Tuesday, March 22, 2050


Probably the single most popular image of Pluto is that of Orthanc, a forty-meter-high shard of nitrogen ice that thrusts its crooked way up from a field of tumbled blocks. The image has appeared on commemorative plates, commemorative coins, postage stamps, website backdrops, placemats, welcome mats, and advertisements for everything from soap to sex boutiques. Wired magazine recently estimated that over forty million people had Orthanc tattood on their bodies.

I first discovered and named Orthanc about nine months after reaching Pluto. I was flying by jet pack south along the 320 degree longitude line, and I was fifty-five kilometers out from Pluto Station when I saw it poking up into the black sky like a long, white fang. The comparison to Saruman's tower from The Lord of the Rings immediately suggested itself, even though the original Orthanc from Tolkien was black, and almost four times as tall. Orthanc was tall enough that I had to travel another five kilometers to reach its base.

The famous image of Orthanc rising up into the sky with Charon perched halfway above the horizon to its left was not the result of random chance. I went to a great deal of effort to compose the shot so it would look like that. I found just the right tumbled block of ice to serve as a vantage point that would put Charon just to the left of Orthanc. Then I decided on the best time of the Plutonian day to make the shadows appear just right, went back to Pluto Station, waited thirty-nine hours, then returned to Orthanc to get the shot. Commentators who have remarked on the similarity between the Orthanc-and-Charon image and the Trilon-and-Perisphere logo of the 1939 New York World's Fair are absolutely correct. I specifically had the Trilon-and-Perisphere image in mind when I shot Orthanc; it was my way of celebrating the hundredth anniversary of the World's Fair.

Plutologists still aren't sure how this slab of ice managed to tear itself up from the surrounding matrix and wind up pointing almost straight up. I've been back dozens of times since making the initial discovery, often taking core samples from various places along Orthanc's flank and from the surrounding ice field back to Pluto Station for analysis. Perhaps some heat source below the ice field caused it to buckle and crack, and caused Orthanc to swing itself up. It's as good an idea as anyone else has come up with. In the eleven years that have passed since I first discovered it, I've never found anything else like it.

Monday, March 21, 2050

Getting Around on Pluto

If you take the diameter of a sphere, square it, and multiply it by pi, you get the sphere's surface area. If the sphere has a diameter of 2388 kilometers, as Pluto has, that gives you a surface area of just under 18 million square kilometers. Any way you slice it, that's a lot of real estate for one man to cover, even in a lifetime.

Fortunately, the mission planners gave me a few options for getting around. The first, of course, is just me and my heavily insulated boots. Even allowing for Pluto's one-fifteenth gravity, one man can only travel so far with a six hour oxygen reserve. Assuming I want to return to Pluto Station before my oxy runs out (and I do), that means I can only travel three hours in any direction. This works out to a range of about thirty kilometers.

Second is the Plutonian bicycle. It took the mission planners a great deal of ingenuity to design and build a bicycle that could operate at 40 Kelvins. In order to avoid the inevitable wear and tear inherent in moving an object from room temperature to 40 Kelvins, I usually keep the bicycle on the surface of Pluto. The saddle is insulated, so I can keep the bicycle at 40 Kelvins while riding it (except for whatever heat builds up while I'm riding it). I'm not sure just what the bicycle is made of, except that it's not metal. The best thing about the bicycle is that it can carry an extra oxygen tank, which extends my time out by another hour and a half. With the extra oxygen thrown in, the bicycle triples my range to about ninety kilometers.

Third is the jet pack. This wouldn't be sufficient to lift a man on Earth, but with Pluto's light surface gravity it works just fine. The jet pack fits onto the back of the oxygen tanks, and uses compressed nitrogen for propulsion. This is by far the most economical propellant on Pluto, since the surface is mostly nitrogen ice. The jet pack extends my range to about 150 kilometers, and allows me to reach heights of about a hundred meters while doing so. All of the aerial views of Pluto you've ever seen were recorded by me while flying with the jet pack. Incidentally, it's been calculated that my use of the jet pack over the last twelve years has just about doubled the density of Pluto's atmosphere.

Finally, if all else fails, I can always move Pluto Station itself around. Since I make a trip to Charon every year to stock up on water, it's simplicity itself to simply choose a new landing site when I return to Pluto. Over the course of twelve years, I've been slowly spiralling away from the south pole. I'll certainly run out of life expectancy before I run out of Pluto.

Sunday, March 20, 2050

Water Run

It may seem odd that I should have abandoned Pluto so soon after landing there, but there was an important step in the establishment of the base to be performed, and it couldn't be performed on Pluto. So, within a few hours of landing at Point South, Pluto Station reverted again to being the Cerberus, and I took off from the spot I had dubbed First Landing.

One of the features that made the Pluto mission so attractive to the Agency (ie, cheap) was that there was a vast supply of water available only 19,600 kilometers away. The main reason the settlements on the moon and Mars are still as small as they are is that both have to be supplied with all of their water from Earth. Me, all I had to do was travel to Charon, which was basically a big drop of frozen water 1217 kilometers in diameter.

There had been some discussion during the planning phase over whether I should link up with the Hades again or just go straight to Charon in the Cerberus. Simplicity ruled the day, as it so often has with the Pluto mission: docking with Hades and moving the whole ship a mere 19,600 kilometers was unnecessary when the Cerberus was perfectly capable of making the trip on its own.

Once the Cerberus acheived escape velocity from Pluto (not a difficult task), I had the computer set course for Charon. Less than twelve hours later, the Cerberus entered orbit around Charon, and I picked a landing spot. As with Pluto, the south pole seemed as good a place as any, and after examing the area with the ship's telescope, I decided the pole itself was suitable. The computer performed the necessary calculations and maneuvers, and within the hour the Cerberus had landed and been transformed into Charon Station.

Gravity on Charon is about half that on Pluto, or about a thirtieth that on Earth. The water ice, though, still had all its normal supply of inertia, so it wasn't a matter of simply tossing ice boulders around. I made use of a couple of tools that had been designed by the mission planners for this very purpose. One was a simple blowtorch that I used to cut free pieces of ice, and the other was a cart with an attached winch that I used to pick up and transport the ice. The outer hull of Charon Station had been fitted with nets, and all I had to do was winch up the ice and then drop it in the nets. All told, it took me three days to load a year's supply of water onto Charon Station. There was no need to worry about all the extra mass, since the Cerberus basically ran on water: electolysis separated oxygen from hydrogen, the oxygen became my atmosphere, and the hydrogen was fused into helium to provide power for the engine.

Once the ice was loaded and the water tanks and fuel tanks were topped up, I could relax and spend some time exploring around Charon's south pole. It's easy to imagine from Earth that Charon is just a big, smooth ball of ice, but it's not so. Charon undergoes enough temperature changes in the course of its 248-year orbit around the Sun that the ice expands and contracts, causing fissures to open up and blocks to be thrust up from below. I took a lot of pictures, and a few of them, such as the Flatiron, the Charon Arch, and the Split Tower, have become iconic symbols of Charon, just as Orthanc and the Target have become iconic symbols of Pluto.

Every year since then, I've made another voyage to Charon, to mine more water ice and do more exploring. I like it there. There's a blue tinge to the water ice that I find particularly relaxing, and it's always with a certain amount of regret that I pack up and leave for Pluto.

Saturday, March 19, 2050

First Steps

During the planning phase of the Pluto mission, the scientists at the International Space Agency wanted to the make the Pluto lander as easy as possible for me to see from a distance, so they conducted a study to determine what color would be most clearly visible against the white and yellow-brown background of the Plutonian landscape. They came up with the most hideous shade of green imaginable. I told them I didn't care how visible that color made the lander look, I'd have to live in the wretched thing for the rest of my life, and there was no way I was going to live in a station that was that horrible shade of green. In the end, we compromised on baby blue. Baby blue I could live with.

They continued the color scheme with the spacesuit, even though nobody would ever see it except me, and I'd be wearing it. After staring out at the landscape for a good long while, I decided to go out for a walk, and I began putting the spacesuit on. It wasn't the first time I had worn it, of course. Apart from all the test runs on Earth, I spent at least half of the outbound trip from Earth spacewalking outside the Hades. I read an old story once about a group of Martian colonists making a months-long trip to Saturn, and they found that they liked spacewalking so much that they had arguments over whose turn it was. It turned out that the story was right -- you could spend hours just floating serenely out in space. It helped the trip from Earth to Pluto pass surprisingly quickly.

The spacesuit itself was pretty simple. Most of it was a skintight leotard that was kept stored inside-out. You just slipped it on over your body. The neck of the leotard was sealed to a collar with a breathing mask and oxygen tanks. You strapped the oxy tanks to your body and the breathing mask to your face. (The tanks were red, btw, rather than blue. There's some sort of tradition among chemists that oxygen tanks always have to be red.) On top of the collar went a clear plastic fishbowl helmet. Then there were the insulated boots and the insulated gauntlets, and you were ready to go out onto the surface.

I had insisted that the lander be as low-tech as possible. No automatic sliding doors; no automatic sliding anything, if they could help it. That's why all the hatches and port covers were operated by hand cranks or wheels. The station airlock, for example, was opened and closed with a hand crank. The airlock was located in the exact center of the station, and opened out onto the surface directly below. After putting on the spacesuit, I cranked open the airlock door, stepped inside, and cranked it shut again. I pressed the button that pumped the air out, and when that was done, I undogged the hatch in the floor and opened it. By design, there was three meters of space between the floor of the station and the surface of Pluto. I rolled out a flexible plastic ladder that reached within half a meter of the surface, and climbed down.

I stepped down onto the surface of Pluto.

I didn't feel like making some Armstrongesque "one small step" statement, so I didn't. I just looked around. Above me was the lower hull of the station, with its three landing legs splayed out, resting on their insulated pads. Below me was the nitrogen ice surface of Pluto, looking about how you'd expect ice to look. The footing was firm -- at 40 Kelvins, nitrogen ice has lost all its slipperiness and is as easy to walk on as dirt. It was dark under the station; at this time of the year on Pluto, the Sun was always about two-thirds of the way up in the sky, so the only light was a bright yellow spotlight from the airlock and a dim bluish glow from Charon sitting parked along the horizon to my left.

I looked at the locator strapped to my right wrist. I had programmed it to show me the way to the south pole, and it was pointing behind me. I turned around and started walking. As I emerged from the shadow of the station I looked up at the Sun. From six billion kilometers away, it was too small to show a visible disk, and dim enough to safely look at directly. It wasn't quite bright enough to wash out all of the other stars; I could see maybe a dozen of the brightest ones.

I continued walking, weaving my way around surface irregularities. I had to detour around a furrow that one of the engines had gouged out during the landing. A hundred meters away from the station, the irregularities in the ice became more pronounced, and I had to pick my way among them. I glanced at my locator from time to time, correcting my course when necessary, then came to a stop when it started flashing. I looked down. I was standing on the exact location of the south pole of Pluto. I looked back at the station, a baby blue dome with various bits sticking out from it, standing on three legs. I looked at the upper half of Charon protruding above the horizon. I sighed a contented sigh. So much room. Room to breathe!

Friday, March 18, 2050

Pluto Station

Landing the Cerberus on Pluto involved a variation on the permafrost problem: a standard rocket engine would simply drill a hole in the nitrogen ice that made up that world's surface, leaving the ship buried in a deep pit. The planners in the Proposals Division came up with a new engine configuration to deal with the problem. Instead of a single engine pointing straight down, there would be three engines pointing down and away, leaving the surface below the lander untouched.

The Cerberus's onboard computer was sufficiently versatile that I could simply point to where I wanted it to set down, and the actual landing would be handled automatically. The surface at the literal south pole of Pluto was too rough to land on, so I had the Cerberus land about 350 meters away, in what I later determined was the 110th longitude. The computer shut down the engine, and I waited to see whether the surface would cave in underneath us. It didn't.

I had been in free fall for the better part of a year, but since Pluto's gravity is only about a fifteenth of Earth's, I didn't have any trouble getting up from the pilot's position and walking around. Now that the lander was down, the mission planners and I had agreed, it was no longer appropriate to call it the Cerberus. This was going to be my home for the rest of my life, and it was also going to be the central research base in the Plutonian system. Now that it was at rest, the lander had become Pluto Station. I walked over to one of the three big viewports that had been built into Pluto Station, and undogged the outer cover. I took a long first look out at the landscape, lit by a Sun that was 2000 times dimmer than back on Earth, but still 500 times brighter than a full moon. It was a wild landscape, with twisted shards and knobs of nitrogen ice studding the ground, below a black sky with Charon off to the right, halfway above the horizon. I spoke the first words ever spoken on Pluto.

"Mine," I said. "All mine."

Thursday, March 17, 2050

Seasons and Latitudes

When the New Horizons probe made its Pluto flyby in 2015, the imaging team at NASA found itself, for one last time, with new worlds to map. They followed the set of longitudes and latitudes for Pluto and Charon established by the International Astronomical Union in the late 20th century. Pluto's north pole (hidden on the dwarf planet's nightside, and therefore unmapped) was at positive 90 degrees, while its south pole was at negative 90 degrees. A line drawn between the two of them, running through the spot on Pluto's equator directly beneath Charon (known as the sub-Charon point), was Pluto's prime meridian, the zero degree longitude. Three hundred sixty degrees were marked out, running east from the prime meridian, the direction of Pluto's rotation. Given Pluto's circumference of 3751 kilometers, that means that each degree of latitude, and each equatorial degree of longitutde, is about ten and a half kilometers long.

The International Astronomical Union had also established that Pluto's north pole was on the same side of the ecliptic as Earth's north pole, despite the fact that the Plutonian pole rotating counterclockwise was the one below the ecliptic. To get a sense of how that works, take a look at a standard globe of the Earth. It's probably resting on a stand, and turns freely on its axis, which is tilted 23.5 degrees from true to represent the tilt of the real Earth's axis compared to its orbital plane. Go ahead and start spinning the globe slowly on its axis, with the north pole turning counterclockwise, just like the real Earth does. Now pick up that globe and tilt the axis even further, until it's a full 122 degrees from true. You'll notice that the north pole is now angled toward the floor. According to the IAU, this means that the north pole has now become the south pole, and vice versa. Antarctica is now at the Earth's north pole, while North America and Eurasia are now in the southern hemisphere. The new south pole still rotates counterclockwise, just like it did when it was the north pole, but since east and west switched places at the same time north and south did, the Earth's rotation is now considered retrograde, moving from east to west. This is the situation on Pluto: tilted 122 degrees from its orbital plane, the south pole is the one that rotates counterclockwise.

Pluto's orbit is such that it passes through one of its equinoxes just two years before it reaches perihelion, its closest approach to the Sun. This is what happened during its most recent equinox in 1987: Pluto's northern hemisphere (which, you'll recall, rotates clockwise, unlike Earth's northern hemisphere) passed from summer to fall, and its southern hemisphere passed from winter to spring. This meant that Pluto's north pole, which had been in direct sunlight for 124 years, slipped into night, and the south pole, which had been in darkness for 124 years, slipped into daylight.

Because of Pluto's unusually eliptical orbit, this equinox goes by a lot faster than the other equinox, which occurs during aphelion, and as a result winter and spring are shorter in the southern hemisphere than summer and fall. Winter and spring in Pluto's southern hemisphere "only" last 52 years each, while summer and fall last 72 years each. Spring was about half over in Pluto's southern hemisphere when New Horizons made its flyby, and the summer solstice was coming up fast when the Hades brought me to Pluto 23 years later.

Summer on Pluto isn't like summer on Earth, even accounting for the fact that Pluto is so much colder. Because Pluto's axis of rotation is tilted 122 degrees from its orbital plane, Pluto is basically rolling on its side as it orbits the sun, with its south pole pointed 32 degrees "below" its orbital plane, and its north pole pointed the same amount above it. When spring comes to Pluto, the pole peeks over the edge of the world, and travels across the dayside until the fall equinox, when it slips over the far edge into the nightside. During the summer solstice, the Sun is only 32 degrees away from the azimuth, or "directly overhead" point, at the pole, which is the closest it ever gets there. This was the reason that the mission planners at the International Space Agency decided to establish our main base at Pluto's south pole, and this was the reason I rode the Cerberus down to Point South after detaching from the Hades. When the Cerberus touched down at Point South on August 22, 2038, I had come to the place where I would be spending the majority of my remaining years.

Wednesday, March 16, 2050

The Permafrost Problem

Back in the 20th century, an oil company was drilling for oil in northern Alaska. The oil company built its local headquarters the way it would have back in Texas, flat on the ground. What the oil company people had forgotten, though, was that the ground in northern Alaska is permafrost, basically frozen mud. In due course, the oil company's headquarters building heated up the permafrost it was resting on, and the permafrost melted, becoming ordinary mud. The building sank.

Establishing a research base on Pluto was like trying to set up a base in Alaska, only much worse. Most of the surface of Pluto is nitrogen ice at a temperature of 40 Kelvins or so, compounded by the fact that Pluto's atmosphere is terribly thin and impermanent. This means that the surface of Pluto will sublimate away at the slightest excuse. Building a base on Pluto was not like people from Texas trying to put up a building on Alaskan permafrost. It was more like people from the Sun trying to put up a building with a temperature of 5000 degrees Celsius on the surface of the Earth without having the rock below it melt into lava.

At first, the Agency's Proposals Division was afraid it would have to use some form of magnetic levitation, like a bullet train, to keep the base on Pluto out of contact with the surface. That would probably have been too expensive, and caused the Powers That Be to turn down the Pluto mission. Fortunately, advances in materials science have led to the development of astonishingly effective insulators. The Proposals Division finally came up with an acceptably cheap design in which the station rests on three insulated pads. The bottoms of the pads are at 40 Kelvins where they come into contact with the surface of Pluto, while the tops of the pads are at room temperature where they come into contact with the station's legs.

As an aside, I face the same problem myself whenever I venture out onto Pluto's surface. The same material insulating the station from the surface can be found in the thick-soled boots I wear over my spacesuit. I also have to wear gauntlets of the same material so I can handle samples of Plutonian surface material without having them evaporate away. If I ever found myself flat on my back on the surface, it would take less than a minute for the heat to be sucked out of my body through the uninsulated spacesuit. I'd become a permanent, frozen feature of the landscape.

Tuesday, March 15, 2050

Looking for Mr. Right

The Agency wanted to send people to Pluto, because that's the sort of thing the Agency was designed to do. However, like all publicly-funded organizations, the Agency was always short of cash, and the cost of sending a team of researchers to Pluto and bringing them back again was prohibitive. The Agency, though, was known for its creativity, and some bright soul at the Proposals Division had the radical idea that you could reduce the cost of a Pluto mission dramatically if you didn't bring the researchers back. In fact, you could cut the cost by about 95% if you just sent a single person, and then left him on Pluto for the rest of his life.

The Proposals Division started putting its proposal together, and one of the preliminary items they investigated was whether you could, in fact, maroon someone six billion kilometers from the Earth and expect him to remain sane. They consulted some psychologists, and the psychologists told them that, yes, you could send someone with a particular type of personality out to Pluto on a permanent basis, and that personality type would remain sane, if you used the word "sane" in its broadest possible sense. It would have to be an extreme misanthrope, someone who didn't like being around other people, and who would, by choice, remain as isolated as possible. To such a person, the thought of being six billion kilometers from the rest of humanity would be like living in paradise.

Of course, in order to function in a useful manner at a research outpost, such a person would also have to be technically proficient to a certain extent, and would have to have methodical habits. This set severe limits on the number of prospective candidates. Before the proposal could go ahead, the Proposals Division would have to know in advance that they could secure a volunteer for the Pluto mission.

And so they came to me.

Fortunately for the Proposals Division, their email was able to make its way through the various filters I have on my account, and the subject line was intriguing enough that I didn't delete it sight unseen. I read their proposal, and sent them a brief response indicating that I would be willing to take part in their mission. It seemed like a low probability event to me, so after I sent my reply, I deleted the email and let the matter drop from my mind. Five minutes later, I had forgotten all about it.

Wheels turned, and documents passed hands, and in due course the mission to Pluto was approved by the relevant authorities. About a year and a half had passed, and I hadn't given the Pluto mission another thought. I had added a couple more filters to my email account, and this time the Agency's email didn't make it though. I have no telecom system, so in the end they had to send someone to my house in the Hebrides. Fortunately for them, I was in a sociable mood that day, so I answered the door and listened to them. We talked at the door for five minutes and then they went away, and I had volunteered to go to Pluto.