Artemis I Pre-Launch Testing at LC-39B (Leading up to and including all WDR's)

[centaurinasa]

https://twitter.com/cbs_spacenews/status/1538855939759128578?cxt=HHwWhIC-nd7UjtsqAAAA

[centaurinasa]

Countdown will resume at 9:20am; T-0 expected at ~4:30pm

https://twitter.com/NASAGroundSys/status/1538863322321326080?cxt=HHwWgMC4zbqCktsqAAAA

[Robert_the_Doll]

"SLS/Artemis 1 (T-6h40m; 8:35am EDT): The GN2 controller is now working normally and both supply lines are showing the correct pressure; the team is ready to proceed with tanking; chilldown will begin at 9:05am EDT; countdown will resume at 9:20am; T-0 expected at ~4:30pm"


https://twitter.com/cbs_spacenews/status/1538863112799105025?cxt=HHwWgsC9xaH2kdsqAAAA

[centaurinasa]

UPDATE: Launch Director Charlie Blackwell-Thompson has now given the 'go' for tanking.

https://twitter.com/NASAGroundSys/status/1538868146785996800?cxt=HHwWgMC-1aOblNsqAAAA

[centaurinasa]

SLS/Artemis 1 (T-6h40m; 9am EDT): LD Charlie Blackwell-Thompson has given a 'go' for tanking; in other news, Jeremy Graeber, assistant LD, says a waiver will be processed for a slightly low electrical resistance reading in the left SRB's APU; not a constraint for fueling

https://twitter.com/cbs_spacenews/status/1538870086706003971?cxt=HHwWhoCwmZmMldsqAAAA

[SpeakertoAnimals]

SLS/Artemis 1 (T-6h40m; 9am EDT): LD Charlie Blackwell-Thompson has given a 'go' for tanking; in other news, Jeremy Graeber, assistant LD, says a waiver will be processed for a slightly low electrical resistance reading in the left SRB's APU; not a constraint for fueling

https://twitter.com/cbs_spacenews/status/1538870086706003971?cxt=HHwWhoCwmZmMldsqAAAA

Proceed. What could possibly go wrong with an electrical problem in a solid rocket engine?

[DaveS]

SLS/Artemis 1 (T-6h40m; 9am EDT): LD Charlie Blackwell-Thompson has given a 'go' for tanking; in other news, Jeremy Graeber, assistant LD, says a waiver will be processed for a slightly low electrical resistance reading in the left SRB's APU; not a constraint for fueling

https://twitter.com/cbs_spacenews/status/1538870086706003971?cxt=HHwWhoCwmZmMldsqAAAA

Proceed. What could possibly go wrong with an electrical problem in a solid rocket engine?

It's just a slightly low impedance and it has been historically at that slightly low point. No concern for powering up the APU when the Terminal Count reaches that point. And the motor itself is fine, it's just the APU portion of the Hydraulic Power Unit (HPU) for the left SRB that lives in the conical Aft Skirt. The APU despite its name, doesn't provide any electrical power, just the hydraulic pressure needed to move the rock/tilt actuators that move the SRB nozzle for steering as commanded by the guidance system.

[centaurinasa]

UPDATE: New start time 9:28 a.m. EDT, T-0 4:38 p.m

https://twitter.com/NASAGroundSys/status/1538875100753174528?cxt=HHwWgICx4Yawl9sqAAAA

[centaurinasa]

The countdown has resumed !! 

https://twitter.com/SpaceflightNow/status/1538877579633074177?cxt=HHwWgoC97avAmNsqAAAA

[centaurinasa]

SLS/Artemis 1 (T-6h40m; 09:28am EDT): NASA resumed the countdown at 9:28am at the T-minus 6h40m mark, eight minutes later than had been expected; core stage liquid oxygen "slow-fill" expected to begin just after 10am; new simulated T-0 is 4:38pm (2038 UTC)

https://twitter.com/cbs_spacenews/status/1538876547414822922?cxt=HHwWlMC4naGEmNsqAAAA

[centaurinasa]

Tanking has begun with chilling down the liquid oxygen propellant lines for core stage. In sequential fashion, liquid oxygen and liquid hydrogen will flow into the rocket’s core stage and interim cryogenic propulsion stage tanks and be topped off as some propellant boils off.

https://twitter.com/NASAGroundSys/status/1538877376742006787?cxt=HHwWhoC9mcS0mNsqAAAA

New Artemis I wet dress rehearsal milestones:
✔ Liquid Oxygen transfer line chilled down
✔ Helium pressurized to flight level
✔ Main propulsion chilldown initiated

https://twitter.com/NASAGroundSys/status/1538880478031269891?cxt=HHwWhsCyzYbpmdsqAAAA

[Overwatchfan123]

LOX tanking is scheduled to start in just a few minutes.

[Overwatchfan123]

They said "This is Artemis Launch Control."

[Overwatchfan123]

The chilling of the transfer lines for the LH2 tank will begin in 10 minutes.

[centaurinasa]

The Space Launch System’s core stage is now being loaded with liquid oxygen in “slow fill” mode for today’s countdown rehearsal.
This begins the process to pump 755,000 gallons of super-cold propellants into the vehicle at the Kennedy Space Center.

https://twitter.com/SpaceflightNow/status/1538887644884701187?cxt=HHwWhsC46ZuKndsqAAAA

[centaurinasa]

We ate now, in fast fill (LOX) Core Stage

https://twitter.com/NASAGroundSys/status/1538890100494454790?cxt=HHwWjMCyxZOZntsqAAAA

[mrhuggy]

They have a go for LH2 fill, pre chilling the lines then on to slow fill.

[centaurinasa]

Now, LC give the GO for Core Stage LH2 tanking

UPDATE: We have now entered chilldown of the
@NASA_SLS
 liquid hydrogen transfer line.

https://twitter.com/NASAGroundSys/status/1538892783259377664?cxt=HHwWgICz2ae1n9sqAAAA

[Overwatchfan123]

According to the Spaceflight Now stream of the WDR, NASA reports that the test director over in Firing Room 1 at the Launch Control Center at the Kennedy Space Center has given a go for LH2 (liquid hydrogen) tanking operations. This will begin with the chilling of the transfer lines of the LH2 tank on the SLS rocket.

[Overwatchfan123]

NASA has now confirmed that LH2 (liquid hydrogen) is flowing into the core stage.