At the Kennedy Space Center in Florida, operations have resumed in view of the launch of the Artemis 1 mission, the first unmanned test flight that will pave the way for the return of the man with the first woman to the moon.
After days of feverish work in which the technicians analyzed the data of the launch stopped last Monday, the expected "go" came from NASA to the new attempt scheduled for Saturday 3 September, within a two-hour launch window that will open at 20:17 Italian time.
The latest weather report predicts favorable conditions at 60%, but there are many unknowns.
'Go' when loading the propellant
In the meantime, the launch director, Charlie Blackwell-Thompson, has given the final go-ahead to load the propellant for the Space Launch System (Sls) rocket of the unmanned Artemis 1 mission to the Moon.
The unknowns
"There is no guarantee that we will take off on Saturday, but we will be there and we will try," Mission Manager Mike Sarafin said during a press conference.
In fact, retrying the launch this weekend involves a "marginal increase in risk", which, however, NASA managers have judged acceptable: the data analysis conducted in recent days indicates that the anomalous temperature of one of the rocket engines found on Monday it was not due to a real engine problem but to a faulty sensor which will be ignored on Saturday.
To avoid new unexpected events, the procedures for cooling the engines will be started 30-45 minutes earlier than expected, in order to have more time to bring them to temperature.
Meanwhile, the loss of hydrogen detected during the rocket loading remains under observation: for the moment it has been repaired and does not seem to give problems at room temperature, but the teams will continue to monitor the situation on Saturday during the propellant loading operations.
In the last few hours, the procedures have therefore been updated and the timing for the launch has been perfected.
Once Orion is turned on, the countdown has also restarted.
The latest weather forecast for Saturday foresees favorable conditions at 60%, with a progressive improvement up to 80% by the end of the launch window.
However, it is estimated that within the two hours there will be 46 moments in which a stop of a few seconds could be given to launch due to the presence of space debris or the satellites of the Starlink constellation along the path of the SLS rocket.
Hopefully, Artemis will have around 38-39 days to test the technologies needed to fly around the Moon and return safely to Earth.
The return is scheduled for 11 October with a ditching off the coast of California.
If, on the other hand, the launch were to slip once again, due to the weather or some technical unforeseen, there could be new launch opportunities on Monday 5 September (with favorable weather at 70%) and again on Tuesday 6 September.
If Artemis 1 fails to launch by Tuesday, then it is likely that the SLS rocket will have to leave the launch pad and return to the integration building (Vab) to replace the batteries of the Safety System that interrupts the flight in an emergency. (Flight termination system).