As expected, Grandpa Bud fails to give an answer as to what the garage code is. He tells you to go see Uncle Art, who is probably outside near his space ship. While heading there, you may want to explore the house and scan some more things, such as the Robinson Aid Station, the Robinson TV, or even the weirdos Spike and Dimitri. When you're done exploring and scanning stuff, exit the house and head into the yard. Uncle Art will be there in a Protecto Sphere. Scan the Protectosphere Generator, then pop into it.
This will initiate a race-like mini-game similar to Super Monkey Ball, but with no monkeys. You will have to maneuver through the obstacle course while inside a Protecto Sphere. Roadkill zumzats are alright, thank God. Some parts will require a bit of patience, like the jump-panels. At the end of the course, you'll see Uncle Art and his space ship, the Anchovy Saucer. Scan them both, then talk to him. Like most video game characters, Uncle Art needs help of course. And the next task involves rounding up some of those pesky purple critters: zumzats. Good thing a concentrated electric charge can stun them. Time to grab your Charge Glove.