Well, Boeing and NASA have finally gotten the SLS rocket’s central core to pass its ignition test. 499.6 seconds of ignition of its four Aerojet Rocketdyne RS-25 engines attest to that. That’s just over eight minutes, which is how long it will take for an SLS to enter orbit when an actual launch occurs.
Apart from the engines, the ignition test also served to check the correct operation of the three onboard computers, 50 avionics units, the navigation systems, the control systems, 500 sensors, the almost 30 kilometers of cable that interconnect everything on board, and the fuel system.
Some of the most spectacular images were of the engine nozzles moving. Although it should be noted that during the test they were moved much faster than it is anticipated that they will ever have to be moved in real flight. In the absence of aerodynamic control surfaces their orientation is what directs the rocket’s trajectory.
That’s how long today’s successful Green Run hot fire test of the @NASA_SLS core stage lasted — providing enough data to determine if the stage is ready to be delivered to @NASAKennedy ahead of the #Artemis I mission: https://t.co/4CvC8wHUln pic.twitter.com/NJo2RiwhIG
— NASA (@NASA) March 18, 2021
All the data collected remains to be reviewed but everything indicates that this time everything has worked as it should, unlike the first time this test was attempted; on that occasion too conservative parameters caused a shutdown of the engines 67 seconds after they were ignited and thus the cancellation of the test.
This central core will now be overhauled and refitted for launch and then sent to the Kennedy Space Center, where it should arrive at the end of April. It will then be shipped to the Kennedy Space Center, where it should arrive at the end of April, where it will receive the lateral thrusters that will be used for its first launch, which will be the Artemis 1 mission.
Artemis 1 will be an unmanned mission that, if all goes well, will put an Orion capsule into orbit around the Moon for six days out of a total of about three weeks that the mission will last. It will be the necessary preamble to the Artemis 2 mission, which will again place an Orion in orbit around the Moon, although in this case already manned.
NASA’s plans, and after multiple delays, were until recently to launch Artemis 1 in November 2021, but with the delay caused by the failure of the first ignition test it is quite unlikely that the launch can take place before the end of 2021; everything indicates that it will rather go to the beginning of 2022. Artemis 2, on the other hand, points to 2023, although that date depends, and very much so, on how things go with Artemis 1.
This in turn makes the Trump administration’s commitment to put a manned mission – Artemis 3 – on the surface of the Moon before the end of 2024 increasingly complicated to fulfill. Although in this house from the moment the date was announced we were absolutely skeptical about it; it must be remembered that not only the SLS and Orion have to be ready but also that there are still missing such fundamental things as a lander to go up and down from the Moon and the suits that will allow the walk on its surface.