Centaur Upper Stage for First Starliner Flight Arrives at Cape

The Centaur heads for ULA’s Cape Canaveral facilities. (Credit: NASA)

The Centaur heads for ULA’s Cape Canaveral facilities. (Credit: NASA)

CAPE CANAVERAL, Fla. (ULA PR) — The dual-engine Centaur upper stage that will launch Boeing’s first Starliner spacecraft on its uncrewed Orbital Flight Test to the International Space Station has arrived at Cape Canaveral for final processing by United Launch Alliance technicians.

The stage arrived Oct. 19 aboard the Mariner cargo ship, the ocean-going vessel that ULA uses to transport rocket stages from the manufacturing plant in Decatur, Alabama to the launch sites.

Wrapped in a protective covering for the transit, the Centaur was offloaded at the Port Canaveral wharf and driven on a specialized trailer to ULA’s Atlas Spaceflight Operations Center for initial arrival checks.

Later, it will move to the Delta Operations Center to be raised vertically, mounted onto the interstage structure and fitted with the adapter that will support Starliner atop the rocket. That combined stack will then be ready for mating to the Atlas V first stage at the Vertical Integration Facility next year.

Mariner left Decatur on Oct. 10 for the journey of nearly 2,000 miles.

The venerable Centaur will resume flights in a dual-engine configuration — which was once commonplace — for this inaugural launch of Starliner. The last Centaur stage to utilize two engines was an Atlas IIAS rocket launch in 2004.

The Centaur enters the Atlas Spaceflight Operations Center. (Credit: NASA)

The Atlas V has needed only single-engine Centaurs to perform all of its launches to date to deliver payloads to their intended destinations, but the Starliner mass along with the need to shape the trajectory to limit astronaut accelerations and optimize ascent abort performance in case of a vehicle failure necessitates the thrust of two engines.

For the OFT launch, the Centaur will be powered by a pair of Aerojet Rocketdyne RL10-4-2 cryogenic engines, burning liquid oxygen and liquid hydrogen to generate nearly 45,000 pounds of thrust.

Centaur flew for the 250th time on Oct. 17 in launching the Air Force’s AEHF-4 protected communications satellite. Two-thirds of those previous launches were dual-engine configurations.

The high-energy stage has launched spacecraft to every planet in our solar system, plus the moon, Pluto and solar observatories, and critical national security, communications and weather satellites.