NASA barge delivers first SLS core stage to Kennedy Space Center

NASA’s Pegasus barge arrives in the Turn Basin at the Kennedy Space Center Tuesday evening. Credit: Steven Young / Spaceflight Now

The core stage of NASA’s first Space Launch System heavy-lift rocket arrived at the Kennedy Space Center on Tuesday evening aboard a specially-built barge, completing a voyage by sea from a test site in Mississippi to begin final preparations for the first flight of NASA’s Artemis Moon program.

The 310-foot-long (94.4-meter) transport vessel completed a nearly five-day trip from NASA’s Stennis Space Center in Mississippi, delivering the SLS core stage for the Artemis 1 lunar test flight to Florida’s Space Coast after an eight-minute test firing of the rocket’s four main engines March 18.

Engineers and technicians at Kennedy will ready the rocket to launch an unpiloted Orion crew capsule on a multi-week test flight around the Moon. If the test flight goes well, the next SLS/Orion mission — Artemis 2 — will carry three NASA astronauts and a Canadian crew member on the first human mission to lunar distances since the Apollo program.

Future Artemis missions will land astronauts near the Moon’s south pole.

Under tow, the Pegasus barge arrived at Port Canaveral, transferred through locks, and then sailed up the Banana River and followed waterways to the Turn Basin at Kennedy, near the spaceport’s iconic Vehicle Assembly Building. The barge docked there just before sunset Wednesday.

NASA previously used the Pegasus barge to transport the giant orange fuel tanks used by the space shuttle. The external tank was built at NASA’s Michoud Assembly Facility in New Orleans, the same location where Boeing manufactures SLS core stages.

The space agency lengthened the Pegasus barge by 50 feet (15 meters) to accommodate the longer SLS core stage. The barge will transport future Artemis Moon rockets directly from the factory at Michoud to the Kennedy Space Center.

Ground teams at Kennedy plan to unload the 212-foot-long (64.6-meter) core stage before sunrise Thursday and wheel it into the Vehicle Assembly Building on a transport cradle. The rocket measures 27.6 feet (8.4 meters) in diameter, the same width as the shuttle external fuel tank.

Officials at Kennedy are eager to start working with the core stage. The two 177-foot-tall (54-meter) solid rocket boosters for the first SLS test flight, supplied by Northrop Grumman, are fully stacked on the rocket’s mobile launch platform in High Bay 3 inside the Vehicle Assembly Building.

“The team has been very excited to finally get the real hardware in our hands,” said Cliff Lanham, senior vehicle operations manager for Kennedy’s exploration ground systems program. “We’ve seen drawings. We’ve seen PowerPoints for the last many years, and to see the real hardware, it really gives everybody kind of a jolt of energy.”

Lanham said the core stage is the “next big piece of the puzzle.” All other components of the Space Launch System and the Orion spacecraft for the Artemis 1 mission are already delivered to Kennedy.

“Part one is getting these boosters stacked, and getting Orion prepared, and we’re working that,” Lanham said in an interview last month. “But now, with the core stage, that makes the big boosters dwarfed because now you’ve got a 212-foot stage that’s coming. That’s going to to re-energize us as well.

“We can really start saying, ‘Hey, we’re going to get there. We’re going to launch this rocket,’” Lanham said.

The core stage will enter the south door of the VAB and remain in the transfer aisle — the cavernous passageway in between the rocket assembly bays — for several weeks of work.

“The minute that barge shows up out here at the Turn Basin, we’re ready to go,” Lanham said last month. “We’ve got to take it off the barge, we’ve got to bring it into the low bay up here.”

Technicians will work on the rocket’s thermal protection system foam and begin installing pyrotechnic charges for the core stage’s range safety destruct system. Then ground crews aim to be ready by mid-May to rotate the rocket vertical and lift it by crane into High Bay 3. The crane operator will carefully lower the core stage in between the two SLS solid rocket boosters.

Workers will connect the core stage with each booster with braces at forward and aft attach points. Next will be stacking of the SLS upper stage, derived from the second stage used on United Launch Alliance’s Delta 4-Heavy rocket, and an adapter that will support the Orion spacecraft.

The rocket will be crowned with a mass model of the Orion spacecraft for structural resonance testing of the fully-stacked launch vehicle. Once that is complete, teams will move the real Orion spacecraft — already integrated with its launch abort system — to the VAB for attachment to the top of the Space Launch System.

The SLS core stage is lowered horizontal at the B-2 test stand at the Stennis Space Center earlier this month for loading into NASA’s Pegasus barge. Credit: NASA

The fully-assembled Space Launch System and Orion spacecraft will stand 322 feet (98 meters) tall. During launch, the rocket’s four RS-25 engines and twin solid rocket boosters will generate 8.8 million pounds of thrust. It can send about 59,500 pounds (27 metric tons) of mass to the Moon, more than any rocket operating today.

NASA plans to roll the Space Launch System out of the Vehicle Assembly Building for the first time as soon as August — but more likely in the fall — to travel to pad 39B for a countdown rehearsal. The launch team will load super-cold liquid hydrogen and liquid oxygen propellants into the rocket and practice countdown procedures.

After that is done, the rocket will return to the VAB for final checkouts and preparations, then will roll out to pad 39B again for launch.

Steve Jurczyk, NASA’s acting administrator, said Tuesday that the agency still hopes to launch the Artemis 1 test flight by the end of 2021.

“The schedule for Artemis 1 will be really challenging,” Jurczyk said in a webinar hosted by the Space Transportation Association. “If things go really, really well … we have a change to launch by the end of the calendar year. But this is the first-time flow of a vehicle at KSC. We’ll undoubtedly encounter challenges.”

Any major issues over the next few months would likely push the Artemis 1 launch into 2022.

“We don’t have a lot of schedule reserves against launching by the end of the calendar year,” Jurczyk said.

Email the author.

Follow Stephen Clark on Twitter: @StephenClark1.