United Launch Alliance has announced their Vulcan rocket is progressing towards its maiden launch as soon as early-2021. While an exact launch target isn’t known yet, the mission will use a newly-built Launch Umbilical Tower while sharing Atlas V’s Vertical Integration Facility and SLC-41 launch pad in Florida.
When first announced in 2014 as a “new booster,” ULA stated that Vulcan’s first flight was targeting 2019. Given an early-2021 target in mid-2020, that is the rocket-world equivalent of “remarkably on-time”.
The need for Vulcan began in 2014 when Russia annexed the Crimean Peninsula in what was internationally considered an illegal taking of sovereign Ukranian land.
As part of its response, the United States Congress redirected the U.S. Air Force to stop relying on Russian rocket engines for U.S. launchers. The issue here was that United Launch Alliance’s (ULA’s) workhorse, the Atlas V was — at the time — the preferred launch vehicle for NASA’s scientific and U.S. military payloads… and it used the RD-180, an NPO Energomash — Russian made — engine.
A flat piece of sheet metal is formed using a stretch press to create a large contoured panel for #VulcanCentaur. These panels are cut into slice-shaped pieces that are welded together to form the tank domes on the Centaur stage. #CountdowntoVulcan: Launching in 2021. pic.twitter.com/uLHa8ostWc
— ULA (@ulalaunch) May 22, 2020
After investigating the possibility of outfitting Atlas V with a new engine, it was determined to be easier to design a new rocket while completely building a new first stage engine.
How is Vulcan progressing?
Vulcan is a heavy-lift launch vehicle designed to primarily meet the demands of the United States Space Force’s National Security Space Launch program.
What’s more, Vulcan is one of the three methane-powered rockets under development, including Blue Origin’s New Glenn and SpaceX’s Starship.
Being much simpler than Atlas V, Vulcan can be assembled in less than 10 months as compared to 14.
Its first stage is powered by Blue Origin’s two BE-4 engines. The second stage, Centaur V, is powered by two Aerojet Rocketdyne RL-10CX engines equipped with nozzle extensions to improve fuel consumption for the heaviest payloads.
To meet the 2021 deadline for flight, ULA teams are working hard to manufacture, test, and certify different elements for the vehicle.
Working in their favor is that most of the technologies for Vulcan have already flown on Atlas and Delta missions — making Vulcan, in some cases, a heritage rocket.
Moreover, the booster flight hardware for Vulcan’s inaugural flight is almost ready, with Tory Bruno, CEO, and President of ULA, noting that ULA is “missing no milestones” as Vulcan heads toward its first launch.
The Vulcan first stage Liquid Methane (LNG) and Liquid Oxygen (LOX) tanks have been manufactured in ULA’s rocket factory in Decatur, Alabama, and subjected to many tests, including structural validation and verification, which was done by Dynetics to make sure the tanks are safe and reliable for flight.
The tanks themselves are made of five, 7000 series anodized Aluminum booster plates with Orthogrid structure, which is much lighter, simpler, and takes half the amount of time to manufacture than the Isogrid used in the Atlas V and Delta IV lines.
Additionally, the thrust structure for the first Vulcan is also complete and undergoing testing. It will transfer over a million pounds of thrust from a pair of BE-4 engines to the rest of the rocket during the booster (Stage 1) phase of flight.
In 2019, Tory Bruno unveiled Vulcan’s new Mobile Launch Platform, which is being assembled at the Cape Canaveral Air Force Station, Florida.
Vulcan, like Atlas V, will be integrated vertically, as will its payloads — a major requirement for some National Security Space Launch and National Reconnaissance Office satellites.
The Delta IV also has vertical payload integration. However, the rockets are assembled horizontally and then taken to their Florida and California pads where they’re raised vertically for payload attachment.
For its launch, Vulcan will use the Atlas V pads, Space Launch Complex-41 (SLC-41) in Florida and SLC-3E at Vandenberg Air Force Base, California.
Both pads are being fitted with new LOX, liquid hydrogen, and LNG tanks and a much more effective acoustic water suppression system. The upgraded pad technologies will allow teams to cut the turnaround time between Vulcan launches by one-third that of Atlas V’s turn-around time.
For Vulcan’s upper stage, the Centaur V, Tory Bruno says ULA is currently building full-scale test hardware to conduct numerous tests and certify it for flight.
Building test prototypes right now
— Tory Bruno (@torybruno) June 5, 2020
It is understood that welding of the Centaur V’s common bulkhead (that will separate the hydrogen side of the tank and the liquid oxygen side) test article is complete and testing underway.
Still, little remains in terms of information on how Centaur V is progressing.
Nevertheless, the stage will be a step upgrade from the pre-existing Centaur III (Atlas V) and the planned Advanced Cryogenic Evolved Stage (ACES) for Vulcan by the mid-2020s.
The Centaur V is made out of 0.9 mm (0.035 inch) thick, 300 series stainless steel. Just like the Vulcan booster, Centaur V is 5.5 meters wide. It is also 12.6 meters long and has twice the thrust than Centaur III, which is outfitted with one RL-10C-1 engine (two for Starliner flights).
The stage’s RL-10CXC engines have an specific impulse (isp) of 453.8 seconds, slightly higher than that of the Atlas V’s Centaur III’s engine — which ranges from 449.7 to 451 seconds depending on the type of RL-10 it uses.
The RL-10 is a hydrogen-powered, cryogenic rocket engine. It is the best vacuum optimized engine ever developed, having the highest ISP of any other engine in the world.
This makes it ideal for interplanetary space missions and military payloads with high energy orbits as it can place payloads into extremely precise orbits and trajectories, thereby preserving fuel and extending the mission’s operational life.
Centaur V also uses hydrogen-powered Reaction Control System thrusters instead of the hydrazine ones used in Centaur III.
What’s more, Vulcan requires a collaboration of many aerospace suppliers, including Blue Origin and Northrop Grumman, for supplying the BE-4 engines and GEM-63XL solid rocket motors, respectively.
Blue Origin’s BE-4 engine is an oxygen-rich, liquified natural-gas-fueled, staged combustion rocket engine. It is the most powerful liquified natural gas-fueled rocket engine ever developed, with the ability to produce over 2,400 kilo-newtons of thrust at sea level.
In 2014, ULA and Blue Origin signed an agreement to co-develop the BE-4 and committed to use it on Vulcan. The engine, however, began development in 2011, prior to the agreement with ULA, and by 2015 had completed more than 100 developmental tests, including a preburner and “regeneratively-cooled thrust chamber” test, using multiple full-scale injector elements.
These confirmed the theoretical model predictions of “injector performance, heat transfer, and combustion stability” and its data was further used to refine the engine.
In 2017, BE-4 was test-fired at 50% thrust for 3 seconds, followed by a 65% design thrust test for 114 seconds in March 2018.
By February 2019, BE-4 had undergone 1,800 seconds of hot-fire testing on ground test stands, and by August 2019, the engine was undergoing full power tests.
In February 2020, Blue Origin opened a massive factory in Huntsville, Alabama, which will serve as a state-of-the-art engine manufacturing facility to produce BE-4 and BE-3U engines at high production rates.
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