Armor and the six faces

Your six faces

• Your hull has six faces: fore, port, starboard, upper, lower and aft.
• A round meets the face it arrives at, and the bow carries the most plate.
• Each face is a grid of 3 by 3 pools of plate, 54 on the hull.
• A round wears only the pool it strikes, and the pool beside it is untouched.
• A fresh pool is as deep as the plate, so a fresh face stops several hits.
• A round into a holed pool meets no plate. The yard counts the HOLED pools.
• Running shows a hostile your stern, where the main drive sits.

Slope

• A slope is how far a plate leans from square to the round that hits it.
• A sloped plate reads thicker along the line of fire, so more rounds stop on it.
• Warships are built with a sloped bow. Freighters are built square.
• A round that strikes at an angle meets a sloped plate too.
• The helm may angle a face 30 or 45 degrees, and the angle shows a wider hull.

Plate weight

• Plate is mass the drive has to push, like cargo in the hold.
• A heavier ship accelerates slower, so it dodges worse and a lighter hostile runs it down.
• Each trip also takes longer and burns more fuel.
• STEEL is the heaviest plate, then LAMINATE, then CERAMIC. SPRAYED ABLATIVE is the lightest.
• The shipyard gives the weight and the acceleration it leaves before you buy.

Each value is read from the game code. Sort by any column heading, or filter by grade or by a word.

• A fast round meets a plate differently from a slow one, because above about 3 km/s the round begins to melt on impact.
• At that speed the round and the plate both flow like a fluid, so strength matters less and density matters more.
• A first guide from Los Alamos says a shield must have the same mass per area as the projectile it stops.
• A Whipple shield is a thin outer sheet set apart from the main armor. It breaks a fast round into a cloud the main armor can handle.
• At the speeds of orbital debris, such a shield protects as well as a single solid wall 10 to 20 times as massive.
• A sloped plate is hit at an angle, so the round must cross more plate. A ship that turns to raise the angle cuts the penetration.
• A plate has mass, and the drive must push every kilogram, so designers always look for ways to save mass.

• A plate is one layer, so the game has no Whipple shield or standoff gap. It models the speed effect by fading hardness and leaning on mass per area.
• The fade starts at 3 km/s, the mirror's melt line, by coldweld's call on 2026-10-04, over the 1.5 km/s the arc first planned.
• The shape of the fade, (3 / v) squared, is AUTHORED. The mirror gives only the 3 to 7 km/s band.
• The joust ignores closing speed and uses muzzle speed, though physically a head-on pass is hypervelocity.
• A plate weighs density times thickness times the hull's skin, with 0.15 mm a point of depth as the one free number. coldweld's goal was a median plated hull about 20 percent slower in laminate.
• The areal-density rule would make plate 3 to 20 times the hull's own dry mass, so the game's plate is a coat, not a full shield.
• Slope is the plate reading rating divided by the cosine of the angle, capped at 75 degrees. This is authored, and the mirror's remark on deflection at shallow angles is not modeled.
• Armor faces are 3 by 3 pools, so a round holes one pool and its neighbor is untouched. coldweld made this call on 2026-10-08.
• Hostile plate is doctrine, not a computed rule: brutes and Mars weld rolled steel, raiders keep light plate, and Earth and the Guild keep laminate and ceramic.
• A material differs by how it fails and how a yard mends it: steel welds back almost whole, ceramic spalls and patches poorly. The loss fractions are chosen so ceramic is scrap after about eight hard fights.
• The bow carries the most plate, with shares of 4, 2, 2, 2, 2, 3 in print order, for the dust reason in the mirror and because the drive sits aft.

1. Atomic Rockets does not provide values for the following:
   1. Density of the four plate materials. Steel and silicon carbide are handbook figures. Laminate and ablative are authored.
   2. Curve of hardness fade inside the 3 to 7 km/s band where a Whipple shield works best.
   3. Cap on the slope factor. The page gives the secant rule. 75 degrees is authored.
   4. Armor grid, armor pool, or wear of a plate one spot at a time.
   5. The Los Alamos paper behind the areal density rule. The page cites it, and its limits are unknown.
2. No source on the shelf provides values for the following:
   1. Plate thickness on a game ship. The point of depth is a game unit.

• Atomic Rockets, spacewardefense, Section 10: Armor, Damage and Survivability, Whipple shield passage: Whipple shields start to become worthwhile at about 3 km/s, when projectiles begin to melt on impact. They are most efficient at 7 km/s, and above that the projectile vaporizes, which is less effective but still far better than solid plate of the same mass. (all uses)
• Atomic Rockets, spacewardefense, Section 10, standoff and Orbital Debris citation: At typical orbital-debris speeds, a Whipple shield protects as well as a single barrier 10 to 20 times as massive. The page cites 'Orbital Debris: A Technical Assessment', p. 124. (all uses)
• Atomic Rockets, spacewardefense, Section 10, long-rod formula and Los Alamos rule: The page's penetration formula, from Luke Campbell, approaches the correct hydrodynamic limit at high velocities. It also says Los Alamos documents give a first rule that an effective shield needs the same areal density as the projectile, and notes the cited paper could not be found. (all uses)
• Atomic Rockets, spacewardefense, Section 10, armor ladder: Metallic armors are the cheapest option but have a very high mass-to-strength ratio, and are likely used only where nothing else is available, such as an improvised vessel. Silicon carbide ceramic is tough, light and heat-resistant, and layering it with tungsten gives a composite. Laminating plates of different materials helps stop spalling. "nothing else is available" (all uses)
• Atomic Rockets, spacewardefense, Section 10, defense against low-mass/high-speed projectiles: A fast light round can be deflected if the armor sits at a shallow enough angle, but the angle must be very shallow and the round very light, so this cannot be relied on. (all uses)
• Atomic Rockets, spacewardefense, Opening fiction passage on a ship's hull: A fictional ship description puts a thick sprayed-on foamed-composite ablative layer on the outside, whose vapor scatters energy weapon fire. It is a design aimed at lasers, not at kinetic rounds. (all uses)
• Atomic Rockets, spacegunconvent, Kinetics: rods and obliquity: Obliquity is the angle between the line of impact and the line perpendicular to the surface. A defending vessel can turn slightly to raise the obliquity and so significantly reduce penetration. (all uses)
• Atomic Rockets, spacegunconvent, Whipple shield and standoff: There must be enough standoff between the Whipple shield and the main armor, or the inner plate is hit by a concentrated cloud of fragments and penetrated. The page says there is almost no test data above about 10 km/s. (all uses)
• Atomic Rockets, basicdesign, Section before 'Everything Is Connected': Mass is the main cost of a rocket ship, so designers look for ways to conserve it. A station can use heavy iron, but a rocket vehicle uses light metals. "always looking for ways to conserve mass" (all uses)