Gamemaster First Orbital Zone: Mercury (IF)

Hard Science-Fiction Setting

First Orbital Zone: Mercury

Mercury remains the Solar System’s forge — harsh, brilliant, and indispensable. Once the heart of the Solar Alchemy Project, it lost half its orbital zone population in Icarus Fall, but the planet itself endured. Two decades later, it is rebuilt and burning hotter than ever.

Present Overview

Population: ~90 million permanent residents, concentrated in the polar basins.

Exports: Heavy metals, fusion components, advanced ceramics, and refined Dedalus salvage.

Imports: Volatiles, organics, and specialist labor.

Power: Fusion (built post-Fall), thermal-gradient, and deep geothermal systems.

Orbit and Hazards

Low Mercury orbit is managed but still dirty in patches. Solar radiation pressure and tidal perturbations clear many light fragments over time, and polar cleanup has opened stable launch corridors. Most freight bypasses LMO entirely, fired straight onto interplanetary trajectories.

Approach notes: Inbound traffic prefers nightside and polar corridors when alignment allows, but routine craft are sun-rated for direct illumination. Only severe solar storms force scrubs or shelter operations.

Space weather hazards

• Flares (X-ray/UV bursts): Seconds–minutes of warning. Sensor bloom, avionics resets, and transient heating on unshaded hardware; EVA is suspended immediately.
• CMEs & SEP storms (solar energetic particle events): Hours–days of elevated radiation and charging. Comms degrade, guidance drifts, and long conductors (tethers, booms, rails) develop lethal potentials and spontaneous arcs.
• Charging & arcing: Mixed materials in the near-Sun plasma charge differentially; gaps flash over, spalling metal and frying electronics.
• Thermal transients: Targets warm unevenly as they rotate; frozen NaK loops and thin radiators can over-pressure and rupture when first light hits.

Operational doctrine

• Ships are sun-rated by default; salvage craft carry deployable shades, radiator shutters, high-albedo blankets, and deep storm shelters around water/slag tanks.
• GO/NO-GO is set by the Mercurian storm index: modest events curtail EVA and cutting; major events scrub all near-Sun ops or require planetary occultation.
• Do not rely on Mercury’s short umbra; treat occultation as a convenience window only. When storm alerts rise, operations retreat to polar shelters or ride out the weather in deep shadow.

Near-Sun heliocentric lanes are another story. The old Dedalus lattice orbits still harbor heavy trusses, hubs, tanks, and “live” electrodynamic tethers. Storms intermittently spike debris density, turning specific lanes lethal for weeks. These relics are both the richest prize and the greatest hazard — dense with exotic materials and unpredictable charging.

The Planet Mercury

Mercury’s people divide broadly into two cultures, shaped by the poles they inhabit. The northern basin of Goethe inherited the traditions of the industrial guilds — disciplined, deliberate, proud of endurance. The southern basin of Cervantes descends from the intellectual and artistic diaspora that once staffed the Dedalus Project — fluent, improvisational, and fiercely inventive. Together they form the twin engines of Mercury’s recovery: iron and imagination.

Industry and Infrastructure

Mercury’s economy revolves around two immense, cargo-only magnetic accelerators, one at each pole. They throw freight containers directly onto slow interplanetary trajectories, with precision timing for Earth, Venus, or Mars. Every shot is scheduled by a joint flight office that allocates azimuths, exploiting any advantageous launch windows that appear.

Solar Line Beta (Goethe Pole): The northern launcher, oldest and most reliable, hurls raw and semi-refined metals sunward toward the inner system.

Solar Line Delta (Cervantes Pole): The southern launcher, rebuilt after the Fall by former Dedalus personnel. Delta is more modern and automated, optimized for refined exports and long-range transfers.

A large accelerator can shift output between destination worlds as alignments change. This flexibility — shared by both polar lines — is the key to Mercury’s dominance in heavy logistics.

Passenger-rated accelerators no longer exist; all human travel is by shuttle and tug.

About small launchers: Pre-Fall mine-site accelerators that once lofted loads to Mercury or solar orbit have little use today. Some remain buried and half-functional — curiosities or clandestine tools for those who prefer their cargo unregistered.

Settlements

Mercury’s population lives underground, concentrated at the poles where sunlight and temperature swings are least severe.

Goethe (North Pole) — The older pole, its mining tunnels date to the Golden Age. Goethe is the industrial heart of Mercury: austere, methodical, proud of endurance. Its people speak with clipped precision and favor sturdy, modular designs. The Solar Line Beta complex stands on its periphery, flanked by foundries that never sleep. Goethe’s creed is that nothing truly fails — it can always be repaired, reforged, or reimagined within limits.

Cervantes (South Pole) — Once the Dedalus Project’s R&R and administrative hub, built as a city of glass, ceramic, and light for engineers working near the Sun. After the Fall, its surviving staff — highly educated and technically daring — repurposed the settlement into a foundry city. The vast recreation domes and surface spin habs that once housed leisure districts now stand abandoned or converted to storage. The Solar Line Delta launches from its southern plain. Cervantes’ citizens value fluency — in speech, art, and design — and their architecture still follows sweeping curves rather than the north’s angles. If Goethe makes the tools, Cervantes designs the systems that use them.

Subsurface Transport

High-speed hard-vacuum maglev galleries link Goethe and Cervantes through the deep crust, with laterals to mine clusters and power wells. Few ever travel the surface; maintenance crews and solar observers are among the rare few who see Mercury’s horizon.

Freight Pods: Maglev slugs move ore and finished goods at 300–800 m/s.

Depth & Stability: Main trunks run deep to avoid diurnal thermal stress and crust creep. Expansion chambers, slip-joint segments, and cooled gallery rings absorb motion from day–night cycling and mercuryquakes.

Gas Management: Local outgassing is vented to cold sumps and captured; alarms isolate sections if pressure rises above trace.

Environment

The day side remains a world of molten metal rivers and 700 K heat; the night side sinks below 100 K. The poles offer relative safety but still face radiation storms. All major facilities include deep shelters and redundant communication tunnels. When the Sun flares, surface work halts and the planet waits it out underground.

Ruins of Solar Alchemy

The wealth and peril of Mercury both spring from the same source — the shattered remains of the Solar Alchemy Project. Every polar launch line, every salvage tug, and much of Mercury’s trade were built to serve the Dedalus Project; today they serve its ruins.

Most of Dedalus died in Icarus Fall. When the storm reached the inner lattice, its thin-film mirrors and membrane sails were shredded in minutes, turning the near-Sun environment into a brief, lethal storm of glass and plasma — a solar storm Kessler to combine every spacer's worst fears. In the decades since, radiation pressure and solar tides have cleared much of the light debris, but the heavy frameworks and armored vaults remain, tracing vast, dangerous arcs around the Sun.

The surviving wreckage drifts mainly in inner lattice orbits just sunward of Mercury, where concentrator rings once hung in formation. Other clusters trail the planet in loose resonance bands, waxing and dispersing with solar storms. Farther out, a few dead-man stations — control habs and storm shelters hardened against pre-Fall solar flares — still tumble along eccentric paths, perihelia burned black, aphelia near Mercury.

Much of what remains is solid engineering: carbon-carbon and tungsten trusses, ceramic spars, and frozen heat-pipe manifolds designed to survive conditions that melted everything else. Storm shelters lined with slag and water endured the blast but cooked their crews when cooling failed; their data racks and cargo bays are still intact. Electrodynamic tethers drift among the ruins, charged to lethal voltages and snapping in the solar wind like invisible whips.

For salvagers, these sites hold prizes beyond metals. The Dedalus rings contained the most advanced manufacturing humanity ever achieved — and the first successful Solar Alchemy experiments, which sought to manipulate fusion products and vacuum states directly. Recovered materials include:

• high-grade rhenium and hafnium alloys
• metamaterial ceramics that remained coherent above 1,000 K
• isotope filters loaded with He-3 and Be-7
• radiation-hardened control cores still holding lattice maps and maintenance keys

Rarer still are the Solar Alchemy artifacts: doped diamonds and anomalous-phase ceramics born under extreme solar flux. Most are single-use samples, but a few display repeatable effects beyond known physics. Antimatter containment never survived the Fall, yet fragments of Penning traps and quench diagnostics still show annihilation pitting — proof the project worked, briefly.

Though the thin debris clouds are mostly gone, the solar Kessler echoes linger. Heavy trusses and hubs with low area-to-mass ratios can persist for centuries, their paths refreshed by each major storm. Salvage teams describe the region as sparse but treacherous: vast empty space punctuated by sudden, violent encounters.

Working these sites is among the most dangerous professions in the system. Solar flux varies wildly; approach windows are measured in minutes, and charged structures can arc without warning. Frozen coolant loops explode when sun-warmed. Collision-avoidance thrusters and shutter routines still fire autonomously, treating intruders as debris. Guidance beacons drift between functioning and deranged, sometimes luring craft into dead lanes.

Most expeditions follow strict protocols:

• operate sun-rated; use deployable shades, belly-to-Sun attitudes, or brief planetary occultation when available — do not rely on Mercury’s short umbra
• map all tethers before cutting anything
• tow targets into shade before breaching
• recover data cores first — they’re worth more than any metal

Note: Mercury’s occultation is shallow and short-range at this distance; treat it as a convenience window, not a requirement. Storm forecasts (flare/CME) govern GO/NO-GO much more than geometry.

Mercury’s insurance guilds demand bonded tugs and Cervantes or Goethe-issued permits for any operation within 0.5 AU. Lone salvagers are presumed either desperate, criminal, or already dead.

Adventure Hooks

Quick mission seeds on Mercury and in the near-Sun Dedalus ruins; scale danger by storm index, timing windows, and faction interference.

Mercury

• Tunnel Gas: Industrial waste gas forces a maglev train to stop halfway. Life support is limited and both rail and train are damaged. Passengers may panic. Perhaps it was sabotage, even a terrorist attack? Possible rescue from the surface — but the tunnel is deep and sunrise is coming.
• Clandestine Shot: A client wants a repaired pre-Fall “small launcher” brought online to fire an unregistered cargo into solar orbit during a flare blackout. What’s in the crate — and who else knows?
• Cervantes Ghosts: One of Cervantes’ luxury spin habitats from Dedalus days has reactivated, broadcasting ancient maintenance codes. Power readings show active life support. Cervantes command wants it secured before whoever restarted it finishes whatever they’re doing inside.
• Graveyard Shift: A critical component must be recovered from a spin hab that did not survive the Fall. It’s been twenty years, but the bodies are all still there, preserved by vacuum and cold. Security systems might still be active — and the structure itself is failing.
• Cold Light District: A half-buried centrifuge ring from the Dedalus era has become home to squatters. The ring drifts slowly, creaking against its foundations. Life support is patched together, stealing power from nearby habs. When the theft is noticed and energy is cut, the section begins to overheat and collapse — can anyone get out before it fails completely?
• Before the Dawn: A shuttle has been forced to land near an abandoned equatorial hab. The habitat no longer spins, so its gravity is near zero and its life support is powered by the shuttle’s salvaged batteries. Goethe and Cervantes authorities argue over who is responsible — and who will risk a rescue before sunrise.
• Sun Ascendant: An extremist sect of Helians hijacks a train or shuttle, demanding that the “rape of the Sun’s metals” be stopped. Can they be negotiated with, can you take back control of the vehicle — or will it end in violence?
• * Vigil of Names: On the twentieth Vigil at a half-buried Cervantes ring, survivors of a crew that lost three-quarters of its number boot an archived maintenance core to play the voices of the dead. The core begins issuing live commands to the grid, siphoning power from Solar Line Delta and risking a launch scrub as a storm watch rises. Do you cut the vigil — their only “reunion” — or reroute power and ride the storm while Helians agitators and Goethe safety inspectors close in?

Dedalus Ruins

• The Black Radiator: A 300-meter lithium radiator panel is tumbling near a resonance band. Its hinge node still holds a live control core and a cache of He-3 filters — and a cooling loop ready to burst at first light.
• Keep-Out Zone 17: A cluster of control beacons still enforces an exclusion bubble with auto-thrust and spoofed ephemerides. Someone is using the zone as a dead-drop.
• Vault 6A: A storm shelter pinged a maintenance handshake last week. Inside: intact process archives and a magnetic containment ring from a particle trap, fused by an old magnet quench — plus a live wire tether that brushes the hull every perihelion.
• Tadpole Window: A dense Dedalus hub has been lingering near Mercury–Sun L5, but venting coolant and jittery auto-thrusters are pushing it out of the tadpole. In 36 hours it slips the resonance and dives sunward. Cervantes has a provisional claim; Goethe has the tug. Can you board, kill the “keep-out” routines, and snag it before the next flare blackout hits?

See Also

• Mercury 2315 — Early Recovery Phase