The main body of the giant NASA rocket, which will return astronauts to the moon, has passed a critical test.
For the first time, engineers fully loaded the main phase of the Space Launch System (SLS) rocket from a super-cold liquid propellant, controlled it, and then built the tank.
It is a propellant fuel and oxidizer – a chemical that burns fuel.
Engineers, before SLS builds its first flight in a period of about one year, checks things worked out as expected.
It was part of a test program called Green Run, which is being conducted at NASA’s Stanislaus Space Center, near Bay St. Louis in Mississippi.
The assessment, known as Wet Dress Rehearsal (WDR), ranked seventh out of eight tests at the main stage. NASA said the rocket received a good response due to its preemptive loading. But a few minutes before the test was scheduled, an unexpected shutdown was experienced.
However, the completion of the WDR should set up the eighth and final test – a “hotfire” – where all four RS-25 engines on the base of the core will be operated simultaneously for the first time.
This very rocket segment will advance the first mission in NASA’s lunar research project – known as Artemis. The mission, scheduled for November 2021, will send the next pay-generation Orion spacecraft to loop around Earth’s only natural satellite.
There will be no crew aboard for this test flight. But the third Artemis mission, in 2024, will be the first humans to land on the lunar surface after the Apollo 17 mission in 1972.
Before the complex rocket segment is relocated to Florida to prepare for launch, the Green Run helps ensure no problems will be noticed.
Within a few hours, Stannis’ engineers loaded more than 700,000 gallons (approximately 2.6 million liters) of liquid hydrogen and oxygen into the main phase.
“This is a very exciting time,” said Jim Maser, senior vice president of Aerojet RocketDin, which built the RS-25 engine. “We’re really getting some very important aspects of the testing program.”
The rocket section is anchored with a giant steel structure known as the B-2 test stand, which was once used in the 1960s and 70s to test engines for giant Saturn V rockets carrying astronauts to the moon.
Propellants on six bells were brought to the site by a wind-blown waterway from the grounds of the Stepanis Space Center.
The badges were molded near the test stand while super-cold (cryogenic) propellants were piped to the main stage in the morning.
Hydrogen and oxygen are gaseous at room temperature, but gases take up a lot of space. By turning them into liquids the equivalent amount can be stored in a small tank.
This requires cooling the hydrogen fuel to minus 253C (minus 423F) and minus 183C (minus 297F) minus oxygen (fuel oxidizer).
After filling, the tank needs to be kept on top – refilled – constantly because at such low temperatures the liquid boils over time.
During testing, the liquids were due to flow through turbopumps – which feed the propellant into the engine combustion chamber – and the engine itself. This helps prepare the systems for launch.
It’s all designed to mimic as closely as possible what will happen in the hours before the actual flight. “We’re just trying to get enough data so that we can move on to the next race. And we want to find out what improvements can be made during this wet dress for hotfire preparation,” said Ryan McKiben, run test conductor for Green NASA. Told BBC News.
On its Artemis blog, NASA said: “First look at the data that the stage performs well during the propellant loading and refilling process.”
While all this was going on, teams from SLS’s main contractor – NASA and Boeing – launched a simulation launch countdown. They were going to take the count all the way to T-minus (remaining time) 33 second point.
But NASA said the test ended just minutes after the planned countdown period. Teams are evaluating the data to pinpoint the exact cause of the initial closure.
Speaking in October, Boeing’s vice president and SLS program manager, John Shawn, explains: “We will spend about two weeks looking at the data to make sure all systems behave as expected.
“We’ll go out and inspect the vehicle, to make sure there are no surprises.”
SLS in number
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The rocket will remain 98 m (322 ft) Its initial, or block 1, low in configuration
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Block 1 can send more than SLS 27 Tons (59,500 lb) For Lunar Orbit – Equivalent to 11 Large Sports Utility Vehicles (SUVs)
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A future version of the SLS, known as Block 2 Cargo, will be launched 46 tons (101,400 lb) On the moon – it’s 18 large SUVs
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Will produce SLS 8.8 million pounds (39.1 megawatts) Push in its block 1 configuration
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Four The RS-25 engine sits at the base of the core stage; They are the same people used in space shuttles
If the data looks good, the engineers will move on with the “hotfire”.
The SLS rocket has a large core stage with two small boosters hanging in the side. The four powerful RS-25 engines at its base are of the same type now used by the retired space shuttle orbiter.
The launch provides the raw power needed to send Orion into space and then throws it to the moon.
Last month, Stannis engineers removed and replaced a component called a clutch on one of the four pre-valves, which provides liquid hydrogen to the RS-25 engine. Showed inconsistent performance during pre-valve tests.
Officials plan to send the Giant Core to its launch site at the Kennedy Space Center in Florida by Jan. 14 to keep the SLS on track for its November flight.
Last week, NASA said the Artemis-1 mission was on its way to launch in November 2021.
The Green Run is largely easily advanced; There was a five-week stop due to Covid-19. In addition, due to tropical weather, especially due to the active hurricane season, work at the site had to be stopped six times.
“Having a schedule has been very important for us,” said John Honeycutt, NASA’s SLS manager, during a press conference in October. “
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