Gamemaster Second Orbital Zone: Venus (IF)

Solar Hard SF Setting

Venus the Planet

Venus is a world of extremes, locked in a slow, strange dance with the Sun. Its day lasts longer than its year, creating long periods of relentless sunlight followed by equally long darkness. The atmosphere grows denser and hotter closer to the surface, crushing and toxic, dominated by thick clouds of sulfuric acid. This hostile environment shapes every aspect of life and technology, forcing colonies to cling to the high-altitude cloud layer where pressure and temperature become more forgiving, and where survival depends on constant adaptation to a volatile, alien sky.

Atmosphere

The dense atmosphere below provides strong shielding from radiation, allowing radio and other electromagnetic signals to travel downwards from cloud cities to the surface and lower layers. This makes Venus one of the few places in the inner system where exploration drones can work remotely over long distances. However, storm ionization layers scatter up-looking sensors; orbital-to-cloud links must be optical through weather windows or tether relays. Ships orbiting above the atmosphere can not reliably use electronic sensors to look down, nor can the cities effectively scan or communicate upward into space. This creates a natural electromagnetic “blind spot” between space and the cloud layer. This is where the cloud cities of Venus thrive.

Colonization

Venus colonization pre-Fall consisted mainly of floating cities high in the atmosphere (50–60 km), where pressure and temperature are Earth-like. These cities hosted advanced biotech research and limited bio-industry, exploiting Venus’ extreme environment as a natural lab. You can survive outdoors here with just a breathing mask and acid-adapted skinsuit.

After Icarus Fall, surface and lower atmosphere installations were lost or abandoned and many cloud cities collased and fell. Twenty years on, Venus has roared back. The cloud layer is once again crowded with aerostat refineries, tethered “skydocks,” and linked city-clusters exporting what the inner system lacks — carbon feedstock from CO₂ cracking, sulfur and sulfuric intermediates, nitrates, industrial gases, plastics precursors, and specialty reagents. Pre-Fall lanes are re-charted, customs is digital again, and Venusian combines bid contracts across Mercury, Terra, Mars, and the Belt.

What changed since 2310

From salvage to surplus — The few fragile cloud cities of the immediate post-Fall era have been rebuilt into a mesh of guild-run habitats with redundant power, comms, and weather routing.

Cloud cities

Held aloft by huge balloons suspended by lifting gasses, preferably H2, but other gasses can be used in a pinch. This can be scaled, but the shell of the gas cells come under strain, limiting a cloud city to about 10.000 tons and about as many people. This means everything in a cloud city is light, almost to the point of being flimsy. Sound privacy is a a luxury, heavy industry is avoided, and shuttles are kept medium-sized or smaller. The living area is below the envelope, sometimes in a flat platform, other times following the underside of the lifting structure. Landing pads are sometimes on top of the envelope, but more commonly on arms extending out from the living area.

Safety and migration

Solar weather, Venus storms, natural acidic rain, all wear on the cloud cities, and they try to dodge these with their limited maneuverability. Operations run on forecast corridors, relay aerostats, and no-heroics doctrine. The main way for a city to steer is to rise or sink to catch a layer moving in the desired direction; there are a few other tricks but these are minor. Maneuvers are local and limited. Drifting on the prevailing wind dominates, making the practical day-night cycle of a cloud city is 4-5 days, completely different from the 117 daylight cycle on the surface.

Power

A cloud city wants to avoid anything that is heavy. This is a problem for power generation. To avoid heavy shielding, D-T reactors are avoided and D-D reactors are mounted on tethers below the city, using polyethylene blocks and distance instead of conventional shielding.

Venus is one of the few places in the system where solar power is still somewhat viable. Cloud cities open up like flowers, showing square kilometers to the sun. Lightweight super-conducting batteries store power, optimized for capacity rather than explosive power.

Different heights, different roles

Radio works inside Venus' atmosphere between cities and down to the surface, but not to orbit. Orbital communication uses lasers, but this is unreliable; atmospheric interference and the random ways wind move cities around create communication shadows.

The higher you are, the less lift you get from the thinning atmosphere, but you get more solar power and better communication with orbit. High cities host communication hubs, solar power, commercial agents, flight control, and tourism. Deeper down cities carry more load and are more industrial.

Specialization and clusters

Cloud cities are small, from 5.000 to 20.000 tons. You can form clusters, but have to separate during storms, and it can be hard to re-form the same cluster, its easier to just bunch up with other cities that happen to be near. These are unpredictable social occasions, sometimes even carnivals, meeting new people and forming new relationships.

Because of this enforced isolation, every city tries to be as self-sufficient as it can. Industrial cities have less people and more machinery, service industry cities the reverse. Each handles its own basics, power and life support, but beyond that they also try to have an independent economic cycle. Rather than being clusters for many industries, each city focuses on a specific job to gain what scale benefits it can. This is more like floating mill towns than true cities, making them sensitive to market cycles. Trade between cities is as important as exports and imports.

Orbital Cities

The usual spin habitats fill Venus' orbits. Anything heavy that can be done in orbit is, and these habitats are much larger than the cloud "cities" below, to the point that orbital Venusians may call them "cloud towns". This is where heavy processing is done, anything requiring heavy machinery, turning raw materials from below into exportable feedstock for printers.

The number of habitats around Venus cannot compare to those in cislunar or Jovian space, there simply is not enough business on Venus.

Surface Communication

Orbital and cloud cities can't keep pace, meaning that orbitals must cooperate to stay in touch with their allies below. A shuttle can easily dock at a habitat in any position, the problem is to stay in touch. Space habs forward messages, then try to find a high-altitude sky city with an open line of sight for a microwave link, who can then send the message by radio through a web of linked cloud cities.

Surface and Low Atmosphere Operations

Accessing the lower atmosphere and surface is very dangerous because of pressure and heat, but exploration, science, and special resource extraction means this is regularly done by drone.

Parachute down, balloon up

Pods go down by chute and return by balloon. All have an emergency secondary balloon and radio for safety. There is great risk and little reason for a human to ever go down.

Balloons use stored H2 as the lifting gas. If both the primary and secondary balloons fail, heated CO2 can be used as a much weaker and unstable lifting gas, this is rarely needed.

Since cloud cities drift quickly on the winds, a balloon-lifted drone will return far away from its host city, with a window every 4-5 days where the city is actually close to where the probe was dropped. This means cities must cooperate to maintain radio contact with probes.

Tethers don't reach

Tethers are superior for short dips, up to 5 km down in calm spots. There is a constant risk of wind tearing the tether, and weather changes can spell disaster at any time.

Rockets are impractical

Fusion rockets built for Venus work very well; the atmosphere provides unlimited reaction mass. The problem is the pressure and heat, a vehicle sufficiently shielded to deep-dive in the atmosphere is so heavy few cloud cities can carry it, you would have to launch form orbit, which imposes further demands on the construction.

Surface installations

There used to be scientific installations on the surface, even a small scientific habit in natural caves. None of this survived the isolation of the Fall and very little has been rebuilt, tough there are plans to do so.

Exports

Carbon — By tonnage, Venus’s flagship export is solid carbon from high-temperature CO₂ electrolysis, which also produces large amounts of O₂. Solid stock drags on buoyancy, so bulk is quickly shuttled to orbit for consolidation. The O₂ is either vented (benign), held as lift gas, or used as a clean thermal propellant for fusion rockets. Using O₂ as a chemical oxidizer is avoided and primarily seen as a fire hazard. This was exported directly after the Fall, but ice from the Belt is cheaper once you have a

Other Exports — Sulfur and sulfuric intermediates, nitrates, industrial gases, plastics precursors, and specialty reagents. All of these together amounts to much less than the carbon exports, and rides into orbit as a small extra load on the carbon shuttles. Some are shipped into orbit in half-refined form with the final processing done in orbit to avoid burdening the cloud cities with both the halfway material and the refining machinery.

The Membrane

Once native life on Venus was ruled out, humanity began adapting life to Venus. This came in the form of a membrane of lichen that forms floating layers in the atmosphere at 50 km altitude. Human supervision ceased with the Fall and it was expected they would die out, but they survived and even thrived.

Below several city-clusters, engineered biomembrane terraces have been regrown at the sharp inversion. These serve to separate the hostile lower athmosphere from the livable upper cloud layer. On top: near-Earth air and light foot traffic; below: hot, acidic, toxic chemistry farms. They serve as bioreactors, heat sinks, and emergency work decks — valuable, temperamental, occasionally predatory.

Adventure Seeds

Refinery blocs — City-states built around cracking stacks and acid plants; tariff-savvy, contract-heavy.

Skydock cartels — Control berths, tethers, and balloon traffic; arbitrate slot rights and weather fees.

Solar Alchemy legacies — Pre-Fall exotic-materials lines are selectively restarted where feedstocks and buyers justify the risk.

Derelict-no-more — “Ghost” cloud bases reoccupied but still half-mapped; old biotech and Solar Alchemy kit under new management.

Mutated membranes — Parts of the biomembrane terraces have mutated, increasing in solidity and buoyance to the point that they can carry som topsoil made from previous generations of the membrane itself. This is a scientific wonder, but might also house survivors or miscreants.

Storm-eye anchors — Platforms pinned in quasi-stable eyes; great throughput, sudden evacuations when the eye walks.

Membrane ranges — Semi-solid terraces with smuggling niches, escaped strains, and corporate claim-jumpers.

Lower-atmo windows — Timed sorties to harvest rare fractions; lost pods, disputed salvage, and contract wars over ascent slots.

Venus Descent Ops

Treat the surface like deep ocean. Keep mass and people at 55–60 km. Send down tethered work-pods or balloon-return pods; reel or float them back. Tether pod: winched from a cloud city; power/comms over the line; hours on task. Balloon return: drop a rugged pod; after work, inflate hot H₂ to ascend for pickup. CO₂ thermal lifter (rare): ingests CO₂, heats it indirectly, and jets it for VTOL — heavy, maintenance-hungry, hard to insure. Rules: Radio works below the clouds; use drones and a relay aerostat. No crews below; short sorties, redundant ascent, preplanned windows. If it can be done at 50–60 km, do it there.

See Also

• Venus 2315