She had brought along some work to fill these hours too, and it was more interesting than Masayo’s wall-scrubbing rotas. After seven months in orbit around Jupiter, the first results of Venus Jenning’s planet-finding survey had been published.
Venus’s survey derived from data from over forty years of work by Earth-based instruments and planet-finder space telescopes, supplemented by observations made by telescopes deployed from the Ark. A greater precision had been possible because to some extent two telescopes at Earth and Jupiter could serve as components of a single instrument nearly a billion kilometers wide.
Because it had been anticipated that better data about nearby exoplanets was going to be acquired after the Ark reached Jupiter, no firm decision about the Ark’s target had been made before launch. But, according to the nominal mission plan, the current phase in Jupiter orbit should come to an end in another nine months-provided they completed the reconfiguring of the Ark, the construction of the warp generator, and the collection of antimatter from Io. They were going to need a decision before they left Jupiter because a warp journey, uncontrolled from within the spacecraft, was point and shoot; once they launched, they would be committed. So they had nine months to decide.
Hundreds of exoplanets had been cataloged. The difficulty was, which to choose?
The sun was a G-class star, compact, yellow, with a stable lifespan of billions of years. But G-class stars were comparatively rare, making up only one in thirty of the Galaxy’s population. Of the hundreds of billions of stars in the Galaxy, the most common, two-thirds of the total, were red dwarfs, small, cool, so parsimonious with their hydrogen fuel that they were very long-lived, lasting hundreds of times as long as a G-class like the sun. The astronomers labeled these M-class stars.
The interstellar cruise was planned for a nominal duration of seven years. Inside its warp bubble the Ark would be able to reach velocities of around three times light speed, so that put a limit on the journey of some twenty light-years. There were around seventy star systems within that radius, most of them systems of multiple stars. But among those seventy targets there were only five G-class stars, excluding the sun.
The nearest was in fact Alpha Centauri A, ten percent more massive than the sun, the senior partner of the triple system that was the closest to Sol, just four light-years away. It had long been concluded that there were no worlds remotely Earthlike to be found in that system: only remotely orbiting gas giants, labeled “cold Jupiters,” and swarms of asteroids that might be the relic of failed planetary formations. The next closest G-class was a star called Tau Ceti, in the constellation of the whale, nearly twelve light-years from Sol. But no suitable candidates had been found there either. The nearest analogies to Earth-worlds of about the right mass, in stable orbits, and orbiting at just the right distance from the parent star, so neither too hot nor too cold-had in fact been found orbiting the “wrong” stars, either dimmer or brighter than Sol, even some of the many M-class candidate planets.
Fueled by all this data, arguments raged both on the Ark and down at Alma. A strong faction led by Gordo Alonzo insisted that the G-class stars had to be the priority, with a risk taken over the planet’s precise analogy to Earth conditions. A different lobby, led vocally by Venus herself, argued for world first, star second. It was a passionate debate; after all, what was under discussion was the selection of Earth II, of a new home for mankind. But it seemed to Holle to be devolving into an almost theological argument, a question of whether you would want your descendants to grow up under a wrong-colored sun.
To complicate this discussion further had been Venus’s accidental discovery of an immense comet nucleus, swimming out of the trans-Jupiter dark and heading on what had looked like a collision course with the Earth. The sudden threat, piled on top of the ongoing calamity of the flood, had felt unbearable, the coincidence monstrous. “Proof that the devil exists,” Gordo Alonzo had growled, “if not God.” According to Venus’s report, more data and analysis had now shown that the comet would pass close to the Earth but would not impact; it would provide a dramatic spectacle when it reached the inner solar system in a few years’ time, but no more. Holle thought the strange incident had brought the fractious planet-spotters on Earth and Ark closer together for a while. But they had soon resumed their arguments.
Masayo’s timer chimed. Holle closed down the report.
Masayo, already suited up, helped Holle put on the layers of her suit, the tight-fitting liquid-cooled undersuit, her pressure garment, and then the bright white micrometeorite outer cover. To do this Masayo had to get up close and personal to Holle in her underwear. Contact between the sexes could be awkward on a ship where there was an imbalance of men over women, a legacy of the chaotic final boarding process. And, in the open hulls, it was too easy to watch your neighbor all day and all night, and work up fantasies. This, in fact, had led to the assault that had got Jack Shaughnessy into so much trouble. But Masayo was brisk, professional, showing no particular interest in Holle beyond getting the work done.
She strapped her personal identification band around her leg, a color code with a crew number, so she could be recognized on visuals once outside the ship. For good measure she slapped an “EVA One” disc on her chest, and a number two on Masayo’s. Then they pulled on their Snoopy-hat comms gear, helped each other with helmet and gloves, and checked over the display consoles on their chests.
When they were done, Holle raised a thumb to a watching camera, and called up to Zane, the duty officer today. “OK, Zane, this is EVA One, both EVA One and Two are good to go.”
Zane’s voice crackled in her ear. “Copy, Holle. Let me run through my checks of the lock.”
They stood and waited. Zane sounded absent, as always. Maybe he was absorbed on some project of his own-the warp assembly was demanding enough. But it seemed to Holle that he increasingly disappeared into the dark places inside his own head. He would lie in his couch, or just float, hanging from some bracket like an empty suit. She’d tried to persuade Mike Wetherbee to take a look at him, but the doctor had protested he was no psychiatrist, and anyhow he was in a tremendous sulk about Miriam’s stranding and wouldn’t consider psychiatric cases. Holle, still smarting herself over her separation from Mel, could sympathize with that. Mike had tried to get Zane to talk to specialists on Earth by the downlink, but the time delay had destroyed any chance of empathy.
However, Zane was on the ball today, it seemed. After a couple of minutes an indicator over the airlock door flashed from red to green. Holle turned to Masayo. “You want to lead?”
“What, a jarhead like me? You go ahead.”
“This is your first EVA of any kind, right?”
“Thanks for reminding me.”
“Just don’t throw up inside that suit, there are only five that fit me and that’s one of them. Let’s go.”
She pulled down a handle and the door slid open, revealing the gleaming airlock chamber, and a small window showing the blackness of space beyond.
50
They emerged from the airlock into sharp, dim sunlight. Holle and Masayo, weightless, stood on the nose of Seba, an insulation-blanketed tower fifty meters high. The tether between the hulls was a triple steel cable that ran vertically up from the nose of the hull, gleaming in the flat sunlight. Holle showed Masayo how to fix the attachment at his waist to the tether cables. Leaning back she followed the tether’s line up through the incomplete circle of the warp generator, hanging directly above her head. Beyond that the second hull, Halivah, was suspended in the sky, nose down, two hundred meters away. It was an extraordinary metal sculpture, hanging in the pale light.