Nasa fires up the sls: 50-year lunar gap ends with 24-hour crewed sprint
NASA’s crawlerway finally groans again. At 00:24 a.m. ET on 2 April the 100-m-tall Space Launch System will thunder off Pad 39B, lofting four humans farther from Earth than any astronaut since Apollo 17. No footprints this time—Orion will whip around the Moon and dive home after 1.1 million km—but every bolt, heat shield and life-support line is being stress-tested for the surface mission that follows in 2026.
The bill so far: €20 billion. The return: a rehearsal for Mars.
Why this nine-day loop matters
Artemis II is not a stunt. It is a full-dress rehearsal for the hardware NASA must trust when lunar gravity is replaced by 22 light-minutes of Earth-Mars silence. The capsule’s life-support rack, the European service module’s main engine, the solar wings that must unfurl after a translunar injection shock—every component gets a baptism by deep-space vacuum. Fail now, rewrite the schedule. Pass, and the next crew rides the same stack with a lander bolted on top.
Reid Wiseman, Victor Glover, Christina Koch and Canada’s Jeremy Hansen know the script. They will spend 90 minutes in the Moon’s shadow, test Orion’s optical navigation against crater rims and fire the service module’s 30 kN engine twice: once to slip into a retrograde orbit, once to come home. The second burn is the one that cannot be simulated on Earth; a mis-timed ignition and the crew skips off the atmosphere or slams in too steep.
The sls paradox: most powerful, least flown
Four RS-25 engines, twin five-segment boosters, 8.8 million pounds of thrust—numbers that still make engineers grin. Yet after this flight the rocket becomes a museum piece. NASA has already ordered the more reusable, cheaper SpaceX Starship-Human Landing System for surface sorties. SLS is a bridge, not a destination, and every launch burns political capital as fast as it burns liquid hydrogen.
That is why tomorrow’s countdown is freighted with more than hydrogen. If the core stage’s redesigned upper engine section leaks, or if the Orion heat shield spalls again as it did on Artemis I, the 2026 landing slips to 2027, handing China’s Chang’e-8 crewed timetable an open goal. Congress will ask why a disposable rocket still eats $4 billion per copy.
Where to watch the stakes ignite
NASA TV goes live at 22:00 ET 1 April with tanking coverage; main engine start is scheduled for 00:24 ET 2 April. Backup windows stretch to 3 April. The agency’s YouTube feed carries raw telemetry; Florida’s Space Coast hotels are sold out at $400 a night. The spectacle lasts 8 min 25 s of powered flight, but the data NASA harvests will decide whether the next crew boards wearing the red-white-blue of Artemis or the red stars of a competitor.
Either way, the Moon is no longer a memory. It is a proving ground with a ticking clock.