Microfactories are presumably a small dimension factory that is able to produce small dimension products. While this technology is currently experimental in the real world, they are mentioned in three instances in Metroid Prime series data.
The Logbook entry for Samus Aran's Gunship in Metroid Prime 2: Echoes and Metroid Prime 3: Corruption reveal that the Gunships in both games contain microfactories designed to produce ammunition. This explains how Samus is able to regenerate her Missile, Power Bomb and/or Beam Ammo within her Gunship. The microfactories do not, however, restore Ship Missile Ammunition in Corruption, which must be collected in the field from killed enemies or broken crates.
Unused, original log data in the internal files of the Metroid Prime 2: Echoes Bonus Disc mention Splitter Microfactories. These were contained within the "Steadfast" class Guardian (Quadraxis in the final game), which used them to generate Splitter class sentry drones (Quads in the final game). In the final game, Dark Quads are spawned separately from Quadraxis.
Starship: Hunter-class Gunship. Vessel registered to Samus Aran. Your ship has been damaged. Auto-repair function initiated. You can return to your ship to recharge energy, reload weapons, and save the game.
Your Hunter-class gunship is one of a kind, its distinct hull lines marking it to friend and foe alike. Custom built for you by the Federated Shipyards at Aliehs III, it contains a mobile energy recharge system and microfactories designed to produce ammunition. A sophisticated onboard computer stores mission data collected in the field for future reference.
|Features of Samus Aran's Gunship|
|Personal||Adam's helmet • Chozo biotech computer • Data records • Logbook • Mii Bobblehead • Samus Screen • Ship Bumper Stickers • In the Cockpit • Music player|
|Armaments||Plasma Beam • Power Beam • Ship Grapple Beam • Ship Missile Launcher • Gunship Multiball • Bunker-Busting Annihilator • Gunship|
|Mission features|| Auto-repair function • Biohazard scanner • Blast Shield • Bombing Run • Command Visor • Commander Adam Malkovich • Cryostasis • Escape Pod |
Heads-Up Display • Helm controls • Landing Gear Legs • Microfactories
Missile Station • Recharge Station • Save Station • Tetra Galaxy Scan Screen • Transmission console • B-Unit
|Cargo||Theronian Bomb (1st piece • 2nd piece • 3rd piece) • Colossal War Golem|
|Passengers||Baby • Anthony Higgs • Dr. Madeline Bergman • Commander Adam Malkovich (computerized) • Dachoras • Etecoons|