CHAPTER ONE: PROXIMA CENTAURI

Sandra tucked her bob of brown hair behind her ear as she sighed, inhaling the recycled air of the starship. She had to admit that the agrotech system which provided astronauts with locally grown food and oxygen was a great invention. Especially for this mission, longer than the previous ones.

She checked that everything was working in the adaptive greenhouse one more time. The AI behind it seemed to work just fine, but a human supervisor checked regularly that everything was going smoothly. They didn't want to be stranded in the middle of nowhere with no food and no plants to help clean the air. It was a routine job, but she was uncharacteristically nervous.

She'd been in her twenties when she had enrolled in the Space Exploration Corps and helped with the setup of the first outposts and colonies in the solar system. Thirty years later she was back in the job, at a time in her life when a change of environment sounded good, so she had promptly accepted.

She was divorced, with adult children, so she had decided wandering away from the Sol System for a decade or more might be a good idea. She hoped she had made the right choice. This mission was definitely different, both in length and in the technology.

Previous missions had lasted a year or two, and there were ways to go home early. This mission? They were going where no human had gone before, and it might be a mission with no return. They were going much farther, and even though they now had starships with artificial gravity, it was still a jump into the unknown.

The Explorer 5 was the first Terran starship to leave the Sol System. Space exploration had needed almost a century before it could actually start, since they'd had to get rid of all the junk in low Earth orbit before launching the first manned starships.

Since the beginning of the 22nd century, the Space Exploration Corps, a UN mini-fleet of four exploration ships, had started reaching the outer boundaries of the solar system, establishing orbital stations all over the place – on dwarf planets, asteroids or gas giants' moons – and even a Mars colony under a protective dome.

The new FTL drives covered one parsec in one month, which meant they could reach any Trans-Neptunian Object in days instead of years, and so they were trying to get out of the Sol System with this mission.

The Explorer model had now been upgraded for interstellar travel with the latest Terran technology. Explorer 5 had a cylindrical plain hull with a spherical section within it. It was equipped with autonomous reconnaissance drones and a landing shuttle.

The Explorers had the command center, navigation and crew quarters located away from the outer surface and buried deep in the ship, and Explorer 5 had an even stronger shield for interstellar travel, since it was going farther than its predecessors.

The spherical section was mounted on gimbals allowing it to rotate, with four decks in it, and artificial gravity. Motors rotated the spherical section to align the decks in a specific configuration, and mechanisms locked them in place until they needed to be realigned in a different configuration.

When the starship was in interstellar space, the spherical section was aligned so the decks were perpendicular to the direction of travel, a configuration like a cylindrical skyscraper on Earth. When the starship was in orbit over some alien planet, the spherical section was aligned so the decks were parallel to the direction of travel, like a submarine on Earth.

The decks were connected by an elevator. The smaller upper deck held the round bridge and right below it was the scientific area – a lab and a meeting room. The bigger deck held the living space – sleeping quarters, two bathrooms, a gym, a small mess hall, a galley and even a sick bay. The lower deck, smaller and at the bottom of the spherical section, held the bay for the landing shuttle.

Occupying a side section at the "back" of the sphere and covering all decks was the adaptive greenhouse based on Space V's original plans. The upgraded version still adapted the volume available for each plant to its growth level, and the appropriate planning of sowing, harvesting and choosing plants allowed for the reduction of energy and water consumption to the bare minimum.

It was equipped with a separate micro-conditioning system for each cultivation level, allowing different types of plants to be grown simultaneously with optimal temperatures and humidity levels, while reducing energy consumption. It also featured an air exchange mechanism with the cabins which captured the CO2 produced by the crew and returned the O2 produced by the plants.

The multi-level adaptive greenhouse technology was what they needed for their long journey, and they also had the means to make plant-based meat off their yields, which would help with their dietary requirements, especially if they didn't find anything edible on the planets they were going to explore.

Sandra had gotten used to the artificial gravity of the starship, and the gentle curves of places built for pressurization, including doors rounded at the corners. The lack of windows no longer bothered her, knowing space without the protection of an atmosphere could be really dangerous.

That wasn't what scared or worried her, though. It was more being in a closed ecological system with the same six people for a decade, maybe more, with no way of going home before the mission was over. She was no longer a young woman who could adapt easily.

The greenhouse might give them fresh food and air, but it wasn't like walking in a park on a nice sunny day. Still better than some space stations or mining colonies, but still a very small world to share with strangers.

Living in a Closed Ecological System wasn't too hard after a while. The crew had to maintain a well-balanced air and waste system, a continuous food supply and reliable sources of energy, thus they adhered to a strict recycling policy. But that was the easy part. They were all adults and professional, but none of them had ever been assigned to such a new, long mission.

The teams on the Explorers were always very mixed. Countries had united under the UN banner to conquer space, so the crews always had all kinds of people. In previous teams she'd worked with Americans, Australians, Africans, Europeans and Asians.

There wasn't a global language yet, and – like the astronauts of the long decommissioned ISS had to speak English and Russian – the Explorers team members needed to be fluent in at least two languages from the official languages of the UN (Arabic, Chinese, English, French, Russian, Spanish).

Sandra liked that, since losing the languages of the world to a dominant global one would mean much of the culture that went along with each of those languages would also disappear. English was a second language for her, but she had become bilingual at an early age, since English allowed her to communicate with many more people.

On this mission they all spoke English, which was easier than some of her previous missions. Clearly through the decades the SEC had learned to form teams with one common language from the official ones. Especially for a long mission like theirs, it was important they could all communicate quickly and easily.

Sandra finished her shift in the greenhouse and grabbed some fruit and vegetables, since it was her turn to cook lunch. She was still a little uneasy when she mingled with the rest of the crew, but she needed time to get used to people. Especially colleagues – although she had no doubt that by the end of the mission they would all be friends.

Her current team included four fifty-something veterans – including her – who had come from the first four Explorers, and three forty-somethings – Harishankar (everybody just called him Hari), Avdotya (who preferred to be called by the shorter form, Dunya) and Conall.

Tashiro was Japanese and had been on Explorer 2 while Sandra came from Italy and had worked on Explorer 1. Amadou, a well-toned West African with a shaved head, came from Explorer 3. Min, a petite Chinese woman who looked younger than her age, came from Explorer 4.

Tashiro, being the eldest, was the team leader. Dunya was a blonde Russian, and Conall a dark-haired, freckled, blue-eyed Irishman. Hari didn't look like someone born in India, because he was fair-skinned and had hazel-green eyes, and only his name betrayed his Hindi origins.

Her comm pinged immediately after lunch, as she came out of the bathroom. Time for their first meeting since leaving the Sol System behind. They were in cruise speed, making one parsec per month, controlled by the most sophisticated navigational computer invented so far. They could have short briefings in the meeting room when in cruise mode.

Sandra entered the meeting room and sat with the others. Tashiro turned on the wall flat screen, showing a quote from Star Trek: The Original Series.

"I'm surprised the SEC hasn't called this starship Enterprise instead of Explorer!" Sandra chuckled. "Because we're doing exactly what they're doing!"

"Except it's going to take us longer than five years and there's only seven of us, instead of a crew of hundreds," Amadou commented.

"Seven, like the main characters on the Original Series," Sandra replied. "Although we don't have the exact same skills. Or the Enterprise, for that matter."

"Yeah, no warp drive for us yet," Conall joked. "But we'll get there – wherever there is!"

Tashiro cleared his throat, and looked at each of them. Sandra and Amadou muttered an apology and signaled him to go on.

"We're headed away from the Sol System and have a number of solar systems to explore, which will take us roughly ten or eleven years," Tashiro said. "So, first stop, Proxima Centauri." A star map replaced the quote on the screen. "What we know so far isn't much. Our probes have reached the planet orbiting within the habitable zone of its star, but it's unclear whether it has an atmosphere or not. It has no moons and might be tidally locked to Proxima Centauri, which leads to an extreme climate with only part of the planet habitable. It probably has kept some water, so we might find lakes or even oceans on the side facing the star, while the other side is covered with ice. In other words, we don't know what we'll find."

"We can start studying the data the probes have sent back, but they're decades old, although decades are just a drop in the history of the universe," Amadou added. "I'm sure we'll find a lot of surprises when we get there."

Sandra nodded, thoughtful. So it began. Not much different from when they wandered the Sol System looking for places where they could start building colonies. First the International Moon Base. Then the Mars Colony.

Traces of oxygen on Ganymede had been spotted since the end of the 20th century, but only now, two centuries later, had the Jupiter satellite been adapted to human life, along with the other Galilean satellites and other big moons that had traces of liquid water.

"We don't know yet if life as we know it can develop on a planet orbiting a star different from our sun," she said. "Our probes sent back data, but it's time we see with our own eyes what those exoplanets are actually like."

"It's a good thing that we finally have the means to get there in our lifetimes," Hari commented. "Or we would have to send out generation ships."

"Into the unknown," Dunya objected. "I mean, we might have sighted potential exoplanets since last century, but we didn't have the means to reach them."

"With the new engines we'll get to Proxima in a month and a half," Conall said.

"I'm grateful that you all joined this adventure." Tashiro smiled. "Your commitment to the expansion of the Terran League is greatly appreciated."

If their journey brought results, the League would build more interstellar Explorer starships and start expanding beyond the Sol System. They were pioneers of the Milky Way.

Sandra finally relaxed, feeling her companions' excitement for their adventure.