Nasa carried out a successful test on part of the most powerful rocket in existence – the Space Launch System (SLS).
Its engines were kept running for more than eight minutes to simulate the time that it takes the rocket to get from the ground into space.
It’s the second such test for the biggest segment of the SLS, after an attempt in January shut down early.
The SLS is to send humans to the lunar surface for the first time since 1972.
The test was carried out on the rocket’s core stage. The SLS consists of the orange core, with its four powerful RS-25 engines, and two boosters attached to the sides. The RS-25s, built by California-based Aerojet Rocketdyne, are much the same engines that powered the space shuttle.
Although the target was to fire the engines for eight minutes, teams from Nasa and prime contractor Boeing only had to keep them on for four minutes in order to gather all the engineering data they needed.
The core that was part of Thursday’s test will be used for the maiden flight of the SLS, scheduled for late 2021.
It is attached to a giant structure called the B-2 test stand, on the grounds of Nasa’s Stennis Space Center, near Bay St Louis, Mississippi.
In the 1960s, the stand tested engines used in the massive Saturn V rocket that launched the Apollo astronauts to the Moon.
Before Thursday’s hotfire, engineers filled the core stage with more than 700,000 gallons of propellant.
That propellant consisted of liquid hydrogen, which is the rocket’s fuel, and liquid oxygen, which helps the fuel burn. They react explosively inside the engines, generating super-heated water vapour from the exhaust.
The heat from exhaust of the engine was 3,316 °C, hot enough to boil iron.
Hundreds of thousands of gallons of water were directed into the flame bucket to cool the exhaust. In addition, tens of thousands of gallons were used to create a water “curtain” around the engines to suppress the noise generated when they fire for eight minutes.
This was done to protect the core stage from vibrations while it is anchored to the stand.
The engines tested on Thursday contributed to 21 successful shuttle flights over the vehicle’s 30-year operational history.
Two were used on the last space shuttle mission, STS-135 in 2011. One flew on the 1998 mission that launched the oldest person ever to go to space – US senator and Project Mercury astronaut John Glenn, who was 77 at the time. The other was used on one of the flights to service the Hubble Space Telescope.
The engines were refurbished following shuttle missions, but they will be discarded after the maiden flight of the SLS later this year.
That mission, called Artemis-1, will send Nasa’s next-generation crew vehicle, Orion, around the Moon to thoroughly test its systems.