twenty-one metres thick. After marking the position with a red flag on a pole, the preparations for the test began.
Cambot, Trulli’s robot submarine, was a segmented metal cylinder some nine feet long and three feet in diameter, one end capped with a menacing array of interlocking drill heads and the other with pump-jet nozzles and folded fins surrounding a complex spool mechanism. Assisted by Rachel, Trulli and Baker carefully lowered it on to a sled. Chase, Nina and Larsson joined in to help them slide the heavy machine to the flag. Sophia elected to watch from the cabin, while Bandra made a show of ‘supervising’ without actually applying any physical effort.
Leaving Cambot at the flag, the engineers returned to the helicopter to bring over a generator, then set about erecting a winch system to lift Cambot by its tail, suspending the drill heads just above the ice. This took a while, the others returning to the BA609 for hot coffee. Disconcertingly for Nina, the sun barely moved in the sky for the whole time: at this point of summer, so close to the Antarctic Circle, daylight lasted almost twenty-three hours.
Once the submarine was hanging like some huge cybernetic fish on display as a catch, everyone examined it, even Sophia’s interest piqued. ‘So how does it work?’ Chase asked.
Trulli was on a ladder, connecting one end of what looked like a long length of rubber hose to the robot’s stern. ‘Most of it’s pretty straightforward. We lower it, it drills down into the ice - but it’s heated as well so it’ll go through faster. The drills get up to sixty or seventy Celsius once they’re at full speed, and the body’s at about thirty degrees, so the meltwater keeps it lubricated while it’s going down.’
‘So where does the truly Trulli stuff come in?’ Nina asked.
He grinned. ‘ “Truly Trulli,” ’ never heard that before. Nah, the clever business is all here at the back.’ He patted the spool. ‘See, usually when people do deep ice drilling, they fill the drill shaft with antifreeze, otherwise it ices over in no time. But that’s not really an option here, ’cause as soon as we broke through into the lake, it’d pollute the ecosystem and kill what Dr Bandra’s trying to find.’ He held up the hose. ‘This is the clever bit. It’s basically a length of flexible pipe, but folded back on itself - like when you turn a pair of trousers inside out by reaching down the leg. Only here, the trousers can be however long we want - kilometres, even.’
‘Bloody big trousers,’ said Chase.
‘We run all the control and power cables down inside both layers of the hose - they’ve got a non-stick coating so they slide over the inside of the umbilicus. This way, it doesn’t matter if the top of the drill shaft ices up. But as Cambot goes down, he unrolls more and more of the hose out behind him from this drum here.’ Trulli nodded at it. ‘Once he breaks through into the lake, we disconnect him from the umbilicus so he can swim free. But because we’re still feeding the power cable through to him, he can explore for as long as we want, then recover him by drilling back up through the ice. In theory.’
‘Let’s hope it works,’ said Bandra, as cold as the surrounding landscape. ‘It would be a horrible waste of everyone’s time and money if something went wrong.’
‘Only one way to find out,’ Nina said. ‘How much longer to get ready, Matt?’
‘Not long. Just got to finish the hook-ups, run all the system checks, then we’re set.’
It took him another twenty minutes, using a laptop inside a battery-heated bag to carry out the final checks. ‘All right!’ the Australian finally announced, sitting on a folding canvas chair. ‘Let’s give it a whirl.’
As well as the laptop, the bag contained a control unit bearing twin joysticks and several dials. ‘Stand back,’ he warned as he turned one of the latter. The drill heads rotated reluctantly at first before warming up and spinning more smoothly. He increased the revolutions, checking figures on the laptop’s screen before looking up in satisfaction. ‘Everything looks good. Nina? You want to give the word?’
‘I think it’d be better if Dr Bandra had that honour,’ she said. ‘Dr Bandra?’
He accepted with poor grace. ‘Go on then, Trulli, get on with it.’
Trulli shrugged and operated the controls. The winch lowered the submarine until the whirling drill heads touched the ice. There was a loud rasp, the sub’s nose instantly obscured by spray as it dug into the hardened surface. Nina looked up at the winch frame. The outer layer of the umbilicus was indeed staying still, the slick, shiny inner layer slowly slithering into its open end. The sight was vaguely unsettling, reminding her for some reason of guts.
Cambot was in no particular rush to descend; it took over two minutes before the robot’s cylindrical body completely disappeared from view. Churning water spewed up behind it. But the shaft was already freezing, the exposed surface taking on a glutinous quality with surprising speed.
‘All right,’ said Trulli, checking the readings. ‘Cambot’s cutting through the ice at a hundred and twenty centimetres per minute. So he’ll take, uh . . .’
‘Fifteen minutes to reach the lake,’ Nina told him. ‘Since he’s already covered the depth of his own length.’
‘Thanks. Wish I could do sums in my head like that - it’d save me a fortune in calculator batteries!’
Another round of coffees in the tilt-rotor followed, Trulli waving everyone back to the shaft almost fifteen minutes later. ‘Okay, he’s getting close,’ he announced. ‘The ice is a bit thinner than I thought - must be irregular. Oh, and I wouldn’t stand there, mate,’ he told Chase, who was investigating the now-frozen opening. ‘All the weight of the ice on top of it means the lake water’ll be under pressure. Soon as Cambot breaks through, it’ll come fizzing up like a can of Four-X on a bumpy ride!’
Chase retreated, Trulli also moving back. Everyone stood in a line, anticipation rising. Even Bandra seemed excited. ‘Less than a metre,’ Trulli said, watching the screen intently. ‘But the ice could break any time, so watch out. Half a metre - whoa, there it goes!’
The expedition members tensed, but nothing happened for a few seconds - then the cap of ice over the shaft suddenly exploded upwards as a geyser burst through the surface. It reached over thirty feet in the air, dropping back down in a cloud of spray. The fountain continued to gush for several seconds before finally dying down.
‘And . . . he’s through!’ Trulli said triumphantly. He checked some more readings. ‘Okay, time for stage two. Capping off the umbilicus, deploying fins and releasing Cambot for free operation . . . now.’
He operated more controls, seemed satisfied. ‘Okay, let’s see what’s down there.’
Nina watched the screen as the Australian worked the controls. Trulli had configured one window to show a live video feed, which at the moment showed little but a cyan fog, but the display next to it was more revealing. It was a LIDAR display, similar to the scanning system used on some of his previous submarines, sweeping back and forth a blue-green laser beam of a wavelength that could easily penetrate water. The resulting image was only monochrome, but she could clearly make out the ‘roof’ of ice covering the ancient lake.
Trulli turned the submarine to view the bottom of the drill shaft. The end of the umbilicus dangled from it, swaying languidly as the robot’s movements pulled the other cables through it. The ice surrounding the hole seemed almost to be glowing in shades of blue and turquoise, daylight from the surface penetrating the translucent mass. ‘Okay,’ he said, turning to Nina. ‘Where d’you want to start?’
‘Where did the sub come out?’
Trulli checked the co-ordinates. ‘Near the seaward end of the valley.’
‘By the dam?’
‘If that’s what it is.’
‘Check it out first,’ Nina said. Trulli nodded and guided the sub downwards. As he had thought, there was a large indentation in the ice ceiling, a rough dome formed by rising heated water from a volcanic vent below. It took a couple of minutes for Cambot to emerge into a larger open space.
The blue glow was still present even through the greater thickness of ice, but Nina was focused on the LIDAR image as Trulli steered the sub to the end of the valley. Off to the side, the terrain was steep and rocky . . . but ahead, the slope leading up to the roof of ice was much more shallow and smooth.
‘
Bandra made a sarcastic noise. ‘How could it be a dam? Antarctic beavers, perhaps?’
Nina switched her attention to the video feed as the sub moved closer. Under the spotlights, the slope’s surface could be seen as loosely packed earth. ‘How wide is it?’
‘Let me get a sonar reading . . . It’s a smidge over three hundred metres across,’ said Trulli. ‘Maybe twenty- one metres at the highest point. Goes right across the valley.’
‘Completely blocking it,’ Nina realised. ‘It
Bandra was getting increasingly irate. ‘What inscription? Who are “they”? Dr Wilde, what is going on?’ He
