It's a valid point they make, in that early settlers to North America had no expectations of being able to return home if things went bad for them. However, we're talking about a much more hostile environment that what those early pioneers faced. Both from a psychological standpoint as well as a mission viability standpoint, I think the first colony would really need to be much larger. Two people just wouldn't have all the necessary skills (and overlap in skills, since you don't want to be one-deep in some critical skill, such as medical) to make long-term survivable likely. The first colony would need to consist of maybe two dozen families, with a good mix of skills and overlap in all critical skills. Yes, I said families, or at least married couples of child-bearing age. First, you fight harder for survivial when your loved ones are on the line, and people are a basic raw material to maintain and expand a colony. Established couples provide a level of mutual emotional and psychological support that would help overcome some of the problems of isolation from the rest of humanity. Sending this many people all at once, or at least in fairly short order, presents significant challenges of its own. One problem is the need to have basic shelter in place prior to the settlers' arrival. Automated equipment could be used to prepare initial habitation; an advance team of a dozen colonists could arrive several months ahead of the "Mayflower" mission, insuring the bare essentials are in place and operational for the main group of colonists following behind.
What's amazing is that we've forgotten that spirit of pioneerism that settled places like America and Austrailia and New Zealand, and that people recoil at the idea of a one-way colonization mission like this. I wonder how many would volunteer for such a make or break, one-way mission? Are there still people out there willing to risk everything (their families included) to conquer a new New World?
