found her first step taking her high into vacuum. She remembered hearing a story long ago about a man who had accidentally jumped off Phobos. That wasn’t really possible—though it would have been on Deimos—as the escape velocity here was still faster than a person in a spacesuit could run. But unless she was careful she might easily find herself at such a height that it would take hours to fall back to the surface unaided, a risk she could not afford to take. She had a limited amount of maneuvering gas, and she intended to conserve it. Until reinforcements arrived she had to consider the possibility that Doradus had defied her warning. She had no intention of exposing herself in space.

  With three long bounds Sparta quickly gained the heights of Stickney’s rim. She stabilized herself on the edge of the deep crater and turned to look up at the Mars Cricket hanging upside down in space, its stubby white wings gleaming in marslight against the powdered-sugar stars.

  As she looked, a streak of light bisected the black sky and touched the shuttle. Instantly a ball of radiance burst so brightly that Sparta barely had time to hurl herself backward over Stickney’s rim. The autopolarizers in her faceplate saved her eyes, but debris from the blast riddled the landscape. Chunks of metal bounced off the rim where she had been standing; at well over escape velocity they rushed on into space.

  At ground zero under the Mars Cricket, she would have been torn to pieces. This time her good luck was only that.

  The crew of Doradus were too disciplined to cheer unless the commander indicated that cheering was in order; nevertheless, murmurs of enthusiasm were heard on the bridge.

  When the fire control officer confirmed that the Mars Cricket had been destroyed, the commander maintained a demeanor of judicious calm. With luck, the meddlesome Space Board officer had still been aboard.

  Unfortunately, he could not count on it.

  Communications had no indication that Mars Station traffic control had detected the firing of the torpedo. The satellites surrounding Mars had not been designed for weapons detection or electronic warfare. But the commander could not count on that either.

  Phony signals from an ECM drone were intended to persuade traffic control that the shuttle still existed; the decoy had followed the lethal torpedo toward the doomed shuttle and had begun broadcasting imitation Mars Cricket transponder code and a characteristic radar signature as it looped slowly away from Phobos. How long could it be before someone decided to question the odd trajectory of the commandeered shuttle? What had the Space Board officer who’d commandeered it already said to the people on the ground? These were exceedingly worrisome questions.

  Behind his patrician mask, the commander of the Doradus was a frightened man.

  From the moment he’d first heard the order restricting landing on Phobos, he’d had to resist a powerful temptation to obey it. The warning made no mention of the Martian plaque; why should he risk discovery of his ship? It would have been simple enough to stick to the cover story of engine failure, return to Mars Station for “repairs,” and wait for another day to retrieve the plaque.

  For Doradus was not what she seemed. She had the lines of a typical atomic freighter, with forward crew module and cargo holds separated from the aft fuel tanks and engines by a long central boom, but these clumsy lines disguised her true power. Her big fuel tanks were segmented, carrying fuel for two separate propulsion systems: her atomic engines were supplemented by a fusion torch comparable to those which powered the Space Board’s sleek cutters. Hidden in her cargo holds there were not only ECM drones and EW decoys, but ultravelocity torpedoes and slow SADs, search-and-destroy missiles.

  It was not for this simple mission to Phobos that the clumsy-looking Doradus had been secretly armed with enough weapons and electronics to destroy a Space Board cutter or an entire space station, and the commander could plausibly argue to those who had equipped him and sent him here that the risk of jeopardizing that later, greater mission was too great.

  But the commander knew what the navigation warning really meant. The Space Board investigator—her name was Troy, he’d been given a file on her—had certainly deduced the truth.

  Far worse than to reveal the secrets of Doradus, far worse than to fall into the hands of the Space Board, would be to fall into the hands of his colleagues … if he failed to use every means at his disposal to recover the Martian plaque. No artifact in the solar system was more precious to the prophetae or more nearly an object of their worship.

  Doradus would be an invincible devourer of armed cutters and space stations when the millenarian day arrived, but how well would the formidable ship do against one woman on a rock? Of all the machines of transport ever invented, a space freighter was surely the least maneuverable.

  Doradus could descend right down to the crater rims, search the surface of Phobos with optical and infrared sensors and radar, and eradicate anything that moved. But this Troy person could make half a dozen circuits of the little world while the crew was persuading Doradus to make one.

  A spaceship accelerates along its major axis, and any significant d
eviation from a straight course demands turning the ship, using the attitude-control jets or, in an emergency, the backup gyros, so that the main engines can blast in a different direction. A typical freighter like the one Doradus pretended to be has a mass of several thousand tonnes, which does not make for rapid footwork. Moreover, so far as maneuverability is concerned, it isn’t the mass but the moment of inertia that matters most, and since a freighter is a long, thin object, shaped like a dumbbell, its moment of inertia is colossal.

  In any event a freighter’s main engine is far too powerful for fine maneuvers; for minor orbital translations—such as spiraling around an asteroid or small moon—the small rockets of the maneuvering system are used. But to translate Doradus through even a few degrees of arc on maneuvering rockets alone took several minutes.

  In the ordinary way these disadvantages are not grave—certainly not for a freighter which expects to have cooperation from the object with which it seeks to rendezvous. Nor for a disguised warship which intends to sneak up on its foes or, failing that, to destroy them from thousands of kilometers away, as Doradus had just destroyed the Mars Cricket.

  But for the target to move in circles of ten kilometers radius was definitely against the rules, and the commander of the Doradus felt aggrieved. Troy was down there, he felt it in his bones. And she was not playing fair.

  18

  Outside on the raw strip at the pipeline head, the Kestrel was ready for launch. In the morning light vaporous wisps of orange writhed over the surface of its booster tanks.

  Inside the ops room of the makeshift landing strip, Blake shook hands with Khalid. “Soon as you get back we’ll hold a reunion,” Blake said, then lowered his voice. “I can’t give you the details, but I can tell you this: Ellen has solved the case.”

  “Then you may not be long on Mars, my friend.”

  “I promise I won’t let her leave before you get back, no matter what comes up.”