Washington, Apr 1 (IANS): After making a public debut on its way to the launch pad, NASA has started a two-day wet dress rehearsal for its Artemis 1 mega moon rocket, the US space agency officials said.

The dress rehearsal will demonstrate the team's ability to load more than 700,000 gallons of cryogenic, or super-cold, propellants into the rocket at the launch pad, practice every phase of the launch countdown, and drain propellants to demonstrate safely standing down on a launch attempt.

The test will be the culmination of months of assembly and testing for SLS and Orion, as well as preparations by launch control and engineering teams, and set the stage for the first Artemis launch.

The approximately two-day test, to be held between April 1 and 3, "will run the Artemis I launch team through operations to load propellant into the rocket's tanks, conduct a full launch countdown, demonstrate the ability to recycle the countdown clock, and also drain the tanks to give them an opportunity to practice the timelines and procedures they will use for launch" NASA said in a statement.

During the rehearsal, mission controllers will countdown to T-1 minutes and 30 seconds and pause to demonstrate the ability to hold for up to 3 minutes, then resume until 33 seconds before, when launch would occur, then pause the countdown.

Then they will recycle back to ten minutes before launch and conduct a second terminal countdown to approximately 9.3 seconds before launch, then end the countdown.

Sometimes called a "scrub," launch controllers may decide not to proceed with launch if a technical or weather issue arises during or prior to the countdown.

At the end of the test, the team will drain the propellant to demonstrate the procedures that would be used during a launch scrub. After draining the tanks, the team will review the test data before setting an official target launch date.

Artemis 1 is currently scheduled to launch no earlier than late May 2022.

The uncrewed Artemis I mission is the first flight of the SLS rocket and Orion spacecraft together. Future missions will send people to work in lunar orbit and on the Moon's surface.

With the Artemis missions, NASA will land the first woman and the first person of colour on the Moon and establish long-term exploration in preparation for missions to Mars. SLS and Orion, along with the commercial human landing system and the Gateway that will orbit the Moon, are NASA's backbone for deep space exploration.