LGM-30G Minuteman III

The complete ICBM system for KSP 1.12, at true scale. By MoWoSf · Version 1.1.1

The US Air Force's land-based intercontinental ballistic missile, rebuilt part by part. It launches from its own silo, flies with its own guidance computer, spreads its warheads with a real post-boost vehicle and ends with a physically modelled nuclear detonation. No MechJeb or kOS needed.

One download, three variants: stock Kerbin, Realism Overhaul / RP-1 on Real Solar System, and Realism Overhaul on Sol (RSS Reborn). Two loadouts: MIRV with three Mk12A reentry vehicles, or a single Mk12A.

Highlights

• True-scale missile: 18.22 m, 35.4 t, 1.68 m and 1.32 m diameters. Every stage, interstage, skirt, shroud and RV is its own part with a custom 3D model.
• Real performance: stage data from Aerojet and Thiokol. With Realism Overhaul the MIRV reaches roughly 8,000 to 9,000 km, depending on the direction, and the single RV well over 12,000 km.
• NS-50 guidance computer: flies the whole mission from LAUNCH to the last impact. It handles the ascent, staging, stage 3 thrust termination, MIRV targeting, warhead release and arming.
• Knows before launch whether a target is in reach: the reach is worked out from the actual missile, its load and the launch site. Targets beyond it show in red.
• MIRV the way it worked:
• targets taken in order down the flight path
• warheads sharing a target come down 20 s apart
• the bus coasts with all warheads on board and deploys them from 2,000 km out
• Vandenberg LF-10 silo:
• the missile hangs on its suspension system with guide shoes and a guide ring
• the closure door rolls back and the umbilical swings away
• the missile hot-launches straight out of the tube
• Penetration aids: chaff from the bus's two dispensers, with heavy chaff down to the 200,000 ft floor.
• MM3Nuke W78 warhead: flash, fireball, Wilson cloud and mushroom cloud after Glasstone & Dolan. The blast wave destroys parts, vessels and buildings.

The missile

Every assembly separates as on the real missile, at its real position and with its real mass:

Detail work from reference photos and cutaways:

• a continuous cable raceway from stage 1 to stage 3 that leaves cleanly with each stage
• panel lines, stringers, riveted seams and round bolt heads
• P-clamped cable bundles and textured flex conduit on the PBV deck
• braided hoses, V-band latches with T-bolts, and pressurant bottles on their stand-offs
• a 4096 px texture atlas with a normal map, paint grain and light weathering

Realism Overhaul version:

• Propellants and Isp: RealFuels propellants (PBAA and CTPB solids, MMH/NTO in the PBV). The specific impulse matches the manufacturers' averages.
• Motor burnout: the solid motors burn out to the last 0.12 % of their propellant, as the Minuteman's do.
• Throw weight: 1,150 kg, as declared for START.
• Integration: RP-1 tech tree, RealAntennas and reentry heating values.

Kerbin version: real dimensions, masses and thrust. The specific impulse is scaled so the missile covers the same share of the planet as the original does on Earth.

MIRV loadout

The post-boost vehicle carries three Mk12A reentry vehicles and puts each one on its own target.

• Order down the track: the active targets are taken in order down the flight path, nearest first.
• Fewer targets than warheads:
• one target takes all three warheads
• with two targets, the nearer one gets one warhead and the further one two
• three targets get one each
• Time on target: warheads sharing a target come down on it 20 s apart. The bus solves the impact time as well as the impact point and puts each later warhead on a slightly higher arc.
• Coast, then deploy: right after stage 3 the bus makes one correction toward the target area. It then coasts with every warhead on board, holding its attitude in a wide deadband; time warp is allowed. From 2,000 km to the nearest target it brings itself to each release point in turn: fine correction, timing, release.
• Footprint check: the bus can spread its warheads over an ellipse about 200 miles down the flight path and 50 miles across. The map draws it, and the window warns when the targets do not fit.
• Short of range: if a target lies beyond the bus, it burns all it has in the direction that gains the most range. It always keeps a reserve for its attitude jets.

Single-RV loadout

One Mk12A on the centre station of the bus, straight up the missile's axis. The PBV shows the matching mount, and the interface offers one target.

NS-50 guidance computer

Press LAUNCH and the missile flies the whole mission itself:

• Launch sequence:
• combat readiness check
• closure door removed, upper umbilical retracted
• hot launch, with hands off the controls while the missile is still in the tube
• Ascent:
• an early, firm pitch-over that keeps gravity losses low
• closed-loop steering in the plane through the target's position at impact
• great-circle routes, over the poles too, with the Earth's rotation accounted for
• Staging:
• every stage and skirt separation, and the shroud jettison
• stage 3 thrust termination at the computed range
• Release and arming:
• each warhead is released along its flight path and spun up by its spin motors
• the computer pre-arms it from its flight safety checks
• the warhead stays safe until 10 km above the ground and arms there
• Warheads stay under physics: released warheads and the bus stay under physics out to 1,000 km. Switching vessels or time warp no longer deletes them on reentry.
• Penetration aids: after each release the two chaff dispensers on the bus put a cloud of dipoles round the warhead. On the way down the bus lays heavy chaff every 15 nautical miles from 400,000 ft to the 200,000 ft floor, where the air strips it away.
• Impact prediction: RK4 integration with drag, planetary rotation and terrain height, shown in the window and as map markers.
• Reach before launch: for every target the window shows distance, flight time and apogee.
• targets the missile cannot reach with its present load are shown in red, with how far short it would come down
• targets at the limit are shown in amber
• Telemetry: every flight is written to a CSV file.

Interface

• Status: the guidance phase, such as "PBV COAST", "PBV BURN PHASE" or "ON TRACK TO TARGET", plus the distance flown and the RV count.
• Flight events timeline: a chronological report in the style of a USAF operational test, with T+ times, altitudes in feet and ranges in nautical miles. It covers:
• launch sequence and staging
• shroud jettison and PBV coast
• deployment, each RV release and the chaff
• reentry, warhead arming at 10 km, and impact or detonation
• Extended scientific log: every guidance computation, for players who want the numbers.
• Target map: a zoomable world map. Click to set a target. It shows great-circle tracks and the MIRV footprint ellipse. Under Sol it loads Earth's high-resolution colour map.
• Camera buttons: switch between the bus and each RV.

Vandenberg LF-10 launch facility

A Minuteman launch facility as a Kerbal Konstructs static at Vandenberg. It is built after the Delta-09 site, the National Park Service records and the Air Force's Minuteman Weapon System History and Description.

• Launch tube: 24.4 m (80 ft) deep, with liner rings and the deflector plate on the floor. It is 4.1 m wide, a little wider than the real 12 ft, for the view down it.
• Missile suspension system:
• the missile stands on a free-floating steel ring with gear teeth
• the ring hangs on three wire cables that run over pulley blocks to coil-spring shock absorbers
• guide shoes round the aft skirt and a guide ring on the tube wall keep the missile centred, and release it at ignition
• Seating: the missile is put back together upright on the tube's axis whenever it is loaded, after a revert too.
• Upper umbilical: an arm from the tube wall plugs into the guidance section and swings up against the wall just before ignition.
• Closure door: rolls back along its rails to the end stop after a 5-second countdown, and closes again a minute after the launch.
• Hot launch: the missile leaves the tube in a sheet of flame and smoke.
• Topside:
• the launcher roof slab and its blast walls
• personnel access hatch and hardened UHF antenna
• IMPSS radar
• support building roof with its vents and diesel stack
• floodlights and a helicopter pad
• chain-link fence with outriggers and a double gate
• Placed automatically: the site is surveyed on the installed planet pack, RSS or Sol, on the first visit to the Space Center.

MM3Nuke – W78 warhead

Selectable yield from 20 t to 1.2 Mt, default 335 kt. Fuze options are radar airburst, contact and manual. The warhead arms after separation and only below 10 km on the way down. A warhead taken off the physics in flight never goes off.

• Visuals, after Glasstone & Dolan:
• double-pulse flash
• fireball with an ionisation glow
• Wilson cloud and condensation rings
• rising mushroom cloud with afterwinds and a dust skirt
• visible shock dome
• ground fires
• Physics:
• a Kinney-Graham blast wave with Mach reflection destroys parts, vessels and KSC buildings
• thermal radiation heats every part in line of sight
• sound arrives delayed with the blast wave, with camera shake
• Exoatmospheric bursts: flash and plasma shell only.
• Preview: a cinematic camera follows the detonation. Alt+N previews it at any time, with no damage.

Exhaust and effects

• Plumes: ROWaterfall plumes per stage with SmokeScreen trails, falling back to RealPlume.
• PBV engine: a custom shader flame with subtle shock diamonds.
• Small jets: the PBV attitude jets, spin motors, shroud motor and thrust-termination ports each have their own effect.
• Sound: engine sound fades as the propellant runs out.

Requirements

• Required: KSP 1.12.x. The missile, guidance computer and warhead work in stock KSP with no other mods.
• Optional – only for the Vandenberg LF-10 silo and the real-scale variant:
• Realism Overhaul, RealFuels and ModuleManager
• Kopernicus with Real Solar System or Sol (Sol also needs ParallaxContinued)
• Kerbal Konstructs and KSCSwitcher
• Recommended with RO: Waterfall, ROWaterfall and SmokeScreen.
• Optional: RP-1, RealAntennas.

Included: 4 ready-to-fly crafts (MIRV and single RV, Kerbin and RO), MM3Nuke, full source code of both plugins, and the Python generators that build every model, texture and config. See README.md for installation and the changelog.

Author: MoWoSf · License: CC BY-NC-SA 4.0

Fan project, not affiliated with the US Air Force, Boeing or Northrop Grumman. Sources: S. Fetter, "A Ballistic Missile Primer"; CSIS Missile Threat; Nuclear Weapon Archive; USAF fact sheets; Glasstone & Dolan (1977).