The smooth running of the operation will determine the launch date of the Artemis 1 mission, the first of the American return to the Moon program (but which will not yet include an astronaut on board).

The test should start Friday at 5:00 p.m. local time and end Sunday evening.

For the past two weeks, the 98-meter-high rocket has been sitting on launch pad 39B at the Kennedy Space Center, with the Orion capsule perched atop it, where astronauts will settle in the future.

On Friday, after the "call to the stations", a 45-hour countdown will be started.

The rocket and the capsule will first be powered up, the communication systems checked, and a whole series of preparations carried out.

Then, about 8 hours before the fictitious liftoff, the rocket's tanks will be filled with more than three million liters of fuel -- liquid hydrogen and oxygen, respectively at temperatures of -267°C and - 170°C.

The countdown will finally be stopped at T-9 seconds, just before the ignition of the engines.

The idea is to simulate a forced abandonment procedure, for example due to the weather or a technical problem.

Subsequently, the vehicle's tanks will be emptied.

NASA plans to deliver the first results of this dress rehearsal on Monday.

But "it will take several days to really assess not only the success of the test, but also if we observed anything unusual that we need to correct", declared this week during a press conference Tom Whitmeyer, responsible for the development of exploration systems at NASA.

He said he hoped for an announcement of a take-off date for Artemis 1 in the following days.

The May launch window will likely be missed, but more are possible in early June or early July.

After the general rehearsal, the rocket will be brought back to its hangar for a final series of checks, then taken out for takeoff.

Artemis 1 will mark the first flight of SLS, whose development took years behind schedule.

The Orion capsule will be propelled to the Moon, where it will be placed in orbit before returning to Earth.

Humans won't land on the Moon until Artemis 3, for now in 2025 at the earliest.

© 2022 AFP