The concept is very interresting and the writting is great. It reminds me of other great space exploration interactive fictions such as "Seedship", "Superluminal Vagrant Twin" or "Even the Stars".
I fell however that I am missing a purpose to really get hooked. I don't know what it could be... Maybe somewhere to drop the knowledge I gathered, the perspective of dying -or changing- with age, the perspective of settling down somewhere and have an epilogue which would depend on hour exploration ? Or maybe somehow, putting a tiny little bit more emphasis on the missions ?
I'll spend more time investigating it though. It might be very inspiring.