Whether the families volunteering for the work in the colony would have the option to return to Earth is a very essential question. The candidates have to understand the implications. This has to be their conscious decision made with full awareness of terms and uncertainties. The humans would have to have an understanding that their work would be crucial for salvation of the earth. They would have to understand that if the earth humanity will vanish, they would never return, if the earth develops slowly on the good path, the colonists may return 30 years later. The children of the colonists are to grow up with the understanding whether or not they may return to Earth. If they are to return to earth, they need to be properly immunized to earth diseases. We have new infections visiting us every few months. If we miss these infections, then later, we often have much more troublesome infections. I realize that your medicine should be able to help with that. Also the children and adults have to keep us with the developments on Earth in order to be able to function properly upon return. This would include basic survival skills such as: not falling down from heights, avoiding harm from cars, being able to drive cars, riding a bicycle, eating healthy, avoiding poisonous foods, avoiding harm from medicine, avoiding deception, criminals, being able to avoid harm from bullies, being able to deal with rudeness and bureaucracy, skills of standing in line, dealing with train and bus schedules and imperfections of those, using money, using human electronics, understanding slang, understanding and making jokes, providing first aid to self and others, troubleshooting, time management, small talk, knowing when to keep one's mouth shut, and an ability to function under pressure and under uncertainty.