“I think so. I’m going to get us down as fast as I can, I’ll have to empty some of the ballonets.”
He tapped away at the control keyboard, and the dirigible tilted forward and they began to drop at emergency speed. The altimeter’s numbers flickered down. The radar screen showed the ground below to be basically flat. The ping got louder and louder— without a directional receiver, that was going to be their only way to tell if they were still approaching it or moving away. Ping… ping… ping… In her exhaustion it was hard to tell whether it was getting louder or softer, and it seemed every beep was a different volume, depending on the attention she could bring to bear.
“It’s getting softer,” Arkady said suddenly. “Don’t you think?”
“I can’t tell.”
“It is.” He switched on the props, and with the whir of the motors the signal definitely seemed quieter. He turned into the wind, and the dirigible bounced wildly; he fought to steady its downward movement, but there was a delay between every shift of the flaps and the dirigible’s bucking, and in reality they were in little more than a controlled crash. The ping was perhaps getting softer at a slower rate.
When the altimeter indicated they were low enough to drop the anchor they did so, and after an anxious bit of drifting it caught, and held. They dropped all the anchors they had, and pulled the Arrowhead down on the lines. Then Nadia suited up and climbed into the sling and winched down, and once on the surface she began walking around in a chocolate dawn, leaning hard into the irregular torrent of wind. She found she was more physically exhausted than she could ever remember being, it was really hard to make headway upwind, she had to tack. Over her intercom the transponder signal pinged, and the ground seemed to bounce under her feet; it was hard to keep her balance. The ping was quite distinct. “We should have been listening on our helmet intercoms all along,” she said to Arkady. “You can hear better.”
A gust knocked her over. She got up and shuffled slowly along, letting out a nylon line behind her, adjusting her course as she followed the volume of the pings. The ground flowed underfoot, when she could see it; visibility was actually down to a meter or less, at least in the thickest gusts. Then it would clear a touch and brown jets of dust would flash by, sheet after sheet, moving at an awesome speed. The wind buffeted her as hard as anything she had ever felt on Earth, or harder; it was painful work to keep her balance, a constant physical effort.
While inside a thick, blinding cloud, she nearly shuffled right into one of the transponders, standing there like a fat fence post. “Hey!” she shouted.
“What’s wrong?”
“Nothing! I scared myself running into the roadmark.”
“You found it!”
“Yeah.” She felt her exhaustion run down into her hands and feet. She sat on the ground for a minute, then stood again; it was too cold to sit. Her ghost finger hurt.
She took up the nylon line and returned blindly to the dirigible, feeling she had wandered into the ancient myth, and was following the only thread out of the labyrinth.
• • • During their rover trip south, blind in the flying dust, word came crackling over the radio that UNOMA had just approved and funded the establishment of three follow-up colonies. Each would consist of 500 people, all to be from countries not represented in the first hundred.
And the subcommittee on terraforming had recommended, and the General Assembly approved, a whole package of terraforming efforts, among them the distribution on the surface of genetically engineered microorganisms constructed from parent stock such as algaes, bacteria, or lichens.
Arkady laughed for a good thirty seconds. “Those bastards, those lucky bastards! They’re going to get away with it.”
One winter morning the sun shines down on Valles Marineris, illuminating the north walls of all the canyons in that great concatenation of canyons. And in that bright light one can see that here and there a ledge or outcropping is touched by a warty speck of black lichen.
Life adapts, you see. It has only a few needs, some fuel, some energy; and it is fantastically ingenious at extracting these needs from a wide range of Terran environments. Some organisms live always below the freezing point of water, others above the boiling point; some live in high radiation zones, others in intensely salty regions, or within solid rock, or in pitch black, or in extreme dehydration, or without oxygen. All kinds of environments are accommodated, by adaptive measures so strange and marvelous they are beyond our capacity to imagine; and so from the bedrock to high in the atmosphere, life has permeated the Earth with the full weave of one great biosphere.
All these adaptive abilities are coded and passed along in genes. If the genes mutate, the organisms change. If the genes are altered, the organisms change. Bioengineers use both these forms of change, not only recombinant gene splicing, but also the much older art of selective breeding. Microorganisms are plated, and the fastest growers (or those that exhibit most the trait you want) can be culled and plated again; mutagens can be added to increase the mutation rate; and in the quick succession of microbial generations (say ten per day), you can repeat this process until you get something like what you want. Selective breeding is one of the most powerful bioengineering techniques we have.
But the newer techniques tend to get the attention. Genetically engineered microorganisms, or GEMs, had been on the scene only about half a century when the first hundred arrived on Mars. But half a century in modern science is a long time. Plasmid conjugates had become very sophisticated tools in those years. The array of restriction enzymes for cutting, and ligase enzymes for pasting, was big and versatile; the ability to line out long DNA strings precisely was there; the accumulated knowledge of genomes was immense, and growing exponentially; and used all together, this new biotechnology was allowing all kinds of trait mobilization, promotion, replication, triggered suicide (to stop excess success), and so forth. It was possible to find the DNA sequences from an organism that carried the desired characteristic, and then synthesize these DNA messages and cut and paste them into plasmid rings; after that cells were washed and suspended in a glycerol with the new plasmids, and the glycerol was suspended between two electrodes and given a short sharp shock of about 2,000 volts, and the plasmids in the gycerol shot into the cells, and voila! There, zapped to life like Frankenstein’s monster, was a new organism. With new abilities.
And so: fast-growing lichens. Radiation-resistant algae, Extreme-cold fungi. Halophylic Archaea, eating salt and excreting oxygen. Surarctic mosses. An entire taxonomy of new kinds of life, all partially adapted to the surface of Mars, all out there having a try at it. Some species went extinct: natural selection. Some prospered: survival of the fittest. Some prospered wildly, at the expense of other organisms, and then chemicals in their excretions activated their suicide genes, and they died back until the levels of those chemicals dropped again.
So life adapts to conditions. And at the same time, conditions are changed by life. That is one of the definitions of life: organism and environment change together in a reciprocal arrangement, as they are two manifestations of an ecology, two parts of a whole.
And so: more oxygen and nitrogen in the air. Black fuzz on the polar ice. Black fuzz on the ragged surfaces of bubbled rock. Pale green patches on the ground. Bigger grains of frost in the air. Animalcules shoving through the depths of the regolith, like trillions of tiny moles, turning nitrites into nitrogen, oxides into oxygen.
At first it was nearly invisible, and very slow. With a cold snap or a solar storm there would be massive die-offs, whole species extinct in a night. But the remains of the dead fed other creatures; conditions were thus easier for them, and the process picked up momentum. Bacteria reproduce quickly, doubling their mass many times a day if conditions are right; the mathematical possibilities for the speed of their growth are staggering, and although environmental constraints— especially on Mars— keep all actual growth far from the mathematical limits, still, the new organisms, the areophytes, quickly reproduced, sometimes mutated, always
