NASA’s Space Launch System (SLS) moon rocket officially became the most powerful rocket ever flown when it lifted off in the early morning hours of Nov. 16, putting out a prodigious 4 million kg (8.8 million lbs) of thrust. That comfortably beat the old record holder—the Apollo era’s Saturn 5, with its 3.4 million kg (7.5 million lbs) of thrust.
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But the SLS won’t hold that title for long. As Space.com reports, earlier this week, SpaceX successfully test-fired 11 of the 33 engines on its Brobdingnagian Super Heavy rocket, a beast of a machine that, when all of its engines are lit, will produce more than 7.25 million kg (16 million lbs) of thrust, nearly double that of the SLS. The Super Heavy stands 69 m (230 ft.) tall, and serves as the first stage carrying the 50 m (164 ft) Starship spacecraft. The entire stack, also known as Starship, stands nearly 40 stories tall—again easily beating out the SLS’s 32 stories.
Unlike the SLS, of course, Starship hasn’t yet flown, but the engine test is preparatory to a first uncrewed launch of the rocket that could happen later this month—though it is likelier to occur in the first quarter of 2023. Whenever the ship launches, it can’t come too soon. NASA has selected the crewed upper portion of the Starship stack as the landing craft for the Artemis 3 mission, which aims to have American astronauts back on the lunar surface as early as 2026.
Meanwhile, NASA’s Artemis 1 uncrewed mission around the moon—which got its boost thanks to the SLS—has been going precisely according to plan. As the space agency announced, the latest step in that plan took place yesterday at 4:53 p.m. ET, when the spacecraft, currently in lunar orbit, fired its engine for one minute and 45 seconds, putting it on a path for a final close lunar flyby before heading home for a planned Dec. 11 splashdown.
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Write to Jeffrey Kluger at jeffrey.kluger@time.com