Elon Musk @elonmusk
@RenataKonkoly @Erdayastronaut First one to fly will, so Booster 4. Booster 3 will be used for ground tests. We’re changing much of design from 3 to 4. Booster 3 was very hard to build. Expect especially rapid evolution in first ~10 boosters & first ~30 ships. — PolitiTweet.org