A crucial test of NASA’s towering Space Launch System rocket is underway — marking one of the final steps before the vehicle launches four astronauts into deep space for the first time since the Apollo program ended more than five decades ago. The mission could launch as soon as February 8.The hands-on test, called a “wet dress rehearsal,” involves filling up the rocket’s tanks with more than 700,000 gallons of super-chilled propellants.A few hours into the test, NASA ran into issues with hydrogen leaks — a problem that also plagued the SLS rocket during its first round of dress rehearsals in 2022 ahead of the uncrewed Artemis I test flight. Ultimately, that mission took off about six months after NASA first attempted a wet dress rehearsal.AdvertisementAdvertisementKept at minus 423 degrees Fahrenheit, the liquified hydrogen, which is the primary fuel that powers the SLS rocket, is notoriously fickle because of its tiny molecular structure that makes the substance difficult to contain.The leaks did not prevent NASA from getting the SLS rocket fully fueled on Monday, however. As of 6 p.m. ET, the space agency said the vehicle had entered “replenish mode” — during which the rocket is only loaded with enough fuel to top off the tanks as small amounts of the propellants boil off.The agency is now working toward the “terminal countdown sequence, which includes simulated launch operations and final readiness verifications,” according to NASA.Just before 10 p.m. ET, however, NASA disclosed another issue. A “closeout team” — which is a …
