NASA’s new moon rocket, Artemis 1, unexpectedly remained on the ground Monday, disappointing hundreds of thousands of Americans, including the Vice President, Kamala Harris, who had gathered to watch what had promised to be an amazing blast-off.
The launch was to be the debut flight of the Space Launch System, a giant, 322-foot-tall rocket to take astronauts to the moon in the coming years. As the Artemis launch called off; NASA has additional opportunities to launch next weekend.
However, that depends on whether there is enough time to diagnose and fix the problems that caused the launch to be called off. Otherwise, the temperature shock of supercold propellants would cause sudden shrinkage of the metal engine parts.
The issue that halted Monday’s launch was a liquid hydrogen line that did not adequately chill one of the rocket’s four core-stage engines, part of the preparations needed before ignition.
It is not uncommon for technical problems to crop up during debut launch attempts. When NASA initially tried to launch the space shuttle in 1981, the flight was called off during the countdown. It then launched two days later.
The countdown, which started Saturday, continued smoothly through early Monday morning when the threat of nearby thunderstorms caused a 45-minute delay to the adding of 700,000 gallons of liquid hydrogen and liquid oxygen into the rocket’s propellant tanks.
The filling of the liquid oxygen tank proceeded without problems, but for the liquid hydrogen, a leak was detected in a fuel line that attached to the bottom of the rocket. That was a recurrence of a problem that occurred during a practice countdown in April.
Engineers were able to fix that problem, and the filling of the hydrogen tank resumed.
The hydrogen issue that arose later in the countdown was a different one. In the last seconds of the launch countdown, some of the liquid hydrogen and liquid oxygen is diverted to flow around the four engines to cool them in preparation for ignition. When done this morning, the oxygen lines all worked, as did three of the hydrogen lines.
But the fourth hydrogen line did not fully open.
This was the first test of the engine chill down, which usually occurs in the final seconds before launch. Dress rehearsals of countdown procedures earlier this year were cut short by technical problems, but mission managers believed the rocket had passed the critical test objectives, and they moved ahead with preparations for launch.
For Monday’s countdown, a chill-down test was added at an earlier point to allow troubleshooting in case a problem showed up.
After several troubleshooting attempts, the Artemis launch was called off.