I am actually fairly perplexed at some answers on both ends of the spectrum. To those of you who would desire to make the age of legal maturity be 25, that would mean spending a third of your life, and well into your physical maturity as an adult, being under your parent's supervision, and not being allowed to take responsibility for your own actions. Sure, many people in their early twenties are obviously not as responsible or mature as those in their late twenties, thirties, or older. But I would actually posit that that has more to do with life experience, they are finding their way in the world, meaning that if you pushed back this age further, it would simply delay even further the emotional maturity of these individuals. Except this would actually come with serious drawbacks, because biologically and psychologically, by your late twenties and early thirties, your brain has begun to more fully cement itself into your established identity, and if you were never given an opportunity to be an adult until this time, it is too late to learn how to be a responsible adult.
To those of you who think the age of voting should be 14, I highly doubt that any one that age has -- or is even capable of the emotional maturity to make decisions regarding the direction a society or entire community should move in. One of you said, most people that age already know how they would vote. But from what I remember being that age, everyone is just forming opinions for the first time about things like politics, and they are highly impressionable, so in general they end up parroting and repeating the views of their parents.
And to those who think it should simply be determined on an individual basis, if you are serious about establishing a nation which occupies a contingent space, I would say that a community in general should move along side of each other. One user put it quite well, I thought, when they said that parents should know how long they have until their child is an adult, so that they (and their teachers) can plan and schedule the moral and educational development of the children. If a teenager was actually able to pass the test at the age of 15, for example, but highschool goes until the age of 18, would they get to drop out and be an adult then?
What I would be in favor of would be a (slightly) younger age of legal maturity and legal responsibility, and a (slightly) higher age for voting. I would propose an educational system which graduates secondary education (highschool) around the age of 16 (on an accererated track above most western countries), followed by a mandatory two year's "gap year" program for them to join the work force, especially on either an internship or apprenticeship, during which time they could either continue living with their parents or move into their own apartment or with room mates. Then at the age of 18, they could either voluntarily start tertiary education (university), or they could continue to work. The reason for this "gap year" program is two-fold. First, I believe maturity and wisdom comes ultimately from life experience, and this would help young people learn about not only themselves, but also about the way that real life (adult life) in the community actually operates. Secondly, there seems to be a huge phenomenon in many developed countries where kids go straight from highschool into college, with no work experience or ideas about what kinds of jobs they would actually enjoy or be passionate about. And yet, they are pressured to decide then what they want to dedicate the rest of their life towards, and often choose either something which sounds promising but they end up having no passion for, or they study something highly impractical and can't get a job in the field. Also, given that this will be a relatively small nation existing primarily on a space station, it will likely be a very safe community for them to start living on their own at a younger age like 16. I would be in favor of a drinking age of 16 also, and the legal age to marry I would say is 18 for a self-elected marriage, but with both the approval of their parents and a judge, they could marry at 16 (which, given those same stipulations, is actually legal in some US states).
When it comes to voting, however, I would actually be in favor of a slightly higher age for voting. Originally in the whole of the English-speaking world, the voting age was 21, but this was lowered to justify sending 18 year olds to war. But I would be in favor of a voting age around 21. Like I said previously, I strongly believe that maturity comes not from years, but from life experience. By this point, these voters will have five year's experience living and working on their own, and understand the basics of daily life and the reality of taking part in the economy, and thus would be more entitled to political opinions. Some of you have said an age of 25 would be warranted. Most of you gave no reason why you believed this, but one person cited that this is supposedly when the psychological development of a person is fulfilled. Simply in terms of voting, as long as all other rights were granted well before that, I would concede this point (which is saying something, as I am only 23). The world of politics, even in a small nation like Asgardia, requires serious contemplation and emotional maturity.
And finally, for some reason, a select few of you are talking about the legal age for driving in Asgardia. Are you kidding me? You want to go live on a space station in Earth orbit, and then fill it with cars, city streets, and freeways? That is just so impractical, on so many levels. Even if Asgardia were big enough to warrant complex infrastructure of that sort, it would be much more likely to take the form of lifts and elevators, or perhaps even some system resembling a subway or metro rail. And there is no way a teenager is operating a space shuttle or transport outside of the station. Those kinds of systems would require much more intensive training than even flying a plane, much less driving a car.