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United Launch Alliance’s first Vulcan Centaur rocket completed a critical test firing of its Blue Origin-built BE-4 engines Wednesday night, clearing one of two remaining technical hurdles before the launcher is cleared for its maiden voyage later this year.
The Vulcan rocket’s two BE-4 engines ignited at 9:05 p.m. EDT Wednesday (0105 UTC Thursday) and burned for about six seconds, generating nearly one million pounds of thrust. 41.
“This is a huge milestone,” said Mark Peller, ULA’s vice president for the Vulcan rocket program. “It’s as close to launching a rocket as possible without actually launching the rocket, so all the airborne elements, the ground systems, everything comes together, a fully integrated test with everything we do on a normal day. The launch, including actually starting the main engine, is all short of releasing the rocket.”
Beller called the flight readiness firing of the first Vulcan Centaur rocket “our last major milestone on the path to launch.”
ULA’s launch team loaded methane, liquid hydrogen and liquid oxygen propellants into the Vulcan first stage and its Centaur upper stage Wednesday afternoon, then paused the countdown clock for several hours to allow engineers to assess whether a lightning strike near the launch pad affected any critical systems. .
Following a final readiness poll by the launch team, the countdown resumed from a built-in position of T-minus 7 minutes and the Vulcan Centaur rocket switched to internal power and propellant tanks to flight pressure before valves were opened to admit methane and methane. Liquid oxygen flows into the BE-4 engine propulsion chambers.
The starting line for the twin engines started at T-minus 5 seconds. The engines fired at about 60% power for two seconds, then the rocket’s flight computer ordered the BE-4s to throttle before shutting down the engines. Test-firing sent a plume of powder ejected from the eastward flame trench on pad 41.
“Nominal flow!” tweeted Tory Bruno, chief executive of ULA.
The Vulcan rocket’s two BE-4 engines are built by Blue Origin, a company founded by billionaire Jeff Bezos. Blue Origin plans to use a set of seven BE-4 engines on its own New Glenn rocket, still in the early stages of development.
Bezos tweeted Wednesday night, “There’s nothing sweeter in rocketry than the word Bezos. “Tori, congratulations to you and the whole team!”
ULA technicians roll the Vulcan Centaur rocket from its vertical hangar 41 in preparation for a test launch Tuesday at the Cape Canaveral Space Force Station.
The flight readiness firing is the culmination of a series of tests and countdown rehearsals to prepare for the first Vulcan test flight at Cape Canaveral. Most recently, ULA’s launch team loaded methane, liquid hydrogen and liquid oxygen propellants into the Vulcan booster and its Centaur upper stage during a May 12 refueling test.
ULA moved the Vulcan Centaur rocket back to the Vertical Integration Facility after the May 12 tanking test to make “adjustments” to the vehicle. According to Tory Bruno, CEO of ULA, that includes adjusting the system with ground hydraulic pressure, changing the topping ratio for liquid oxygen, and changing the purge and cool gas flow to the BE-4 engine ignitions.
With those modifications complete, ground crews planned to conduct a flight readiness firing on May 25, but ULA postponed the test firing after discovering a problem with the BE-4 engine ignition system. Before ULA rolled the Vulcan launcher back to 41 on Tuesday, it prompted the rocket to return to the hangar for repairs.
ULA says it installed additional instruments on the rocket to monitor the performance of the engines during flight readiness firing. Engineers will spend the next few weeks analyzing data from test firings to make sure everything is working as designed.
But the launch schedule for the first Vulcan Centaur flight remains unclear.
ULA reports that work is more than 98% complete with the Vulcan rocket’s qualification program, with unfinished work related to final ground testing of the Vulcan rocket’s Centaur upper stage. A hydrogen explosion in March crippled structural testing of Vulcan’s Centaur upper stage at NASA’s Marshall Space Flight Center in Huntsville, Alabama.
The blast damaged the test station and a Centaur upper stage test article. The Vulcan rocket uses a larger, improved model of the Centaur upper stage that currently flies on ULA’s Atlas 5 rocket.
If engineers determine that no changes to the Centaur upper stage are necessary on the first Vulcan rocket, the test flight will take off this summer. In comments last month, Bruno said it could be delayed until later this year if corrective measures are needed at the center.
“Pending data review and investigation results, we will develop a plan to begin,” ULA said in a statement Wednesday night. “Testing is an integral part of our launch vehicle development program, and we will fly when we believe it is safe.”
ULA is a 50-50 joint venture between Lockheed Martin and Boeing that merged their Atlas and Delta rocket programs in 2006. The Vulcan rocket will fly in several configurations, with different numbers of strap-on solid rocket boosters and different payload fairing sizes available. In each aircraft, depending on mission requirements.
The Vulcan rocket for the program’s first test flight has a colorful paint job with a bright red flame emblazoned on the side of the 17.7-foot-long (5.4-meter) first stage. For tanking tests and flight readiness firing, the Vulcan rocket was not equipped with solid rocket boosters or payload fairings. In that configuration, the vehicle is about 166 feet (50.7 meters) tall.
With the test launch complete, ULA planned to drain the rocket’s propellant tanks and return the Vulcan Centaur to its hangar for inspection. Technicians must repair or replace heat blankets around engines that may have been singed by test firing. ULA will replace the disposable igniters in the BE-4 engines before moving forward with the final launch products.
The Vulcan rocket’s maiden flight will be the first to use the new methane-fueled BE-4 engines from Blue Origin. At full speed, each BE-4 engine can generate about 550,000 pounds of thrust. With two, zero, two, four or six solid rocket boosters, each Vulcan core stage adds thrust during the first two minutes of flight.
Ground teams will install two Northrop Grumman-built solid-fuel boosters and a payload shield from Beyond Gravity, formerly known as Rook Space.
The Vulcan rocket’s Centaur upper stage, called the Centaur 5, has been upgraded to the upper stages currently flying on ULA’s Atlas 5 rocket. With two Aerojet Rockettine RL10 engines, the Centaur 5 has a wider diameter to accommodate larger cryogenic hydrogen and oxygen propellant tanks. A Centaur flying on an Atlas 5 rocket usually flies with a single engine.
Once all Vulcan rocket structures are operational, the new rocket will completely replace and grow the lift capacity currently provided by all of ULA’s rockets. A larger Vulcan rocket variant with a single core stage and improved upper stage engines that will begin flying in the next few years will have a higher payload lift capacity than ULA’s Delta 4-Heavy, which consists of three liquid-fueled first stage boosters linked together. .
Vulcan Centaur with upgraded upper stage engines will be capable of carrying up to 60,000 pounds (27.2 metric tons) to low Earth orbit.
Eventually, ULA plans to reuse BE-4 engines from Vulcan launches, but not the entire first stage.
ULA launched the Vulcan rocket in 2015, then targeted the first launch of the new vehicle in 2019. The company selected Blue Origin’s BE-4 engine for the first stage propulsion system in 2018. At that time, ULA aimed to launch the first Vulcan test. Flight in 2020.
But delays, primarily due to problems encountered in BE-4 engine production and testing, forced the first Vulcan test flight to slip by several years. Bruno said earlier this month that Blue Origin and ULA had completed final qualification testing of the BE-4 engine ahead of the first Vulcan launch, clearing an obstacle that had threatened to delay the Vulcan’s debut earlier this year.
On its first flight, the Vulcan rocket will launch a commercial lunar lander developed by Astrobotic, which will attempt to deliver NASA experiments and technology demo payloads to the lunar surface. The astrobotic lander, named Peregrine, is part of NASA’s Commercial Lunar Payload Services program, which buys rides to the moon for agency payloads aboard commercially owned spacecraft.
Two prototype satellites for Amazon’s Khyber broadband network will also be on the first Vulcan launch.
ULA’s Vulcan rocket has been selected by the US Space Force to launch the military’s large national security satellites for the next five years. The military requires two “certification flights” before the Vulcan rocket is approved for national defense launch missions.
A second Vulcan test flight will begin in early 2024 with Sierra Space’s Dream Chaser spacecraft, the new resupply ship for the International Space Station. It will be followed by the first Vulcan launch with a military national security payload.
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