Starship
The largest rocket ever built, designed so both stages can be reused. NASA picked it as the lander that will carry astronauts to the Moon's surface.
Why it matters
SpaceX argues that if both stages can land and fly again like airliners, the cost of reaching space could fall as much as a hundredfold. It is designed to carry more than 100 metric tons to orbit, and on its first orbital flight it deployed next-generation Starlink satellites.
How the technology works
A Super Heavy booster with 33 methane-fueled Raptor engines lifts the Starship upper stage, then returns to be caught by the launch tower. The Starship stage, with six Raptor engines, reaches orbit, can be refilled in orbit by tanker Starships for Moon and Mars trips, and reenters behind a heat shield.