SpaceX now offers commercial space travel. Elon Musk’s aerospace company announced Monday that it will fly two private citizens to the moon and back. The individuals have already been selected — they approached SpaceX with the idea — and paid a “significant deposit” for the trip. They’ll undergo health and fitness tests and begin initial training this year, at which point their identities will be revealed upon their approval. The journey is slated to take place in the fourth quarter…