Three steps to a moon base

SUPER-HEAVY-LIFT ROCKETS: NASA is relying on the Space Launch System (SLS) for its 2024 lunar return plan—although the rocket is over budget and behind schedule. China is working to upgrade its current Long March 5 rocket (which failed in its second flight) to the Long March 9. Russia says it has finalized the design for its Yenisei rocket, but experts wonder if it will actually get built. Blue Origin and SpaceX's rockets use reusable stages, which could make them much more economical. SpaceX's Starship is the most futuristic of the lot, comprised of reusable stages and a built-in crew capsule.