Aerojet Rocketdyne [AJRD] is exploring using additive manufacturing to improve the injector and possibly the chamber of its RL-10 engine, according to a top executive.
Aerojet Rocketdyne Vice President of Advanced Space and Launch Julie Van Kleeck told Defense Daily Wednesday in an interview at the company’s Arlington, Va., office that Aerojet Rocketdyne started working on additive manufacturing, also known as 3D printing, a number of years ago, but has significantly invested in the processing and the technology over the past four years. Van Kleeck said the company is now focusing on how to use additive manufacturing in production and qualifying processes.
The RL-10 is used by United Launch Alliance (ULA) as upper stage engines on its Atlas V and Delta IV launch vehicles. The RL-10A-4-2 powers the Atlas V while the RL-10B-2 powers the Delta IV. ULA is planning to retire the Delta IV in the 2018-2019 timeframe due to its high price tag.
ULA is also developing a next-generation launch system, called Vulcan, which will use Blue Origin’s BE-4 engine as its first stage. ULA Chief Executive Tory Bruno said in April that the company will select Vulcan’s upper stage from four competitors: Blue Origin’s BE-3U, Aerojet Rocketdyne’s RL-10 and an XCOR engine (Defense Daily, April 13).
Van Kleeck said Aerojet Rocketdyne is looking at additive manufacturing for other RL-10 components, but didn’t specify which. One of the challenges involved with incorporating additive manufacturing into demanding propulsion systems like rocket engines, she said, is getting the processing right. Van Kleeck said establishing the powder beds, feeds, speeds and environments are critical for getting the right material processes and that the company is investing time in this step.
Additive manufacturing is the process of joining materials to make objects from 3D model data, usually layer upon layer, as opposed to traditional, subtractive manufacturing technologies.
Van Kleeck said additive manufacturing can reproduce a lot, if not most, of what is possible through subtractive manufacturing. She said additive manufacturing can produce new designs in the areas of small passages, cooling and complex geometries more quickly and at lower cost than subtractive manufacturing.
“There are some challenges you have to work through, but…we think there are far more benefits and possibilities than there are in some of the engineering challenges,” Van Kleeck said.
One of the challenges involved with additive manufacturing is validation and demonstration. Manufacturers, standards organizations and others maintain high standards for critical structural materials, including those used in aerospace applications. Providing a high level of confidence in the structural integrity of components built with additive manufacturing may require extensive testing, demonstration and data collection.
Additive manufacturing is reducing the aerospace industry’s important materials measure, the “buy-to-fly” ratio, by more than half. This ratio is the amount of material needed to make one pound of aerospace-quality material. Engineers are taking advantage of additive manufacturing to simultaneously reduce material requirements and easily create engine parts with complex internal structures.
According to the Energy Department, jet ducts in Boeing [BA] F-18 fighters can be made with smoothly curving channels that allow more efficient air and fluid flow than those created with the difficult traditional method of boring through solid structures. The Air Force is also studying how to best validate that parts created via additive manufacturing will have the strength and endurance to survive in demanding atmospheres like space (Defense Daily, April 20).
Van Kleeck also said Aerojet Rocketdyne responded to the Air Force’s draft request for proposal (RFP) for a next generation rocket propulsion system. She said the Air Force’s draft RFP is “too broad” and should focus on an engine solution, as opposed to an overall launch vehicle. The Air Force, as directed by the 2015 National Defense Authorization Act (NDAA), wants a next-generation rocket engine in place by 2019 to replace the Russian-developed RD-180 that currently powers the Atlas V.
Van Kleeck said the draft RFP isn’t structured to give the best chance to get off the RD-180 by 2019.
“We believe the country has an engine problem, not a launch vehicle problem,” Van Kleeck said.
Aerojet Rocketdyne has proposed using the AR-1 with the Atlas V launch vehicle in addition to Vulcan and other launch vehicles. An industry source familiar with the issue said Wednesday the company has proposed using AR-1 with Orbital ATK’s [OA] Antares. Though there are engineering challenges with swapping rocket engines and launch vehicles, Van Kleeck said the AR1 is “as close to plug-and-play as you can get” and that modest software changes would be needed to use the AR1 with the Atlas, which Aerojet Rocketdyne is interested in for its low cost per launch.
ULA spokesman Jessica Rye on Wednesday said the company holds the rights to build and launch the Atlas V and has no intention of selling or transferring them. She said ULA expects to launch Atlas V into the next decade as it works with customers to meet requirements and transition to Vulcan, which expects to produce its first flight in 2019 and full certification in 2022-2023. ULA is a joint venture of Lockheed Martin [LMT] and Boeing [BA].
The industry source close to the issue said Aerojet Rocketdyne, with Dynetics and Schafer Corp., submitted an inquiry to the Air Force “exploring” the future use of the Atlas V. Van Kleeck on Wednesday declined to comment on how much Aerojet Rocketdyne might expect to pay if it can obtain Atlas V launch and data rights or if it would need to hire experienced Atlas V engineers to build the rocket.