By Joey RouletteCAPE CANAVERAL, Florida, April 1 (Reuters) – NASA is set to launch four astronauts as soon as Wednesday evening on a 10-day flight around the moon, marking the most ambitious U.S. space mission in decades and a major step toward returning humans to the lunar surface before China’s first crewed landing.NASA mission managers on Monday polled “go” to launch the Artemis II mission’s towering, 322-ft (98-m) Space Launch System (SLS) rocket topped with the astronauts’ Orion crew capsule as early as 6:24 p.m. EDT (2224 GMT) on Wednesday.AdvertisementAdvertisementIt will launch from NASA’s Kennedy Space Center in Florida just one pad away from where the last moon-bound astronauts of the U.S. Apollo program lifted off more than half a century ago.The Artemis II crew includes NASA astronauts Christina Koch, Victor Glover and Reid Wiseman and Canadian astronaut Jeremy Hansen, who landed in Florida from Houston on Friday.They had been in a two-week quarantine leading up to liftoff and spent time with their families over the weekend at the Kennedy Space Center’s beach house, a spot where astronauts rest before blasting off into space.”Certainly all indications are right now, we are in excellent, excellent shape as we get into count,” launch director Charlie Blackwell-Thompson told reporters on Monday.AdvertisementAdvertisementWeather conditions appeared favorable for an on-time liftoff, with only a 20% chance of souring within the agency’s two-hour launch window on Wednesday. If the weather worsens and triggers a scrub, NASA could try again to launch any day u …