I'm trying to find the name of a 80's movie about 4 kids who build this 'spaceship' out of garbage cans and stuff and use a special formula to make a bubble around their contraption (which is sent to them in a dream) that can make it travel into space where they encounter a weird alien that is actually only a alien kid who knows about earth through TV signals that he picked up. Any takers?

Explorers. Sorry. I found it.