What's that movie where they make the spaceship?

Probably a 90's movie, but not positive. Earth picks up communications from space, and they figure out a pattern - something to do with primes I think - and figure out how to interpret the signals. From further communication they get the plans to a space ship - a big round one, which they finally try to send off with a lady on board. From earth's perspective, it looks like the spaceship just falls straight to the ground without going anywhere, but the lady comes out telling the tale of having gone through a wormhole to some distant place and talking to some being, but they think she's a liar.