Notes on planetology

There are five planet types in the galaxy. System-map color and orbital gas both come from the type.

Orbital gas
An orbital gas extraction plant sits in low orbit and collects what leaks from the atmosphere. The product depends only on planet type, not on player choice:

• Earth-type, green — Oxygen O
• Gas giant, red — Hydrogen H
• Uninhabitable (dried-out), yellow — Carbon dioxide (dry ice)
• Dead, white — Nitrogen N
• Asteroid — no atmosphere; the plant yields no gas

The plant's base cycle is 3 hours and 1000 gas. Warehouse 3000, energy use 250. Technologist and Orbital plant technologist increase both cycle length and yield. Chlorine is not mined in orbit. The factory packs only oxygen, hydrogen, and nitrogen (blueprints from the Confederation). Carbon dioxide is already harvested as dry ice — it is a mineral, with no separate pack.
On an Earth-type homeworld the plant is started by hand from orbit. The remote "start gas mining" order does not run on Earth-type planets.

An Earth-type planet is chosen for colonization as the most suitable for life. Exploiting other planets is allowed. The Confederation guards the home planet and its orbit and does not protect foreign worlds.

Any planet has 4 defense lines.
1. Ships in planet orbit
2. Orbital defenses
3. Ships on the planet surface
4. Planetary defensive structures.

Earth-type planets
Rare: usually one per star system. The colonist has full inviolability on the surface under Confederation protection. Minerals may run short over time, so other planets are developed. Mining structures are limited by deposits. The orbital plant yields oxygen.

Gas giants
Hundreds and thousands of times larger than habitable worlds. No solid surface as such and very high erosion: hydrogen is collected in orbit for fuel. Often havens for pirate bases — fuel is easy and there are many such planets to hide among.

Uninhabitable (dried-out) planets
Once similar to Earth; life may have existed, but no native intelligence has been found. Some structures were left by the "Strangers". Organics burned off; the atmosphere is dense carbon dioxide. The plant harvests it as dry ice; a nanodispenser splits it into oxygen and carbon.

Dead planets
Usually close to the star, or former large asteroids or comets. The shell is thin; nitrogen is collected in orbit.

Asteroids
Appear when Hyper Gate (terraformer) shatters a planet. Tiny surface, no atmosphere. Surface and middle-layer mining on an asteroid is 100 times richer than on a normal planet. An orbital gas plant is useless here.