II. The Snowball
To say Sensors was a location within the Rhylanor would be a misstatement.
Parts of the sensor system ran through every section of the starship. Retractable booms and antennas sprouted from her outer hull. Her different sensors were scattered throughout the ship: the gravitometer near her center of mass, where the ship itself would interfere least with its delicate workings; her electromagnetic sensors actually painted on the hull in places, using a superconducting polymer. Dense fiber optic conduits wormed their way between the equipment and the main computer, constantly routing information and instructions. But the system itself needed a coordination point; and this is what spacers commonly referred to as Sensors. It was a large room amidships the Rhylanor on her port side.
Captain Moak and General Darrell entered the room and looked around. A sweeping view of Jasmine, the nearly-frozen gas giant, was visible through the viewports that made up one wall of the room. Holodisplays showing the relative positions of the ships in the squadron floated ghostly in the air. Technicians bustled among them, murmuring instructions to the computer into thier comdots. Nobody noticed the Rhylanor's commanding officer and the leader of the squadron's Marines until a petty officer glanced at the door and, startled, shouted "Captain on deck!"
Moak and Darrell strode into the room, quickly acknowledging salutes. "As you were," muttered Dealos. "Where's the OD?"
"Lieutenant Laragii, sir." A young black-haired man in gray coveralls approached and saluted.
"Are you tracking the Snowball, Lieutenant."
"When is it forecast to hit the planet."
"Let me check, sir." The lieutenant punched some numbers into his datalink. "Er, that's strange...it should be impacting right about now, sir."
"Can we get it up on a display?"
"Of course, sir. Burman, put the Snowball up on Holo Four."
"Aye!" Burman, a middle-aged man in worn coveralls, sprang to a console and began adjusting the controls. He seemed nervous...probably all the brass in the room, Moak decided. He vaguely remembered that Burman had been transferred from the Scout Service onto the Rhylanor before she departed for Jasmine. Rank was pretty informal in the Scouts.
"Here we go, sirs," Burman said. "This is where the Snowball should be."
The holodisplay showed a view of Jasmine, but nothing else.
"Backtrack along its last known path," said Laragii.
"Yes, sir." The view in the holodisplay swam vertiginously-the illusion of depth was excellent-before finally resting on a dull gray, heavily cratered lump of rock floating in space. Jasmine was visible directly ahead, but further away now.
They had first started tracking the object a week and a half ago. A large mass had suddenly appeared on the fringe of the squadron's sensors-unusual, for they were far outside a rather uninteresting system. Rhylanor itself was a lump of rock with a thin envelope of atmosphere orbiting a red ember of a sun. Its strategic importance on the main trade routes was what had brought its billions of inhabitants, not its desirability as a place to live.
A boat had been sent out to look at the object, which the crew had nicknamed the Snowball. It was an ordinary ball of frozen gases, with a denser than normal rock core; a fairly common object in the cometary cloud. And it was on a collision course with Jasmine.
The Imperial charts list no gas giant for Rhylanor. But those charts were drawn up for commercial shipping. Far outside the Rhylanor system, beyond where any normal merchant would go, was Jasmine-so small it was barely a gas giant, circling in the empty blackness of space, barely warmer than absolute zero. Even at three gravities, it was almost a two-week trip each way to reach Jasmine from the inner system. It takes a week, no matter how far you travel, to reach another world in hyperspace; merchant ships can't waste two weeks to get to the outer system to refuel by scooping up the hydrogen atmosphere of a gas giant; and even if they had been so inclined, the low temperature of Jasmine would make such operations even more hazardous than normal.
But this was wartime, and siege operations changed everything. Denied even the paltry oceans of Rhylanor as a fuel source, the Zhodani ships were willing to travel two weeks for the opportunity to jump out of the system. Thus, the Rhylanor and its squadron had been dispatched to the frozen gas ball of Jasmine, so far outside the system that it was almost impossible to pick out Rhylanor's dim sun against the background stars.
Moak studied the holodisplay. "There's something not right about that image," he said.
Darrell, who had grown up in an asteroid belt, saw it right away. "There's no ice on that rock."
Burman displayed a spectroscopic analysis next to the image. "You're right, General," he said. "No water line showing."
"None of any of the trace metals the survey team detected, either," said Moak. "How did it lose all that ice? Sublimation?"
"Out here?" said Darrell. "It's far too cold for all that ice to evaporate off. And why isn't it where we expected it?"
"I have that answer," said Burman. "It's now moving slower than it was when we first detected it." He displayed a graph in the holochamber.
"Maybe it passed by another comet, when we weren't tracking it," said Laragii. "We haven't always been able to keep a telescope on it."
"Look at that graph," said Moak. "A comet couldn't cause that kind of drop in velocity. You'd need a planet, or-" He paused. "Did the survey team do a density scan."
"No, Captain, they didn't have a densitometer. We could only spare one of the cutters."
"Where are you getting this image from? One of the System Defense Boats?"
"Yes, sir. The Unicorn. It's, uh, approximately 300,000 kilometers from the Snowball."
Moak pressed the intercom unit on his belt computer. "Bridge," he said.
"Raini, this it the Captain. Order the Unicorn and the-" He studied the tactical holodisplay for a moment. "-and the Enkiddu to close on the Snowball. Order them to have weapons systems ready. And please put the squadron on yellow alert."
Moak turned back to Burman. "Please chart the orbital track of the Snowball," he said.
The view zoomed back and up. Jasmine and the Snowball, exaggerated in size and color, were two marbles coasting against a black background. A graceful purple curve joined them- "Wait a moment, Burman. Run the Snowball back to when we first tracked her. Now, project her orbit from then. Good. Now, run it forward, and correct the orbital track as we go."
Suddenly it was startlingly clear. The purple curve began to change shape, moving, growing longer as the Snowball decelerated and changed direction. "Course corrections. My God," said Darrell. "That thing's moving under its own power." He pressed his intercom button. "Sergeant Kelly, get the Marines into armor and in position."
"Lieutenant, take a neutrino reading," said Moak. "I want to know if they've got a fusion reactor."
"Sorry, Captain, but there's just enough radiation from Jasmine to interfere with our sensors."
"Captain, look!" said Burman.
The image of the Snowball in the display was changing. The rock was breaking up in front of them, chunks of it sliding off into space. "Is it calving?" asked Burman. "Gravity from Jasmine might be breaking it up-"
A white stab of flame burst from the center of the Snowball, pointed directly at Jasmine. "Fusion rocket!" shouted Laragii. "Six gees, at least."
"Get me a new course track!" shouted Moak, already afraid of the answer.
"It's an orbital insertion burn," said Laragii, checking his data link.
From the collapsing rock of the Snowball, several ships now began to emerge, with raked, geometric hulls. Several had the telltale bulging look of fuel tankers. "I have targets," said Laragii, calmly. "A dozen at least."
"Zhodani," muttered Burman.
Darrell was already springing for the door. "Computer, red alert," said Moak. "I need to be on the bridge."
"A lift car is arriving," said the computer's calm voice.
"Order the fleet to close in on those tankers. We've been ambushed."