“We need to test these things more often,” Delwin said.
“Stuck by temperature or torque?” Devi asked.
“Don’t know. We can look at it when we get the main system going again. By temperature do you mean hot or cold?”
“Either. Although cold seems more likely. There’s condensation in all kinds of places now, and if some of it froze, it might make that valve stick. I think every criticality that is a moving part should be moved every week or so.”
“Well, but that would be a wear in itself,” Aram said wearily. “The testing itself might break something. I want better monitoring, myself.”
“You can’t monitor everything,” Delwin said.
“Why not?” said Aram. “Just another little sensor for the ship’s computer to keep track of. Put a sensor on every single moving thing.”
“But how would a monitor sense that something is stuck?” Devi asked. “Without a test it wouldn’t have any data.”
“Pulse it with electricity or infrared, and read what you get back,” Aram said. “Check it against a norm that you’ve set.”
“Okay, let’s do that.”
“I guess it won’t matter if we get through this little crisis and get into orbit.”
“Let’s do it anyway. It would have been embarrassing to have the ship blow up just as it arrived.”
The team in there continued to work on the main cooling system, by way of waldos located all over the spine, especially in the reactor room itself, all the while watching their work on screens. The main cooling system, like its backup, was a matter of very simple robust plumbing, which moved distilled water from cold pools, chilled by a little exposure to the near vacuum of space, through the tubes running around the nuclear rods, and the steam turbine chambers, to the hot pods, and thence back to the cold pools; all hermetically sealed, nothing much in the way of gates, the pumps as simple as could be. But as they soon determined, when the system had shut off, cause for that still unknown, a pump valve had cracked and lost its integrity, and with the water thus moving poorly through the system, the pipes nearest the reactor pile had gotten hot enough to boil the water passing through, which in turn had forced water away from the hot spot in both directions, making things even worse. Before the automatic controls had shifted to the backup cooling system, which in the event was experiencing its own problems, an empty section of the main system’s pipe had melted in the rising heat. The electricity was again available, but the pipe and coolant were missing.
As a result of all this, they had lost water that could not be completely recovered; they had a broken pipe section, therefore a broken main reactor cooling system; and the temporary loss of both cooling systems had caused the reactor rod pool temperature to redline, and parts of it to begin shutting down. Now the backup cooling system was functioning, so it wasn’t an immediate emergency, but the damage to the main cooling was serious. They needed to get a new pipe made and installed as quickly as possible, and some of them were going to have to do some really expert waldo work to get the melted section of pipe cut out and a new section installed in its place. When all that was repaired, they would have to open the main cooling system’s fill cock and refill it with water from their reservoir. Possibly some of the lost water could be filtered out of the air and later returned to the reservoir, but some was likely to stay dispersed throughout the spine, adhering to its inner surfaces and sticking by way of corrosion.
That night, back in their apartment, Devi said, “We’re breaking down, and running low on consumables, and filling up with unconsumables. This old crate is clapped out, that’s all there is to it.”
The telescopes housed in the bowsprit of the ship were extremely powerful, and now as they crossed Tau Ceti’s planetary orbits, they could look at the planets more closely. Planet E and its Earth-sized moon remained the principal objects of interest, with Planet F and its second moon also getting long looks.
Planets A, B, C, and D all orbited very close to Tau Ceti, close enough to be tidally locked. They glowed with heat on their sunward side, and the sunny side of Planet A was a sea of lava.
The low metallicity of Tau Ceti, and thus all its planets, was discussed endlessly by the ship’s little astrophysics group, who were finding that what metals the system contained were concentrated most heavily in Planets C, D, E, and F, which was useful for their purposes.
The telescopes shifted from one target to the next as they drifted downsystem. By far the greatest part of their viewing was now given to E’s moon. It was ocean-covered for the most part, with four small continents or large islands, and many archipelagos. It was tidally locked to Planet E, and had .83 Earth’s gravity. Its atmosphere averaged 732 millibars of pressure at sea level, the air mostly nitrogen, with 16 percent oxygen, and about 300 ppm of CO2. There were two small polar caps of water ice. On the Nguyen Earth-analog scale it scored .86, one of the highest scores yet found, and by far the highest found within 40 light-years of Earth.
The probes that had passed quickly through the Tau Ceti system in 2476 had found that the oxygen present in the atmosphere was abiotic in origin, by using the Shiva Oxygen Diagnostic, which analyzed for an array of biologic marker gases like CH4 and H2S. If these were found in an atmosphere along with oxygen, it indicated the O2 was almost certainly biological in origin. Atmospheric O2 found without the other gases also present indicated the oxygen had been produced by sunlight splitting surface water molecules into hydrogen and oxygen, with the much lighter hydrogen later escaping to space. E’s moon’s oxygen had scored very strongly to the abiologic end of the rubric’s scale, and the moon’s remaining ocean, combined with its nine-day periods of intense sunlight, gave this finding a solid physical explanation. In essence, part of the ocean had been knocked by sunlight into the atmosphere.
On their way in to E, they inspected Planet F’s second moon, a so-called Mars analog, also of interest to them. Its surface g was 1.23 g, and it was almost without H2O, being entirely rocky. It was speculated that an early collision with F had created this moon, in much the way Luna had been created by the early collision of Neith and Terra. F’s second moon would have Planet F bulking hugely in its sky, being only 124,000 kilometers away. Planet F’s first moon was quite small, and ice-clad, probably a captured asteroid. It could conceivably serve as a water supply for the second moon. So the F system was considered to be a viable secondary option for inhabitation.
But first they flew to E’s moon, which was now being called Aurora.
Approaching Planet E they decelerated until they were so close they had to decide whether to orbit E or Aurora, or position themselves at E’s Lagrange 2 point. Ship would not have to expend much fuel to get into any of these orbital configurations. After consultations the executive council chose to orbit Aurora. People became more and more excited as ship closed on the watery moon.
Except in Nova Scotia, where it was known that Devi was becoming quite ill. The result was a confusion of spirits. It was exciting to reach their destination at last, and yet it was precisely in this unprecedented situation when they might most need their chief engineer, now nearly legendary for her diagnostic power and ingenious solutions. How would they fare on Aurora, if she were not there? And didn’t she deserve more than anyone to see this new world, to experience the dawn of their time there? These were the things people in Nova Scotia said.