I didn’t have nightmares the night before the launch because I got no sleep. Of course, this was to be expected.

Saying goodbye to my parents in the departure lounge was hard. None of the parents managed to keep their tears to themselves, but to our credit, we students remained calm and strong. We’d role-played the scenario again and again in class. When I saw my mother set her jaw in its familiar determined fashion, I knew that she and Dad were going to be all right without me. I was making them so proud.

We felt like a tight little team, the four of us standing shoulder to shoulder for the student group portrait, then as part of the whole group portrait of twenty-four astronauts leaving for Earth. Most had already served on previous missions and we knew several by name but it was the first time we’d met Dr Carter Barat, the ship’s Chief Medical Officer, who also turned out to have invented the celephet.

Doc Carter, as he introduced himself, smiled very handsomely and directly at me and asked to take a quick look at my celephet once we’d done our last personal equipment safety checks. I had the weird feeling that the new Doctor was keen to see mine in particular. As he’d approached me, Nisien had pointed at his celephet rather comically, but Doc Carter ignored him completely. He asked if I wouldn’t mind turning around. I lifted my hair and he stood so close, I could feel his breath on the back of my neck. A pat on the shoulder told me that he’d finished.

We rode to the edge of the Dome in wagons, up a series of escalators to the upperDome. Having locked down our helmets and given our suits final checks, we went through the northern three air locks. In the final one, Halley took my hand and although it was hard to feel much through the thick gloves, I could sense a small squeeze. None of us students had ever set foot outside the Dome before. Halley and I turned to look at each other through our green-tinted visors and I could see excitement and fear written on his face. This was it, what it had all been leading up to.

Outside, all was calm. A small breath of wind kicked up the dust, which was a weird brownish colour seen through the visors, as was the sky. The small sun was very bright. Without our suits, the water in our bodies would be nearing boiling point already. I remember looking down at my boots shuffling through the grit, making the first marks I’d ever made upon the true surface of our planet. When I turned to look at the upperDome, it appeared very lonely, an insignificant looking grey-veined bubble in the dust, but one that contained my whole life and everything I loved. The thought of leaving it made my legs weak and I had to fight the impulse to run back. Thankfully, my well-rehearsed breathing technique kicked in again — inward breaths through the nose to the count of seven, outward breaths through the mouth for five — and I found myself calming down. I decided not to look back any more. During the hour-long flight to the launch pad, we passed only one other Dome in the distance, which Halley thought might be London. Apart from that, the land was barren and featureless, just rocks and hills, a big contrast to the interior of our green Dome.

Each of these Domes’ subterranean environments are carefully engineered, with its own limited ecosystem: light is mainly artificial of course, and there are only a certain number of different plants for oxygen production and food, three species of bee for pollination (there are supposed to be at least twenty thousand species on Earth) and everything is carefully balanced and constantly monitored. Earth always seemed so fecund and exotic to me, with its incredibly complex plant and animal life. Of course, it was also a scarily chaotic world with so many dangers and illnesses, unlike Mars, a planet devoid of disease.

‘What are you looking forward to most?’ Halley asked through the radio link.

‘Rain,’ I said, in a strange voice. ‘And waterfalls. Preferably standing under a waterfall in the rain.’

‘Getting super soaking wet,’ smirked Halley. ‘What is this thing with you and rain?’

‘Don’t know.’ I shrugged. ‘Just always liked the idea.’

We’d been playing this game for ages. Seeing a waterfall in the rain was a pretty tame ambition by our standards but the best I could come up with just then. Previously, we’d thought up some great ones: a frog eating blackberries on top of a pyramid … a domestic cat skiing down an exploding volcano (too cruel). Even if these fake wishes were possible, the chances of getting to see them were nil. Although there was talk of a possible link-up with scientists in the south of France, most of our time would be spent in Cardiff helping the two archaeologists on the mission. We did have a realistic list of must-sees, of course, but we also had to keep reminding ourselves that this wasn’t a pleasure trip.

To see rain, real, natural rain descending from the skies, was achievable and would be wondrous, nothing any of us students had seen before.

At last we reached the spacecraft, standing alone in the middle of the desert. A little further off was the Dome which housed the huge factory converting the liquid hydrogen fuel for each journey from underground water ice. After a further round of safety checks, we climbed a staircase and entered a low chamber, larger but in other ways similar to the launch simulator we’d been practising in at the SSO. Two circles of chairs pointed outwards like a starburst. We were packed together snugly with lots of cushioning. After some final encouragement, the base team left and I felt the heavy door close and lock behind them. For six hours we’d have to stay in these chairs. Our suits would deal with bodily functions. After that, we’d be free to move.

My heart was hammering as the ship’s engines powered up. For the first time, I had to concentrate to bring my breathing under control, which was made more difficult when you were lying down. A deceptively fragile-looking cage structure closed over us. There was a deafening roar and the whole chamber started to shake. The seconds felt like hours. I shut my eyes and breathed and counted and waited for the G-force to kick in.

All sound fell away. My whole body was crushed back into my seat as the ship shot forwards. I could not move a muscle. It felt like I was about to explode. Tears streamed down my cheeks into my ears. I tried taking my mind to a calm place, like I’d been taught.

My place was the Museum. I tried to imagine myself wandering about in its marble rooms, bare feet padding across the cool floor. I tried to visualise myself among the rocks and fossils … the metamorphosed basalt … the crinoidal limestone … and tried desperately to feel at peace.

It had to stop soon. If it didn’t, I was going to die.

I was going to die.

The horrendous pressure eventually began to subside. It lessened, bit by bit, over the next twenty minutes and when the launch was finally over, everyone clapped and cheered in their muted, muffled way. The cage released with a hiss and rose up to lock on to the ceiling of the chamber. Our seats began to tilt up. Halley gave me a double thumbs up, as far as his gloves would allow. I was so glad it was over. Glad I hadn’t died.

Aside from the launch chamber where we slept, the four other chambers were for scientific work, exercise and recreation and were loosely timetabled, though nobody seemed to mind if anyone spent longer than they were allowed in one. Students were granted more time in the recreation rooms than other astronauts, but we were expected to continue our studies each day, concentrating mainly on the natural history of Earth and known history of human beings. We were supposed to make weekly group transmissions to school and I knew how exciting it was at school when we received broadcasts from mission students. We’d also receive feedback from our Professors.

I already knew a little of the history of previous SSO missions to Earth, but Nisien helped me fill in the gaps one afternoon when the four of us were talking in the smaller recreation chamber.

‘Do we actually appreciate how lucky we are to be on board the Byd 33, as opposed to the Byd 9?’ Nisien asked.

‘No, but I guess we’re about to.’ Halley winked at me.

‘Well, to start with, the earliest expeditions took twice as long to reach Earth.’

Robeen gave Nisien a sidelong look, as though she was waiting for her chance to jump in. She never let Nisien get away with knowing everything if she could help it.

‘Wow, I didn’t know that,’ I said, cursing myself when I saw the smug look creep across Robeen’s face.

‘Yeah,’ said Halley. ‘Imagine keeping each other company for that length of time.’

‘Indeed.’ As usual, Nisien hadn’t picked up on Halley’s not-so-subtle irony. ‘But much worse than that, on the Byd 9 the artificial gravity failed, so the astronauts spent most of their time weightless. No gravity, no weight. There they were, floating around and when they got to Earth…’

‘When they got to Earth,’ Robeen jumped in, ‘where the gravity is three times that on Mars, half of them died. It’s quite a famous disaster story. Simply put, their bones collapsed under the strain. They’d been losing bone mass for the whole trip anyway and with the effect of the extra gravity…’ Robeen did a sort of crumpling mime with her fingers.

‘Your face…’ Halley sniggered at me.

‘No, come on, it’s not funny,’ I said. ‘It’s horrible.’

He carried on laughing and I gave him a shove.

‘Ah, but actually the really clever thing,’ Nisien held his finger aloft, ‘and this is why you mustn’t worry, Bree, is that the artificial gravity on board the Byd 33 increases subtly over the period we’re travelling, which means that when we get there…’

‘…because we’ve continued to exercise…’ Robeen added.

‘We won’t notice the gravity difference between Mars and Earth.’ Nisien and Robeen uttered this last sentence together, rushing to get to the end first. They glared at each other and Halley had to bite his lip to stop himself laughing.

‘I wasn’t worried,’ I said. ‘I knew all that stuff, well, most of it. If there was a risk of us getting crushed, we’d have been warned. I just feel sad for the ones who made those early trips and didn’t survive. They gave their lives, didn’t they, so we could be doing this right now?’

This was fairly typical: discussions between the four of us normally became a boringly predictable competition between Robeen and Nisien and although I occasionally learned something new, I found it tiring. I sometimes stepped in to try and keep the peace, but Halley did his utmost to whip up the competition between them, then he’d sit back and enjoy the results. Of course, there were no full-blown arguments. This would have broken one of the fundamental rules aboard the Byd: arguments between crew members were not tolerated because they endangered the mission. We had to be professional at all times. The tension between Nisien and Robeen simmered, but at least we always worked out who was going to say what in our weekly broadcasts to school, when it was vital to put on a good show and appear a harmonious team.

Clever as Robeen was, no one could match Nisien on knowledge not just of the present Byd ship, but of every single Byd ship ever. He probably knew more than any of the engineers who worked on the present craft. It wasn’t just the big differences like the number of chambers on board or the types of thrusters in the engines. He knew all the little details: the number, shape and exact position of the windows, the fact that the doors on board two of the Byds, numbers 14 and 27, opened to the left rather than the right, the subtle changes in the logo, currently a silhouette of the SSO dragon, only with a larger glittery eye. The length and breadth of Nisien’s knowledge was staggering. Much of the detail seemed of no use, but it was all equally fascinating to him.

So our journey continued…