Mark Megahan
After a couple of scrubbed attempts, the Artemis I mission has blasted off for the moon. Things were touch and go for a while at Cape Canaveral on Wednesday, November 16. The problems were minor and fully resolved before launch.
Artemis I blasts off
A long awaited two-hour launch window opened up at 1:04 a.m. for the third attempt to launch the historic Artemis I lunar mission.
This one has nobody onboard (no tardigrades either,) and won’t touch down on the surface but the “25-day un-crewed flight around the moon will test the capabilities of both the SLS rocket and Orion spacecraft.”
All the NASA technicians were holding their breath and moving carefully as they topped off the SLS liquid hydrogen tank. They kept adding more hydrogen occasionally as they filled the liquid oxygen tank.
The SLS liquid hydrogen tank is being topped off and will continue to be replenished as the liquid oxygen tank continues filling. Replenishment of the tank is necessary because the super-cold propellant will boil off and turn to gas during the tanking process. pic.twitter.com/CZ988YUnzV
— NASA_SLS (@NASA_SLS) November 15, 2022
Hydrogen is so volatile, even when liquid, that it boils away constantly. The Artemis team started filling the tanks Tuesday afternoon when launch director Charlie Blackwell-Thompson “gave the go for tanking.”
Equipped with four RS-25 engines, the booster stage propellant tanks took until 7:50 p.m. to fill completely. At least the weather cooperated and went from 80% favorable for the overnight Artemis I launch up to 90%.
As the weather report improved, the gremlins started popping up.
Hydrogen leak detected
At 9:30 p.m. they had to stop the clock and NASA tweeted out that “a red crew is being sent to the pad.” They had detected a leak “a liquid hydrogen replenish valve on the core stage.”
Spectators waited anxiously as engineers swarmed around Artemis determining “what impact, if any, the detected leak inside the liquid hydrogen replenish valve on the launch.” Time was running out by the moment.
It took a full two hours before NASA officials announced that the Artemis “red crew” has “left the launch pad following the liquid hydrogen replenish valve leak.” They didn’t add anything about what had been found.
We are going.
For the first time, the @NASA_SLS rocket and @NASA_Orion fly together. #Artemis I begins a new chapter in human lunar exploration. pic.twitter.com/vmC64Qgft9
— NASA (@NASA) November 16, 2022
At midnight, an hour before the launch window opened, the Artemis team put out a tweet declaring the crew had “remedied the leak.” They also found a bad ethernet switch and were replacing it as well.
When the clock counted down to 10 minutes, it went into automatic hold mode. The status report declared “we are in our planned hold at T-10 minutes. Currently, the upper stage liquid hydrogen is 78% filled. Core stage has been topped off – both liquid hydrogen and liquid oxygen are 100% filled. The ethernet switch has been replaced and will be verified.”
It all checked out. Everything was green and the clock started ticking down the last ten minutes to 1:47 a.m. The launch of Artemis I was as beautifully spectacular as it was successful.
