Shyster's thread of Spaaaace.
Shyster's thread of Spaaaace.
For the same reason it's not 12 or 93.
Shyster's thread of Spaaaace.
Dunno. IIRC, it was 31 seconds for the Shuttle, so whatever the SLS is doing in that time, it takes two more seconds.
So far, the countdown has been proceeding nominally. The SLS core stage is currently fully fueled and in "topping off" mode, and the second stage is on the process of being filled with liquid oxygen and hydrogen. Fueling is actually ahead of schedule, and it looks like NASA has fixed the leaky connectors that hindered earlier wet-dress rehearsals. Weather looks good, and the range is currently green.
So far, the countdown has been proceeding nominally. The SLS core stage is currently fully fueled and in "topping off" mode, and the second stage is on the process of being filled with liquid oxygen and hydrogen. Fueling is actually ahead of schedule, and it looks like NASA has fixed the leaky connectors that hindered earlier wet-dress rehearsals. Weather looks good, and the range is currently green.
Shyster's thread of Spaaaace.
Problem:
An intermittent leak in a hydrogen replenish valve has caused a Stop Flow condition. NASA is sending a specially trained "Red Team" to the pad to see if the leak can be fixed. The valve in question is in the base of the launch pad and not on the tower.
An intermittent leak in a hydrogen replenish valve has caused a Stop Flow condition. NASA is sending a specially trained "Red Team" to the pad to see if the leak can be fixed. The valve in question is in the base of the launch pad and not on the tower.
Shyster's thread of Spaaaace.
The Red Team is on site at the pad and is working to torque down the bolts on the leaky valve.
Shyster's thread of Spaaaace.
Red Crew is clear of the pad. The bolts were loose. Now getting ready to test the valve.
Shyster's thread of Spaaaace.
The range has lost signals for one of its radar sites. That would be a no-go for launch. Range is working on resorting connectivity. It sounds like an ethernet switch pooped the bed and needs to be replaced.
Propellant loading has resumed. The hydrogen lost to boil-off during the stop has been replenished and the core is back in top-off mode.
One of the reasons that it takes a couple days to turn around the SLS after a scrub is that literally thousands of gallons of LOX and LH2 boil off in the lead up to launch, and NASA literally has to truck in many tanks of hydrogen and oxygen to replace those losses before it can try for another launch.
Propellant loading has resumed. The hydrogen lost to boil-off during the stop has been replenished and the core is back in top-off mode.
One of the reasons that it takes a couple days to turn around the SLS after a scrub is that literally thousands of gallons of LOX and LH2 boil off in the lead up to launch, and NASA literally has to truck in many tanks of hydrogen and oxygen to replace those losses before it can try for another launch.
Shyster's thread of Spaaaace.
The valve has been confirmed to be leak-free, so the Red Team fixed the issue. The only problem being worked is the loss of connectivity for the range radar.
Shyster's thread of Spaaaace.
T-10 minutes and holding. This is a planned hold in the countdown. Launch window opens in ~30 minutes. Still no-go on the radar issue, but that is in work.
Shyster's thread of Spaaaace.
The launch window lasts for several hours, so there is time to resolve issues.
The network switch has been replaced and testing is underway. The switch is also required for the flight-termination system to work properly, so it is a critical piece of communication hardware.
The network switch has been replaced and testing is underway. The switch is also required for the flight-termination system to work properly, so it is a critical piece of communication hardware.
Shyster's thread of Spaaaace.
Still in hold and now into the launch window. Both stages are fully fueled and in top-off mode. It looks like the range issue still has not been resolved.
Shyster's thread of Spaaaace.
Polling for launch is imminent.
Shyster's thread of Spaaaace.
Go for terminal count.
Shyster's thread of Spaaaace.
SLS is pressing for flight.
Shyster's thread of Spaaaace.
FTS is armed. APUs have started.
Shyster's thread of Spaaaace.
Internal power.
Shyster's thread of Spaaaace.
GLS is go for auto-sequence start.
Shyster's thread of Spaaaace.
Liftoff!
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SRB separation.
Shyster's thread of Spaaaace.
Fairing and launch-abort separation.
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Shyster's thread of Spaaaace.
Yay, spaceflight! Fun to watch a moonshot; the future is an exciting time.