NASA Set for Two-Day Wet Dress Rehearsal for Artemis I Mission Starting Saturday
By Space Coast Daily // June 17, 2022
coverage can be seen on Space Coast Daily TV
BREVARD COUNTY • KENNEDY SPACE CENTER, FLORIDA – NASA is on track to begin the approximately two-day wet dress rehearsal for the agency’s Artemis I mission.
The test will begin at approximately 5 p.m. EDT June 18 with “call to stations,” when the launch team arrives at their consoles inside the Launch Control Center at NASA’s Kennedy Space Center in Florida.
The rehearsal will run the Artemis I launch team through operations to load propellant into the rocket’s tanks, conduct a full launch countdown, demonstrate the ability to recycle the countdown clock, and also drain the tanks to give them an opportunity to practice the timelines and procedures they will use for launch.
Approximate times for milestones during the test are below.
During the test, the timing for some events on account of several planned operational demonstrations tied to specific capabilities and test objectives may differ from the day of launch countdown.
These demonstrations include tests on the cryogenic systems and an approximately three-minute hold inside the terminal count, which would not normally occur on launch day.
If needed, the test team may also hold as necessary to verify conditions before resuming the countdown, or use the test window or extend beyond it, if consumables and resources allow them to complete test objectives.
Prior to Call to Stations
The Orion crew module hatch is closed (will occur at ~L-37.5 hours for launch)
The crew access arm is retracted (will occur at ~L-30 hours for launch)
Leak checks are completed on the Orion spacecraft and the launch abort system is closed (will occur at ~L-29 hours, 30 minutes for launch)
5 p.m. EDT, June 18 – L-45 hours, 40 minutes and counting
The launch team arrives on their stations and the countdown begins (L-45, 40 minutes hours)
Fill the water tank for the sound suppression system (L-45 hours)
Orion spacecraft power up start (L-41 hours)
SLS core stage is powered up (L-35 hours, 20 minutes)
Final preparations of the four RS-25 engines complete (L-30 hours, 30 minutes)
Engines will not fire during this test
1:40 a.m., June 20 – L-13 hours and counting
The SLS interim cryogenic propulsion stage (ICPS) is powered up (L-12 hours, 50 minutes)
All non-essential personnel leave Launch Complex 39B (L-12 hours)
6 a.m. – L-8 hours, 40 minutes and counting
Built in countdown hold begins and lasts approximately 1.5 hours (L-8 hours, 40 minutes)
The launch director and mission management team chair conduct a weather and tanking briefing (L-8 hours, 20 minutes)
The launch director and mission management team chair decide if they are “go” or “no-go” to begin tanking the rocket (L-7 hours, 50 minutes)
6:40 a.m. – L-8 hours and counting
7:35 a.m.: Core stage liquid oxygen (LOX) chilldown start (L-7 hours, 05 minutes)
8:15 a.m.: Core stage LOX slow fill start (L-6 hours, 25 minutes)
8:30 a.m.: Core stage LOX fast fill start (L-6 hours, 10 minutes)
8:35 a.m.: Core stage liquid hydrogen (LH2) chilldown start (L-6 hours, 5 minutes)
8:40 a.m.: Core stage LH2 slow fill start (L-6 hours)
9:00 a.m.: Core stage LH2 fast fill start (L-5 hours, 40 minutes)
10:10 a.m. – L-4 hours, 30 minutes and counting
10:10 a.m.: Core stage LH2 topping start (L-4 hours, 30 minutes)
10:15 a.m.: ICPS LH2 chilldown (L-4 hours, 25 minutes)
10:15 a.m.: Core stage LH2 replenish start (L-4 hours 25 minutes)
10:20 a.m.: Orion communications system activation start (L-4 hours, 20 minutes)
10:40 a.m.: ICPS LH2 fast fill (L-4 hours)
11:10 a.m. – L-3 hours, 30 minutes and counting 
11:15 a.m.: Core stage LOX topping start (L-3 hours, 25 minutes)
11:20 a.m.: Core stage LOX replenish start (L-3 hours, 20 minutes)
11:20 a.m.: ICPS LOX chilldown start (L-3 hours, 20 minutes)
11:25 a.m.: ICPS LH2 validation and leak test start (L-3 hours, 15 minutes)
11:30 a.m.: ICPS LOX fast fill start (L-3 hours, 10 minutes)
11:40 a.m.: ICPS LH2 tanks load topping start (L-3 hours)
11:40 a.m.: ICPS/SLS telemetry data verified with Mission Control Center and SLS Engineering Support Center (L-3 hours)
12 p.m.: ICPS LH2 replenish start (L-2 hours, 40 minutes)
12 p.m.: ICPS LOX validation and leak test (L-2 hours, 40 minutes)
12:20 p.m.: ICPS LOX topping start (L-2 hours, 20 minutes)
12:30 p.m.: ICPS LOX replenish start (L-2 hours, 10 minutes)
12:40 p.m.: WDR-specific core stage LOX/LH2 stop flow and recover test (L-2 hours through L-55 minutes)
2 p.m. – L-40 minutes and holding
2 p.m.: Final NASA test director briefing begins
2 p.m.: Built in 30-minute countdown hold begins
2:25 p.m.: The launch director polls the team to ensure they are “go” for terminal count for test purposes
2:30 p.m. – T-10 minutes and counting (WDR Run 1)
2:34 p.m.
Orion ascent pyros are armed (T-6 minutes)
Orion set to internal power (T-6 minutes)
Core stage LH2 terminate replenish (T-5 minutes, 57 seconds)
2:36 p.m.
Core stage auxiliary power unit starts (T-4 minutes)
Core stage LOX terminate replenish (T-4 minutes)
ICPS LOX terminate replenish (T-3 minutes, 30 seconds)
2:38 p.m.
ICPS switches to internal battery power (T-1 minute, 56 seconds)
Core stage switches to internal power (T-1 minute, 30 seconds)
3 minute launch ready hold (T-1 minute, 30 seconds)
Wet dress rehearsal only
ICPS enters terminal countdown mode (T-1 minute, 20 seconds)
2:41 p.m.
ICPS LH2 terminate replenish (T-50 seconds)
Ground launch sequencer sends “cut-off” command (T-33 seconds)
Perform Critical Safing and Planned Recycle back to T-10 minutes and holding (takes approximately one hour)
T-10 minutes and counting (WDR Run 2)
Orion ascent pyrotechnics are armed (T-6 minutes)
Orion set to internal power (T-6 minutes)
Core stage LH2 terminate replenish (T-5 minutes, 57 seconds)
Core stage auxiliary power unit starts (T-4 minutes)
Core stage LOX terminate replenish (T-4 minutes)
ICPS LOX terminate replenish (T-3 minutes, 30 seconds)
ICPS switches to internal battery power (T-1 minute, 56 seconds)
Core stage switches to internal power (T-1 minute, 30 seconds)
ICPS enters terminal countdown mode (T-1 minute, 20 seconds)
ICPS LH2 terminate replenish (T-50 seconds)
Ground launch sequencer sends “Go for automated launch sequencer” command (T-33 seconds)
Core stage flight computer to automated launching sequencer (T-30 seconds)
Ground launch sequencer manual cut-off at T-9.34 seconds
Teams will then proceed conducting critical safing and core and upper stage cryogenic fuel drain operations.
