SpaceX's first hire, Tom Mueller, was lead designer of Falcon 1's Merlin engine. Now he's building in-space mobility startup Impulse Space, which crossed $1 billion in total funding, including a $500M round announced just yesterday. We've got Tom on an all new TWiST, dropping this afternoon on X, YT, and podcast platforms. cc: @lrocket, @GoToImpulse, @Alex, @Jason