NASA Stacks Twin Boosters for Space Launch System Rocket

NASA has finished assembling two booster rockets to fuel the Space Launch System (SLS), the massive next-generation launch vehicle.

The SLS is the spacecraft that will send astronauts to the Moon under the US Artemis program.

When completed, NASA said that the SLS would be the world's most powerful rocket.

The SLS comprises two solid rocket boosters (SRBs) on either side of a massive core stage with four powerful engines at its core.

The two SRBs that have been completed at Kennedy Space Center will fly on the SLS's first flight, known as Artemis 1, in late 2021.

Each identical booster is divided into five parts, with the forward and aft assemblies serving as bookends.

The SRBs have been piled on a structure known as the mobile launcher, which will aid in the SLS's testing, checkout, and servicing, as well as its transfer to the launch pad at Kennedy Space Center.

NASA Stacks Twin SLS Rocket Boosters: How Did They Do It?

According to NASA, Florida's Kennedy Space Center staff have vertically stacked the booster rockets' 10 segments for several months inside the Vehicle Assembly Building (VAB).

Engineers from Exploration Ground Systems installed the first section on November 21, 2020. They repeated the same procedure until they installed the final nose assembly on March 2.

The team would finish installing electrical instrumentation and pyrotechnics before testing the boosters' systems prior to the arrival of the core stage.

As the SLS core stage arrives at Kennedy, technicians will move it to the VAB, where it will be stacked between the two boosters on the mobile launcher.

It will have a thrust of up to 8.8 million pounds, making it 15% more powerful than the Saturn V rocket that launched the Apollo lunar missions.

At lift-off, the boosters, which are identical to those used to launch the now-defunct space shuttle, can produce 75 percent of total thrust.

The orange-colored core stage, which is currently undergoing evaluation at NASA Stennis Space Center near Bay St Louis, Mississippi, is the final large piece of the SLS waiting to be slotted in on the mobile launcher.

Lori Garver, the former NASA deputy administrator, said per Newsweek that SLS has cost $20 billion in 11 years and could cost another $7 billion.

Former NASA Administrator Jim Bridenstine also said in 2019 that buying SLSs one at a time from Boeing, which is contracted to develop rockets, could cost as much as $1.6 billion per launch. That's around $800 million if purchased in bulk.

When Is The Hot-Fire Test?

In mid-March, NASA plans to conduct a "hot-fire" test the core, which will include igniting all four engines. Engineers hope to keep them going for the entire eight minutes it takes the SLS to enter orbit.

The first attempt at a hotfire in January was cut short after just a minute due to a problem with the core stage hydraulics.

The rocket would send an unmanned Orion spacecraft around the Moon to perform a thorough assessment of both vehicles.

The 12 month lifetime of the joints that link each section of the solid rocket boosters is short. The stacking of the boosters indicates that the countdown to launch has already begun, though engineers have indicated that there might be ways to prolong the certification time.

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