ULA’s Vulcan Rocket To be Rolled out in Stages

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UPDATED at 7:22 p.m. EDT

COLORADO SPRINGS, Colo. — United Launch Alliance on April 13 laid out an incremental but ambitious plan for replacing its workhorse Atlas 5 rocket with a vehicle that initially would feature a new first stage, then a new second stage and ultimately reusable engines that would be recovered in midair after each mission.

The plan would provide a competitive alternative to SpaceX’s low-cost Falcon 9 rocket but entails risk for ULA as it funds a significant development program for as many as nine years as its competition gains momentum.

Diagram of  Vulcan rocket
Diagram of ULA’s Vulcan rocket. Credit: ULA

Tory Bruno, ULA’s president and chief executive, declined to detail the company’s exact investment in the project but suggested that new rockets typically cost about $2 billion to develop, including $1 billion for the main engine. During a press conference on the eve of the 31st Space Symposium here, he said that cost would be borne by ULA and its strategic partners, but that the company would not turn down government money if that becomes available.

ULA is a 50-50 joint venture of Boeing and Lockheed Martin. Bruno said the parent companies will relinquish a share of their ULA profits to allow the Denver-based rocket maker to invest in its newly named Vulcan launcher.

The first step in the Vulcan program is a new first stage featuring the methane-fueled BE-4 engine, which is being developed by Blue Origin of Kent, Washington. ULA is also working with Aerojet Rocketdyne on the AR-1 engine, in case the Blue Origin-funded BE-4 runs into developmental issues.

The impetus behind Vulcan is competition from SpaceX and the requirement to replace the Russian-built RD-180 engine that serves as the main powerplant for the Atlas 5. Congress imposed a ban on future use of Russian engines in U.S. national security missions following Russia’s annexation of Crimea from Ukraine last year.

In addition to the new engine, the Vulcan’s first stage would feature a stretch version of the fuel tank used on ULA’s liquid-hydrogen-fueled Delta 4 rocket, which the company is phasing out in 2018-2019 because it is too expensive.

The second stage of the initial Vulcan, which slated to debut around 2019, would feature the same Centaur upper stage and fairing now used on the Atlas 5, Bruno said. These fairings could be 4 or 5 meters in diameter.

The rocket could be augmented by up to six solid-rocket boosters, giving it greater lift capability than the largest version of the Atlas 5 but not as much as the Delta 4 Heavy, which features three core stages in a side-by-side configuration. Bruno said he plans to issue a request for proposals within the next 12 months or so for the large boosters, which would likely be built by either Orbital ATK or Aerojet Rocketdyne.

ULA told the Air Force in February it plans to start two separate U.S. Air Force certification processes for the Vulcan rocket later this year, one with the BE-4 and one with the AR-1. Certification is required for the Vulcan to carry U.S. national security payloads.

Bruno said ULA’s first choice is the BE-4, which he said is two years ahead of AR-1 in development, but that it continues to work with Aerojet Rocketdyne on the latter engine as a backup option. He said ULA will make a final first-stage engine decision in 2016.

Expanded diagram Vulcan six boosters
Expanded diagram of ULA’s Vulcan rocket in its six-booster configuration. Credit: ULA

The next step in Vulcan’s evolution is a new upper stage known as the Advanced Cryogenic Evolved Stage, or ACES, which would be able to operate in space for weeks at a time. This would dramatically increase Vulcan’s lift capability, ULA officials said.

The ACES stage would feature a pressure-stabilized fuel tank and anywhere from one to four cryogenic engines, depending on the mission. The candidate engines are: a new variant of the RL10 produced by Aerojet Rocketdyne and currently used on both the Atlas 5 and Delta 4; Blue Origin’s BE-3; and an engine being jointly developed with XCOR Aerospace.

ULA will select the ACES engine in the next few years, Bruno said.

ACES, ULA officials said, would have “almost unlimited burns” and extend on-orbit operating time from hours to weeks. The liquid-oxygen/liquid hydrogen-fueled stage would recycle fuel that otherwise would boil off and use it for for attitude control and electrical power, ULA officials said.

This would eliminated the need for the stage to carry hydrazine fuel and liquid helium, said George Sowers, ULA vice president of advanced concepts and technologies. The key to that is a combustion engine being developed for ULA by Roush Racing, Sowers said.

The ACES upper stage, expected to debut on Vulcan in 2023, would open a whole new range of possibilities by virtue of its ability to operate in orbit for weeks after launch with no limits on the number of times it could restart itself, Sowers said. This would enable what Sowers called a distributed launch concepts whereby mission capabilities could be assembled on orbit, he said.

The ACES-equipped Vulcan, augmented by strap-on boosters would have 30 percent more lift capacity than the Delta 4 Heavy, currently the largest vehicle in the U.S. fleet, Bruno said.

 

Aerial Recovery

Ultimately, ULA plans to reuse the Vulcan’s first-stage engines through a process called Sensible Modular Autonomous Return Technology. After first-stage burnout, the two engines would be severed from the tank and deploy an inflatable heat shield to slow their re-entry. They then would deploy steerable parachutes, which would slow their descent enough so they could be recovered in midair by helicopter.

Once recovered, the engines would be re-certified and used again. The reusability feature is especially important as engines make up about two-thirds of the rocket’s cost, ULA officials said.

ULA hopes debut the first stage reuse and recovery capability by 2024, Bruno said.