Space Launch System’s hot fire test, expected to begin at 5 p.m. EST (2200 GMT) Saturday at NASA’s Stennis Space Center in Mississippi, caps a nearly year-long ‘Green Run’ test campaign to validate the rocket’s design.
It is seen as a vital step before a debut unmanned launch later this year under NASA’s Artemis program, the Trump administration’s push to land humans on the moon again by 2024.
Saturday’s test will see the rocket’s four Aerojet Rocketdyne RS-25 engines ignite for roughly eight minutes, generating 1.6 million pounds of thrust and consuming 700,000 gallons of propellants on a test stand to simulate internal conditions of liftoff.
“This is a once-in-a-generation kind of test,” Jim Maser, Aerojet Rocketdyne’s Senior Vice President of Space, told Reuters. “This will be the first time four RS-25s fire together at the same time.”
The expendable super heavy-lift SLS is three years behind schedule and nearly $3 billion over budget. Critics have long argued for NASA to transition from the rocket’s shuttle-era core technologies, which have launch costs of $1 billion or more per mission, to newer commercial alternatives promising lower costs.
By comparison, it costs as little as $90 million to fly the massive but less powerful Falcon Heavy from Elon Musk’s SpaceX, and some $350 million per launch for United Launch Alliance’s legacy Delta IV Heavy.