In her hotel room, Sparta broke the commlink and keyed the camp’s airstrip dispatcher on an open channel. With her other hand she was dragging her clothes from the closet and throwing them on the bed.
The Space Board lieutenant did not look happy to hear from her. “Affirmative. The bartender confirms that there was a man matching the description you gave us–red-haired, of small stature, expensively dressed–in the Phoenix Lounge on the night of the murders. But he wasn’t registered at the hotel or anywhere else that we can determine. No one remembers seeing him before that, and no one’s seen him since.”
“We and the local patrol have had people at the shuttleport and the truck terminals ever since the murders, Inspector, as I explained before. There’s been a satellite alert on unscheduled traffic from the surface. Nothing’s left the planet, and nothing’s left Mars Station, since yesterday afternoon.” Polanyi caught himself. “One exception . . .”
“They had a premature main engine cutoff during launch. They indicate MECO was due to a computer glitch and they can probably handle it on board. The only thing they have to worry about is bumping Phobos.”
For an invisibly brief fraction of a second Sparta’s face became a neutral mask. The thing that was tugging at her memory sprang into consciousness–a remark made by Captain Walsh on the Space Board cutter that had carried her and Blake to Mars Station:
“. . . We could have dumped him on Phobos, picked him off on the next orbit. . . . I just thought of it this minute. Phobos looks pretty good on this approach. . . .”
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.
“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.”
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.”
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 intruments.
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 toomuch-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 eject 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.