Authors: Christian Cantrell
"Welcome," Subha said, spreading her arms and looking around her, "to the Emerald Eye of Venus."
The dome was sometimes poetically referred to as the Emerald Eye of Venus because of what it must look like from the sky. The atmosphere was too thick for satellites to get a true-color picture in the visual spectrum, but from just under the clouds, the geodesic dome, with its concentric green circles and large black tank in the center, must look eerily like a giant green eye staring up from the surface of the planet.
Subha gave them some time to experience the dome before she resumed the tour. The group had started to dissipate around the platform that encircled the black tank.
"Let's start with the dome itself," Subha said. Her tone was becoming more business-like, less like a new friend and more like their new boss. "We're standing inside of a geodesic structure two hundred meters in diameter containing over 8,000 panels. There are several reasons why we chose a dome over a more standard quadrilateral design. First, domes are the most efficient way to enclose space. Second, the strength of the structure is inherent in its design which means that it can easily withstand the pressure of the atmosphere, yet no material and space were wasted on structural supports. Third, domes are aerodynamic which means they can more easily resist wind and weather. Fourth, domes allow you to capture more light than any other structure, and since we have 126 Earth days of sunlight followed by 117 days of darkness, we need to capture every last photon of sunlight we can. And finally, domes are surprisingly easy to build. All the materials were fabricated on Earth, so all we had to do was put them together. Domes have the wonderful quality of serving as their own scaffolding as they're being assembled which means they can be built higher than any other structure without the use of a crane."
The group had reassembled in front of Subha while she spoke. Several questions had occurred to Arik, but he felt they were premature. She clearly had plenty more to say.
"The plants we grow here are called tulsi ferns. They were genetically engineered to produce ozone rather than oxygen, to produce positively obscene quantities of it, and to produce it equally whether in light or darkness. That means as long as they get enough light while the Sun is up, they'll keep producing ozone throughout the entire Venusian night."
"How many plants are there total?" Cadie asked. Arik smiled; he had been trying to calculate the number himself.
"Who wants to take a guess?"
"A hundred thousand," Arik said.
"Close. Roughly a hundred and
ten
thousand. If there were only a hundred thousand, you guys would never have been born."
There were narrow walkways that ascended the terraces at regular intervals, and Subha took a few steps up one to allow the group to get a closer look at the plants.
"All our plants are aeroponically grown which means we don't use any soil whatsoever. The part you can see is called the canopy and must remain exposed in order to gather light for photosynthesis. Below the canopy, the root zone is entirely suspended, and every 42 minutes, sprayed with an atomized nutrient solution. If you look carefully, you can see that the root trays are pentagonally shaped so that the atomized nutrient spray can ricochet at the correct angles to be distributed evenly."
Arik crouched down, and could see that the canopies converged at narrow circular openings, presumably leading to the ferns' complex root systems below. Subha sat down on a stair to give the group time to examine the plants. Nobody tried to touch them.
"Why aeroponics rather than hydroponics or geoponics?" René asked.
"A geoponic system would have been impossible," Subha said. "First of all, soil is heavy, and in the space business, weight is fuel, and fuel is money. Every gram of one thing you lift into space is a gram of something else you have to do without. And it's not just the weight of the soil you have to consider. You also have to consider the weight of the containers you have to store it in to prevent it from floating around and destroying your instruments in the event of an emergency. And then you have to move the soil once it's here which takes a great deal of work and equipment, and you have to engineer a far stronger terracing system which means even more materials and more weight.
"Aeroponic systems are not just easier and cheaper to transport — they're also much more efficient to maintain. Air can be circulated throughout an aeroponic system more efficiently and with less energy than a geoponic or hydroponic system, and nutrients can be delivered far more precisely. That means we need less of it, and it means less runoff to manage and process. You see that tank down there?" She pointed to the black cylinder in the center of the dome — the pupil in the emerald eye. "If we had to deliver nutrients to the roots indirectly by fertilizing soil, we would need a nutrient storage container at least four times that size."
The group was clearly impressed with what they were witnessing. The complexity and the genius behind V1's life support system was turning out to be far beyond what any of them had expected. Arik took a moment to appreciate that this could very well be the most stimulating and unique experience of their entire lives thus far. He wondered what kinds of discoveries and breakthroughs and developments might one day challenge this moment.
"But most importantly," Subha continued, "the roots are more easily contained in an aeroponic system which means if a pathogen were to be introduced, any affected plants could be quickly quarantined. That's why the plants aren't packed closer together. We could probably generate between 20 and 30 percent more oxygen if we reduced the space between plants, but if we allowed root-to-root contact, a single pathogen could wipe out our entire oxygen supply. That's also the primary concern with pure hydroponic systems. Pathogens travel very quickly through water. Although our system generates very small amounts of runoff, none of it is allowed to come into contact with any other root systems."
"I have a question," Arik said. His hand was raised and Subha turned and looked at him. He hesitated, suddenly worried that what he was about to ask might come across as smug or insulting — or worse, ignorant.
"What is it?"
"Why not just convert CO
2
directly into oxygen? Why use plants at all?"
"That's actually a very good question," Subha said, though Arik couldn't tell whether she was being sincere, or whether she was about to belittle him. She stood up, smoothed out her skirt, and started down the walkway toward the center of the dome. "Why even have a greenhouse at all? Why not just use electrolysis to convert carbon dioxide directly into oxygen? The answer is that it's actually significantly less practical than letting photosynthesis do the work for us. It takes a tremendous amount of energy to maintain the necessary environment to promote the conversion of large amounts of CO
2
into O
2
, and even if we had unlimited energy, only about 20% of CO
2
becomes breathable oxygen. The rest becomes carbon monoxide which would require still more energy to either safely vent, or process again into even smaller amounts of O
2
." She looked at Arik and smiled, emphasizing the irony in what she was about to say. "In other words, we could do it, but we prefer to use our energy for things like computing power rather than manufacturing air."
Subha was obviously alluding to the fact that Arik probably consumed more CPU cycles than anyone else in V1.
"Photosynthesis is also much safer," Subha continued. She began leading the group around to the far side of the nutrient tank. "Thanks to the dome, in the event of a total power loss, we would still have air. You see those two lockers?" She pointed out two tall metal boxes below the platform. "Those contain environment suits. If we were ever to lose power and the air circulation system stopped running, everyone could gather in areas with ducts directly connected to the dome, and we could send two people out to fix whatever broke."
This was obviously not a scenario the group had ever contemplated. They had all participated in oxygen lockdown drills, but the scenario Subha was describing was an even more desperate contingency plan. They looked at the lockers in silence.
"But I'm glad you raised that point, Arik," Subha said. "Just because photosynthesis is more practical than electrolysis doesn't mean that a greenhouse is the best way to promote it. In fact, half of you will be researching an alternative to photosynthesis which we call AP, or
artificial
photosynthesis."
"Photosynthesis without the plant," Arik said.
"Exactly," Subha said, pointing at Arik. "How many of you know what stemstock is? I mean where it
actually
comes from?"
"It's meat synthesized from the stem cells of livestock," Cadie said.
"That's right. The Agriculture Department has perfected meat without the animal, and now we need to perfect photosynthesis without the plant. As much as I love our ferns, the day is coming when we're going to need more oxygen than they are able to provide us. Without more oxygen, V1 is as big as it's ever going to get, and it will always be vulnerable to things like pathogens and any number of other events that can unexpectedly destroy plant life."
"What about terraforming?" Arik said.
"Artificial photosynthesis could make terraforming Venus entirely possible," Subha said. "If AP is as efficient as we think it will be, it might be possible to build AP machines, and disperse them across the surface of Venus to make the air breathable in anywhere from — oh, I don't know — maybe a few hundred to a few thousand years. Of course, that would be a huge amount of work, and it's likely to be extremely expensive, but it's probably possible."
"I mean by engineering a plant that will grow in Venusian soil," Arik said. "Then you could terraform the entire planet essentially for free."
Subha frowned at Arik.
"Arik, the Venusian soil, as you well know, is completely sterile. If you can engineer a fern that will grow in the soil of the least hospitable planet in the inner solar system, then you should have AP figured out by the end of the week."
The remark got the intended reaction from everyone but Cadie. Subha gave Arik a reconciliatory smile.
"Why don't we start with AP," she said, "and see what happens from there."
I
t was always assumed that the Global Space Agency would establish the first off-Earth colony on Mars. Mars was considered a relatively inviting planet. Somewhere around 4 billion years ago, the dynamics of the planet's molten core changed which almost completely eliminated its magnetic field and allowed the Sun to blast most of its atmosphere off into space. The remaining carbon dioxide, nitrogen, and argon gas now constitute less than 1% of the atmospheric density of Earth. But in the world of planetary exploration, no atmosphere was considered better than a harsh atmosphere. Since humans wouldn't have been able to breathe it anyway, the mission engineers viewed it as one less thing to have to worry about in the design of long-term structures. Having almost no atmosphere to trap in heat also meant that Mars had a relatively hospitable temperature range of -140° Celsius to a balmy 20° above zero in the summer.
But the biggest problem with Mars was gravity. Hundreds of experiments had proven that humans could live for extended periods of time in microgravity, but nobody knew what would happen to people spending an entire lifetime in an environment with only 38% of the gravitational force humans had known for their entire 200,000 years of existence. Preliminary studies suggested an extensive loss of bone and muscle density, and a weakened immune system — symptoms which were clearly incompatible with a great deal of dangerous physical work, and very limited medical facilities.
Raising children on Mars was another major concern. The goal of Project Genesis was not to construct off-Earth outposts or temporary bases where personnel would be rotated in and out on a regular basis like they were on the Moon. These colonies would eventually have to be able to replenish almost all their own resources, including themselves. Even though it was accepted that none of the original colonists would be able to return to Earth any time soon, it was also accepted that someday people would freely travel back and forth. Going from Earth to Mars was fine, but there was serious doubt as to whether a child born and raised on Mars could ever adapt to Earth's much more formidable gravitational demands.
Various forms of artificial gravity were considered. Centrifugal force can create a feeling of gravity inside a structure that rotates with enough speed, and linear acceleration can easily generate a G or more of force for finite periods of time (unfortunately the laws of physics don't allow for indefinite acceleration), but designing permanent planetary habitats around these concepts was never very realistic. Of course, it was theoretically possible to transport enough mass from Earth or elsewhere in the solar system to actually increase gravity on Mars, but no one even bothered to seriously calculate how much mass was required, how long it would take, where it might come from, and how much energy it would take to move it.
Just when the entire project was in danger of being restructured into yet another semi-permanent outpost as opposed to a true off-Earth colony, a frustrated French planetary scientist suddenly blurted out that they would have been much better off if they had just chosen Venus rather than Mars. The remark was made during the crestfallen adjournment of a six-hour meeting which had proven the impracticality of using diamagnetism to simulate a gravitational force against any organism much larger than a frog. The entire room was stunned. The answer had been right in front of them the entire time. Mars was simply the wrong planet. Venus, being almost 82% as massive as Earth, easily had enough gravity to make the risks of long term health problems acceptable and manageable, probably even negligible. The incredible pressure of the atmosphere (92 times as dense as Earth's) and the excessive amount of heat trapped by the large amounts of carbon dioxide and nitrogen were certainly obstacles, but unlike the gravitational problems of Mars, they were addressable. Designing and building habitable structures for Venus was much more like building submersibles for countering the pressure of the deep ocean rather than capsules for surviving the vacuum of space. Venusian atmospheric pressure is equivalent to an ocean depth of about one kilometer which is trivial for deep sea technology. There were already decades of research, knowledge, and technology relevant to living for long periods of time underwater. Habitable structures on Venus, the GSA realized, were as simple as communities of interconnected nuclear submarines with heat shields.