RT Muskonomy (@muskonomy)🚨BREAKING: Elon Musk says SpaceX is now prioritizing building a self-sustaining city on the Moon before Mars• A Moon city could be possible in under 10 years• Moon launch windows happen about every 10 days• Travel time to the Moon is about 2 days• Mars launch windows happen every 26 months• Travel time to Mars is about 6 months ...