NASA’s new megarocket is poised to take the U.S. to the moon and on to Mars

SINCE AUG. 17, NASA’S MASSIVE SPACE LAUNCH SYSTEM (SLS) moon rocket has stood silent on pad 39B at the Kennedy Space Center, towering over the Florida swamps. But as soon as Saturday, Sept. 3, that silence is expected to be broken in the most dramatic way possible, when the giant machine’s six engines light, generating a record 8.8 million lb. (4 million kg) of thrust, muscling the rocket off the pad and hurling an uncrewed Orion capsule on a mission to orbit the moon. The launch will kick off NASA’s Artemis program, which aims to have astronauts back on the lunar surface by 2026. (An initial launch attempt on Aug. 29 was scrubbed because of a technical glitch in one of the engines.)

There is no overstating the scale and ambition of the SLS. Until now, the Apollo program’s Saturn 5 held the record for the most powerful rocket ever launched. When its five engines first lit on Nov. 9, 1967, they produced 7.5 million lb. (3.4 million kg) of thrust, rattling the windows in the TV press booths and causing plaster dust to flutter from the ceiling of the nearby launch control center. The SLS is a bigger beast,