NASA is finally ready to test-fire the engines of its SLS megarocket - Space.com

The delayed hot-fire engine test of the rocket's core booster is set for Jan.

It's a critical test for NASA and the final step in the agency's "Green Run" series of tests to ensure the SLS rocket is ready for its first launch, Artemis 1, that will send an uncrewed Orion spacecraft around the moon later this year.

Video: NASA's SLS rocket core stage will soon be test fired.

In the upcoming hot-fire engine test, engineers will load the Boeing-built SLS core booster with over 700,000 gallons of cryogenic (that's really cold) propellant  into the rocket's fuel tanks and light all four of its RS-25 engines at once.

"This test will demonstrate that this newly designed and developed core stage is ready for launch," SLS stage manager Julie Bassler said today (Jan. 12) during a news conference.

"Testing provides an opportunity to learn and make sure that the rocket is ready to fly astronauts to the moon.".

Following this upcoming hot fire test, the team behind the test will "need several days to analyze the data and determine if we are ready to move forward with refurbishing the core stage and shipping to Kennedy," Bassler said.

Following the success of this hot fire test and subsequent uncrewed missions to the moon, "the next key step in returning astronauts to the moon and eventually going on to Mars," Jeff Zotti, the RS-25 program director at Aerojet Rocketdyne said during the news conference. .

"This powerful rocket is going to put us in a position to be ready to support the agency in the country's deep space mission to the moon and beyond," he said.