under which the fuel cans glowed red hot as their nuclear reaction ran unchecked, building up heat and pressure in the moderator.
Steam rose in wisps from around the edges of the covers; it could not be far away now. As if knowing that their work was done, the robots assembled in a circle on top of the core, oblivious to the screeching alarms and red warning lights that splashed the roof and walls of the containment.
In the control centre, the unseeing eyes of Peter Abrams had frosted over in the vacuum; they gazed out across the blood-spattered ruin of the room, to where the management system displayed message after message, warning of the reactor overload.
At the edge of the reactor complex, robots had forced open the sealed doors between the reactor containment and the rest of the mine. When the explosion happened, it would rip into the mine and drench it with deadly radiation. Other robots had attacked the containment in strategic points, digging into it with their powerful arms, creating lines of weakness that would help it to shatter.
Starved of coolant flow, and with no means of stopping its energy production, the reactor core was white- hot, and could not be restrained any longer. Steam bubbles formed in the moderator, reducing the cooling and increasing the pressure, and the reaction finally ran away, releasing a hundred times more energy than the reactor’s normal maximum output.
In a fraction of a second, the boiling water in the reactor core flashed into steam, and the pressure vessel breached, near where the robots stood. In a titanic explosion, the pressure vessel exploded, blowing the robots to pieces, bursting the containment, and sending a blast wave of fire and shattered rock rocketing out of the reactor complex into the mine.
Inside the silo, the countdown reached five seconds, and the shuttlecraft stirred as the engine turbines spun up with a rising whine. Moments later, the four engines ignited, and an overlapping sequence of muffled bangs rocked the craft as the engines lit and rose to full thrust.
‘Eat that, you motherfucking machine,’ Clare hissed, as searing hot exhaust swirled round the circular pit of the silo and into the open doorway of the docking corridor, where the robot stood.
The shuttle lurched off the pad, its thrusters firing to keep it level, as it rose up out of the silo.
The cabin windows had just cleared the lip of the silo, when the shuttle rocked violently to one side. An alarm sounded as the autopilot disconnected, along with a warning from the flight computer.
‘
‘What the fuck—’ Clare grabbed the sidestick and pulled the shuttle upright, the thrusters blasting out against the silo’s walls.
Below them, the silo dissolved in a cloud of shattered rock and dust as the blast wave from the reactor reached it. The control room window exploded into the silo, sending the shuttle across to the other side.
Clare fought to hold the craft steady in the centre of the silo. It lurched and bucked as the explosion wave burst over it. If they hit the walls, it would all be over.
Unable to maintain height, the shuttle started to fall back into the silo. Clare slammed the thrust levers forward, sending a sheet of flame up and round the windows, as the shuttle slowly cleared the silo and laboured into the sky, a wide fan of dust flying over the crater floor.
Below it, the silo collapsed inwards in a cloud of dust and rubble. Secondary explosions threw rocks and more dust into the sky, narrowly missing the climbing shuttle. The entire silo complex was collapsing; great pits were opening up in the crater floor. Matt looked across to the distant reactor complex, aghast; the reactor appeared to have exploded; its cooling radiators and power converters toppling over into a great pit, from which a great cloud of vapour belched, lit from below by the red light of the exposed core.
The shuttle was behaving strangely; it wasn’t climbing fast enough, as if there was insufficient thrust. The craft seemed to be drifting sideways as it rose, as if something was tugging it off course.
‘
‘Something’s wrong here,’ Clare said, her voice showing concern. The shuttle lurched to one side in an odd way, and Clare’s eyes darted to the engine controls, then to the attitude display.
The shuttle’s engines were generating plenty of thrust. A dead weight seemed to have attached itself to the craft, and the last lurch was from the weight moving around.
‘Check the cameras!’ Clare’s face had gone white. ‘No, over to the right of the landing gear controls.’
Matt found the camera controls, and punched up various external views: the silo, shrinking below them; a black sky; a view of one of the engines; a landing gear leg; another landing gear leg—
‘Oh, shit.’ Matt caught his breath.
Looking up into the eye of the camera, a robot clung onto the landing leg strut below the main cabin door. It must have grabbed one of the shuttle’s landing legs as it had lifted off past the airlock opening. As Matt watched, it swung its free arm and grabbed hold of the landing strut, higher up. The shuttle lurched.
‘It’s climbing up the landing gear!’ Matt yelled.
‘Which one!’
‘The one – the one below the door.’
‘Number four. Okay, that makes sense, I’m having to roll to the right to hold us steady. How heavy is that thing?’
‘About two tonnes.’
‘Jesus.’ Clare checked the navigation display. The white line of their ascent was peeling away from the magenta line of their flight plan, falling further and further behind.
‘We can’t make orbit with that fucking thing hanging on,’ she said, ‘we’ve got to get rid of it.’
Matt watched the display helplessly, powerless to do anything as the robot hauled itself higher.
‘We won’t have to worry much longer, it’s going for the propellant tanks.’ Matt pointed at the camera display.
Clare risked a quick glance at the display. The robot had advanced up the landing leg by two metres. It was pulling itself hand over hand, up the hydraulic strut. In a few moments, it would be within reach of the fragile pressurised tanks that contained their fuel and oxidiser supplies. One savage swipe with a pincered hand, and it would all be over; even if the tanks didn’t explode, the engines would flame out and the craft would fall back to smash into Mercury.
The shuttle started to rotate as it climbed; the weight hanging on one corner made it difficult to control, and Clare swore as the craft fought against her control inputs. The mine surface facilities turned in front of the shuttle’s windows, and Matt watched as the mine entrance, the exploding reactor complex, the wrecked refinery, and the landing pad moved past in an endless sequence of ruin.
Below the fleeing shuttle, the blast wave from the reactor explosion tore its way through the mine. Already weakened by the stresses from explosive decompression, the mine passages started to give way, bursting inwards in showers of rock and tangles of cables.
An explosive shock wave erupted up the main intake shaft, destroying the shaft station. The hoist motor, supporting the dead weight of the long wire ropes and cage, collapsed in ruin, and slithered partway down the shaft in a mass of broken rock, guide ropes and falling girders. The upper shaft walls fell in behind it, blocking the shaft and sealing it with thousands of tonnes of rock.
Outside on the crater floor, the explosion tore through the passages connecting the surface facilities. The passages collapsed in pits of sinking rubble as the roofs fell in, opening up long scars in the crater floor.
The explosion reached the hangar levels, and the main entrance to the mine. The outer doors burst, and a cloud of flame, dust and rubble exploded out from the mine portal. The hangar roof groaned, and then collapsed, sinking to the ground in an avalanche of falling rock that filled the hangars and surged out over the crater floor, burying Erebus Mine forever.
The shuttle rose high above the spreading ruin of the mine, and Matt shut his eyes against a sudden flood of brilliant sunlight; some crack in the mountain peaks spilled the light of the circling Sun into the dark bowl of the crater. The craft spiralled out of the shadow of the crater floor, and the horrors of what they had seen there plunged back into inky darkness once more.
Sunlight glittered off the reflective foils of the shuttle’s thermal blankets, and it climbed higher, up and out of the crater, until the sunlit peaks of the crater rim came into view.
A bright point of light burst out from the tallest peak. The huge dish of the deep space antenna on the mountain peak, where Elliott and Abrams had made contact with Earth, was catching the sunlight. It was like a
