At approximately 6:45 a.m. EDT, the launch director and mission management team chair gave the “go” to begin tanking the rocket. Meteorologists with Space Launch Delta 45 said there were no weather violations for the test. All elements are powered up and teams have moved the side flame deflectors into position and completed final preparations and closeouts of the umbilicals that connect the mobile launcher to the Space Launch System rocket and Orion spacecraft.
The flame deflectors divert ignited propellant away from the rocket and ground infrastructure at liftoff. Although the engines will not be lit during the test, launch controllers are using the wet dress rehearsal to practice countdown milestones like they would on launch day.
The umbilicals provide power, communications, coolant, and fuel to different parts of the rocket. Additional accessories provide access and stabilize the rocket and spacecraft. During launch, each umbilical releases from its connection point, allowing the rocket and spacecraft to lift off safely from the launch pad.
Cryogenic loading operations are schedule to begin around 7:20 a.m., or with L-7 hours, 20 minutes remaining in the countdown.
Once propellant loading operations begin, liquid oxygen (LOX) and liquid hydrogen (LH2) will flow into the rocket’s core stage and interim cryogenic propulsion stage tanks and be topped off and replenished as some of cryogenic propellant boils off. The team will also conduct leak checks to ensure propellant loading is proceeding as expected.
NASA is streaming live video of the rocket and spacecraft at the launch pad on the Kennedy Newsroom YouTube channel. Venting may be visible during tanking operations. NASA is also sharing live updates on the Exploration Ground Systems Twitter account.
The next blog update will be provided when core stage propellant loading is underway.