Below Mercury

A view of the Inner Solar System appeared on the viewscreen wall behind Rawlings, silhouetting his head and shoulders.

At the centre of the display, a tiny Sun burned, and the planets circled round it like glittering marbles in space, following the coloured ellipses of their orbits as they moved round in accelerated time.

The display zoomed in on the three innermost planets. The blue globe of the Earth moved slowly at the edge of the screen, Venus a little faster, following the yellow circle of its closer orbit, and finally Mercury, pursuing its highly eccentric orbit close to the Sun.

‘This is the situation of the planets right now,’ the silhouette of Rawlings said, freezing the display. ‘The launch window we’re recommending is here—’ he fast forwarded the display a few months ‘—in the early hours of May fourth. Transfer orbit insertion at zero six thirty UTC will put you onto a minimum-energy trajectory to Mercury, with a journey time of just over ninety-seven days.’

The display moved forward again, and a thin green line sprouted from Earth and curved inward, converging on Mercury. The mission planner stopped the display as the green line touched the innermost planet.

‘Your rendezvous with Mercury is on August ninth, six days before Mercury’s closest approach to the Sun. The orbit insertion manoeuvre takes you over the North Pole, and into a standard polar orbit.’

Rawlings zoomed in closer on the display, and the tiny dot of Mercury expanded until it became a grey globe. A graphic of a space tug appeared at the end of the green line, moving against the background of the stars. The mission team watched as the tug fired its engine, slowing down and moving into a circular orbit around Mercury.

Clare leaned forward. The tiny aircraft-shape attached to the front of the tug occupied her full attention.

‘Just a moment,’ she said.

Rawlings halted the animation.

‘What kind of ship are we going down to the surface in?’ She pointed at the screen.

‘You’re going to be flying one of the Martian spaceplanes – most likely a modified Olympus two-forty,’ Rawlings said quickly, glancing towards the back of the room. ‘We had one back from Mars last month that needed a major overhaul. We’ve bumped it up the priority list, and it’ll be refitted for the mission.’

‘You’ve got to be kidding.’ Clare shook her head in disbelief. ‘Why are we taking a spaceplane down to Mercury? Why can’t we use one of the crew shuttles?’

‘Because we don’t know what state the landing pad is in after the refinery explosion,’ Helligan’s drawl cut in from behind her. ‘If the pad’s been put out of action by the explosion, a shuttlecraft won’t be able to land.’

Clare started to speak, but Helligan waved a hand dismissively, and continued: ‘Look, shuttlecraft are designed for landing on flat, concrete pads; they’re not able to land on crater floors. And they don’t have the radiation shielding for an extended stay on the surface. Those spaceplanes are built to operate off dirt strips on Mars – they can take hard landings on rough terrain, and they’ve got plenty of shielding. It’s a safer option.’

Clare subsided for the moment. Helligan had a point. If they had to land on the uneven terrain of a crater floor, she would rather be in the spaceplane. Still, it was a big, heavy craft to haul all the way to Mercury.

‘What about living space when we’re on the surface? We might be there for some time,’ she asked.

‘Inflatable Mars habitat modules, carried in the spaceplane’s cargo bay,’ Rawlings answered. ‘The spaceplane can supply all the power and air you need to run them while you’re there. The habitats have adequate radiation shielding for your stay, but you’ll have to retreat into the spaceplane if there’s a major solar event. In the most extreme cases, you may need to take shelter in the mine itself.’

Clare nodded as she made a note in her pad. They seemed to have thought it all out.

Rawlings was looking at her, as if waiting to see if she had more objections. She nodded for him to continue.

Rawlings turned back to the display behind him, and restarted the animation from where the space tug entered orbit round Mercury.

‘Your orbit takes you directly over the South Pole, every ninety-six minutes,’ he continued. ‘Now, for the landing, you’ve got to make a special manoeuvre.’

The animation showed the spaceplane undocking from the tug, and nosing round to latch onto a large, torpedo-like fuel tank, before starting its descent.

‘This drop tank provides the spaceplane with extra fuel for the mission, as there will be no refuelling facilities on the surface. The drop tank is jettisoned shortly after the de-orbit burn.’

On the display, the empty tank fell away from the spaceplane. The display zoomed in further, following the craft as it fell out of the black sky toward the spreading landscape below.

‘Even with this extra fuel, making a descent to the surface and returning to orbit again is right on the limits for the mission. There is very little margin for error. You will be carrying a heavy load of fuel and equipment, which will limit your hover time over the surface before you have to commit to a landing. We have tried to maximise —’

‘Look, just cut to the bad news. How much hovering time do we have?’ Clare’s voice interrupted.

The mission planner stopped, and he glanced at the back of the room first, before answering Clare’s question.

‘It’s going to be – sub-optimal. We calculate that with your fuel margins, and projected allowances for error, you’re looking at a little over – ah, ninety seconds.’

‘Sub-optimal?’ Clare threw her pen down. ‘Have you any idea how little time that is when you’re looking for a landing site?’

Rawlings nodded, and opened his mouth to reply, but Clare carried on, her voice rising: ‘Let me spell it out for you. Even if we hit the de-orbit burn spot on, and we descend into the crater without wasting any fuel, we’ve got to locate the landing pad in the dark. There are no landing lights on the pad. Call that thirty seconds, if we’re extremely accurate with our navigation. A quick circuit round the pad to make sure it’s safe to land, and that there’s no obstacles to an abort. Another sixty seconds. And that’s it – we’ve used up our ninety seconds. That is just not enough margin. Minimum rules for manned missions are—’

‘—being revoked for this mission,’ Helligan’s voice cut Clare off. Helligan waved at Rawlings, and the lights came back up in the room.

‘This isn’t a routine flight, boys and girls,’ Helligan continued. He stood up and walked slowly round to the front of the room as Rawlings sat down. ‘This is a cutting-edge exploratory mission to an abandoned, probably wrecked, base with no operational refuelling facilities. You’re going to be close to the limits of fuel the whole way.’

He let his words sink in.

‘Now, the captain here—’ he managed a little smile as he paused, ‘—has reservations about what we’re asking her to do. I’d like to remind you that all of you are volunteers and you’re under no obligation to proceed. If any one of you wishes to leave the mission team, I for one will have no problem in accepting that.

‘But let me make one thing clear. You bail now – right now – or you carry on with the training. If we spend all this time and money in preparing you for this mission, and then you pull out at the last minute, then I will personally ensure that you never go into space again, and that your superiors are left in no doubt about your prospects for future advancement. Do I make myself clear?’

He looked at them all in turn, receiving answering nods and affirmations. He finished up with his eyes on Clare.

She stared back, hating Helligan with a seething anger that wouldn’t go away.

‘Yes, sir,’ she said, leaving the gap between the words as long as she dared.

Helligan’s porcine eyes narrowed.

‘You were saying, captain?’ he asked, his voice and gaze like steel.

‘I was pointing out that ninety seconds of fuel leaves barely any decision time, sir.’ Clare’s voice was quiet, but clearly audible in the hushed room.

What’s wrong, Foster, aren’t you up to it? Are you so worried you’re going to crash, that you’ll abort the landing unless you’ve got five whole fucking minutes to work yourself up to attempting it?

Helligan’s voice blasted back at Clare, but it was just in her head. Helligan hadn’t spoken. He was still looking at her, as if weighing her up.