Planet, ho! You’ve been in space for months. Years, maybe. Now a formerly distant world is finally filling up your viewport. All you have to do is land. But you’re careening through frictionless space at, oh, call it 200,000 mph (assuming you’ve cracked fusion). Oh yeah, and there’s the planet’s gravity to worry about. If you don’t want your touchdown to be remembered as one small leap for a human and one giant splat for humankind, follow these simple steps. —Nick Stockton