The Relay Space Race

Traveling faster than the speed of light seems impossible, so space exploration will probably be time-consuming. So suppose you finally reach a planet inhabited by intelligent species. Wouldn't you want to spend ages there, studying their customs and languages? But you'd also like space exploration to continue.
The solution: take some of the aliens on board and leave some of your crew behind. That way, they don't have to build their own ship, we get to study their culture in-depth, and space exploration isn't delayed.
Now to store this fabulous idea somewhere until we finally leave the friggin' solar system.