Three hours from apogee, when Liberty 2,673 would reach the top of its elliptical orbit, flight com told him to start activating the bomb carrier missile.
Ry pulled his head back from the sextant. ‘Roger that, flight com. I’ll pull the manual out.’ The sextant folded back neatly into its storage position. He’d been examining Tree 3,788-D with the device on full magnification. Trees were usually about eleven kilometres long, with little variance: slender spires of crystal with a tip at one end always pointing planetwards, while the other flared out into a broad bulb over a kilometre wide. Their surface was made from deep folds and wrinkles in the crystal, which hosted slow blooms of moire light that slithered along their length in random surges.
Laura Brandt said Captain Cornelius’s ship had estimated up to thirty thousand Trees in the Forest that hung above Bienvenido back in the Void. Nigel Sheldon had destroyed about twenty-four thousand when he set off the quantumbuster in the centre of the Forest – collateral damage to the distortion applied to the fabric of the Void. After the Great Transition, the surviving Trees had dispersed into the Ring, using what Laura said was some kind of gravity-manipulation propulsion, like that of the Skylords, left behind in the Void. Some of them had taken longer than others. The newly formed Space Vigilance Office had catalogued their movements, then started to observe them closely with telescopes and Bienvenido’s newly built radars. They kept a file on every Tree, classifying them into two distinct types: S for standard, and D for damaged.
First-flight astronauts were always assigned to D Trees, as they were usually easier targets. 3,788-D was short, barely nine kilometres long, indicating a good two kilometres had broken off during the quantumbuster blast. Broad sections of it were permanently dark. The Space Vigilance Office had only recorded it releasing seventy-eight Faller eggs in two hundred and fifty years – well below average.
According to the sextant observations, it wasn’t moving. Not yet, anyway, Ry corrected himself. That made the mission so much easier. Trees inevitably moved when the missiles got close.
Ry unlocked the console’s missile section and took the thick manual from its recess. He didn’t really need to; every page was perfectly clear in his memory. But the microphones in the command module were picking up every sound, and transmitting it continually to mission control where tape recorders faithfully documented each cough, knock, and fart he made. If there was no sound of the manual’s pages being turned, someone might get suspicious about just how good his memory was – and why. It was a high level of paranoia, he acknowledged wryly, but with the PSR you could never be sure. And he certainly wasn’t going to take the risk. So the manual was opened with a soft rustling sound, and he started down the checklist.
Prepping the missile took ninety minutes – powering up its systems and loading the inertial guidance system with the data from the command module guidance computator. The missile itself rode above the command module: a cylinder with the same two-and-a-half-metre diameter as the rest of the Liberty. At the front was a radar dish, then the electrical instrument section. Below that was the actual warhead: a fission bomb with a yield of three hundred kilotons, the largest practical size Bienvenido’s bomb factories could make. Propulsion was dual stage, with a hypergolic-fuel rocket for launching it from the command module, and a clustered solid rocket motor stack for final high-velocity delivery. The total mass was two point two tonnes.
‘Missile systems at preflight stage five, and holding steady,’ Ry reported an hour from apogee. The Liberty was close enough now that he could make out the shape of Tree 3,788-D without any magnification. Even the dark areas were visible, slim fissures amid the bright entrancing shimmer.
‘Good to hear that, Ry,’ Anala replied.
It was probably his imagination, but her voice seemed fainter – maybe just the static crackle that came with such a long-distance radio beam.
‘Taking final radar reading of target,’ he said. A muted mechanical clanking reverberated through the command module’s frame as the radar dish scanned round. Nixie numbers shifted and settled, sending a warm orange glow across his face as he floated over to that section of the console. ‘Navigation data locked and transferred. Flight profile confirmed. Requesting final missile sequence initiation.’
‘You have a green light for missile fuel-tank pressurization, Liberty two-six-seven-three.’
Ry went back to the port, where he could see the Tree – noticeably larger now. Radar gave him a separation distance of three hundred and twenty-seven kilometres. He flicked three switches on the missile console, moving them to mid-position. ‘Commencing propellant-tank pressurization.’
‘SVO reports Tree movement,’ Anala said. ‘One per cent gee.’
Ry pulled himself over to the port, and swung the sextant out of its recess. Two readings a minute apart, centring the crosshairs on the bulbous end of 3,788-D. The coordinates were different. Sure enough Tree 3,788-D was on the move, accelerating at just under one per cent of Bienvenido gravity.
He grinned savagely through the port. You can run,’ he told Tree 3,788-D, ‘but you can’t hide.’
Most Trees moved when a Liberty spacecraft approached. That was the thing Ry found most amazing about them. Something so huge being able to move. The Silver Sword had burned two hundred and seventy-five tonnes of propellant in order to lift a six-and-a-half-tonne Liberty into space. Tree 3,788-D was nine kilometres long, and it was accelerating. A small acceleration, true, but he couldn’t even visualize the energy level necessary for such a motor. And some Trees accelerated at up to five per cent gee. Seventeen Liberty astronauts had burned all the fuel in the service module so they could still intercept their fleeing target, completely altering the spacecraft’s orbit and thus throwing away their chance of a successful re-entry. Only one of them – Matej – had ever made it back.
The next twenty minutes were spent calculating the catch-up burn that would change the Liberty’s course to give the missile its highest strike probability. Ry fed the figures flight com gave him into the guidance computator, and fired the service module’s main rocket for sixteen seconds.
The missile’s guidance data had to be reloaded to take the new course into account. Then it was time; the Tree was only seventy-five kilometres away. He entered the bomb arm code on the missile console’s red keyboard, and confirmed three green lights. A final check of missile systems, and he turned the launch key. The Liberty shuddered as the missile detached. Ry saw sparkling gas flowing past the ports, and used the joystick to turn the Liberty, aligning it for the retro burn. He caught sight of the missile through the port, its exhaust flaring wide from the small rocket nozzle at its base, accelerating towards the Tree. Radar confirmed its course was steady.
Ry fired the service module rocket again, retro burning to build distance between him and the impending blast, and putting him back onto his original re-entry trajectory. It was a busy time, requiring two further short burns.
‘Course correction verified,’ Anala told him after the second one. ‘Good burn, Liberty two-six-seven-three.’
‘Thank you, flight com. Appreciate that.’
‘Flight control wants you to put Liberty into shield one orientation.’
‘Roger. Beginning RCS manoeuvre for shield one.’
He reached for the joystick. Basically, shield one was positioning the Liberty so the back of the service module was pointing directly at the Tree, so when the atom bomb went off, the bulk of the spaceship would be between him and the blast, shielding him from the brutal gamma-ray pulse. He cancelled the thermal roll and began to turn the Liberty.
The missile panel buzzed a warning. Ry scanned it quickly, not quite understanding. That particular warning sound was for attitude correction. The numbers in the Nixie tubes were slowly changing, as if he was updating the missile’s guidance computator.
‘Flight com, I have a problem,’ Ry said. He started flicking switches, trying to cancel the error. The numbers kept on changing.
‘S
ay again, please?’ Anala asked.
‘There’s a malfunction in the missile guidance system. Course vectors are changing.’ He growled in frustration as the numbers locked. Nothing he was doing was making any difference.
‘Wait, please. Missile command is analysing your telemetry.’
‘They’re going to have to hurry,’ Ry muttered. He tried to reload the original vector, but it wasn’t registering. An amber light came on at the side of the missile control panel. ‘No, no, no. Don’t do that!’ The light turned green, indicating the missile’s tiny RCS nozzles were belching out cold gas, changing its attitude in accordance with the new data. ‘Uracus!’
‘Liberty two-six-seven-three, telemetry is showing you transmitting a new course to the missile.’
‘Negative! I’m not! It’s changing. Oh crud.’ Another light turned amber, the missile’s engine was preparing to fire. ‘It’s going to course correct. Flight control, do I abort? Do I abort?’ His thumb hovered above the red key.
‘Liberty two-six-seven-three, cancel your update to the missile.’
‘I haven’t updated! It’s malfu— Crud!’ Ry stared helplessly at the console as the light changed to green. The missile was fifty kilometres from the Tree, and the engine burnt for three seconds. He read the new numbers again, and instantly worked out the course that would take the missile on. Procedure always had the strike aimed at the base of the bulbous end, the biggest target, but this new trajectory would take it to the midpoint – so it wasn’t going to miss. ‘It’s still aimed at the Tree,’ he said numbly.
‘Major Evine, what’s happening?’
Ry recognized the new voice in his headphones: Colonel Matej. That was a severe break with protocol.
‘Something changed the missile’s course,’ Ry said, hating how inadequate that sounded.
‘Did you change the missile course, Liberty two-six-seven-three?’
‘No, I did not.’ Ry took a breath and made an effort to calm down. His medical telemetry would be showing them his quickened heartbeat and respiration – rising temperature, too. ‘There’s some kind of malfunction. I’m going to attempt to regain control of the missile.’
His fingers flew over the missile panel, flicking switches in a sequence he knew should work, wiping the computator’s memory ready for a clean reload.
‘What are you doing?’ Colonel Matej asked.
‘Clearing the false data from the missile. I can reload the correct course.’
‘Negative. Missile desk has confirmed the new track. It is still on course for the Tree.’ There was a short pause. ‘But how did you know that?’
Ry grimaced, furious with himself. It took the big electrical computator sitting in the basement of the Cape Ingmar flight control building to work out orbital vectors. No normal human brain could perform that kind of calculation. ‘I guessed the burn wasn’t long enough to divert it,’ he said. Come on, Matej, you know an astronaut could make that guess.
‘Okay. Consensus down here is to let it run. If the kill burn doesn’t initiate as programmed, we’ll consider a data reload.’
‘Roger that.’ Ry stopped trying to correct the anomaly, and looked at the missile countdown clock. They were seven minutes away from the kill burn, when the solid rocket cluster would ignite and send the missile streaking in towards the Tree. ‘Can I have an update on Tree 3,788-D, please, flight com?’
It took a moment, but Anala’s voice returned to his headphones. ‘SVO is saying the Tree acceleration is holding constant. Its course is stable. Missile will not require a further update.’
He nearly said it hadn’t had an update – that something very strange was happening. The new data had to come from somewhere, and flight control had an override channel for the Liberty’s computator in case anything happened to an astronaut; they could continue the missile launch by remote. But why would anyone change the impact point? He just couldn’t understand that. Unless—Fallers!
They would be the only beneficiaries from a sabotaged Liberty mission. But the missile is still going to hit the Tree. So it can’t be them. Who, then?
‘Ry, are you all right?’ Anala asked.
He realized his heart must have jumped at the thought. If they can alter the missile course from the ground, what else could they change? But the flight centre team gets blood checked almost as often as astronauts. ‘I’m fine,’ he said, eyes tracking across every readout on the console, trying to spot any anomaly, but everything seemed to be functioning normally. The Liberty’s battery power was lower than he would have liked at sixty-two per cent, but still well inside mission parameters. His eyes were fixed on the missile countdown display as the numbers wound down.
‘The doctors would like to remind you to pull the viewport blinds down,’ Anala said.
‘Roger that, flight com.’ He reached out and pulled the silver blinds across each of the command module’s ports. It was to protect his eyes from the explosion. ‘Strapping in, and locking down guidance data.’ The electromagnetic pulse from an atom bomb explosion was fierce, and had knocked out circuits and instruments in the early Liberty craft until Demitri and his team came up with methods of hardening the electrical components on board. But even then, the protection wasn’t always a hundred per cent effective. Ry began copying the readouts onto a pad – not that he needed to, but the technicians who recovered the capsule might notice the absence. If the computator did get knocked out, he could reload it quickly enough.
‘Stand by, one minute,’ he said. His gaze was fixed on the missile panel. If anything happened now, there’d be no chance of correcting it. The numbers flicked downwards. On ten seconds, a green light indicated separation of the missile’s hypergolic-rocket engine module. Then, right on time, the green light for the solid rocket ignition lit up.
Ry let out a soft breath of release. He watched the radar, seeing the missile’s velocity build as the solid rocket cluster accelerated it at seven gees. The distance from the Tree shrank rapidly.
‘Looking good,’ Anala said.
Twenty seconds.
All his console readouts were stable. ‘Switching on external cameras,’ he announced. Footage of the Ring Trees exploding in nuclear fury always played well in the newsreels.
Ten seconds. The solid rockets were spent. Missile acceleration dropped to zero. The radar return was perfect, the Nixie numbers measuring distance to the Tree merged together as they wound down to zero.
His earphones emitted a loud hissing, then went silent. Tiny cracks of intense light shone around the edge of the port blinds. Needles in the dials connected to the hull radiation instruments flipped over to maximum. Lights dipped from the bomb’s electo-magnetic pulse. He held his breath, scanning the console. There were two amber lights. One for an RCS tank pressure valve, which didn’t matter – the valve was triple redundant. And a second for a radar servo – again, the backup could cope. A red light glowed for the omnidirectional radio antenna receiver. He switched the backup set on immediately. His earphones started hissing again.
‘Clean detonation,’ Anala called through the static. ‘Visible down here.’
‘Good to hear, flight com. Tell everyone to go ahead and start their Treefall parties. Systems nominal up here.’ He checked the flight director attitude indicator and fired the RCS.
‘It looks like you’re manoeuvring, Liberty two-six-seven-three,’ Anala said, and there was a note of strain in her voice which was evident even through the static.
‘That’s confirmed, flight com: manoeuvring. I want to see,’ he said simply.
He stabilized the Liberty side-on to the Tree, and put on dark sunglasses before opening a blind.
There it was, a perfect sphere of dazzling white plasma – Bienvenido’s latest and very temporary secondary sun. It expanded fast, dimming as it went. A slender flare extended out from the northern surface. Ry frowned at it. Then the tip began to curve over. ‘What the crud . . . ?’ The tenuous line across the infinite blackness began to dwindle. ‘I can s
ee something,’ Ry gasped. He snatched the camera from its locker and tugged at the lens cap with comic ineptitude.
‘What is your visual, Liberty two-six-seven-three?’
‘Something’s moving.’ The explosion’s plasma shell was shading down to a purple-blue, becoming translucent as its luminosity faded. The tenuous trail of ions had almost vanished. He managed to click off three fast shots. ‘Something came out of the plasma shell.’
‘Repeat, please.’
‘There’s something out there.’ He peered through the camera’s viewfinder, trying to focus the lens properly. The tip of the dying streak was meandering aimlessly as it dissipated.
‘SVO will begin tracking the debris constellation when the plasma shell scatters. There’s too much ionization interference right now.’
‘That wasn’t debris, flight com. The trail the object left in the plasma shell curved. Whatever made it was changing course. It was under acceleration. It’s a spaceship of some kind.’
There was a long pause. ‘Liberty two-six-seven-three, please confirm you said there is an alien spacecraft in the Ring.’
Ry didn’t like the way all emotion had vanished from Anala’s voice. In his mind he could see the flight control centre, all the dozens of technicians sitting at their desks, looking round at Anala with nervous astonishment, none of them saying a word.
‘Affirmative, flight com. I don’t think I’m alone out here.’
‘Can you see the anomaly now?’
Ry pressed his face against the cool glass of the port, twisting round so he could scan as much of the empty panorama as he could. There were definitely some chunks of Tree visible out there now the plasma shell had dissolved, faint-glowing splinters tumbling slowly across the blackness. One segment must have been a kilometre long – presumably the end of the spire. But all of them formed a central cluster, expanding slowly. At least I did kill 3,788-D.