The weak have no place here, in this life or any other life. Weakness leads to slavery. Weakness leads to all kinds of misery, physical and mental. Weakness is death.
I think that everyone has something about themselves that they feel is their weakness... their 'disability.' And I'm certain we all have one, because I think of a disability as being anything which undermines our belief and confidence in our own abilities.
My weaknesses... I wish I could come up with something. I'd probably have the same pause if you asked me what my strengths are. Maybe they're the same thing.
It will not be we who reach Alpha Centauri, and the other nearby stars. It will be a species very like us - but with more of our strengths and fewer of our weaknesses.