Martian Rainbow

by Robert L. Forward

  "We are on way," Joseph said. He reached up to the two-meter-long carrier frame and unloosened three more harnesses.

  "Let me ride up front," Chris said, reaching for the first harness. "I want to analyze some air samples as we go up."

  Joseph helped them with their harnesses and, as soon as he was sure they were all properly buckled in, he started the motor on slow. Gus walked a few steps, then found himself treading air, while Chris' long legs took him to the peak of the slope before he started flying. On the way up, Joseph gave them a guided tour of the lava layers they passed on the cliff face.

  As they approached the top, Gus could see no sign of Tanya. He was slightly worried, thinking that she might have fallen while they were traveling up, but then they got a call over the radio.

  "You traveled faster than I expected," Tanya's voice said. "I thought from what I heard over the radio that Joseph was going to show you every little ice crystal he could find in the cliff face to support his silly notion of Mars covered with glaciers ten kilometers thick. I'll be right out."

  The outer airlock door opened in a small yellow plastic prefabricated hut snuggled up to a boulder. Tanya exited and came bounding over to the cliff edge where they would land.

  "Not glaciers, Tanya," Joseph said in annoyance. "Frozen oceans. And not ten kilometers deep, just five or so."

  "Just five. Five's still ridiculous. Quiet, now. I'll bring you to a halt." The motion of the cable slowed and halted. Gus also noticed with relief a long red lever connected to a transmitter box that he could have slapped, and a red pull-cord at the turn wheel that would have shunted the carrier frame and its cargo off the cable and onto a siding track with a decelerator section.

  As Tanya helped them out of their harnesses, she babbled on happily. "I warmed up the hut for you while you were coming up the cable. It felt good to get out of the suit for a while and clean up. Now you can, too—without a woman in the way. Go ahead—while I monitor lifting the supply load."

  "We lost one and a half millibars on the trip up," Chris said, peering at the readouts on his portable analyzer. "I'll have to get well upwind from the hut before I do any composition meaurements, though. I'm sure the water vapor and the hydrocarbons I'm seeing are coming from leaks during the airlock cycle."

  Leaving Tanya talking by radio to Mike McGuire below, the four men cycled their way into the hut. Gus was the first one through the airlock into the cramped six-person hut. Two paces took him from the exit door of the airlock to the entry door to the toilet. As he took off his helmet, he smelled a combination of mustiness from the plastic walls and scorched dust from the hot coils of an electric heater. The smells were faint in the half-atmosphere air pressure of the Russian-built hut. There were six bunks, three each along two walls. He put his helmet on the bottom bunk and started getting out of his Marsuit. By the time Joseph had finally cycled through the lock, he had to wait to open the door in order to give the other three men enough room to struggle out of their suits.

  Gus went into the tiny bathroom. Because it didn't have zero gee facilities, it reminded him of one on an airplane back on Earth. The sink was damp—recently wiped clean—and there was a small wet hand cloth folded neatly over one of the drying racks on the wall overhead. He picked it up and brought it closer to his nose. The faint scent of womanly sweat mixed with cleansing lotion brought back memories of hardworking but idyllic days on the Moon in a crawler.

  That afternoon, they walked along the edge of the cliff a number of kilometers, Tanya pointing out different lava flows that she had dated. They came to a long, rounded ridge that went straight down the mountain. Gus started to look for a way to climb it.

  "Come this way," Tanya said, pulling on his elbow. She led them to a crevice and they walked through into a large, underground cavern that arched high overhead. The crevice had formed at the site of a large fault plane that had sliced right through the cavern, opening it to the sky and letting a two-meter-wide sheet of sunlight in.

  "A lava tube!" Ozaki exclaimed. "But such an immense one! There is nothing like this on Earth."

  "A big volcano deserves big lava tubes," Gus mused, looking around. He walked out of the patch of sunlight into the darkness on the uphill side of the cavelike tube, pulled down the viewer on his helmet, and activated his helmeyes. Using the zoom feature he looked up-slope. The larger the zoom, the more sensitivity the helmeyes had to use, and still there was no end to the cave. He centered the viewer reticle at the darkest point in the image, triggered the laser range finder, and waited. The range indicator came up all nines. There had been no return. Chris walked by him, holding his analyzer out in front of him, the light from his chestpack making a pool of rippled brightness and shadow on the rugged gray floor.

  "We have walked up the tube for fifteen kilometers," Tanya said. "There was no end in sight. We can trace it on survey photographs for over two hundred kilometers."

  "The down end empties over the cliff edge," Joseph said.

  While he had his range finder activated, Gus took quick range measurements in the other directions.

  "Fifty meters high by three hundred meters wide," he said as he raised his visor and rejoined them in the sunlit section of floor.

  "Truly immense," Ozaki said upon hearing the numbers.

  "No traces of hydrogen sulfide. Must be a pretty dead vent," Chris reported from the gloom.

  "We have dated this flow at two hundred ten thousand years," Tanya said. "The youngest one we have found in this region of the volcano is over one hundred thousand years old."

  "We haven't been all the way around yet," Joseph said. "There is still a lot to do." He led the way back out of the lava tube.

  "Mars is a big place," Gus admitted.

  "With exceptionally big structures," Ozaki said, coming out the crack in the gigantic lava tube. He once again stood looking in awe up toward the peak of the planetoid-sized volcano they were climbing. It was seventeen kilometers above and three hundred kilometers distant from where they were. "I am so used to volcanoes like Mount Fuji, or the Hawaiian Islands, where you can get close enough to the structure that the sides are steep and the peak towers over you. Here on Olympus Mons, once we are on top of the steep ramparts, the average slope is only a few degrees, and the top of the peak is barely visible over the curvature of the horizon."

  When evening came, they gathered in the hut, stored their suits and helmets in storage lockers, and raised one rack of bunks to give themselves a little more room. They cooked one of their more substantial meals in the compact microwave oven, then pulled down the table from the ceiling to eat and plan their next day's journey. There were no chairs, the middle bunks doubling for that duty.

  There was also the inevitable housekeeping. Tanya did the dishes, Chris re-sorted their supplies, Ozaki filled and checked the air and water tanks in their suits, Joseph cycled and checked the hut utilities, and Gus did everyone's dirty laundry in the miniature ultrasonic-washing, microwave-drying launderette.

  They got to bed early, since the next day would be a long one. Chris went to sleep nearly instantly in one of the top bunks, despite the fact that he had to sleep curled up since the bunk was substantially shorter than his nearly two meters. His snores reverberated in the chamber formed around his head by the top corner of the hut and the flimsy wall of the toilet.

  Gus had a hard time getting to sleep and lay in the bottom bunk, his eyes wandering over the dimly illuminated curved shapes formed in the bed above him by Tanya's body. The curved shapes moved as Tanya rolled over, and a thin hand reached down over the edge of the bed. He reached up and squeezed it. It squeezed back and withdrew up under the cover.

  THE NEXT day was more riding on cable lifts. There was a crawler at the top of the southeast lift that they could have used, but since this was just a fast, get-acquainted visit to Mount Olympus for the "foreigners" taking over the planet, it was faster to use the cableway the Russians had installed during their first few crawler transits of the superlarge volc
ano. The cableway was in thirty-kilometer segments, so there was never more than a fifteen-kilometer walk if the cable broke or a motor failed.

  "We all go together, this time," Joseph said as they approached the end station of the southeast cableway.

  "I see we get seats this time," Gus said.

  "Three hundred kilometers in a harness wouldn't be fun," Tanya said. "I had to do some thirty-kilometer segments that way in the early days. Sling seats are much better. Here, let me show you how to adjust it."

  With Chris and his analyzer in the lead and Tanya at the rear, followed by the bag of supplies, they started slowly up the slope. As they gained experience balancing and handling the jolts as they passed over idler pulleys along the way, Tanya increased the speed by sending radio commands to the motor at the base station.

  "We are moving with exceptional rapidity," Ozaki said, looking down at the volcanic blocks streaking by underneath his feet.

  "Forty kilometers an hour," Tanya replied. "I can go faster if you want."

  "Great!" Chris said, obviously enjoying the ride. "Jack it up higher!"

  "No!" Ozaki said. "This is sufficient speed."

  "I agree," Gus said.

  They came to a flat plateau region about ten kilometers in diameter. Five kilometers to the north was a triangular rock jutting a few hundred meters up out of the plateau. Five kilometers to the south was a larger rock, even more triangular, with sharp edges, that jutted up more than half a kilometer. As the cable-run took them between the two jagged spikes, Tanya slowed the cableway to a stop.

  "Now," she said, "I would like our three distinguished foreign scientists to observe the formations to the north and south of us. Although Comrade Kilometers-high-glaciers up front has ridden over this plateau many times, he has failed to comprehend what is right before his eyes. You will observe that these formations have sharp edges and nearly vertical faces on all three sides. Do they look like a flow of volcanic lava that has run into a glacier? No! They look like up-faulted rocks, exactly what one would expect around the edges of a massive volcano. I rest my case."

  "Tanya!" Joseph said in annoyance."I have already admitted these massifs along the cliff edge are suggestive of up-faulting, but only on this southeast side. You don't see them anywhere else around the periphery. Let us go on."

  "Well, Ozaki," Gus said, "it looks as if the Russians have left us plenty of research questions to work on here."

  "Indeed," Ozaki said, allowing a soft chuckle in his reply.

  AFTER they left the small plateau, they came to the end of the first cable-run.

  "Southeast Eleven!" Tanya announced as they arrived.

  "Eleven?" asked Gus. "Shouldn't it be two?"

  "We numbered them according to altitude," Joseph said, pointing to a sign. The sign had "11,030 m" painted on it. "We are now over eleven kilometers above Martian 'sea level'. We have sixteen more kilometers to go."

  After a few minutes of stretching their legs and looking around, they switched to the next cableway and continued their long climb to the top.

  IT WAS four hours later and the sun was nearly overhead, when a station came into sight that was more than just a motor and a frame. This one boasted another hut.

  "Southeast-Eighteen," Tanya reported. "Halfway point and some welcome relief."

  "Thank goodness," Gus said as he felt the cable slowing. "I was about to have to use my suit system."

  Joseph slipped from his seat while the cable was still moving and ran quickly toward the door of the hut. Gus was right behind him. Chris went off away from them to make some measurements of the atmospheric composition.

  "Raise the seat!" Tanya yelled after them as she helped Ozaki out of the harness. The two of them followed the rapidly moving form of Gus up the well-trod path to the hut.

  Chris was the last one through the airlock. "Only a little over one millibar pressure," he reported. "We are five-sixths of the way to space. I'm also seeing a different mix. Five percent nitrogen instead of the two and a half percent at Martian 'sea level'. Also higher concentrations of carbon monoxide, ozone, NOX compounds, and ions."

  AFTER an energy-bar lunch and a small sip of water, they were back in the sling-seats again. Chris came down from a small rise where he had been scanning the horizon.

  "The mountain just seems to disappear, the closer we get," Chris said plaintively as he got into his seat.

  "The caldera is eighty kilometers in diameter and we are one hundred fifty kilometers away," Ozaki said. "It should not be a surprise."

  "The only way to really 'see' this mountain is from space," Gus said.

  "Yes," Ozaki replied, nodding in agreement. "It is extraordinary from there."

  Tanya tongued them into motion and they started once more up the gradual slope.

  IT WAS sunset when they reached the last station at the edge of the Mount Olympus caldera. While Tanya and Joseph went off to use the facilities of the large twelve-person cabin at this research station, Chris, Ozaki, and Gus, awed by the majestic wonder of the scene, forgot their bodily discomforts and moved closer to the edge. They were right on the edge of the steep slope of the deep southwest collapse crater.

  "Holy moly!" Chris said quietly to himself as he looked over the edge of the three-kilometer-high cliff.

  "It must have been some sight when it was active," Gus said, looking down at the nearly flat surface far below. "A twenty-kilometer-diameter pool of glowing, molten rock."

  "Or the larger caldera during an earlier day," Ozaki said, waving his arm at the horizon. "Molten lava as far as you could see."

  THE NEXT day they spent exploring the caldera. Tanya showed them the samples she and others had collected and the take-apart model that they had constructed that allowed one to visualize the sequential history of the various eruptions that had been identified by caldera overlapping and sample dating.

  "Our youngest sample is a core from the floor of the northeast collapse crater," Tanya said. "It dated out at only thirty thousand years."

  "Young, by geologic standards," Gus said, impressed. "The mountain is no doubt still alive."

  "Any signs that the fire dragon inside is stirring?" Ozaki asked.

  "Our seismic net has not picked up anything significant yet," Tanya replied.

  "I pick up an occasional whiff of volcanic-type gas molecules," Chris added, "but nothing significant."

  Gus and Ozaki took the model outside and compared it with what they saw. They then took another cable ride, this time down into the caldera of the volcano.

  "I see you have started drilling a coring hole," Gus said as he looked around after reaching the bottom of the southwest collapse crater. Chris stuck the port of his analyzer down the borehole.

  "I had a team of technicians carrying out a detailed core-sample survey program, but their work was interrupted by some unannounced visitors," Tanya said dryly.

  "Let me know what you need for a crew to get it operating again, and I'll get them for you," Gus said. "As a guest of the Sagan Mars Institute, you have equal rights to support equipment and manpower."

  "Thank you." Tanya patted him on the arm. "When we return, I shall form a crew and set them to work."

  Once back up top, they boarded a crawler and made their way around the caldera to the other side. Chris insisted that they take the long way around, since according to the topographic map, the highest point on the volcano—and probably on Mars—was in that direction. When they came to the middle of the 26,500-meter contour on the crawler's map they found a sign reading "26,551 m." Below it was a long list of names written in Cyrillic, and a date.

  "Tan ... ya Pav ... lo ... va ... A.D. 2035," Gus said, spelling out the last name on the list and the date. For the first time in a long time Gus felt second-rate. The Russians had been here first—years ago. Now the U.S. was reduced to stealing the planet away from the Russians. But the Russians had been greedy; now Mars belonged to itself—and all the people who cared enough to come there to settle.

 
; "Joseph is on list, too," Tanya said.

  "I want to make a composition measurement," Chris said. He got quickly into his Marsuit and cycled out the crawler airlock.

  "Now go back a ways and wait until I call you," Chris said from outside through his suit radio. "You're polluting the air—what there is of it!"

  Shortly after Joseph had driven the crawler away, Chris called them back again and he climbed back in.

  "Things stabilized fairly fast once you were a few hundred meters off," he reported as he took off his Marsuit. "Total pressure only 439 microbars, less than a half a thousandth of an Earth atmosphere. In the old days you could have packaged that and sold it as a vacuum. Carbon dioxide down to 91 percent instead of 95 percent, and lots of interesting excited molecules to stick into my stratospheric model."

  They had dinner at the edge of the northeast collapse crater, the near twin to the southwest crater. Joseph had maneuvered the crawler so that the view window of the crew quarters in the rear segment of the crawler was looking out over the cliff. There was another Russian cabin there, but they decided to stick with the facilities in the crawler.

  They continued on around the caldera, stopping occasionally to visit a site that the Russian scientists had found interesting. It was night again when they finished the 180-kilometer journey.

  "Here we are at Northwest Twenty-six," Joseph said as he brought the six wheels of the crawler to a halt beside the twelve-person cabin. "Time for dinner and early bed. It will take all day to ride down the north side of the mountain tomorrow."

  "I have an idea," Tanya said brightly from the couch-bed in the living quarters. "So that we all have more room, why don't you, Chris, and Ozaki sleep in the cabin, and Gus and I can sleep out here in the crawler?"

  "Fine by me," Chris said, reaching for his Marsuit.

  "But ... the cabin," Ozaki objected, very perplexed. "The cabin ... it holds twelve people. Plenty room—"