True, there was the supply ship from home every six months. But when it departed, the denizens of the station were stranded for another half year. There was one, count it, one, ship capable of reaching the Inner System stationed at Pluto. The Nenya could, at need, bear the entire station staff home, but it would be a long and grueling flight of many months. Alternatively, she could gun for Earth and get there in sixteen days—but with a maximum of only five people aboard, which meant everyone else would be utterly stranded while she was gone. So far, the Nenya was insurance no one had used.
She could also function as an auxiliary control station for the Ring. But without the anchor of Pluto’s mass to provide calibration, the Nenya’s Ring Control Room was not capable of the sort of fine measurement the station could get. The Nenya’s real value was psychological. She represented a way home, knowledge that it was possible to get back to Earth.
The Gravities Research Station was the only human-habitable place for a billion kilometers in any direction, and every waking moment of their lives, everyone at the station was aware of that fact.
In the silence of the Plutonian night, Larry could imagine that the planet itself resented the presence of humans. Life, light, warmth, activity weren’t welcome here, in this land of unliving cold. Larry shivered at the mere thought of the frigid desolation outside the station.
Without making any conscious decision to go there, he found himself walking toward the observation dome. He needed to get a look outside, a look at the sky.
The darkness, the emptiness, the coldness that surrounded the windowless station preyed on all their minds. The station designer had known all that, and had made sure the station was brightly lit and painted in cheery colors. But the designers had also known it was important for the staff to be able to look on the empty landscape, the barren skyscape; perhaps more importantly, the station staff needed to be able to look toward the distant Sun, needed to use the small telescope in the observation dome to spot the Earth, needed to be able to prove to themselves that light and life and the warm, busy, lively homeworld were still there.
And so is all the weirdness, Larry reminded himself. All the raucous, angry pressure groups, unsure of what they were for, but certain of what they were against. They were a big part of his memory of MIT, and they had frightened him. And scared him worse when they had showed up back home in Pennsylvania. But then, they frightened a lot of people. And in the wake of the half-imaginary Knowledge Crash, the rad groups were spreading.
Larry made his way down the darkened access tunnel to the dome building. The route was long, and he had to find his way there by touch. The way to the dome was deliberately left in darkness, so that a person’s eyes would have the length of time it took to pass through the tunnel to adapt to the gloomy darkness of the Plutonian surface.
At last he stepped out into the large, domed room. It was a big place, big enough for the entire staff to crowd in for important meetings.
Larry stepped to the edge of the room and looked through the transparent dome at the world around him.
In stillness, in silence, the sad gray landscape of Pluto was laid out before him, dimly seen by the faintness of starlight.
Virtually all of the land he could see would have been liquid or gas, back on Earth. Pluto’s surface was made of frozen gases—methane, nitrogen, and traces of a few other light elements. All the surface features were low and rounded, all color subdued. To the west, a slumped-over line of yellowish ammonia-ice hills had somehow thrust its way up out of the interior.
Elsewhere on Pluto, a thin, bright frosting of frozen methane blanketed the land. Only at perihelion, a hundred years from now, would the distant Sun be close enough to sublimate some of the methane back out into a gas.
But here, on this plain, the methane snow was cooked away by waste heat from the station, exposing the dismal grayish brown landscape below. Here, water ice, carbon compounds, veins of ammonia ice, and a certain amount of plain old rock made up the jumbled surface of Pluto, just as they made up the interior. No one yet had developed a theory that satisfactorily explained how Pluto had come to be made that way, or accounted for the presence of Pluto’s moon, Charon.
Larry stared out across the frozen land. The insulation of the transparent dome was not perfect. He felt a distinct chill. Ice crystals formed on the inside of the dome as he exhaled.
Not all the landscape was natural. Close to the horizon, the jagged, shattered remains of the first and second attempts to land a station lay exposed to the stars. Larry knew the tiny graveyard was there as well, even if it was carefully hidden, out of sight of the dome.
The design psychologists had protested vehemently against building again in view of the first two disastrous attempts, but there had been no real choice in the matter. Both of the “earlier” stations had collapsed to the ground and shattered, like red-hot marbles dropped into ice water. But cleaning up the wreckage would have been prohibitively expensive and dangerous—and perhaps not possible at all.
This small valley was the only geothermically stable site in direct line of sight with the Ring. Here was an upthrust belt of rock that, unlike the water-ice and methane, could support the weight of the station without danger of melting. Even with the best possible insulation and laser-radiative cooling, the station’s external skin temperature was a hundred degrees Kelvin. That was cold enough to kill a human in seconds, freeze the blood in the veins—but flame hot compared to the surrounding surface, hot enough to boil away the very hills.
This was the only site where the underlayer of rock was close enough to the surface to serve as a structural support. Anywhere else, the heat of the station would have melted the complex straight through the surface.
If this station held together long enough to sink, Larry reminded himself, staring at the sad wreckage on the horizon. The first two didn’t.
But this station had been here fifteen years. So far, the third try had been the charm.
So far.
Larry tore his eyes away from the wreckage strewn about the landscape and glanced toward the telescope. It was a thirty-centimeter reflector, with a tracking system that kept it locked on the tiny blue marble of Earth whenever the planet was above the local horizon. You could bring up the image on any video monitor in the station, but nearly everyone felt the need to come here on occasion, bend over the eyepiece, and see the homeworld with his or her own eyes.
There was something reassuring about seeing Earth direct, without any electronic amplification, without any chance of looking at a tape or a simulation, to see for certain that Earth, and all it represented, was truly there, not a mad dream spun to make Pluto endurable.
Larry leaned over and took a look. The telescope was set on low magnification at the moment. There she was, a tiny dot of blue, the bright spark of Earth’s Moon too small to form a disk. Larry stepped away from the telescope after only a moment. He was looking for something else in the sky tonight. He needed to see the Ring. The mighty Ring of Charon.
Pluto does not travel the outer marches of the Solar System by himself. The frozen satellite Charon bears the god of the Underworld company. Charon, with an average diameter of about 1,250 kilometers, is, in proportion to the planet it circles, larger than any other satellite. It rides a very close orbit around Pluto, circling the ninth planet every 6.4 days.
The rotation of both satellite and world are tidally locked: just as Earth’s Moon always shows the same face to Earth, so Charon always shows the same face to Pluto. The difference is that Pluto’s rotation is likewise affected, its rotation synchronized to match its satellite’s orbit. Viewed from Charon, Pluto does not seem to rotate, but presents one unchanging hemisphere.