(Tribune News Service) — The reigning title holder for world’s most powerful rocket saw action on both its center core and its two solid rocket boosters this month, with pieces for the Artemis II launch coming together as NASA aims to send humans on a trip around the moon next year.

Arriving by train to Florida on Monday were all 10 segments for the two side boosters of the Space Launch System rocket that will launch the Orion spacecraft with four humans on board from Kennedy Space Center as early as November 2024. The core stage of that booster remains in New Orleans, but teams last week installed the last of four converted space shuttle engines to the base of the stage.

The core stage’s primary contractor Boeing still has more work to do before it can be shipped by barge from NASA’s Michoud Assembly Facility to KSC, currently on track for a November arrival, but the tail end finally got the last of its four R2-25 engines stuck in place. Aerojet Rocketdyne, which was recently acquired by Melbourne-based L3Harris, manufactured all four engines that were originally designed for the Space Shuttle Program, but have since been converted for use on the SLS.

Two of the engines have been to space for a combined 20 missions already, including both Space Shuttle Endeavour’s last flight on STS-134 and Space Shuttle Atlantis’ last flight and final mission of the shuttle program, STS-135, in 2011. The other two engines are making their first trip to space, but the parts were mostly manufactured for the shuttles. All four have at least one component that flew on Space Shuttle Columbia on STS-1 in 1981.

RS-25s have been to space a combined 409 times, and former shuttle program engines will be used through Artemis IV, with brand new RS-25s used for Artemis V and beyond.

The next task is to integrate the engines with propulsion and electrical systems.

The core stage is the biggest part of the SLS rocket, standing at 212 feet with tanks that hold 733,000 gallons of cryogenic liquid hydrogen and liquid oxygen. It’s the propellant that shoots through the four RS-25s to provide 2 million of the SLS’s 8.8 million pounds of thrust on liftoff. The engines burn through the propellant for more than eight minutes during launch.

Attached to the core are the two solid rocket boosters, manufactured by Northrop Grumman in Utah. They had been awaiting the call from NASA to make the 2,400-mile trip to Florida, finally making the trek this week. They were loaded onto specialized transporters to endure each segment’s heavy load.

Each booster is made up of five segments, which actually give the rocket more than 75% of its power on liftoff with 3.3 million pounds of thrust each. The segments combined with the nose and nozzle weigh more than 1.6 million pounds with each filled with the solid polybutadiene acrylonitrile fuel. At launch, boosters burn through the propellant at a rate of six tons per second for just over two minutes before falling away from the core stage.

They are now in the hands of NASA’s Exploration Ground Systems Program based at KSC where they will be prepped at the spaceport’s Rotation, Processing and Surge Facility.

They will then make their way to the Vehicle Assembly Building where they will be stacked vertically into their full 17-story-tall booster form, then be installed alongside the core stage after its arrival from New Orleans.

The mission marks the second launch of the SLS rocket, which became the most powerful to make orbit when Artemis I lifted off on its uncrewed flight to the moon in late 2022. It broke a record held by the Saturn V rockets of the Apollo era.

That’s a title that would get pushed to No. 2 if SpaceX’s in-development Starship and Super Heavy rocket manages to make orbit with its more than 17 million pounds of thrust. Its second attempt to orbit is on hold awaiting approval to fly from the Federal Aviation Administration in the wake of its first attempt ending with the rocket self-destructing over the Gulf of Mexico back in April.

For NASA, it’s going to need both powerhouse rockets to continue its plans to return humans to the moon’s surface on the Artemis III mission as a version of Starship is contracted to be the astronauts’ Human Landing System.

Plans are for Starship to dock with the Orion spacecraft while it orbits the moon and then take two of that mission’s four-person crew, including the first woman, down for about a weeklong mission to explore the lunar south pole.

While that mission is still on NASA’s roadmap for as early as December 2025, delays to Starship could push that mission deeper into the decade. That potential delay is among sources for rising costs to the Artemis program.

In a September report to congressional committees, the U.S. General Accountability Office stated that “senior NASA officials told GAO that at current cost levels, the SLS program is unaffordable.”

NASA has already spent $11.8 billion during its more than decade-long development and lone launch, and President Biden’s 2024 budget request projects another $11.2 billion to support four planned Artemis missions through 2028.

Artemis II, though, is on track as it won’t land on the lunar surface, but simply prove that the Orion spacecraft can safely bring humans out to the moon and back. Its crew, NASA astronauts Reid Wiseman, Victor Glover and Christina Koch along with Canadian astronaut Jeremy Hansen, recently worked through a test run of launch day activities at KSC.

Their Orion spacecraft designed by Lockheed Martin along with the power and life-support source, the European service module have all been at KSC for some time. Once the SLS core stage and boosters are in place, it will be topped by the Interim Cryogenic Propulsion Stage provided by United Launch Alliance, and then finally by Orion and the service module.

Orion still has more testing, though, and won’t be ready to stack at the top of the SLS rocket in the VAB until May.

That still keeps teams on track to launch within 14 months, a feat that will send humans out to the moon for the first time in more than 50 years.

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