Chapter 6: Drop-Tank
Karl's alarm chirped at 0400 ship-time—four hours before the planned ignition window. He woke already moving, muscles remembering the work before his mind caught up. The cockpit smelled of warm electronics and the faint ozone tang that meant the reactor had been cycling hard overnight. He checked the board: core temp 810 K, field variance one percent, batteries ninety-seven percent. The new brick from the derelict was sipping its final amps, indicator blinking green. Good. Today he would ask the ship to give up a limb, and he wanted her healthy for the surgery.
He drank a third of a liter, ate half a brick, and floated aft. The port-side thruster pod hung at the end of a dog-leg corridor, a bulbous cylinder mounted on trunnions like a cannon slung under an ancient warship. Mass estimate: 220 kilograms dry, forty kilos of residual cryo-propellant locked in dead pipes. Total sacrifice: 260 kilos plus mounting struts. Enough to buy the missing 230 m/s if he could coax the pod to burn without exploding.
First step was isolation. He closed every valve feeding the pod, tagged them with red wire, and vented the local manifold to space. Frost bloomed across the pipe joints, crackling like breaking glass. He waited until the gauge read vacuum, then cracked the collar bolts with a socket wrench extended to two meters for leverage. Each turn squealed, metal protesting after decades of thermal cycling. When the last bolt spun free he hooked a chain fall from the overhead beam and ratcheted until the pod sagged against its flex-lines. The lines held, but he heard the high-pitched ping of stressed alloy—warning music he had learned to respect.
He powered the portable plasma cutter, lowered his visor, and began severing the hard-lines. Sparks floated in slow motion, cooling into silver beads that drifted like tiny planets. Cut by cut the pod came loose, until only the main feed umbilical remained—a braided hose thick as his wrist, armored against micrometeor swarms. He hesitated. Severing that line would starve the pod of pressurant, but it would also remove the last path for back-flow fire. He sliced halfway, paused to let residual gas bleed, then finished the cut. The hose whipped once, vented a ghost of vapor, and went still.
Now came the delicate part: turning a static thruster into a drop-tank. Karl had spent the night sketching on the nav screen. Concept was simple—bridge the pod's inlet to Folly's main tank with a temporary flex-hose, use the pod's own pintle valve as the burn nozzle, jettison when tanks equalized. Execution would be plumbing gymnastics in vacuum while wearing mittens. He floated to stores, pulled a three-meter section of high-pressure flex-hose rated for cryogens, and clamped it to the main feed. The other end he mated to the pod's inlet flange, torqueing each bolt twice, then once more for the fear factor. He wrapped the joint with molecular epoxy tape—Rios's gift—and cured it with a quick pass from the heat gun. The tape smoked, bonded, hardened. No leak detected when he cracked the valve a quarter turn. So far so good.
Next he needed control. The pod's original igniter circuit was dead—micro-fractures in the control board, traces blackened by arc-over. He could hot-wire it, but that meant running a copper strand two hundred meters back to the cockpit, more weight, more fail points. Better to build a local trigger: a mechanical timer bolted to the valve stem, set to open after a pre-programmed delta-v. He scavenged an old spring actuator from the damaged coffee machine—ironic sacrifice—and welded it to the pintle. The actuator could hold torque for twenty minutes before relaxing, enough time for him to retreat inside, strap down, and ignite main thrust. Crude, but crude had kept him alive before.
He tested the assembly three times, dry-cycling the valve with gloved fingers until the motion felt smooth. Then he pressurized the line from the main tank, slowly, listening for the high whine of escaping gas. None came. The flex-hose held, joints sweating frost but intact. He allowed himself one deep breath, fogging the visor, then cleared it with a wipe. One more task: attach the jettison charge. He pulled a shaped cutting strip from the emergency kit—thin sheet explosive used to free jammed hatches—and wrapped it around the forward trunnion. A single signal from the cockpit would fire the strip, sever the strut, and kick the pod away with spring pushers. If the timing failed he would ride the drop-tank all the way to empty and lose the delta-v margin. No second chances.
When the last bolt was tight he floated back and surveyed the work. The pod now hung beneath Folly like an iron parasite, hose curved in a graceful arc, epoxy seams glinting silver. Ugly, fragile, perfect. He took photographs for the log, then cycled inside, stripped the suit, and ran a full systems check. Reactor steady, batteries full, fuel gauge reading thirty-eight percent—exactly where he needed it. He plotted the burn sequence: ten minutes of low-thrust warm-up, twenty minutes at eighty percent mix, jettison at plus thirty, final flip and brake at day twenty-four. Numbers aligned within two meters per second of target. Close enough for jazz.
He strapped into the pilot chair, keyed the intercom though no one answered, and spoke the ritual words. "All hands, prepare for main engine burn. Drop-tank ignition in T-minus sixty minutes. Secure loose items. Seal helmets. This is your captain speaking." His voice cracked on the last syllable, emotion catching him off guard. He cleared his throat, wiped his eyes with the back of a glove, and began the count.
While the timer ticked he ran final checks: attitude thrusters primed, gyro bias set, nav solution locked, jettison charge armed. He powered the inertial logger so future him—if future him existed—could review performance and learn. Then he dimmed the lights to five percent, letting the ship settle into pre-burn hush. The only sounds were reactor hum, pump tick, and his own heartbeat counting down the seconds.
At T-minus five he donned the helmet but left the visor up. At T-minus two he rested a gloved finger on the hot-fire switch. At zero he pressed it and felt the ship sigh. A low rumble vibrated up through the deck as the drop-tank valve cracked open. Thrust built slowly—0.02 g, 0.03 g—until the couch pressed against his spine with gentle insistence. The flex-hose stiffened, frost streaming off its surface like comet tail. On the monitor the acceleration curve climbed and held steady at 0.08 g, exactly the number he had dreamed of in the dark.
Karl watched the fuel gauge. Both needles—main tank and pod—began falling in perfect synchronization, a ballet of depletion. He whispered, "Drain together, die together," and kept his hand near the jettison switch. Twenty minutes became fifteen, became ten. Velocity counter ticked upward: plus 50 m/s, plus 100, plus 150. At plus 180 the pod tank reached ten percent. He counted to five, then pressed the fire button.
A muffled pop vibrated through the hull. The cutting strip sheared the forward trunnion; spring pushers kicked the pod away. Acceleration dropped from 0.08 g to 0.05 g as the hose snapped free and sealed automatically. Karl watched the pod tumble into the black, a lonely cylinder venting the last of its cryo, sunlight glinting off its skin like a farewell wink. When it vanished from scope he keyed the log. "Drop-tank jettison complete. Delta-v delivered: 228 m/s. Margin: plus two. Pod, you were a good limb. Rest easy."
He throttled back to whisper mode, let the ship coast, and ran the new plot. Haven-3 now lay twenty-four days away at current trajectory, with four days of braking reserve. Food sufficient, water sufficient, filters plentiful. Reactor steady, batteries climbing. For the first time since the explosion the numbers formed a bridge instead of a wall. Karl unstrapped, floated to the observation blister, and pressed his helmet to the glass. Ahead lay black ocean and a yard that might be salvation or slaughter. Behind him a sacrificed thruster pod tumbled forever, carrying its debt into the dark.
He whispered into the void, voice steady, almost a shout. "Debt paid in velocity. Course locked. Haven-3, make ready. Hasser's Folly is coming." Then he pushed back to the cockpit, strapped in, and began the long coast toward whatever waited beyond the next star's shoulder.