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3D printing or additive manufacturing is ongoing revolution in manufacturing with its potential to fabricate any complex object and is being utilized from aerospace components to human organs, textiles, metals, buildings and even food. Additive manufacturing is defined by ASTM International as the process of joining materials together, layer by layer, based on three-dimensional model data.
Additive manufacturing is known to be a good prototyping method. It is allowing the manufacturers to make many iterations at a lower cost and quite quickly. Moreover, as you have to work on a CAD software to create your parts, you only have to make modifications on your 3D file if you need to change something. It is really allowing to work way faster than with other processes. The 3D printing technology is getting further boost in aerospace and aeronautics as many 3D printers which can print heat resistant materials are now entering the market.
For the last several years, aerospace companies have been examining ways to use additive manufacturing, or 3D printing, to aid the production of rocket engines. These industries are using this technology both for prototyping and production from motors to complete rockets. At their core, rockets consist of four main systems: payloads, guidance, propulsion, and structures. The payload is whatever the rocket is carrying. The guidance consists of sensors that keep the craft on target, and propulsion is made up of the fuel and engine that make it go. The structures are the rest of the frame, cone, and fins of the rocket—parts that are typically fabricated using ultra-precise CNC milling machines and hand welding.
One company that has been at the forefront of these developments is rocket-building firm Relativity Space, which after its founding in 2015 grew rapidly to raise $45.1 million in three years. In 2017, the firm announced it was working on a new Stargate 3D printer which would allow it to go, “from raw material to flight in less than 60 days”, and in the long-term 3D print the first rocket on Mars. A year later, the company signed a contract with the U.S. Air Force to operate its own launch facility on one of their sites and test its 3D printed rockets at Cape Canaveral. Most recently, Relativity Space was called upon by aerospace and defense contractor Lockheed Martin to 3D print projectiles for an upcoming experimental NASA mission.
Other companies operating in this space include Spanish aerospace firm Zero 2 Infinity which is using 3D printing as part of its Blooster balloon-assisted rocket. UK-based aerospace company Orbex hopes its 3D-printed rockets, made with the latest metal 3D printer from German manufacturer EOS, will blast off from Scotland by the end of the year. And in the U.S., young rocket engine maker Ursa Major is taking orders now for its new Arroway propulsion engine designed to displace the now-unavailable Russian-made propulsion sources. It’s also 3D printed using available metal 3D printers. U.S. start-up Rocket Crafters has concluded testing of its Comet Series hybrid 3D printed rocket engine.
“The Owl Spreads Its Wings” is Rocket Lab’s seventh Electron launch this year with a 100% mission success rate for 2022. Sep 2022, it completed 30th Electron launch and delivering 150th satellite to orbit, the mission also marked the 300th Rutherford engine flown to space on Electron. Designed and built by Rocket Lab, Rutherford is the world’s first 3D-printed, electric pump-fed orbital rocket engine. Rocket Lab, one of only a few small satellite launchers that fly commercial flights, has relied on additive manufacturing to create engines, valves, manifolds, and a number of other complex components; its CEO, Peter Beck, says, “There’s no way that we can produce the volume and the performance of the engines that we’re producing now without 3D-printing technology.”
In Sep 2022 Rocket Lab successfully test-fired a reused Rutherford first-stage engine for the first time. This is a significant technical achievement as Rocket Lab develops Electron into the world’s first reusable orbital small rocket.
British aerospace company Orbex, which announced that its 3D printed rockets will be the first to launch from the UK’s new spaceport in early 2022.
The RS25 engine developed by Space Launch System has a 3D printed component called pogo accumulator, a shock absorber placed inside of the rocket engine. Aerojet Rocketdyne, has been working on printing components of its venerable RL10 engine. In early June, the company announced that a printed copper thrust chamber successfully completed a series of hotfire tests. The company isn’t alone in exploring new ways to apply additive manufacturing to propulsion and related systems.
Printer manufacturers are also developing large-scale 3D printers. Instead of components, it will be possible to print larger parts more easily. Relativity Space, for example, is working to 3D-print entire rockets, including their engines, and has raised tens of millions of dollars to support its work. Kieatiwong, though, is hopeful that his company can achieve a breakthrough with its new approach to engine design.
SpaceX has built a rocket engine using 3D printing, it is called SuperDraco. This process has been used on different levels. First, for testing, 3D printing has been used instead of the traditional casting method. 3D printing has also been an advantage for the manufacturing process, and it really reduced the lead-time. The 3D printed parts were even more resistant than traditional ones.
NASA engineers, created a rocket engine prototype using two different metals: copper alloy and Inconel. They used a process called brazing, in order to join 2 different types of metal, creating a brand new component. This advanced process is offering promising possibilities for the future 3D printed metal parts.
In 2018 Agile Space Propulsion strated producing Rocket Thrusters, using 3D Printing
Colorado-based company Agile Space Propulsion has a specific goal: to design and manufacture rocket engines using 3D printing technology. In particular, Daudi Barnes, wants to develop thrusters, the small maneuvering engines used in rockets. According to Barnes, as rockets get cheaper, there is an increasing need for thrusters, and the miniaturization of electronics is spurring demand for more space vehicles for a variety of purposes.
Barnes has already developed a prototype thruster for a lunar lander for NASA. Using 3D printing, Barnes was able to come up with a prototype in merely nine weeks, and it performed better than the engine that had been in production for so long. Agile Space Propulsion has already developed a 100-pound thruster and is currently working on a five-pound one. Barnes points to the use of 3D printing in much of aerospace, for both small and large engines.
“In traditional manufacturing, there are a lot of steps, a lot of parts, and there are restrictions on what you can do,” he said. “For instance, you can drill a straight hole, but you can’t drill a curved hole.” 3D printing, on the other hand, can create curved channels, and can cut down on the number of steps involved in making something like a thruster. “The end product is more sophisticated, more capable and lighter, and that’s a really big thing,” said Barnes. “I can print in one day something that took months to make. Just the time savings alone is a big cost-saver.”
“Cost reductions have opened up opportunities,” Daudi Barnes said. “People are saying: ‘Wow, if all of this is more affordable, we can do more missions now.’” Rocket launches have been downsizing and becoming lighter and cheaper, partially thanks to 3D printing, which enables complex parts to be made in fewer components, or even in a single component. It also allows for a great deal of lightweighting. “Weight is everything in space,” said Barnes. “It costs $1 million to put 1 kilo on the face of the moon. If you can make a spacecraft half a kilo lighter, you’re saving a ton of money.”
Additive Rocket Corp. reported in 2018 of combining additive manufacturing with a tool called generative design
For Aerojet, using additive manufacturing helps to reduce the number of parts in engine components, and thus speed up production by more than 50 percent and lower costs. The use of additive manufacturing is a key element in Aerojet’s updated version of the engine, the RL10C-X, intended to lower its cost without compromising reliability or performance. Aerojet is developing that engine with United Launch Alliance, who plans to use it in the upper stage of its Vulcan rocket under an agreement among the companies.
“What additive manufacturing does is that it opens up the opportunities of design freedom and removes all the traditional barriers that engineers have to keep in mind,” said Andy Kieatiwong, co-founder and chief executive of Additive Rocket Corporation (ARC). ARC combines additive manufacturing with a tool called generative design, where computer algorithms develop thousands of different designs that meet a set of constraints and then iterate on them to find the optimal solution. That can result in designs that are not possible to produce without 3D printing and can even be beyond the imagination of conventionally trained engineers.
The exterior looks like a typical engine, but he showed cutaways of its interior that revealed dozens of channels carrying kerosene and liquid oxygen in patterns than he likened to blood vessels or a tree trunk. “That’s one of the best ways to move fluid through a system,” he said.
That “biomimetic” architecture is a hallmark of generative design. “The benefits of this system cascade up through the entire propulsion system,” he said. It lowers the pressure differential in the engine, so less energy is needed to move the fuel, which reduces the size of valves, pumps and tanks supporting the engine. It also improves the heat transfer through the nozzle to lower its temperature, increasing its lifetime.
Russian Scientists Develop a New Technology for Manufacturing Gas Turbine Engine Parts in 2020
Gas turbine engines are used in the aircraft industry. Heat-resistant materials are needed to produce them; the mechanical processing of these materials is quite sophisticated and requires much time and effort. Industrial enterprises and mechanical engineers are interested in facilitating the production of gas turbine engine parts and improving their quality.
Anton Kazansky, a postgraduate student of the Faculty of Mechanical Engineering of South Ural State University proposed hybrid additive casting as a new method of manufacturing parts. The postgraduate student explained the relevance of this technology by increase labor productivity and reduce production costs. The technology is tested by the student of South Ural State University and his scientific advisors, D.Sc., Dean of the Faculty of Mechanical Engineering Viktor Guzeev, and Ph.D., Dean of the Aerospace Engineering Faculty Viktor Fedorov
“The essence of the additive casting method is to combine two technologies to create a new one. With the help of additive technologies and remelting of the workpiece in a ceramic form, it will be possible to obtain parts that do not need subsequent mechanical processing. According to our research, there are no complete analogs of this technology in the world,” Anton Kazansky said.
NASA developed 3D printed rocket engine components that could be used as part of the Artemis project to return astronauts to the Moon, and prepare for a future mission to Mars.
Through its Rapid Analysis and Manufacturing Propulsion Technology project (RAMPT), NASA has optimized a blown powder Directed Energy Deposition (DED) technique to fabricate several large-format parts. The advanced printing process has enabled NASA to significantly reduce the lead times and costs of producing complex engine components such as nozzles and combustion chambers.
NASA established its RAMPT program to develop novel manufacturing technologies, with the overall aim of increasing the scale and performance of its thrust chamber assemblies. At present, the rocket chamber takes the longest time to produce, is the most expensive, and is the heaviest part of all those that make up NASA’s rocket engine systems. Working with government and industry partners, RAMPT is not only reducing the engine’s cost, but developing an integrated specialty supply chain for materials, hardware and testing.
RAMPT has made significant advances in the development of an enhanced DED 3D printing technique, which has enabled it to create numerous rocket parts. The printing method works by injecting metal powder into a laser-heated pool of molten metal (or its melt pool). Then, a print-head, composed of a blown powder nozzle and laser optics, is attached to a robot, which creates components in a layer-by-layer process.
Leveraging the emerging technology, NASA scientists were able to fabricate much larger pieces than previously possible, which are limited only by the size of the room in which they are created. The new DED process was also proven capable of create highly complex parts such as engine nozzles with internal coolant channels.
Now we’re printing one for the RAMPT program that’s five times that height, reported in August 2021. This is one of the largest rocket engine components ever 3D printed.” The exact dimensions of the approximately two-ton additively manufactured full-scale RS25 nozzle liner are 111 inches in height and 96 inches in diameter. The massive part was built over the course of several months — a greater than 50% reduction in processing time compared to traditional manufacturing techniques.
Firefly Aerospace announced in Nov 2020 that it will transition its manufacturing of large parts to an Automated Fiber Placement (AFP) system from Ingersoll Machine Tools
The company developed its Wide and High Additive Manufacturing (WHAM) additive manufacturing system several years ago in partnership with Oak Ridge National Laboratory (ORNL), initially targeting the aerospace, wind energy, automotive, and defense sectors. Now, Firefly is looking to utilize Ingersoll’s high-speed, large-scale robotic AFP systems to essentially 3D print composite structures with large dimensions, a task which poses limitations when using metal 3D printing.
Firefly will install its first AFP system at its manufacturing and test facility in Texas in May 2021, after which the Alpha rocket airframe will be requalified using AFP manufacturing processes. The second AFP system and automated assembly line is destined for Firefly’s new Florida Space Coast factory and launch site at Cape Canaveral, set to be installed by the beginning of 2022.
Firefly estimates the facility will be capable of producing 24 Alpha rockets per year, fabricated from all carbon-fiber structures including barrels, fairings, domes, and payload components, using AFP. Meanwhile, the Texas plant will transition to automated developmental builds of Firefly’s larger Beta launch vehicle. It’s estimated that the firm’s new automated rocket factories will deliver a 30-50% reduction in composite materials waste, while reducing hands-on labor, build times, and overall costs.
According to Markusic, integrating Ingersoll’s AFP technology into its production lines represents not only Firefly’s investment in its own future as a company but also in the future of the “cis-lunar space economy”, which refers to the economic activities taking place in space, either on the Moon or in orbit around the Earth. “As Firefly approaches our first Alpha launch, our focus is transitioning to scaling our operational capabilities to meet the fast-growing commercial, government, and scientific mission demand for space access with the lightest, strongest, fastest built precision-made rocket in the industry,” he added.
On Sept. 2021, Firefly Aerospace (Austin, Texas, U.S.) conducted the first flight test of its all-composite Alpha rocket. According to a a company statement by Firefly Aerospace on Sept. 3, the rocket launched successfully, flew for about 2.5 minutes and achieved supersonic speed, prior to an anomaly that caused the vehicle to explode prior to reaching orbit.
Alpha is a two-stage, small-satellite launch vehicle designed to carry 1,000 kilograms of customer payload to low Earth orbit (LEO), and all major structural components are constructed from carbon fiber/epoxy prepreg
Relativity Space 3D printing Rockets
Relativity was founded in 2015 by Tim Ellis and Jordan Noone, two young aerospace engineers who had the big idea to create fully 3D-printed rockets. Before Relativity’s inception, Ellis was at Blue Origin and Noone was at SpaceX working on the Dragon capsule, Ellis told Space.com.
Relativity’s inaugural launch, set for 2022, will see the company blast its Terran 1 rocket, a two-stage, fully 3D-printed rocket, into space in a test flight to show its viability. This will be the first launch of a completely 3D-printed rocket. The mu Space satellite would launch in 2022 on what Relativity officials call the first 3D-printed rocket ever built. According to them, this vehicle — Terran 1 — is designed to carry up to 2,756 lbs. (1,250 kilograms) into low Earth orbit, with a cost of $10 million per launch.
Relativity’s first Terran 1 booster test campaign culminated with two long-duration static fires in September 2022. The final 57 and 82-second static fires weren’t quite the “full mission duration” tests Relativity had hoped for, but the company concluded that the data gathered was enough to clear the booster for flight.
According to Ellis, one of the most important insights gained from those tests was into Terran 1’s uncharacteristically complex autogenous pressurization system – unprecedented for such a small rocket. Generally speaking, orbital-class rockets store helium gas in small ultra-high-pressure tanks (COPVs) and use helium to pressurize their propellant tanks as they are drained of propellant. Autogenous pressurization refers to an alternative in which a portion of a rocket’s liquid oxidizer and fuel are turned into hot gas and injected back into their respective tanks to pressurize them.
Relativity Space says they can 3D-print a rocket in less than 60 days. Relativity’s 20-foot-tall printer, Stargate, has been serving the company since 2017. Relativity officials say their Stargate machine is the largest metal 3D printer in the world, with the capacity to transform raw materials into a rocket, like Terran 1, in less than 60 days. Stargate use a variant of what’s known as directed energy deposition. The most prevalent form of 3D printing is called fused deposition modeling—a material, often plastic, is melted and squeezed out of a nozzle in precise patterns to build an object. Combine that with welding and you have directed energy deposition.
The basics of welding involve supplying a steady stream of metal wire with one hand and heat with the other. Stargate does this automatically, feeding wire out of an extruder on the end of a tall robotic arm. The metal is heated using electric plasma (and sometimes a laser) and then laid down according to a computer’s instructions. A combination of electronic controls, thermal imaging cameras, and sensors mounted near where the material is deposited adapt the print as it’s created.
“Our vision of 3D printing is software-defined automation for aerospace,” says Ellis. “That’s getting toward the long-term vision of 3D-printing rockets on Mars. These are exactly the tools we’re going to need to actually build stuff on other planets.”
While currently striving to deploy and resupply satellite constellations into orbit around Earth, Relativity is also making bold statements about its future. By scaling rockets quickly, company officials hope to ”build the future of humanity in space,” according to the website. ”We believe the future of humanity is interplanetary.”
Propulsion Company Ursa Major Delivers in March 2022, First-Ever Rocket Engines Qualified for Both Hypersonics and Space Launch Applications
Propulsion Company Ursa Major Delivers First-Ever Rocket Engines Qualified for Both Hypersonics and Space Launch Applications.
Phantom Space, a space technology and transportation company, will use Hadley to power its two-stage expendable rocket, which transports satellites and other space cargo into Earth orbit and beyond. Stratolaunch, an aerospace vehicles and technology company, will use Hadley to power its reusable hypersonic testbed vehicle, which is designed to reach Mach 6, or six times the speed of sound.
By making flexible rocket engines that can be used for multiple purposes, Ursa Major helps customers get to launch three times faster at a low price and without the development cost of building engines in-house. By supporting other aerospace startups, Ursa Major is helping shape the modern space economy with entrepreneurial thinking and innovation.
“Hadley’s greatest strength is that she simply exists,” said Silas Meriam, senior test operations engineer, Ursa Major. “No one else is making engines with 5,000 pounds of thrust at this level of reliability—and they’re available now.”
Because Hadley is mostly 3D-printed, Ursa Major can make data-driven design improvements and manufacture them essentially in real-time.
Hadley highlights:
– Can be used in first stage, upper stage, and hypersonic applications
– More than 30,000 seconds of run-time at Ursa Major’s own facilities
– Sufficient engine life to support pre-flight ground testing or static-fire testing, as well as flight, without additional modifications or inspections
– Wide range of customizable throttle levels and thrust profiles to meet customer needs
– Seven-degree thrust vectoring provides more control and maneuverability for typical flights, and may also enable vertical landing and return-to-launch-site burns, among other capabilities
India’s Space-Tech Startup Skyroot Aerospace Unveils 100% 3D Printed Dhawan-1 Rocket Engine in Sep 2020
Skyroot Aerospace, a Hyderabad-based Startup working towards Democratizing Space Access, unveiled its 100% 3D printed cryogenic engine named Dhawan-1. The Dhawan-1 rocket engine will be operating on 100% cryo propellants like Liquid Natural gas (LNG) and Liquid Oxygen (LoX). Skyroot’s Prarambh mission was expected to be launched in November 202.
A cryogenic rocket engine uses liquid cryogenic fuel and oxidizer, stored at very low temperatures. According to reports, the cryogenic temperature has been defined to refer to temperatures below -150 degrees Celsius. Engines using cryogenic fuels are used in the upper stages of rockets for propulsion technology. Sharing more details on the Dhawan-1 rocket engine, Pawan Kumar Chandana, Co-founder and CEO, explained, “Liquid Natural gas (LNG) is a clean-burning, low-cost, highly-reusable, and safe cryogenic fuel, which is also ideal for long-duration deep space missions carrying satellites or humans.”
He added, “We have completed tests to check the fuel flow and structural integrity of the engine. Skyroot is presently building a dedicated test facility to carry out “hot fire” testing of Dhawan-1 rocket engine.” According to the Startup this 3D printed cryogenic engine is expected to be used in the upper stage of its Vikram-II rocket for propulsion. Speaking at the launch, Naga Bharath Daka, Co-founder and COO, Skyroot Aerospace said, “Our rocket engine is named ‘Dhawan-1’ in honour of eminent Indian rocket scientist Dr. Satish Dhawan, who played an instrumental role in the development of the Indian Space Programme. Dhawan-1 rocket engine is a 100 percent 3D printed cryogenic engine with regenerative cooling.” Skyroot revealed that it’s Senior Vice President V. Gnanagandhi, former ISRO scientist and Padma Shri awardee, is responsible for leading the cryogenic propulsion team.
Australian cold spray 3D printer manufacturer SPEE3D has announced plans to “revolutionize” the space sector with low-cost metal 3D printed rocket engines. In July 2021, the company received AUD $1.25 million from the Australian Government’s Modern Manufacturing Initiative (MMI) ‘Space’ Translation Stream grant, and a further AUD $312,000 from the Northern Territory Government, to carry out its latest project, SPAC3D.
Through SPAC3D, SPEE3D will seek to manufacture high-quality, inexpensive metal 3D printed rocket engines for Australia’s emerging industrial space industry using its cold spray technology. SPEE3D’s patented cold spray additive manufacturing technology is reportedly capable of printing metal parts between 100 and 1,000 times faster than traditional metal 3D printing methods. The technology is also supposedly one of the only processes capable of printing metal parts on-demand at a cost that is more competitive than conventional manufacturing.
Instead of relying on lasers or other heat-based energy sources, cold spraying leveraged kinetic energy to spray a metal powder onto a substrate via a high-velocity compressed gas stream. This gives the material enough energy to deform and bond to the solid part below, forming additional layers. In February 2019, SPEE3D was selected by the Royal Australian Navy to take part in a two-year AUD $1.5 million project to pilot trial its metal 3D printing technology with the aim of streamlining the maintenance of the Navy’s patrol vessels.
India’s Agnikul Cosmos has developed what it claims is the world’s first single-piece 3D-printed rocket engine.
In Nov 2022 Chennai-based space-tech startup Agnikul Cosmos successfully completed the test firing of Agnikul—the company’s 3D-printed rocket engine—at the Vikram Sarabhai Space Center in Thiruvananthapuram. Agnilet claims to be the world’s first single-piece 3D-printed rocket engine.
The Agnilet rocket engine is designed to be used in Agnibaan—a small satellite launch vehicle that can carry payloads of up to 300 kilograms to a low-Earth orbit—which the company is currently developing. The Agnilet rocket engine is a “semi-cryogenic” engine. It uses a mixture of liquid kerosene at room temperature and supercold liquid oxygen to propel itself.
“When you use older manufacturing techniques, there is a lot more complex hardware and manpower involved. With 3D printing, you can make hardware nearly as fast as you can make software. This is why we were able to make hundreds of iterations of the design so that we could finally reach a stage where we can 3D print an entire engine in one shot,” said Ravichandran over a video interaction.
But 3D printing is not without its disadvantages. “3D printing is still slow if you compare it to injection moulding or planar-based manufacturing where you can manufacture millions of pieces every month. So it is not meant for manufacturing in large volumes. But rocket engines and a lot of the components of launch vehicles can be manufactured using this method,” explained Ravichandran.
But for an actual space launch, it is not just the engine that needs validation. Other systems, including avionics packages and guidance and navigation systems, also need to be tested and validated. Agnikul is working on validating the entire launch vehicle and is hoping to have a test launch by the end of the year. During the test launch, the Agniban rocket will be carrying payloads that are designed to test its systems.
References and Resources also include:
https://spacenews.com/printing-the-next-generation-of-rocket-engines/
https://www.technologyreview.com/s/613743/relativity-space-3d-printed-rocket/
https://www.space.com/relativity-space-3d-printed-rocket-thai-satellite.html
http://www.spaceref.com/news/viewpr.html?pid=59702
https://indianexpress.com/article/technology/science/agnikul-cosmos-3d-printed-rocket-8273191/
