NASA’s SLS Moon Rocket Returns to Launchpad Today for More Tests – Spaceflight Now

NASA’s SLS moon rocket rolls toward platform 39B early Monday. Credit: Michael Caine/Spaceflight Now/Coldlife Photography

NASA’s Space Launch System’s first lunar rocket blasted off to the launch pad early Monday at the Kennedy Space Center in another attempt later this month to fully load it with ultra-cold propellants, the culmination of countdown rehearsals that officials aim to complete before Moving forward with a launch later this summer.

The towering 322-foot (98-meter) rocket began flight at 12:15 a.m. EDT (0415 GMT) on Monday with the first movement of Hi-Bay 3 inside the Vehicle Assembly Building, the iconic Kennedy hangar that was originally built to stack it. The Saturn 5 satellite missile service during the Apollo program.

The SLS moon rocket and its mobile launcher were mounted on platform 39B on a diesel-powered tracked carrier. The 4.2-mile (6.8 kilometre) journey took about 10 and a half hours to complete. Lowering the lunar rocket platform onto the launch pad’s support pillars marked the official conclusion of the flight at 10:47 a.m. EDT (1447 GMT), according to a NASA spokesperson.

The full stack weighs about 21.4 pounds to subtract.

The massive rocket is the largest ever built by NASA, and is the centerpiece of the agency’s Artemis lunar program, which aims to return astronauts to the lunar surface later this decade. NASA is preparing the first SLS lunar rocket for the Artemis 1 test flight, a test mission to send an uncrewed Orion capsule around the moon and back to Earth on a meager cruise before flying with people.

NASA’s Artemis 1 lunar rocket approaches platform 39B on Monday near the conclusion of its 10-and-a-half-hour launch. Credit: Stephen Clark/Spaceflight Now

In the run-up to the Artemis 1 launch, NASA teams at Kennedy stacked the SLS lunar rocket and rolled a launcher into the 39B platform for the first time on March 18 before a “wet rehearsal” to test countdown procedures and fully load the rocket with more than 750,000 gallons of ultra-cold liquid hydrogen and propellants. liquid oxygen.

But a series of technical obstacles prevented the NASA launch team from completing the countdown rehearsal in April.

A problem with ground equipment at the launch pad delayed the daily test from 3 April, and then had problems with the supply of nitrogen gas to the launch pad. Nitrogen is used to purify the compartments inside the SLS moon rocket.

A refueling attempt on April 4 was cut short due to concerns about the temperature of liquid oxygen flowing into the rocket’s core stage, then engineers discovered a problem with the helium valve in the upper stage of the SLS.

A helium valve problem prevented the launch team from pumping propellants to the upper stage in the next refueling attempt. But NASA tried again on April 14 to load cryogenic fuel into the primary stage, but encountered more problems with the nitrogen supply. After temporarily overcoming the nitrogen problem, the launch team detected indications of a hydrogen leak near the umbilical junction at the bottom of the core stage.

NASA officials then decided to return the rocket to VAB for repair.

NASA’s Space Launch System moon rocket stands inside the Vehicle Assembly Building on June 3, ready to return to Panel 39B for another countdown rehearsal. Credit: NASA/Glenn Benson

The Artemis 1 bomber retreated into the hangar on April 26, and technicians inside High Bay sealed the secret junction in hopes of fixing the hydrogen leak. Workers also swapped out a helium checkered valve on the upper stage, which failed due to rubber debris stuck in the mechanism. NASA said teams within the VAB also worked to ensure no more debris emerged as a problem for the new valve.

Meanwhile, upgrades to an offsite nitrogen gas station near the Kennedy Space Center have been completed to expand the system’s capacity on the SLS lunar rocket. The nitrogen facility is operated by Air Liquide.

With troubleshooting, NASA teams have returned the Artemis 1 lunar rocket to Panel 39B for another countdown timer rehearsal, or WDR, later this month. If all goes according to plan, the next attempt to fully refuel the SLS lunar rocket is scheduled for June 19.

Before that, ground teams at the Space Center will prepare the rocket for a training countdown. These tasks will involve loading the steering mechanism, or gimbaling mechanism, onto the rocket’s two solid-fuel boosters with hydrazine fuel, which feeds hydraulic power units into the booster thrust control system.

The countdown test will end with a cut-off inside the T-minus 10 seconds, before the rocket’s four primary stage engines ignite.

If the launch team is able to accomplish the WDR, NASA will return the Space Launch System to the assembly building for final sealing and testing. NASA will tow the rocket to platform 39B again for the real launch campaign, currently scheduled for no later than August.

The agency did not set a formal target launch date until the successful completion of the World Development Report.

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