"Dr. Yooghurt? Yeah, the loon and I used to work on the dumpiest science projects in the known reaches of the universe. He was terrible 'n I told him. But I guess he must have come a long way since then, to set up a big lab down on Neptune of all places." - Mad Malik
You need to complete his side-quest to get various ship items, this is required for one of the endings. The quest starts by giving the Ugh-Stew to the person who wants it, then trading the item to her for the Rusty-Casette, which you give to Dr.Yooghurt to start the side-quest. You'll get a vehicle which allows you to explore Cloud Ocean for the needed items.