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.

  • Jeff2Space

    J-2X was never needed for the EUS. Developing it was just a dumb decision all around.

  • Michael Halpern

    The way I see it, ACES’ IVF in a Methalox system would be a great kick stage to complete fully reusable vehicles like BFR, and make up for the payload penalty of reusable S2, even if you don’t consider it a reusable stage ( it isn’t without retrieval in a practical sense unless designed for large deployments in lower orbits where you could make it a capsule) it can fit in an RLV launch architecture

  • Robert G. Oler

    Lol. Hope you are well

  • envy

    No engine out capability for most of the flight, if any. If either RL-10 fails the crew is probably going in the drink.

    Fortunately, RL-10 is one of the most tested and reliable engines around.

  • envy

    Why? Methane upper stage has no significant advantages over the RP-1 stage, compared to the large amount of work it would take to get it flying. Methane is not a great choice unless you are reusing the upper stage and/or landing it on Mars, both of which require the other features of BFR (the ones you say are a “step too far”).

    Methane is often represented as “higher energy”, but the truth is that it’s lower density more than cancels the higher specific energy by increasing the stage dry mass. Even when sub-cooled, it has no better performance than sub-cooled kerosene. It’s better for deep-space operations, but kerosene is entirely feasible for that as well.

    There’s no reason to do methane without full reuse. And full reuse means BFR.

  • ThomasLMatula

    The less government money in the BFR/BFS the better. Government involvement will just slow it down. It’s a lesson Boeing used to know under President Bill Allen who made Boeing the leader in commercial airliners.

  • ThomasLMatula

    Yes, the USAF has no idea what to do with a rocket capable of launching 100 tons daily. Now the U.S. Space Force might have some ideas…

  • Michael Halpern

    Said rocket can’t single launch direct GEO without a kick stage,

  • passinglurker

    either its a legitimate advantage or an excuse to tac on a price tag either way the military and associated industrial complex liked them. Additionally at this point the tameness of expander cycle also takes on another advantage. It’s a lot safer to adapt to 3d printed parts.

  • Michael Halpern

    meh 3d printing has become standard for many rocket engine parts, I would be surprised if Raptor and BE-4 didn’t have a lot of 3d printing

  • passinglurker

    Still less risk involved because again expander cycle is tamer

  • Michael Halpern


  • rod57

    Thrice you use ‘anent’ – is it a typo (for ‘about’) or what does it mean ?

  • Lee

    It’s an archaic word meaning “in regard to”. He’s possibly the only person left on Earth who still uses it. I’ve been reading avidly for 45 years and have wide experience with obscure words, but anent was a new one on me too….

  • rod57

    Much obliged – I thought he had a bug in his phone.