The 322-foot-tall rocket that will carry four astronauts around the Moon completed its slow, deliberate journey to Launch Pad 39B at Kennedy Space Center on March 20, marking the final major milestone before a launch window that opens April 1 at 6:24 p.m. Eastern Time [1]. If Artemis II flies on schedule, it will be the first crewed mission beyond low Earth orbit since Apollo 17 returned from the lunar surface in December 1972 -- a gap of 53 years.

The rollout began late on March 19, with the 5,000-ton stack -- NASA's Space Launch System (SLS) rocket topped by the Orion crew capsule -- crawling the four miles from the Vehicle Assembly Building to the pad aboard the same crawler-transporter platform that carried Saturn V rockets a half-century ago [2]. The journey took roughly 10 hours.

The mission itself is a 10-day flyby. Commander Reid Wiseman, pilot Victor Glover, mission specialists Christina Koch and Jeremy Hansen will loop around the far side of the Moon at a distance of roughly 6,400 miles from the lunar surface before returning to Earth [3]. There is no landing. Artemis II is a shakedown cruise for the Orion capsule's life support, navigation, and re-entry systems, all of which must be proven in deep space before NASA can commit to a crewed lunar landing on Artemis III.

The road to the pad has been anything but smooth. Artemis II was originally scheduled for late 2024. Issues with the Orion heat shield discovered after Artemis I's uncrewed flight in 2022, followed by problems with SLS solid rocket booster components, pushed the date repeatedly. Late last month, NASA detected a helium flow issue and rolled the stack back to the VAB for repairs, replacing an electrical harness before declaring the vehicle ready for a second rollout attempt [2].

Additional launch windows are available on April 3-6 and April 30 if the April 1 date slips [4]. Each window is roughly 120 minutes, constrained by orbital mechanics that dictate the Moon's position relative to Earth.

The mission carries risk that NASA has been transparent about. CNN reported that the agency's internal risk assessment flagged the heat shield as a residual concern, though engineers concluded the modifications made after Artemis I were sufficient [3]. The SLS rocket has flown only once, on the uncrewed Artemis I mission in November 2022, which was itself delayed by years.

Ground teams are now conducting final pad checks, including fueling rehearsals and communication verifications. The four crew members arrived in Florida last week for capsule simulations.

Pad 39B last hosted a crewed lunar mission on December 7, 1972, when Apollo 17 launched with Gene Cernan, Ron Evans, and Harrison Schmitt. Cernan, the last human to walk on the Moon, died in 2017 urging NASA to return. The rocket now on his launch pad is the answer -- 53 years late, but pointed in the right direction.

-- KENJI NAKAMURA, Tokyo