Terraforming a Planet

This is a work in progress.
I'll gladly accept contributions.

Stage 1: Information gathering
It's important to gather as much accurate information as possible. Without it you risk failure, and the destruction of an entire world.

Important information you will need to know:

Planetary mass (kg)
Planetary radius (m) - polar, equatorial, volumetric
Atmospheric (mean logarithmic planetary) radius (m) - very difficult to determine
Rotational period (s)
Tilt of rotational axis
Surface geology
Planetary magnetic field (T)
Atmospheric pressure (Pa)
Atmospheric constituents and composition
Surface albedo
Surface temperature (K)
Background radiation
Height of the highest mountain
Depth of the lowest canyon
Orbital Semi-major axis
Orbital eccentricity
Orbital period (s)
Orbital inclination
Luminosity of the star the planet orbits
Light spectrum of the star the planet orbits
- Satellite mass (kg)
- Satellite radius (m)
- Satellite rotational period (s)
- Satellite albedo
- Satellite orbital radius (m) - minimum, maximum and mean
- Satellite orbital eccentricity
- Satellite orbital inclination
- Satellite orbital period (m)

Questions to answer:

Does the planet have an orbiting ring system?
Is there an asteroid belt nearby?
Does the planet have a Silicate mantle?
Does the planet have a Iron-Nickel core?
Does the stellar system have more than one star?
Does the stellar system have outer gas giants?
What are the resources of the stellar system?
How thick is the interplanetary medium?
Is the stellar system close to a supergiant star?

Stage 2: Determine the best course of action
This stage determines what will need to be done and when to do it.
Note: the availability of a resource is not limited to the planet. A resource can come from anywhere, depending on it's economic, technological and physical feasibilities. It may already be available on the planet, or from a moon, asteroid belt, interplanetary medium, interstellar medium, gas giant, another planet, or another stellar system.

0 Is there life already on the planet?
Yes stop
No go to 1
1 Is there enough N₂ available for an Earth-standard atmosphere?
Yes go to 2
No stop
2 Is there enough Oxygen available to "water" the planet and for an Earth-standard atmosphere?
Yes go to 3
No stop
3 Is there enough Hydrogen-1 available to "water" the planet?
Yes go to 4
No stop
4 Determine the H-value from Equation 1
H-value > 2 : the planet has too much gravity go to 5
H-value <= 2, H-value > 1 : gravity is acceptable go to 8
H-value = 1 : the planet has an "ideal" gravity go to 8
H-value < 1 : the planet cannot hold Hydrogen-1 go to 6
5 Atmospheric pressure (P_o)
P_o > 1 Earth-standard atmosphere Action 1 then go to 4
P_o <= 1 Earth-standard atmosphere Action 2 then go to 4
6 Determine the additional mass (x) needed from Equation 2
x >= original mass. The planet cannot be terraformed stop
x < original mass. The planet can be terraformed go to 7
7 Is there enough additional mass (x from 6) available?
Yes Action 4 then go to 1
No stop
8 Atmospheric Temperature (T)
T > 300 K Action 5 then go to 4
T <= 300 K, T >= 275 K go to 9
T < 275 K Action 6 then go to 4
9 Atmospheric pressure (P_o)
P_o > 1 Earth-standard atmosphere Action 7 then go to 4
P_o = 1 Earth-standard atmosphere go to 10
P_o < 1 Earth-standard atmosphere Action 3 then go to 4
10 Is the atmosphere breathable by humans?
Yes Action 8 then go to 11
No Action 9 then go to 4
11 Has a strong Ozone (O₃) layer formed around the planet?
Yes go to 12
No Action 10 then go to 8
12 Is the partial pressure of O₂ below 25 kPa?
Yes go to 13
No Action 11 then go to 4
13 Is background radiation at acceptable levels?
Yes go to 14
No Action 12 then go to 1
14 Is cosmic radiation at acceptable levels?
Yes go to 15
No Action 13 then go to 15
15 Colonisation can begin! Action 14

Action list

Action 1
Remove all but one Earth-atmosphere from the planet. The excess atmosphere can be transported from the planet and dumped on a frozen moon, in the outer system, for later use.

Action 2
Remove mass from the planet. The planet should be mined for high-density metals. Silicates should also be removed if the mantle is too thick. The excess mass is transported from the planet. It could be used to form an orbiting moon, or as a resource to terraform other planets in the system.

Action 3
Add N₂ to the atmosphere until one Earth-atmosphere is achieved.

Action 4
Add additional mass to the planet. Ensure the mass is:

high-density
low in Carbon
degassed - heated to remove gases such as CO₂

Action 5
Decrease the atmospheric temperature. This can be partially achieved through Action 7.
Additional methods include:

Construct a 0° inlcination moon
Change planets albedo at the surface
Reduce the concentration of greenhouse gases in the atmosphere

Carbonate and sulfate minerals will begin to form when the atmospheric temperature drops below a critical temperature. The critical temperature is dependant on the surface geology and the mineral. This will slowly remove some CO₂ and SO₂ from the atmosphere.
Note: Shading the planet with large reflective mirrors is not a good idea. The reflected light will generate a force pushing the mirrors into a lower orbit, and eventualy burn up in the atmosphere and crash to the surface.

Action 6
Increase the atmospheric temperature.
Methods include:

Decreasing the planets surface albedo
Increasing Carbon dioxide (CO₂) concentrations in the atmosphere
Increasing methane (CH₄) concentrations in the atmosphere
Change planetary albedo at the surface

Action 7
The atmospheric gases should be compressed and stored. The gases can be stored in reflective cylinders, on the surface or in orbit. When conditions are favourable the gases can be distilled and stored seperately. CO₂ and SO₂ can be ionised. The Carbon and Sulfur can be stored and the O₂ released or stored seperately.
Note: As atmospheric pressure decreases, the planets mantle will expand. Deep rifts will open in the surface and mountains will slowly push up. Volcanic activity will increase and lava flows will initially become more common. The expansion of the mantle will slightly increase the planetary radius and surface area. This expansion will slightly decreased atmospheric pressure, but not enough to generate a positive feedback loop. The atmosphere in the rifts will be more dense than at the radius, and contribute towards lowering atmospheric pressure.

Action 8
Water is now added to the planet. H₂ and O₂, in a 2:1 ratio, is slowly released into the atmosphere. If H₂ and O₂ are available as stored gases then they should be used first. When the stored supply is exhausted, H₂ and O₂ should be imported.
Note: bodies of water will form in depressions and at low elevations. These areas should be evacuated in advance.
Note: an increase in surface water will decrease the planetary albedo and in turn increase the greenhouse effect. However, convection currents will form in the atmosphere, allowing the planet to better regulate it's temperature.
Note: CO₂ and SO₂ will dissolve in water. This will initially remove some of the CO₂ from the atmosphere, allowing it to cool. The presence of water will also increase the rate of formation of Carbonate and Sulfate minerals.

Action 9
The atmospheric constituents must be replaced, converted or exchanged with breathable consitituents. Stored gases should be used where possible. If stored gases are not available then imported gases are used.

Action 10
Colonisation cannot begin until a strong Ozone (O₃) layer has formed. Additional O₂ released into the atmosphere and complete removal of all ozone-depleting gases will accelerate the formation of ozone.

Action 11
Organic material will spontaneously combust around 25kPa. Reduce the concentration of O₂ in the atmosphere by releasing H₂.

Action 12
Colonisation cannot begin until background radiation is at acceptable levels. The source of the radiation will need to be determined. Radon (Rn) gas or long-life radioactive elements can be stored in sheilded locations, or transported off the planet. Colonisation can wait until short-life radioactive elements decay naturally.

Action 13
Colonisation may be limited to lower elevations. If the cosmic radiation levels are too high at lower elevations then the planet may not be colonisable, or habitats may need to be insulated or subterranean.

Action 14
Plants are added to the planet. The weather, atmospheric pressure; temperature; and constituents will fluctuate significantly. All possible resources will need to be transported to the planet and stored in advance, either in orbit or on the planets surface.
The colonists will be responsible for maintaining a balance by:

recycling everything they use and having a minimal negative impact on the environment
releasing stored gases as need
compressing, distilling and storing atmospheric gases as needed
strategically planting particular species in specific areas
monitoring weather conditions and predicting environmental changes
site re-planting, or re-seeding after storm damage
dispersing species across the planet

0	Is there life already on the planet?
	Yes	stop
	No	go to 1
1	Is there enough N₂ available for an Earth-standard atmosphere?
	Yes	go to 2
	No	stop
2	Is there enough Oxygen available to "water" the planet and for an Earth-standard atmosphere?
	Yes	go to 3
	No	stop
3	Is there enough Hydrogen-1 available to "water" the planet?
	Yes	go to 4
	No	stop
4	Determine the H-value from Equation 1
	H-value > 2 : the planet has too much gravity	go to 5
	H-value <= 2, H-value > 1 : gravity is acceptable	go to 8
	H-value = 1 : the planet has an "ideal" gravity	go to 8
	H-value < 1 : the planet cannot hold Hydrogen-1	go to 6
5	Atmospheric pressure (P_o)
	P_o > 1 Earth-standard atmosphere	Action 1 then go to 4
	P_o <= 1 Earth-standard atmosphere	Action 2 then go to 4
6	Determine the additional mass (x) needed from Equation 2
	x >= original mass. The planet cannot be terraformed	stop
	x < original mass. The planet can be terraformed	go to 7
7	Is there enough additional mass (x from 6) available?
	Yes	Action 4 then go to 1
	No	stop
8	Atmospheric Temperature (T)
	T > 300 K	Action 5 then go to 4
	T <= 300 K, T >= 275 K	go to 9
	T < 275 K	Action 6 then go to 4
9	Atmospheric pressure (P_o)
	P_o > 1 Earth-standard atmosphere	Action 7 then go to 4
	P_o = 1 Earth-standard atmosphere	go to 10
	P_o < 1 Earth-standard atmosphere	Action 3 then go to 4
10	Is the atmosphere breathable by humans?
	Yes	Action 8 then go to 11
	No	Action 9 then go to 4
11	Has a strong Ozone (O₃) layer formed around the planet?
	Yes	go to 12
	No	Action 10 then go to 8
12	Is the partial pressure of O₂ below 25 kPa?
	Yes	go to 13
	No	Action 11 then go to 4
13	Is background radiation at acceptable levels?
	Yes	go to 14
	No	Action 12 then go to 1
14	Is cosmic radiation at acceptable levels?
	Yes	go to 15
	No	Action 13 then go to 15
15	Colonisation can begin!	Action 14