Martian Rainbow

by Robert L. Forward

  Gus looked up at the young mop-head towering over him and laughed. "More like Mutt and Jeff, you mean!"

  THEIR FIRST hop took them westward to Elysium Saddle. There Chris and Gus kept their political fences mended by having dinner with Ozaki Akutagawa.

  "This is excellent sushi," Gus said, picking up another delicious morsel carefully with his chopsticks. "Where did you get the rice?"

  "It is a special dwarf strain that we developed for space," Ozaki responded. "Grows well, even when crowded, and all it needs is a modest amount of soil and water. I must show you our gardens after dinner. We have the fish ponds and rice paddies laid out with bridges and benches so that a stroll through them allows one's spirit to think it is back on Earth. It is very important for those who work here with me."

  "How many are there now at the Nippon Mars Volcanic Studies Institute?" Chris asked. "I understand your fourth ship arrived last week."

  "We now number fifty-two," Ozaki said. "Our plans are to expand on the preliminary survey that Dr. Pavlova and Dr. Armstrong carried out. It will take that many people to completely map all the volcanoes and fossae on the Elysium bulge within a reasonable period of time."

  Gus had a wonderful time the rest of the evening drinking warm rice wine and talking volcanoes with Ozaki. Chris was bored, but polite.

  THE NEXT few sols they spent walking around the base, visiting with the workers at the superconducting wire plant that was one of the Independence Tasks assigned to the Elysium Saddle base.

  "Because of our lack of equipment, we have to make the stuff by a batch process," the foreman said. "So we only make about thirty kilometers a day."

  "Doesn't sound like enough," Chris said. "What do you need to increase your production rate?"

  "Don't really need to. As long as you keep plugging away, thirty kilometers a day is a cable around the circumference of Mars in one mear. We'll be ready to tie the electrical grid together by the time the bases have their solar cell farms deployed." He took them to a crawler trailer, which had been modified to hold a big spool of wire. At the rear end was a plowlike attachment.

  "The superconducting material we can make with our crude metallurgical control is the old-fashioned type that only stays superconducting if kept below freezing. This plow will bury it in the permafrost to keep it cold."

  "Where do you plan the first line?" Gus asked.

  "We've already started on the run from Elysium Saddle to Isidis Basin," the foreman replied. "It was only three thousand kilometers and a straight shot across the Elysium plains once we got around the fossae."

  "Isidis," Chris said. "That's where we go next."

  ISIDIS base was relatively small. Like all the bases, it had a nuclear reactor as the prime power supply. However, the initial charge of uranium fuel would not run forever. Like all the bases, Isidis had as a primary Independence Task the job of surrounding the base with a growing field of solar cells that would carry the electrical load during the day. Once all the bases were connected together with a grid of superconducting wires, those bases still in the sunlight could help power those bases where night had fallen. They were shown the multiple drill-hole aluminum bus bar installation near the power station where the direct current coming in over the superconducting link from Elysium would be sent into the ground to complete the circuit.

  After the obligatory pep talk after the evening meal at the base cafeteria, Chris and Gus had a few minutes to relax at the Insidious Delight, the local cafe and beer garden.

  "I've got a remote station monitoring the atmospheric composition at the low point in the basin," Chris said. "While I'm here, I think I'll take a crawler out this evening and check the calibration. It's only twenty kilometers away. Want to come?"

  "No." Gus feigned a sigh. "You go off and play scientist while I slave away at being an administrator."

  After Chris had left in the crawler, Gus found a chance to play scientist and attend an evening lecture by Joseph Stanislavsky, who had been out exploring along the southern perimeter of the Isidis Basin. Joseph used a large high-resolution flatscreen on the wall for his presentation and first put up a standard map of Mars with the topographic contours at one-kilometer intervals.

  "Now, notice," he said as he tapped the icons on his control flatscreen. "If you draw a line around Mars at the one-kilometer contour interval, not the zero contour—after all, that was chosen arbitrarily—you will see what I call the true 'sea level' of Mars."

  The one-kilometer contour shifted in color from black to a bright blue that contrasted well with the rusty color of the map. The blue contour snaked above and below the equator all across the map of Mars.

  "Note how, except for the Olympus and Tharsis volcano complex, all the highly cratered highlands of Mars lie south of the one-kilometer contour and all the uncratered lowlands lie north of the contour." He touched an icon and a dashed blue line appeared that dipped below the Solis plain south of the Tharsis Ridge, again separating heavily cratered territory from smooth plains.

  "It is my thesis," he said, touching another icon on his screen so that the uncratered plains north of the blue contour line turned light blue, "that all this area was once filled with water—the Boreal Sea. But water covered with ice. Thick ice, in many places frozen all the way to the bottom—a glacier. When the Olympus and Tharsis volcanoes grew, they grew up out of those thick layers of ice to form the shapes they now hold.

  "If my thesis is correct, then Isidis plain was once a bay in the Boreal Sea. And since it is on the equator, it may have become warm enough at various times that the ice would melt, forming a bay of liquid water. If my thesis is correct, then when I look around the southern perimeter of Isidis plain I should find—at the one-kilometer contour level—evidence of terraces formed by water action at the shores of the Isidis bay."

  He switched the picture to one taken of some terraces. "Ladies and gentlemen," he said, proudly pointing at the terrace features, "a picture of the terrain at one-kilometer elevation, directly south from here."

  Gus was impressed, although some of the others weren't. The argument was still going on when Gus went to bed, knowing he had a busy day tomorrow.

  Their next hop took them south across the equator to Hellas, the lowest point on Mars. After touring the various facilities, giving little pep talks to small groups and answering questions and trying to solve problems, both Gus and Chris were tired and went to relax in the Hell Hole beer garden in the basement of the hub building. There was someone familiar there.

  "Jay Plantagenet!" Gus said, coming up and slapping the young man on the back. "What are you doing here?"

  "Giving my crew of techs a little break in civilization before we start off on our crawler trek again," Jay said. "I'm combining my research with my Independence Task, which is prospecting for heavy metal ores. We spent the last six weeks in the Hellespontus Mountains. Now we're on a survey traverse of Hellas Basin on our way over to Hadriaca Patera, to see if that volcano spewed up anything worthwhile."

  "You've got a crawler free?" Chrisasked. "I'd like to borrow it to go check out my automated station."

  "Sure," Jay said. "I've got lots of free time, I'll 'buddy' you."

  "I'd like to come along, too," Gus said, then dredged up a hoary Mars joke. "Feels good to go outside and get a breath of fresh air."

  "At least you'll have a little more to breathe than usual," Chris said. "The air pressure here at four kilometers below sea level is nearly twice that over most of Mars."

  "How deep would it have to be to get up to one atmosphere?" Jay asked, curious.

  Chris did a quick mental calculation. "The present air pressure on Mars is less than one percent of Earth's, so we have to go up by a factor of more than a hundred. Three scale heights is a factor of twenty. Four is a little over fifty. Four and a half scale heights would do it. The scale height on Mars is around eleven kilometers, so you'd need a hole about fifty kilometers deep."

  "Only forty-five if you started digging here at the bott
om of Hellas Basin," Gus suggested.

  "If you'd been around at the right time, Hellas would have been dug that deep," Jay said with a smile. "But I don't think you would have wanted to be around. A little dangerous."

  "What do you mean?" Chris asked.

  "From what I've found so far, I'm now almost positive that Hellas Basin is really an impact crater. A huge one. It could have easily been over forty-five kilometers deep."

  "But it instantaneously filled in due to isostatic rebound," Gus said. "Look at it now, only four kilometers deep."

  "Instantaneous to geophysics people like you and me that think a thousand years is a short interval of time," Jay said. "I'm still working on my crater impact and rebound models for Mars, taking into account the thicker crust and the lower gravity. It may have taken hundreds of years for the hole to fill in. My model also predicts something that may be of interest to you volcano types."

  "Really?" Gus said, interested. "What?"

  "According to my model simulations, the shock waves from the meteorite that caused the Hellas Basin were so strong, they upset the inner core and fractured the crust on the opposite side. That led to the growth of the Tharsis Ridge and its volcanoes."

  "Your volcano theories are like your handball," Gus objected. "Full of tricky off-the-wall shots. I'd believe it more if the ridge were directly opposite the basin. As it is now, that meteorite would have had to come in at a steep angle."

  "Stranger things have happened," Jay said, shrugging and starting off toward the stairwell.

  FROM HELLAS Basin, Chris and Gus took off in a hypersonic single-stage-to-orbit vehicle to visit the bases on the two moons about Mars, Phobos and Deimos. The orbiter had an engine that scooped in the relatively thick air at the bottom of the basin, heated it to high temperature in an antimatter-powered heat exchanger, and exhausted it at high speed to accelerate the vehicle up to almost orbital speed before switching to rocket mode for the last portion of the climb. It was nerve-racking to zoom at hypersonic speeds low across the cratered terrain, but the air there was like the air at thirty kilometers altitude on Earth.

  Chris and Gus spent a great deal of time talking with everyone on the two moons of Mars. These people, isolated from the social contacts enjoyed in the larger bases on Mars, lived and worked under difficult and dangerous conditions. Yet they were essential to the long-term survival of the Territory of Mars. Their last get-together was with the entire contingent of the base on Deimos. They met in Asaph Hall, the small communal dining area and meeting room of the base.

  "I want to let you all know how much we appreciate your work here," Gus said to the small group of forty men and eight women crowded into the small room. "To survive, the Territory of Mars must import its medicines, its antimatter, its electronics, its precision machinery, and the other things that we need to keep alive. A nation cannot import forever, it must export something to balance those imports. The only thing exportable from the surface of Mars that is light enough to justify the cost of shipping it back to the Earth's surface is knowledge. Scientific knowledge." He paused to shake his head, then continued.

  "Until recently, we had a customer for that knowledge, the United States. Now that customer has become aberrated and no longer desires knowledge. We have found other customers for scientific knowledge, but they in total do not provide sufficient imports to keep us going. We must have something other than knowledge to export. That's where you and your Independence Task come in." Gus patted the shoulder of a man sitting next to him.

  "Your director, Tom—oops!" Gus had patted Tom too hard and now found himself floating upward in the low gravity. Tom, legs twisted around the rungs of his floor-fixed chair, pulled him back down to titters from the amused crowd.

  Gus, embarrassed, fixed himself firmly to a table and continued. "As I was saying before my oratory took me to such great heights," he joked, "your director, Tom Manley, took me out on a visit to your materials separation facility today. It is marvelous what you have done, using electrostatic and diamagnetic forces to separate out the different elements and compounds. He tells me you should have your first shipment ready to go in a few weeks. A cluster of graphite fiber storage tanks containing hundreds of tons of water, hydrocarbons, and nitrogen fertilizers destined for the gardens of the EEC Eurospace Hotel at L-5. What really impressed me was that except for the engine, the whole ship is cargo, all built right here on Deimos. You even supply the water for the reaction mass to push the cargo there. I applaud you." He clapped his hands and Chris did, too. Smiles spread around the room.

  "Of course," Gus continued, "the reason the EEC is buying your products is that they can't get them from the Moon, and they find it is cheaper to ship those vital compounds in from Mars than haul them up out of the gravity well of Earth. Also, because of the facility you have built here, you deliver processed products, ready to use, while the asteroid prospectors can only deliver unprocessed carbonaceous chondrite asteroids. The EEC benefits from lower costs and Mars benefits from an improved balance of trade."

  Chris then added, "We flatfooters really appreciate what you tippy-toers are doing. Let me know if there is anything you need."

  "Just keep the Hellsbridge scotch whisky coming," one said. Although every base found room to grow barley and brew beer, only one place made decent whisky. Everybody concluded it must be something in the permafrost field in Hellas Basin where they drew their meltwater from.

  "A few more good-looking dames would be nice," a man's voice said from the back, knowing that with an overall Mars ratio of six to one, Deimos, with its five-to-one ratio, had more than its share.

  "A few more decent gentlemen would be even nicer," a woman's voice retorted.

  CHRIS AND Gus took the orbiter down to the Chryse spaceport, a little to the northeast of Mutchville in the middle of the Chryse Plains. At 3.5 kilometers below sea level, it was the second lowest spot on Mars. After visiting the hopiter refurbishment depot there, Chris and Gus took the almost-obligatory crawler visit to the Mutch Memorial, one hundred kilometers away to the southwest. Although Gus had been there before, Chris, like many who came to Mars, had not had a chance to see it yet.

  The Viking 1 lander was sitting out in the open, just as it had been doing for sixty years, its top surfaces covered with a slight film of red dust. There was a low wall of rocks in a circle around it that hinted to the visitors to keep their distance. Inside the ring, however, there were some footprints leading up to the lander and back again. The older, faded ones had been made by the first human visitors to Mars, Russian cosmonauts. At the request of NASA, they had removed one of the cameras, obtained samples of paint and plastic-covered cables, and brought them back for analysis to look for any signs of degradation caused by the Martian weather.

  "There is one set of footprints inside the ring that looks fresh," Chris said, sitting on "Big Joe" like many another tourist before him. "I wonder what thoughtless jerk made those."

  "I did," Gus said quietly. "One of my first assignments after taking over Mars was to restore the camera to the lander and install the plaque dedicating the Viking 1 lander as the Thomas A. Mutch Memorial."

  "Oh ..." Chris said.

  THE NEXT hopiter jump took them to Melas Chasm in the middle of the Mariner Valley. The rest of Mars seemed to disappear as the hopiter dropped into the five-kilometer-deep canyon and came to rest on the landing pad beside Melas base.

  Because of the copious quantities of sandy soil and subsurface water available, and its near-equatorial latitude, the Independence Task of Melas was to be the farm belt of Mars, supplying the smaller bases with food varieties they could not afford to grow themselves. Gus and Chris visited one typical farm.

  "Watch out!" Chris yelled, as something struck Gus from behind.

  Gus turned around to fird out it was a brown and white miniature goat, and it lunged again, this time at his kneecaps. Gus fended it off.

  "I'm sorry about that," the keeper said. "We've bred milk production into them so tha
t they produce as much as a cow, but we haven't been able to breed out the butting instinct."

  "That's all right," Gus said, nursing the bruised stubs on his left hand. "It didn't hurt much. Just surprised me, that's all."

  THE NEXT base was a small one just up the valley from Melas. It was called Sinai Springs, and was close enough that it was reachable by crawler. Gus and Chris got a ride to the base on the weekly crawler that brought in food supplies. The frozen food rode uncovered in the trailer, where it stayed deep frozen in the Martian sunshine. Their driver was Ben Meier. He let the crawler move through the deep Ius Canyon on autonomous guidance while he told old war stories to Chris about how his Israeli squad had made the first strike against the Russian base at Novomoskovsk.

  They slept through the night while the crawler traveled onward on automatic; they awoke to find the Geryon Mountains had closed off their horizon to the north, while the view toward the south had also shifted closer and now looked more like a normal Earth mountain range, with branched valleys coming down to the floor, rather than the precipitous cliffs usually found in the Mariner Valley. Chris and Gus were up in the observation domes, taking in the scenery.

  "Looks like the Owens Valley region in California," Chris observed from the middle dome.

  "Except there are no tourists with ski racks on their cartops," Gus called back from the front dome. "Say! What's that up ahead? I could swear I saw something large and white—and it seems to be moving!"

  "That's our slush-glacier," Ben said proudly. "Must have built up enough pressure to break through."

  "Glacier?" Gus said. "On Mars!?"

  "Man-made," Ben said. "We'll start selling ski racks for crawlers any time now."

  THEY DROVE north of the spreading glacier field. Off in the distance Gus could see a large stream of water shooting over a rise and down the valley toward them, where it joined a lake of slushy water ponded in by frozen ice flows. The water obviously came from a large pipe that plummeted down the side of a steep cliff to the south of them. At intervals along the pipe were small blockhouses.