A rocket engine with an extended pedigree marked a giant milestone on Monday. It’s 60 years for the reason that hydrogen-fueled RL10 engine debuted onboard a Centaur higher stage launched from Cape Canaveral on Nov. 27, 1963.
With that first launch, the RL10 engine, at present manufactured by Aerojet Rocketdyne, turned the primary engine powered by a mixture of liquid hydrogen and liquid oxygen to be fired in area. The milestone got here at a pivotal time for the US, because it was simply 5 days after the assassination of former President John F. Kennedy.
Since that time 60 years in the past, 522 RL10 engines have flown in area, with the lion’s share of these flights aboard United Launch Alliance’s (ULA) Delta and Atlas rockets. These engines energy the Delta Cryogenic Second Stage and Centaur higher stage respectively.
“Centaur and the RL10 have made it attainable for us to launch spacecraft at better measurement and weight over any of the opposite higher stage designs in use,” mentioned Gary Wentz, ULA vp of presidency and business packages, throughout a media occasion celebrating the milestone. “It has delivered incredible missions to the Solar, our Moon, asteroids, each planet within the [solar] system.”
The engine was developed by Pratt & Whitney within the late Fifties via the oversight of NASA’s Lewis Analysis Middle, which was renamed the NASA John H. Glenn Analysis Middle at Lewis Area in 1999. Centaur was initially developed by Common Dynamics.
The mix helped show the viability of liquid oxygen and liquid hydrogen as a propellant mixture for future launch autos. The RL10s themselves would go on for use aboard the Saturn 1, Atlas, Titan and Delta rockets.
The engine additionally loved use onboard the experimental suborbital automobile, the DC-X, which was utilized by NASA and the Division of Protection to display a vertical rocket touchdown.
“It’s very thrilling to be at 60 years and it’s a testomony to the unimaginable teamwork that’s gone on between Aerojet Rocketdyne and ULA over all these years, a testomony to all of the individuals who labored on this product all these years and an unimaginable design that was initially specified by the lat Fifties,” mentioned Jim Maus, Aerojet Rocketdyne vp of program execution and integration.
Maus mentioned regardless of the successes they’ve seen over tons of of engine flights, they proceed to lean on ULA’s motto of specializing in launching one after the other.
“After we go to launch day, we’re very targeted on that day’s launch,” Maus mentioned. “And so, once you come to a giant milestone, you sort of stand again and acknowledge, you understand, take a look at all that we’ve accomplished. So, it’s nice to be a part of the workforce that does that and we’re actually thrilled to be at 60 years.”
Evolving the RL10
At the moment, there are two variants of the RL10 in use: the RL10C-1-1 on ULA’s Atlas rockets and the RL10B-2, which is used on the ULA Delta 4 Heavy and NASA Area Launch System (SLS) rockets.
The latter variant has a restricted life although since there is just one extra Delta 4 Heavy rocket, which is scheduled to launch in 2024 on a mission for the Nationwide Reconnaissance Workplace (NRO). A single RL10B-2 can be used on the SLS’s Interim Cryogenic Propulsion Stage (ICPS) for the primary three Artemis missions to the Moon.
Later variations of the SLS will use the Exploration Higher Stage, which is being engineered by Boeing. That will probably be powered by 4 RL10C-3 engines, which collectively will present greater than 97,000 kilos (431kN) thrust. For comparability, the only RL10B-2 on the Artemis 1 ICPS produced about 24,750 kilos (110kN) of thrust.
So far, Maus mentioned there have been eight main upgrades of the RL10 engine. The subsequent main iteration of the engine, the RL10C-X, which remains to be in growth, will energy future model of ULA’s forthcoming Vulcan rocket.
The largest change seen with this model of the engine comes via its use of additive manufacturing strategies, extra generally generally known as 3D printing.
“We’re already flying the RL10 with an additive manufactured injector, however now we’re doing an additive manufactured thrust chamber and we’re going via that certification proper now,” Maus mentioned. “That engine will probably be delivering the best efficiency of what we have now accessible in safety in the present day and can lengthen the lifetime of the RL10 into the longer term.”
Maus added that the brand new manufacturing strategies may even convey price financial savings, however declined to enter specifics on the drivers of the associated fee discount.
“It’s been a big enchancment in price on the chamber of the engine. We’re additionally placing a big carbon silicone nozzle on it, that’s pushing up the ISP to offer us good efficiency,” Maus mentioned. “After which, the turbo equipment and what I’ll name the powerhead and the spine of the engine is similar to what we’ve been flying on the steadiness of the stock. So, that it’s going to proceed to delver the very excessive reliability on day one, launch one.”
The particular date of launch one nonetheless stays TBD, however Maus mentioned they’re aiming to debut the RL10C-X in 2025 on a ULA Vulcan rocket. That mentioned, Maus famous that they’ve orders for the present RL10C-1-1 engines via 2026.
Each NASA and ULA are driving what Maus described as a backlog of greater than 150 engines, that are a mixture of the legacy variations in addition to the X-C variants with the additive manufactured options. He mentioned NASA remains to be making a dedication on whether or not they wish to buy extra of the legacy engines or start to purchase engines utilizing the additive manufacturing know-how for future Artemis missions.
In a typical yr, Maus mentioned Aerojet Rocketdyne produces between 16 and 18 engines, however with the incorporation of extra additive manufacturing into their manufacturing line, they’re ramping as much as 40 engines yearly.
“We rapidly acknowledged that by 3D printing the combustion chamber, we might actually make a giant change to the price of the engine and the reliance available fabricators,” Maus mentioned. “So, shifting away from the stainless-steel fabrication to the 3D printed copper, we’re in a position to now construct geometries we couldn’t have constructed in any other case with additive manufacturing. After which, we’re in a position to produce the engine now with the excessive volumes and the excessive charges that ULA wants.”
Traditional engine, new rocket
In lower than a month, ULA plans to debut its Vulcan rocket. The mission, dubbed Vulcan Cert-1, will use a pair of RL10C-1-1A engines to energy the Centaur 5 higher stage and ship Astrobotic’s Peregrine lunar lander on its option to the Moon.
After transport an upgraded Centaur 5 from its manufacturing facility in Decatur, Alabama, ULA built-in higher stage onto the Vulcan booster on Nov. 19. The mission is about to fly no sooner than Dec. 24, 2023.
ULA is getting ready for a moist costume rehearsal within the first half of December throughout which the absolutely built-in Vulcan rocket will probably be rolled out to the launch pad and fueled because it if had been launching. Maus mentioned Aerojet Rocketdyne engineers will probably be on headsets throughout that fueling check to observe the Centaur and the way the engine is cooled and conditioned as will probably be on launch day.
“We’ve got engineers all the information coming off the engine throughout moist costume rehearsal and we are able to just about perceive in actual time that every thing goes proper,” Maus mentioned. “However then after all, there’s a knowledge evaluate that’ll come after that to make sure that every thing carried out as required.”
Ron Fortson, the director and common supervisor of launch operations for ULA, mentioned they are going to then roll the rocket out to the launch pad the day earlier than liftoff and get on console to start the countdown about 12 hours forward of time.
Fortson mentioned integrating the RL10C-1-1A with the Vulcan automobile went easily.
“The whole lot went nicely in our manufacturing facility after which right here, it already comes absolutely assembled and we simply mate it with our rocket and we’re able to go,” Fortson mentioned. “So, it’s been an awesome exercise.”
Fortson mentioned he and the workforce at ULA have been working carefully with Aerojet Rocketdyne as they work in direction of the debut of the RL10C-X engine in a few years.
“We’re working very carefully with them on their design and their testing. As soon as that’s all accomplished, we’ll be trying ahead to really simply integrating it onto our Vulcan rocket,” Fortson mentioned. “After which after all, we’ll be all of our missions which can be coming ahead when it comes to what these necessities are and ensuring we are able to fulfill these necessities with this new engine.”
He mentioned there seemingly received’t be a specific flight profile that can required for the debut of the RL10C-X on Vulcan, including that “This engine’s going to be able to doing something we want it to do.”
“I feel no matter necessities we have now for it, we’re assured that this engine will have the ability to fulfill it,” Fortson mentioned.
“We’ve got a philosophy of check such as you fly, which suggests the engine will solely see in flight that which it has skilled on the bottom inside the limits of what we are able to check or analyze,” Maus mentioned. “So, we’ve been via all of that testing during the last a number of years to know how the engine operates within the Vulcan scheme.”
Maus mentioned as they look ahead to flying the RL10 on new rockets and in new iterations, they look ahead to one other key milestone: flying people through the Industrial Crew and the Artemis packages.
“We’ve been bringing astronauts right down to West Palm Seashore, to our facility to speak to our workforce in regards to the actuality of what we ship and it’s very motivating for us to see our passengers standing in entrance of the room, telling us about how a lot they’re relying upon us,” Maus mentioned. “However the actuality is, we design and construct a extremely dependable product and it has demonstrated its reliability.”
