NASA managers gave the “go” to begin filling the Space Launch System’s core stage with more than 700,000 gallons of super-cold liquid hydrogen and liquid oxygen Saturday at the Stennis Space Center in Mississippi, aiming for the first firing of all four of the huge rocket’s main engines later in the day. NASA TV’s live coverage of the test-firing begins at 4:20 p.m. EST (2120 GMT), around 40 minutes prior to the start of the two-hour test window.
Rocket Lab scrubbed a launch attempt Saturday for its first mission of 2021 to review sensor data. Officials did not immediately set a new target launch date. The company’s light-class Electron rocket is set for launch from New Zealand with a small clandestine satellite for OHB, a German aerospace company.