A first-person space simulation of a whole galaxy

Every thrust is force over mass, and nothing stops the ship but you. Six degrees of freedom on a fixed 60 Hz physics tick, with the ship at the origin of a double-precision universe: Neptune orbits 4.5 billion kilometres out and the numbers hold to under a millimetre at Pluto. No body is inflated and no distance is compressed.

Four flight modes sit on the selector: full fly-by-wire, in which the ship stops itself; heavy fly-by-wire; damped Newtonian; and full Newtonian, the default. The Calliope has two engines, left and right, each with its own start, fuel and failure. Lose one and you get half the thrust and a yaw, and AUTOTRIM trims it out and shows THRUST ASM CTRL on the ECAM. Time runs from x1 to x1024, and a COURSE CRCT autopilot cruises at 100 kilometres a second.

Between stars: lock a star, arm the drive, fly from rest to light speed by hand in about fifteen seconds, and the jump fires at 1.0c. You arrive in the target system with its planets already moving on their orbits.

The Calliope has two decks and ten rooms, walkable in flight. Stand up mid-cruise and walk aft while the planets slide past the canopy. Her crew of seven, Arien Sarhavi at navigation, Cassie, Kade, Corso, Ellis, Odile and Talos, a bronze robot deck hand, keep a watch bill and eat at the table, with 280 motion-capture clips each. Her doors, ramp, holotable, chairs, tablets, shower and screens all answer to E.

Her systems are live: reactor, power bus, helium-3, life support, cabin air, cabin heat, and water as both propellant and radiation shield, a 20 tonne jacket. The dose model behind the cabin readout agrees with flown dosimeters, from the ISS to Curiosity, within a factor of two. The ship can kill you: a hull breach, a cabin that warns, counts down, dims the view and muffles the sound, and a reactor that can be pushed past SCRAM INHIBIT at the risk of an explosion, with ten recorded computer-voice lines on the way.

The Aporia is the second playable hull, a frigate, walkable and flyable from any of her four bridge seats. Behind them is a sky fleet of 82 hulls: freighters, frigates, destroyers, dreadnoughts, carriers, interceptors, bombers, a liner, a scout and 27 landers. Over Luna they fly as traffic: up to four flyovers and two landers at once over two pads, with the Calliope parked on pad 1. Landers cruise in from 3.8 kilometres, fly a glide slope at 32 metres a second from 110 metres up and touch down at about four metres a second. Every hull flies real physics and banks steeper in the Moon's gravity, and a ship you are watching is never despawned.

Every gas giant in the galaxy wears the project's own procedural weather, each with its own seed: cloud bands stirred through a wind field built for each planet over forty steps, zonal jets after Ingersoll 2004, vortex streets, named storms, a straight-sided hexagon at the pole, Juno-style polar cyclones, ammonia ice over the ammonium hydrosulfide deck, haze with multiple scattering, and a night-side glow on the hottest giants. 88 looks cover every giant subtype the simulation generates, and all 1,965 giants in the galaxy carry one.

Fly down and skim the cloud tops: close patches hold 0.21 kilometres a texel on a Jupiter, and a 4096 map bakes in 0.37 seconds. The day side fades toward night across the disc as it does in Cassini's frames, and hot giants lock one face to their star where the physics says so. Rings take Saturn's optical depths from Cassini occultations, 687 bodies are ringed, and fly into a ring and it becomes ice: 19,696 pieces in Saturn's B ring.

Fly to Cygnus X-1 and watch it bend the real stars behind it. The Schwarzschild case uses Bruneton's 2020 precomputed beam tracing; when the hole spins, the closed-form Kerr ray of Gralla and Lupsasca (2020) is solved per pixel and lands within 0.013 pixels of the offline oracle. The shadow is black to the last pixel, the photon ring is smooth, nearby stars stretch into arcs, and the thin disk carries gravitational and Doppler shift together, so its colour and brightness come out of one formula.

Twelve stops are flyable: Cygnus X-1, Gaia BH1, V404 Cygni and Sagittarius A*, with masses and spins from the literature, and seven neutron stars with hot lensed surfaces and turning polar caps: the Crab, Vela, Geminga, RX J1856.5-3754, PSR J0437-4715, Hercules X-1 and SGR 1806-20. Each hole sits at its true distance from its companion star, every compact stop lends the ship a Level 12 Experimental Heat Shield, and a speed regime scaled to the hole, LOCALVEL-BH, keeps the approach flyable.

Hold a fortified company town against droid assaults, with tanks at the wire and a gatling in your hands. The base is 36 buildings on a 280 metre levelled pad on a Mars-sized desert world, behind 1,531 metres of concrete: 889 jersey barriers, 34 sandbag strongpoints, three gates and 18 fighting positions with 60 to 97 metres of open pad between them, so an attack can come from any bearing.

Six tanks sit hull-down at the wire, from the MX1 main battle tank with its 105 mm gun to the MX2 heavy with 150 mm HEAT and a roof minigun, the MX3 with twin lasers and a missile rack, and the MPV-35 with twelve tubes. Each turret picks a target, tracks it and fires when it has the shot, on the same solver the starships' turrets use. Armour is its own target kind: small arms land five percent, a tank's rear carries a fifth of its front armour, so infantry flank. Open the scenario window and it shows YOUR FORCES against OPPOSING FORCES with the seed on screen. HEAVY WEAPONS gives you one to three tanks against two to four enemy tanks behind a droid line; DROID ASSAULT sends eight to sixteen droids at you alone. After a few seconds of calm the enemy arrives through a tear in the sky, a gate, or by beaming in, and they hold, press, flank, take cover and throw grenades.

Nine weapons sit on keys 1 to 9, among them the Rotary Cannon, a gatling firing 1,200 rounds a minute from a 100-round magazine and smoking after thirty, and the cargo tractor grabs, stacks and throws crates at 22 metres a second. When the last droid falls the victory music plays and the After-action Report opens: order of battle, battle damage assessment and own losses, your units by spoken callsign, experience on a first-edition tabletop scale, six honorary ranks per faction and 24 medals, among them the Corona Aurea and The Grey Wolf.

Cycle the airlock, take off your helmet, and step into a furnished moonbase. The site is at 77.77 north on Halden Mare, on a 250 metre pad cut dead level at the shore of the lava sea. Its atrium is a 120 metre glazed dome with a deck, a promenade, four pavilions and 136 plants, inside a nineteen-piece base cluster. The medical and crew habitat and the workshop are furnished, with real windows, working airlocks at all four entrances with a sealed dwell and door interlock, terminals, task lighting and habitat displays.

Four astronaut suits are in the game, and Cassie follows you out and takes Stay, Follow, Scout and radio orders. Luna's Crater Base, with its traffic overhead, is already open.

The planetary scout flies on NASA's F-16 wind-tunnel data (NASA TP-1538, Nguyen et al., 1979): full coefficient tables, mass and inertia, and an afterburning engine. A 9 g limiter and a 25 degree angle-of-attack ceiling; full-stick rolls at up to 324 degrees a second; real stalls and spins, recovered with rudder; Mach 1.285 at sea level and 1.98 at altitude. Because it is an exploration vehicle it has vectored thrust with five nozzle detents and an autohover, a speedbrake, a moving map and a primary flight display, in a cockpit that reads as the Calliope's own. It flies over Fernrock today.

And because we could: a Boeing 737 flight deck over a procedural planet. Start in the captain's seat at 10,000 feet and 283 knots, trimmed hands-off, with nine tonnes of Jet A-1. It is not fly-by-wire: a real stabiliser and trim, engine thrust that pitches the nose up, and a phugoid, with aerodynamics worked from first principles and published Boeing figures and drag within two to five percent of an established open model. A three-tank fuel system, captain's and first officer's primary flight displays, and a 69-key flight computer keypad. The same 737 is the model for the Calliope's overhead panel.