What is this space movie ?

It's about a huge spaceship where thousands of people live. Theres a family with a girl I think and she goes to school on that space ship and theres robots that teach them. I think she ends up sneaking out and finding out that something is going on and someones trying to do something bad to the space ship, it has something to do with a disk? She tries to stop it but keeps getting in trouble. I can't remember where all this is from...