Terrestrial Rocket Science

By Paul Scott Abbott

The U.S. National Aeronautics and Space Administration has been at the forefront of astrodynamics since its founding in 1958, but not all rocket science applies to actual treks into space.

While the Earth’s most powerful rocket is slated to blast off from NASA’s Kennedy Space Center on Nov. 22, the moonward Artemis I launch won’t mark the first challenging journey for its 212-foot-tall, 85-tonne Space Launch System core stage.

Culminating years of precise logistical planning and a significant lengthening of NASA’s Pegasus barge, the massive SLS rocket unit in April completed a six-day, 900-mile trip by water to the Kennedy facility on Florida’s Atlantic Coast from the agency’s Stennis Space Center near Bay St. Louis, Mississippi.

The heavy-lift transport operation involved open-water barge transit, propelled by an ocean tug, through the Gulf of Mexico, around the tip of Florida and up the Atlantic coastline, before engaging a pair of smaller tugs for the final leg up the snaky Banana River to a Kennedy Space Center wharf.

There, following an intensive ballasting process, the SLS core stage was carefully offloaded and placed on four wheeled, self-propelled module transporters and slowly moved less than a mile to Kennedy’s iconic Vehicle Assembly Building, where it is being integrated with the Orion spacecraft, solid rocket boosters and other components, and undergoing extensive pre-launch testing.


‘High-level Operation’

In describing the successful move to Breakbulk, Liliana Villarreal, NASA’s exploration ground systems program operations flow manager, couldn’t help but make a football analogy.

“It’s not winning the Super Bowl – because that’d be the launch – but it’s definitely getting a couple of good touchdowns,” she said. “It’s a pretty high-level operation.”

Villarreal has more than two decades of experience at Kennedy Space Center, having begun work at Kennedy in 2000 as an engineer for The Boeing Co., supporting assembly missions for the International Space Station, before joining the NASA operations team in 2007. Boeing is a major NASA contractor, including as manufacturer of this Space Launch System, or SLS, core stage and other Artemis mission rocket units at the NASA Michoud Assembly Facility in New Orleans.

Villarreal was part of a team of more than 50 specially trained workers involved in the final steps of the operation to deliver the core stage following its Kennedy arrival. The contingent included barge personnel and technicians, plus engineers and safety and quality specialists from NASA, as well as employees of Boeing and primary NASA exploration ground systems contractor Jacobs Engineering Group.

When launch time comes, the 27.6-foot-diameter, aluminum alloy SLS core stage is to have its tanks filled with propellants consisting of 844 tonnes of liquid oxygen and 144 tonnes of liquid hydrogen, bringing total launch weight to considerably more than 1,000 tonnes.


To Moon, Mars, Beyond

Whereas the Artemis I launch scheduled for November is to be an uncrewed lunar orbit and return mission, increasingly complex future flights aim to deliver Orion spacecraft, astronauts and supplies to the moon later this decade, laying the foundation for eventually sending humans to Mars and perhaps beyond.

According to NASA engineers, the ability of the super-powerful SLS rocket to send craft, astronauts and supplies to the moon on a single mission is critical to reducing the number and complexity of in-space operations and increasing opportunities for mission success.

NASA has deployed barges to terrestrially move large spaceflight structures for decades. However, because the SLS core stage is much taller – or longer when laid horizontally on a barge deck – compared with previous rocket units, it required a barge longer than even the original 260-foot-long Pegasus, which was specially designed and built in 1999 to transport the giant external tanks for the Space Shuttle from the Michoud facility in New Orleans to Kennedy Space Center.

Responding to this latest demand, NASA tasked Conrad Shipyard in Morgan City, Louisiana, with refurbishing the Pegasus barge, including removing a 115-foot-long section and replacing it with a 165-foot-long section, extending its total length to 310 feet, or about the length of a football field.

With expertise furnished by the U.S. Army Corps of Engineers Marine Design Center in Philadelphia and Bristol Harbor Group of Bristol, Rhode Island, the Pegasus modifications were completed in 2015. By 2017, the lengthened barge was carrying core stage test articles from Michoud to NASA’s Marshall Space Flight Center in Huntsville, Alabama.


Size, Canopy Stand Out

NASA’s team leader for logistics, engineering and marine operations, Arlan Cochran, is based at the Marshall facility and serves as master of the Pegasus barge, not only on its April trip to Kennedy with the SLS core stage but also on three or four trips a year carrying various oversize articles between the Marshall, Michoud and Kennedy installations.

“The main uniqueness of the barge is its size,” Cochran told Breakbulk. “Plus most barges don’t have a canopy.”
The protective canopy is needed to shield the highly sensitive cargoes from foul weather, but, Cochran said, it can act as a sail in high winds, sometimes helping increase operating speed but at other times forcing the barge to slow down to maintain course. Typically, he said, the Pegasus barge creeps along at 8 knots or less, slowing to half that speed along rivers.

The bendy Banana River near the very end of the journey to Kennedy Space Center can present some of the greatest challenges, according to Cochran, who commented, “There’s a reason they call it the Banana River. It has a lot of turns.”

Another waterway posing tricky transit is the Pearl River, which is part of the inland portion of the route between Marshall Space Flight Center and the Michoud and Kennedy facilities. The Pearl River proved particularly pesky on recent moves when there had been abundant rain, bringing the waterway to flood stage while Cochran and crew dealt with current and wind issues.

Whenever the Pegasus barge is in use, a minimum of two crewmembers are on watch around the clock, Cochran said.


Weather Plays a Role

Just as with rocket launches, meteorological fortune plays a crucial role in NASA’s earthly moves, according to Villarreal and Cochran.

“The No. 1 challenge is to be sure there is good weather,” Villarreal said. “We were fortunate that the weather was just perfect. Those are the best days.”

The ideal weather and smooth water facilitated precise integration between the Pegasus barge and the berth in the shadow of the Vehicle Assembly Building. That, Cochran said, eased the leveling process involving moving water via the barge’s 27 ballast tanks in what Villarreal described as the “very unique integration between the barge and the wharf.”

In keeping with NASA’s longstanding practice of testing, testing and more testing, the agency successfully transported a full-scale mock-up of the core stage to Kennedy Space Center on the Pegasus barge in September 2019, in that instance from the Marshall facility with a stop at the Stennis installation.

As with the real SLS core stage more than a year and a half later, the mock-up was offloaded from the barge at Kennedy’s Launch Complex 39 wharf and slowly wheeled on four self-propelled module transporters – two in front and two in the rear – to the Vehicle Assembly Building for testing.


Space Race Heating Up

Now, as pre-flight testing of the SLS core stage and units with which it is being integrated continues in advance of NASA’s scheduled November launch of Artemis I, the global race into space keeps heating up, with a trio of billionaires and the private sector assuming considerable roles.

Although South African native Elon Musk has yet to blast into space himself, his SpaceX was awarded a US$2.9 billion NASA contract for a lunar landing system, only to have the pact swiftly suspended while the U.S. Government Accountability Office adjudicates protests. Musk’s stated objective is human colonization on Mars.

Meanwhile, Englishman Richard Branson was one of six Virgin Galactic passengers who soared 50 miles above the New Mexico desert on July 11 in a rocket plane launched from Spaceport America, with a promise of commencing commercial flights into space in 2022.

And, nine days later, on July 20, on the 52-year anniversary of American astronaut Neil Armstrong taking the first human steps on the moon, Amazon founder Jeff Bezos and three others shot 65 miles into space above West Texas in a craft built by Bezos’ rocket company, Blue Origin.

Bezos also has his sights set far into the heavens but says his priority is to use spaceflight to solve problems on Earth, which he termed “the only good planet in this solar system,” adding, “Big things start small.” 


A professional journalist for more than 50 years, U.S.-based Paul Scott Abbott has focused on transportation topics since the late 1980s.

Image credit: NASA/Juan Busto