Rocket no Natsu

There used to be a season called "Rocket summer"...
The Earth has become a member of the Galactic Federation and has accepted multiple emissaries from aliens. Silver rockets are launched from the Earth on daily basis, but one day all inter-galaxy contacts cease and space port doors get shut.

Main character has dreamed of space travel since childhood. One day he decides to help girl Chise to participate in self-made rocket competition "50 Miles Over". Together with princess from the other star they form a rocket club. Will their dreams come true?

[From vndbreview]