After two weeks of preparatory work on the launch pad at Kennedy Space Center, NASA is ready to put its large new rocket and its complex plumbing system to the test. This will be the final major rehearsal before the space agency declares that, after 11 long years and tens of billions of dollars in development costs, the Space Launch System is finally ready to fly.
The “wet dress rehearsal” is slated to begin at 5 pm ET (21:00 UTC) on Friday, when the launch control teams will arrive on console at the Launch Control Center. At that point, engineers and technicians will begin to power up the Orion spacecraft and the rocket itself. But the real action will not take place until Sunday.
At around 6 am ET, a team from NASA and the launch vehicle’s contractors will enter a “launch day” countdown; shortly thereafter, they will start to fuel the rocket’s core stage with liquid oxygen. The loading of liquid hydrogen will begin about an hour later. NASA has posted a tentative schedule with key milestones on its website.