1. Selection of Settlement Sites
We expect that a planet that is Earth–like in its size and distance from its star, will likely be the best one for the settlement(s) if its star is like the Sun. Astronomers classify stars on the basis of their color and the composition of their visible surfaces. The Sun is classified as a G star. There are five other G stars within 20 light years distance from the Sun. Consider a spaceship that cruises at a speed equal to c as it travels amongst the stars. Neglecting the amounts of time needed to accelerate to, and decelerate from, the interstellar cruise portion of the mission, 20 years is roughly the duration of one human generation.
The five other G stars include the following: Tau Ceti, Delta Pav, Eta Cas, Procyon, and Alpha Cen A. The last–named star is part of Alpha Centauri, which is the star closest to the Sun. It is at a solar distance of 4.37 light years. But, when examined through a telescope, Alpha Cen is found to actually be a triple star. A dwarf star (called Proxima Cen) orbits distantly (i.e., at a distance of 2.2 degrees) about a binary pair of other, larger stars. The two other stars are called Alpha Cen A and Alpha Cen B, respectively. Planets around Alpha Cen A would seem to offer attractive possibilities for settlement(s), because of their relative closeness to the Sun and because A is a G star. However, the nearby presence of Alpha Cen B argues against the choice of selecting Alpha Cen A; not only would there be two “suns” in the sky of a hypothetical planet around star A, there would be a periodicity in the separation between A and B. The disruptive tidal effects on settlements(s) at the close approach of another massive star would be unlike anything experienced on Earth.
2. Mission parameters
It is vital to the success of the mission to obtain accurate intelligence about the planets being considered for human settlement. This intelligence must be obtained prior to committing to landing on a specific target. This almost certainly means that robotic scouting missions to each potential settlement must first be conducted. Probably the only valid reason for violating this principle would be lack of time. These first, autonomous missions should head for planets with oxygen important in their atmospheres, and map the planetary surface for continents and for any bodies of liquid water, such as oceans. They should also search for evidence of existing habitation, such as cities, lights and roadways. They should also search for modulation of electromagnetic emissions at all wavelengths. If a scout detects any interference with itself, it should immediately inform the spaceship of this interference attempt, and then self – destruct, to avoid unintentionally revealing anything about humanity to non - humans.
When the target planet is reached and target areas on it have been selected, the spaceship will enter into a parking orbit about the planet. After the settlers have gone down to the planet, the spaceship should remain in the parking orbit for some time, perhaps one month or more. If it should prove necessary for the settlers to re-embark the spaceship must stand ready to accept them. This would be the case if some unforeseen challenge to the settlers arises, a challenge that makes settlement impossible. It is possible that the spaceship will never leave the parking orbit, should it be found that the settlements are unable to support themselves without its support facilities (e.g., medical).
Re-usable shuttles will be needed for each settlement mission. Carried by the spaceship, they will be needed to transport settlers down to the planetary surface. Each shuttle must be capable of landing its complement of settlers and their cargo, then returning itself back up to the spaceship. Each shuttle must be capable of launching itself from the surface, fully loaded with settlers and their cargo, should need arise.
Cargo for the mission will include consumables such as food and water for the settlement(s). Recycling must be practiced. Seeds of edible plants will also be cargo items, but experimentation will be needed before any planting in the target’s soils is attempted. If practical, fetuses of farm animals may also be carried, for supply to the settlement(s). The spaceship’s cargo must also include power supplies (nuclear as well as solar), tools and automated factories for use by the settlers, to help them in construction of shelters, and to assemble rovers to assist in exploration. Three complete libraries consisting of all the information that humanity possesses at the time of departure from Earth must also be carried, with easy to use readers for these memories. Finally, there must be medical support such as well equipped and staffed hospitals.
4. Mission Personnel
Two types of personnel will be aboard each spaceship. One group includes members of the crew; the other group consists of the settlers. The missions of the two types are different: members of the crew are to operate and maintain the spaceship during its flight to and around the selected planet. They also provide for the transport of the settlers to and from the planetary surface. Settlers complete their training during the space flight, and also choose the final landing sites for their settlements, during the landing and settlement phases of the mission. The quality of their training is critical for mission success; it is vital that they absorb as much as possible of the information provided, so that they react correctly to challenges that will arise. They will likely face challenges unlike those faced by any humans in all of history.