.@elonmusk on why Starship is hard. "Starship is the most complicated machine ever made by humans, by a long shot. Any project I can think of would be easier than this, and that's why no one has made a fully reusable orbital rocket." Most people treat rockets like airplanes with bigger tanks. Elon is saying full reuse is a different class of problem — heat shield, engines that fly twice, tanker rendezvous, and a vehicle that has to work as a system, not a one-shot firework. • Expendable rockets — throw away the machine every flight • Partial reuse — booster returns; upper stage still dies • Full reuse — same ship flies again; cost collapses toward airline economics Hard is the point. Reuse is the unlock. Starship is the vehicle. "It's a very hard problem that many smart people have failed at."