Podcast - Siemens - Beyond the Horizon: The Future of Gas Turbines
Siemens Podcast Network
Lauren Viel • June 21, 2021
When it comes to getting an aircraft off the ground, it’s no longer a question of “if” it will fly. We’ve moved into the era of “how”- and the emphasis today is on efficiency. This encompasses energy consumption, endurance, speed, and overall performance. Today, we’re looking into the future of turbine engines and exploring what lies just beyond the horizon of existing technology. We’re looking towards what’s next.
Today, I’m talking to Roger Smith and David Laudermilch of Sierra Turbines. Roger started as a software engineer for Apple nearly 20 years ago, and today, he’s the CEO of this innovative California company. David is a Design Engineer with previous experience working with companies like Saab and Rolls Royce. Together, they’ve taken their experience working for industry leaders in software and transportation and turned towards the production of gas microturbines.
In this episode, you’ll hear how each of their rather unique career trajectories eventually led them to this Silicon Valley startup. We’ll talk about the early challenges of getting a microturbine company off the ground, the technologies that merge in order to create their products, and the interesting work they’re doing in collaboration with NASA.
Sierra Turbines Engine
Metal 3D Printing: Who Needs Supports?
Support-free AM technology is proving its advantages with greater design freedom and less engineering time.
Kristin Mulherin
FEB 11, 2021
Velo3D
At a Glance:
In the metal AM process, supports in anchor parts prevent distortion.
Support structures are made of the same materials as the part and prevent distortion, but add considerable design and manufacturing constraints.
In two applications focusing on microturbines and shrouded impellers, VELO3D demonstrates how its support-less technology eliminates the need for support structures.
In metal 3D printing (or additive manufacturing) there is one dominant technology for printing industrial, production-quality parts: powder bed fusion (PBF). PBF technology is widely used to produce medical implants, gas turbines, aerospace parts and multiple other applications across the dental, energy and automotive sectors. It is the most mature and widely used technology because it can produce production-quality parts that cannot be produced by any other method. However, PBF has its challenges, one of which is the need for “supports” when printing parts using typical PBF systems.
What Are Supports?
The word “support” can be misleading, especially to those who come from the polymer 3D printing space. Supports in metal 3D printing work counter-intuitively like “anchors” that hold down, rather than hold up, features within the part. This is to prevent a part from distorting from the residual stresses caused by the high processing temperatures, which will not only destroy the part but also typically cause the re-coater to crash.
Velo3D
When are Supports Typically Needed?
Not all features require supports, but many do. The features that almost always require supports in typical laser-PBF systems are overhangs, holes and channels. Considering additive manufacturing is touted to produce more complex parts with more intricate features, it can be misleading—and frankly, disappointing—to then learn that this can only be accomplished with the addition of multiple supports and counter-intuitive build configurations.
Granted, in polymer 3D printing supports this might not be as big an issue, since they can be dissolvable or easily removed. But with metal 3D printing, supports can be difficult to remove (even if they are accessible), leave defects on the surface from which they are removed, and add significant time and material costs to the overall workflow.
Overhangs
The first feature that requires support is overhangs, which is typically needed if they drop below 45 deg. from horizontal. How many features can you imagine in a typical component that meet this criterion? Often many. A demonstration of what happens as the angle dips below 45 deg. is shown below.
Protolabs
There are three solutions to this problem: reorient the part in the build chamber, redesign the part or add extensive supports. Many resort to reorienting the part in the build chamber, but this comes with its own problems. Take a circular part, such as the impeller shown in the image below.
Velo3D
Many people approach shrouded impellers like this by tipping them up at a 45-deg. angle. The problem with printing at an angle is that breaking the axisymmetry of the part leads to many issues. First, the circularity of any component that rotates is critical. When printing at an angle, this can be very easily compromised in terms of dimensional stability alone. Additionally, in the case of L-PBF 3D printing, the mechanical properties in the Z-direction can be different than in the X/Y plane due to the layer-by-layer process. So, by printing at a slant you will end up with mechanical properties that change as you go around the circle. This is especially problematic in applications where the part is exposed to high stress.
Inconsistent surface finish is another concern. The surface finish will be different at varying degrees of slant. This is not a concern if printed flat, because the variances would at least be symmetrical. Some might say that post-processing will address this, which is true—unless you have those very complex internal features so heavily touted as a selling point for metal AM. Alternatively, abrasive slurry polishing is a popular solution, but it will not address these surface finish variations without removing a lot (and often inconsistent amounts) of material.
Instead, VELO3D has developed a capability, called SupportFree technology, that angles down to a fraction of a degree and can be printed entirely without supports. So, in the case of the impeller above, it can be printed flat and without internal supports, maintaining part axisymmetry and greatly minimizing post-processing.
Holes and Channels
The second type of features that often require supports are holes and channels. It is widely accepted that L-PBF systems can only produce horizontal holes and channels around 8-10 mm in diameter before requiring supports. There are design choices that can be made to try to avoid this, but none of them are ideal. Changing channels into teardrop, elliptical or diamond shapes (per below) are the most common.
Velo3D
There are a few reasons why this would not be desirable. First and foremost, holes and channels are incorporated into designs for one primary reason: to facilitate the flow of a fluid (liquid or gas). In most cases, a circle is the most efficient shape for the flow of fluid, whereas the above shapes will certainly have a detrimental effect on fluid dynamics. Also, the top of the teardrop and corners of the diamond are serious stress concentrators—a big concern when it comes to pressurized fluids. Some might recommend filleting these corners, but this does not entirely remove the stress concentrators; it merely lessens them. And it certainly does not help the situation with flow dynamics.
Alternatively, with VELO3D SupportFree process, holes and channels with inner diameters can be produced up to 100 mm (~4 in.) in diameter. This 10-fold increase in allowable inner diameter greatly opens the design window for increasingly complex interior channels and truly allows the design to be optimized for function rather than manufacturability.
Why Does it Matter?
SupportFree gives you design freedom. The ability to print those complex geometries and intricate internal features gives the designers and engineers an easier point of entry to adopting additive manufacturing. Without it, extensive Design for Additive Manufacturing (DfAM) knowledge is required, which teaches the designer the ins and outs of the required compromises rather than the unlimited design freedom. In short, this technology gives the power to design for optimal functionality rather than manufacturability.
Real Applications
So, what kind of applications benefit the most from SupportFree? In short, optimized designs that control the flow of fluids or transfer of heat.
Great examples of this include microturbines, air foils and impellers, heat exchangers and manifolds with large inner diameters. The first application, microturbines, cannot be represented any better than by Sierra Turbine’s gas microturbines for hybrid UAV propulsion. And the second case study introduced below, Hanwha Power Systems, is a perfect representation of what can be done with shrouded impellers.
Sierra Turbines – Hybrid UAV Propulsion
Sierra Turbines used the VELO3D AM system to produce a gas microturbine that could not have been produced any other way. This microturbine enables hybrid propulsion for high payload UAVs with 40 times less maintenance, 10 times more power density and a 50% reduction in weight. By printing this part with 3D technology, the firm was able to take an assembly of 61 components and produce them as a single part.
Velo3D
From the start, Sierra Turbines realized additive manufacturing was the solution to creating a truly unique and differentiated product. The company spoke reached out to existing vendors and was told that it could produce anything so long as it had angles of 45 deg. or higher. However, when it came to the airflow through the gas turbine engine, that constraint would disrupt the flow and does not really lend itself to an efficient engine. Ultimately, Sierra Turbines found that the VELO3D platform was the only solution that did not require it to redesign its part in order to be manufactured.
How was this accomplished? The answer comes through utilizing Flow software to control the process and having the hardware that allows us to do it. From a library of pre-developed recipes, the simulation software can assign each feature a set of ideal processing conditions. Whether it is low-angle walls, vertical walls, or lattice and bulk structures throughout the part, specific processing conditions were automatically applied to mitigate feature-specific failure mechanisms and eliminate the need for extensive DfAM and specialized operator knowledge.
Velo3D
This 3D Printed Turbine Replaced 61 Parts With 1: Here Is What That Means
Additive manufacturing makes possible a radical microturbine that increases power-to-weight ratio, reduces cost and extends time between overhaul.
ROGER SMITH, CEO, SIERRA TURBINES INC.
When we founded Sierra Turbines in 2017 in San Jose, California, we were looking to serve markets hungry for advances in compact, power-dense power generation for applications in auxiliary power units, backup generators and other standby electrical-generation needs. Another market is that of propulsion systems for unmanned aerial vehicles, both for jet propulsion and hybrid-electric drive-trains.
Cross-section of a Sierra Turbines engine combustor highlighting the complexity of the interior. Notice the thin air foils, and smooth lattice that helps the combustor effectively atomize fuel prior to combustion. With traditional manufacturing, this part would have required the assembly of 61 discrete components, but additive manufacturing consolidated it into a unified geometry with fine details and features that are unattainable via any other method. Photo Credit: Velo3D
We had some pretty straightforward design objectives from the start, but they were actually quite lofty when compared with existing microturbines: A 40× increase in time-between-overhaul (TBO, which is typically only 40-50 hours for most small turbine engines, significantly increased power-to-weight ratio, and decreased unit cost compared to machines of comparable power.
The path to achieving these goals required improvements in both design and manufacturing.
Microturbines have historically been simplified versions of their full-size counterparts, but cost restrictions and scalability have until now prevented the adaptation of the complex part geometries found in larger gas turbines. From very early on in our Aurelius microturbine project it was clear that additive manufacturing (AM) was likely the only technology that would enable the freedom to produce complex features that would have been prohibitively costly using machining or welding.
The static assembly of a gas turbine core is an ideal application to showcase the benefits of AM, some of which in this case are:
- Reduced part count — the Aurelius Mk1 core design replaces 61 separate components with one part.
- Closer tolerances, due to part consolidation, elimination of interfaces, and increased dimensional accuracy.
- Reduced assembly work and postprocessing.
- Freedom to design complex geometries.
The Advantages of Part Consolidation with AM
The cost and energy savings resulting from the consolidation of 61 parts into one part cannot be overstated. Production and transport of different raw materials, manufacture of individual parts using different processes, shipping of individual parts, tedious assembly work, joints of dissimilar materials, reliance on extra seals or fasteners, and more: All of this waste is simply eliminated by the integration of many parts into one 3D printed part that requires minimal postprocessing.
Reducing the number of parts has also reduced the number of interfaces between parts, which in turn reduces the number of seals and fasteners required. Also, the reduction of interfaces eliminates potential sources of leakages and losses, which can negatively impact engine efficiency. Finally, all the internal oil and fuel circuits in the Aurelius are integrated into its one-piece static “Unicore.”
This high level of integration required the right AM machine. We found that not all AM equipment could produce the thin-walled, high-aspect-ratio combustor in our Aurelius design. The system we use is the Velo3D Sapphire metal 3D printer. The non-contact recoater blade used in this AM machine allows support-less printing of overhangs down to zero degrees and lower, and this same feature helps allow for our thin walls. The system is able to print in the Hastelloy X nickel superalloy, which is the material of choice for many large gas-turbine combustion chambers due to its excellent oxidation and corrosion characteristics.
New Designs with Additive Manufacturing
With the consolidation of parts comes also the opportunity for novel design solutions. As the designer is freed from the constraints of traditional manufacturing, he or she can instead focus on defining the geometry needed to perform the required task. For instance, AM enabled a rethinking of fuel spray and flame shape in our combustion chamber. Traditionally, fuel is injected at many points around the diameter of the combustion chamber, and these column-shaped flames are then stabilized by controlling the flow of air around them.
Instead, our design employs a 360-degree fuel injector by which fuel is delivered equally around the entire circumference of the combustor, and atomized while passing through a finely spaced lattice geometry, designed with nTopology software, and only producible with additive manufacturing. The resulting ring-shaped flame is stabilized by strategic swirling of the air inside the combustion chamber.
Efficiency and Decreased Time Between Overhaul
A further benefit of using AM is the ability to create more mass-efficient structures compared with current state-of-the-art turbines. We expect a significant thrust-to-weight ratio improvement over currently available turbines of comparable power.
Finally, and perhaps most importantly, the time between overhaul of the Aurelius Mk1 is projected to be 40 times that of current turbines on the market. This is achieved through the cumulative effects of numerous improvements in bearing design and integration, manufacturing tolerances, lubrication and thermal management features, all made possible by AM.
The recently printed geometry of the Aurelius Mk1 core is a work-in-progress that has helped us define what is possible in terms of component integration and “printability” in Hastelloy X. Our work going forward highlights another benefit of additive: It enables development of a product without the burden of large tooling costs or expensive prototypes.
Two 3D printed turbine combustors that serve as the core of Sierra Turbines’ small engine. They are compact enough to fit in the palm of a hand. Additively manufacturing these engine components took about 50 hours versus months that would have been required for traditional manufacturing. Photo Credit: Velo3D
For future gas turbine development, we aim to further leverage the power of AM to integrate features such as an efficiency-boosting heat exchanger, integrated sensors, and more novel insulation and cooling geometries. Whatever innovative designs we come up with, we are confident that advanced additive manufacturing capability can produce it.
SpaceX CRS-21 Safely Splashes Down Off the Coast of Florida, Returning Science From the Space Station Back to Earth
The SpaceX Cargo Dragon vehicle begins its separation from the station after undocking from the Harmony module’s international docking adapter. MEDIA CREDIT: Image courtesy of NASA TV
KENNEDY SPACE CENTER (FL), January 14, 2021 – SpaceX’s Dragon spacecraft splashed down safely off the coast of Florida last night, concluding a month-plus stay at the International Space Station (ISS) to bring back thousands of pounds of scientific research and cargo. With this successful splashdown, SpaceX completed its 21st Commercial Resupply Services (CRS) mission to the orbiting laboratory for NASA. This also marks the first mission of the upgraded Dragon cargo spacecraft with double the powered locker capacity of previous capsules, allowing for even more research to travel back to Earth for analysis.
More than 30 payloads sponsored by the ISS U.S. National Laboratory were a part of this return mission, leveraging the expanded cargo features allotted by the updated Dragon spacecraft and the expanded crew complement on ISS. Some payloads returning were launched on other spacecraft—as part of the historic SpaceX Crew-1 launch and Northrop Grumman CRS-14—and took advantage of extended time on ISS.
When SpaceX CRS-21 launched to the orbiting laboratory in December, it carried more than 20 ISS National Lab-sponsored payloads, representing dozens of research experiments. Investigations on that mission included a wide variety of research—from biomedical and microbial studies to materials and physical sciences experiments and education investigations to inspire the next generation of researchers and explorers. Below highlights some of the investigations sponsored by the ISS National Lab that returned on SpaceX CRS-21.
Three projects returning on this mission were funded by the National Center for Advancing Translational Sciences (one of the centers within the National Institutes of Health) through its joint, multiyear Tissue Chips in Space initiative with the ISS National Lab. Tissue chip research on this mission included a heart disease investigation from researchers at Stanford University, a second tissue chip investigation from the Massachusetts Institute of Technology focused on post-traumatic osteoarthritis, and a muscle atrophy tissue chip experiment from the University of Florida that builds on a previous tissue engineering investigation that launched in 2018.
Also returning on this mission is an investigation from researchers at the University of California, San Diego who are using a brain organoid model to study neurological diseases. This experiment examined how microgravity affects the survival, metabolism, and cognitive function of human brain cells in an organoid model. Brain organoid models are used in the study of autism and Alzheimer’s disease, which represent a significant health burden on Earth. In microgravity, these disease models may be accelerated.
Another returning payload was launched on the Northrop Grumman CRS-14 mission to demonstrate the manufacture of single-piece turbine blade/disk combinations (blisks) in microgravity for use in the aerospace industry. Made In Space sent its Turbine Ceramic Manufacturing Module to the ISS seeking to validate its latest new commercial facility on the space station. Producing blisks in space could result in parts with lower mass, less residual stress, and higher strength than those manufactured on Earth. The facility is being returned to Earth for further analysis following its successful in-orbit operations.
Two separate payloads looking at the production of ZBLAN optical fibers in microgravity are also part of the SpaceX CRS-21 return mission. Under the sponsorship of the ISS National Lab, FOMS Inc. and Physical Optics Corporation have both sent multiple payloads to the space station in recent years that aimed to produce high-quality ZBLAN fibers in space. ZBLAN fibers are difficult to produce on Earth due to the formation of impurities in the fibers resulting from gravity-driven forces. Early indications from these recent attempts at producing ZBLAN fibers in microgravity have been promising and may lead to new commercial pathways for scalable in-space production and manufacturing that bring value to our nation and drive new market opportunities in low Earth orbit.
When the historic SpaceX Crew-1 mission took flight from NASA’s Kennedy Space Center in Florida in November 2020, it did so with the first ISS National Lab-sponsored investigation to launch on a Commercial Crew Program mission to the orbiting outpost. The payload, a student experiment from the Genes in Space program, sought to evaluate the cognitive changes reported by some astronauts following spaceflight by examining the expression of circadian genes, which regulate sleep and wakefulness, in space. A better understanding of circadian dysregulation in astronauts could enable the design of effective safeguards for astronauts both on the ISS and on potential future deep space missions.
This splashdown also represents the first Commercial Resupply Services mission to safely return off the coast of Florida, as opposed to splashdown in the Pacific Ocean. By splashing down off the coast of Florida, payloads can be transferred back to Kennedy’s Space Station Processing Facility more quickly to be returned to researchers and their Implementation Partners with minimal loss of microgravity’s effects on the research.
To learn more about the ISS National Lab and its sponsored research, including the current opportunities available to propose flight concepts, please visit www.ISSNationalLab.org.
Media Contact:
Patrick O’Neill
904-806-0035
PONeill@ISSNationalLab.org
NASA to Air Departure of Upgraded SpaceX Cargo Dragon from Space Station
Editor's Note: This advisory was updated on Jan. 11 to reflect the new targeted departure date and the correct weight of returning science and cargo.
The SpaceX Dragon that arrived to the International Space Station on the company’s 21st resupply services mission for NASA is scheduled to depart on Tuesday, Jan. 12, loaded with 4,400 pounds of scientific experiments and other cargo. NASA Television and the agency’s website will broadcast its departure live beginning at 8 a.m. EST.
The SpaceX Crew Dragon spacecraft is pictured approaching the International Space Station for a docking on Nov. 17, 2020.
Credits: NASA
The upgraded Dragon spacecraft will execute the first undocking of a U.S. commercial cargo craft from the International Docking Adapter about 8:40 a.m., with NASA astronaut Victor Glover monitoring aboard the station.
Dragon will fire its thrusters to move a safe distance from the station’s space-facing port of the Harmony module, then initiate a deorbit burn to begin its re-entry sequence into Earth’s atmosphere. Dragon is expected to make its parachute-assisted splashdown around 8:14 p.m. Wednesday, Jan. 13 – the first return of a cargo resupply spacecraft in the Atlantic Ocean. The deorbit burn and splashdown will not air on NASA TV.
Splashing down off the coast of Florida enables quick transportation of the science aboard the capsule to the agency’s Kennedy Space Center’s Space Station Processing Facility, and back into the hands of the researchers. This shorter transportation timeframe allows researchers to collect data with minimal loss of microgravity effects. For splashdowns in the Pacific Ocean, quick-return science cargo is processed at SpaceX’s facility in McGregor, Texas, and delivered to NASA’s Johnson Space Center in Houston.
Dragon launched Dec. 6 on a SpaceX Falcon 9 rocket from Launch Complex 39A at NASA’s Kennedy Space Center in Florida, arriving at the station just over 24 hours later and achieving the first autonomous docking of a U.S. commercial cargo resupply spacecraft. Previous arriving cargo Dragon spacecraft were captured and attached to the space station by astronauts operating the station’s robotic Canadarm2. The spacecraft delivered more than 6,400 pounds of hardware, research investigations and crew supplies.
The upgraded cargo Dragon capsule used for this mission contains double the powered locker availability of previous capsules, allowing for a significant increase in the research that can be carried back to Earth.
Some of the scientific investigations Dragon will return to Earth include:
Cardinal Heart
Microgravity causes changes in the workload and shape of the human heart, and it is still unknown whether these changes could become permanent if a person lived more than a year in space. Cardinal Heart studies how changes in gravity affect cardiovascular cells at the cellular and tissue level using 3D-engineered heart tissues, a type of tissue chip. Results could provide new understanding of heart problems on Earth, help identify new treatments, and support development of screening measures to predict cardiovascular risk prior to spaceflight.
Space Organogenesis
This investigation from JAXA (Japan Aerospace Exploration Agency) demonstrates the growth of 3D organ buds from human stem cells to analyze changes in gene expression. Cell cultures on Earth need supportive materials or forces to achieve 3D growth, but in microgravity, cell cultures can expand into three dimensions without those devices. Results from this investigation could demonstrate advantages of using microgravity for cutting-edge developments in regenerative medicine and may contribute to the establishment of technologies needed to create artificial organs.
Sextant Navigation
The sextant used in the Sextant Navigation experiment will be returning to Earth. Sextants have a small telescope-like optical sight to take precise angle measurements between pairs of stars from land or sea, enabling navigation without computer assistance. Sailors have navigated via sextants for centuries, and NASA’s Gemini missions conducted the first sextant sightings from a spacecraft. This investigation tested specific techniques for using a sextant for emergency navigation on spacecraft such as NASA’s Orion, which will carry humans on deep-space missions.
Rodent Research-23
This experiment studies the function of arteries, veins, and lymphatic structures in the eye and changes in the retina of mice before and after spaceflight. The aim is to clarify whether these changes impair visual function. At least 40 percent of astronauts experience vision impairment known as Spaceflight-Associated Neuro-ocular Syndrome (SANS) on long-duration spaceflights, which could adversely affect mission success.
Thermal Amine Scrubber
This technology demonstration tested a method to remove carbon dioxide (CO2) from air aboard the International Space Station, using actively heated and cooled amine beds. Controlling CO2 levels on the station reduces the likelihood of crew members experiencing symptoms of CO2 buildup, which include fatigue, headache, breathing difficulties, strained eyes, and itchy skin.
Bacterial Adhesion and Corrosion
Bacteria and other microorganisms have been shown to grow as biofilm communities in microgravity. This experiment identifies the bacterial genes used during biofilm growth, examines whether these biofilms can corrode stainless steel, and evaluates the effectiveness of a silver-based disinfectant. This investigation could provide insight into better ways to control and remove resistant biofilms, contributing to the success of future long-duration spaceflights.
Learn more about SpaceX missions for NASA at:
https://www.nasa.gov/spacex
Stephanie Schierholz / Monica Witt
Headquarters, Washington
202-358-1100
stephanie.schierholz@nasa.gov / monica.j.witt@nasa.gov
Leah Cheshier
Johnson Space Center, Houston
281-483-5111
leah.d.cheshier@nasa.gov
Editor: Sean Potter
https://www.nasa.gov/press-release/nasa-to-air-departure-of-upgraded-spacex-cargo-dragon-from-space-station
Redwire Technology Successfully Manufactures Ceramic Part in Space for the First Time
World’s first-ever demonstration of ceramic additive manufacturing in space
Jacksonville, FL (December 2, 2020) – Redwire, a new leader in mission critical space solutions and high reliability components for the next generation space economy, announced today that the company’s Ceramic Manufacturing Module (CMM) successfully manufactured a ceramic part in space for the first time.
The commercially developed in-space manufacturing facility successfully operated with full autonomy using additive stereolithography (SLA) technology and pre-ceramic resins to manufacture a single-piece ceramic turbine blisk on orbit along with a series of material test coupons. The successful manufacture of these test samples in space is an important milestone to demonstrate the proof-of-potential for CMM to produce ceramic parts that exceed the quality of turbine components made on Earth. The ceramic blisk and test coupons will be stowed and returned to Earth for analysis, aboard the SpaceX Dragon CRS-21 spacecraft. CMM, developed by Redwire subsidiary Made In Space, is the first SLA printer to operate on orbit.
“This is an exciting milestone for space enabled manufacturing and signals the potential for new markets that could spur commercial activity in low Earth orbit,” said Tom Campbell, president of Made In Space. “Building on our in-space manufacturing expertise and our partnership with NASA, Redwire is developing advanced manufacturing processes on orbit that could yield sustainable demand from terrestrial markets and creating capabilities that will allow humanity to sustainably live and work in space.”
CMM aims to demonstrate that ceramic manufacturing in microgravity could enable temperature-resistant, reinforced ceramic parts with better performance, including higher strength and lower residual stress. For high-performance applications such as turbines, nuclear plants, or internal combustion engines, even small strength improvements can yield years-to-decades of superior service life.
“The Ceramic Manufacturing Module’s successful on-orbit operations is an important step towards full-scale manufacturing of materials products that can improve industrial machines that we use on Earth,” said Michael Snyder, chief technology officer of Redwire. “The space manufacturing capabilities demonstrated by CMM have the potential to stimulate demand in low Earth orbit from terrestrial markets which will be a key driver for space industrialization.”
CMM was developed in partnership with the ISS Research Integration Office at NASA’s Johnson Space Center. The ceramic facility is one of three ISS pilot payloads developed through this partnership that aims to catalyze and scale demand for commercial capabilities in low Earth orbit by producing high-value products for terrestrial use. Made In Space first demonstrated the SLA printing technology found inside CMM through a series of parabolic flights funded through NASA’s Flight Opportunities program in 2016.
Additional technical partners for the CMM mission include HRL Laboratories of Malibu, California and Sierra Turbines of San Jose, California.
The successful CMM mission builds upon Redwire’s flight heritage with four other additive manufacturing facilities developed by the Made In Space team that have successfully flown and operated on the space station.
To learn more about CMM, visit https://madeinspace.us/capabilities-and-technology/ceramics-manufacturing/.
Ceramics Manufacturing: Increasing Capability + Scaling Commercial Industry in Space
Made In Space (MIS) is set to launch its newest manufacturing facility to the International Space Station (ISS), introducing another brand new manufacturing capability from the MIS team. This significant milestone will be the fifth facility launched by the company and the fifth unique capability brought to the ISS.
The Ceramic Manufacturing Module (CMM) will be on Northrop Grumman’s 14th commercial resupply mission aboard the Cygnus spacecraft. The technology is a commercial in-space manufacturing device designed to provide proof-of-potential for single-piece ceramic turbine blisk (blade + disk) manufacturing in microgravity for terrestrial use. This marks the first ceramic facility on the ISS.
Techniques + Comparison
The Ceramics Manufacturing Module (CMM) is a unique manufacturing technology that introduces both an innovative new manufacturing capability on-orbit and a new material medium to fabricate with. CMM will demonstrate the viability of manufacturing with pre-ceramic resins in an additive stereolithography (SLA) environment. Manufacturing on-orbit in the microgravity environment could enable temperature-resistant, reinforced ceramic parts with better performance including higher strength and lower residual stress, due to a reduction in defects caused by gravity, such as sedimentation and composition gradients that occur in terrestrial manufacturing.
The CMM facility performs a uniform stereolithography printing process that has been validated on NASA-sponsored parabolic flights for high-resolution parts. The initial design process and technical advisory during the parabolic flights were provided by commercial partner, B9Creations. The manufacturing process being flown employs the use of pre-ceramic resins. These resins are the soft materials present before the manufacturing begins that become hardened during the process.
Stereolithography or Digital Light Processing (DLP) is a mature, high-resolution 3D printing approach based on UV curing of liquid resins in a layer-by-layer fashion. Beyond a range of polymers, this method is also used for additive manufacturing of ceramics. To this end, ceramic particles are suspended in the liquid resin. MIS will print an advanced ceramic matrix composite (CMC) material that consists of a pre-ceramic resin reinforced with ceramic particles. The microgravity environment on the ISS is considered especially beneficial for processing such particle suspensions as the settling of particles is mitigated.
This new additive manufacturing process varies in technique from our heritage 3D printing facilities. The MIS Additive Manufacturing Facility (AMF) that has been operating on the ISS since 2016, uses a manufacturing process called Fused Deposition Modeling (FDM). This process builds an object by selectively depositing melted filament material in a predetermined path, layer-by-layer. AMF’s legacy has been the foundation for the technology roadmap and manufacturing programs for MIS while developing new capabilities that will leverage additive manufacturing in space for unprecedented applications.
Industry Applications
The project focuses on advanced materials engineering ultimately leading to reductions in part mass, residual stress, and fatigue. The facility is designed to accommodate additive ceramic sample materials identified by MIS and customers as having the highest value for production. This will help to validate the uniformity, low density, and high performance of printed ceramic blisks as compared with ground analogs. For high-performance applications such as turbines, nuclear plants, or internal combustion engines, strength improvements of even 1-2 percent can yield years-to-decades of superior service life.
Once the manufacturing device returns to Earth, the manufactured blisks are then heat-treated or pyrolyzed to create the final product of a Ceramic Matrix Composite (CMC). CMCs have the potential to perform at hundreds of degrees hotter than the best superalloys and can have a clear advantage over previously used metal components used in aircraft engines.
MIS is developing this technology for commercialization alongside technical partners HRL Laboratories of Malibu, California and Sierra Turbines of San Jose, California.
“Our main interest in utilizing space-enabled materials lies in harnessing the performance benefits they enable for our and our partners’ products, and thus giving us a competitive advantage in meeting demand in these two markets:
1) space vehicle applications, such as satellites in various orbits and spacecraft heading to the lunar and Martian surfaces, that must handle highly reactive atomic oxygen or withstand high-energy particles
2) Earth-based high-performance applications, such in Sierra Turbines’ ultra-high temperature turbine blades, where the absence of buoyancy-driven convection and sedimentation allows vastly improved micro-structures not possible to create terrestrially”
Roger Smith, CEO, Sierra Turbines
Single-piece turbine blisks have significant advantages over current assemblies used in aircraft jet engines and integrated rotors. CMCs are typically lighter than high-temperature alloys by 30-50 percent and are capable of handling much higher operating temperatures, measuring above 1100 °C, which can improve fuel economy and efficiency in larger aircraft engines. Successful production in microgravity may provide additional gains in decreasing the mass and residual stress of these parts and increasing their fatigue strength which could convey significant advantages to the aviation industry.
Internal projection of the blisk to be printed in the pre-ceramic resin
Ceramic blisks before and after being pyrolyzed
Leveraging Space-Enabled Manufacturing for a Sustainable Low-Earth Orbit Economy
Ceramics produced in microgravity will open opportunities for complex-shaped, temperature resistant, and environment resistant ceramic structures addressing defects common to terrestrial printed parts including porosity and non-uniform shrinkage. The parts that are produced on-orbit will be compared with parts produced terrestrially with MIS hardware as well as commercially available materials.
Ceramics Manufacturing Module Team
CMM is part of MIS’s expanding Space-enabled manufacturing portfolio. Space-enabled manufacturing is a form of in-space manufacturing that leverages microgravity to manufacture materials that are either completely new or far superior to their Earth-manufactured counterparts. MIS has a comprehensive suite of ISS rack-based payloads for a variety of advanced manufacturing techniques and facilities with broad applications not limited to proof-of-potential “blisks”. The primary objective for each of these facilities on their first flight will be to demonstrate the technology operates as intended and to produce the material product so that we can analyze those samples on the ground.
These space-enabled materials are realized through the unique microgravity environment that has the ability to alter materials at their atomic level to create a superior product in-space compared to the terrestrial analog of that material. By identifying advanced manufacturing processes that address specific markets and add greater value to the products needed in those markets, along with a scalable approach for meeting the market’s need, space-enabled manufacturing creates a space-Earth value chain to spur commercial activity.
This type of manufacturing represents a key differentiator in how space is utilized for commercial expansion. By leveraging the microgravity environment we are able to economically manufacture new and innovative products that can be sold on Earth. Space-enabled manufacturing is critical to the MIS mission because it creates a profit motive that can scale demand for on-orbit manufacturing capabilities and services which translates to the growth of new markets in the LEO economy and increases demand from terrestrial customers.
Northrop Grumman is targeting liftoff of its Antares launch vehicle for no earlier than 10:26 p.m. EDT Tuesday, Sept. 29, from the Mid-Atlantic Regional Spaceport’s Pad-0A at NASA’s Wallops Flight Facility on Wallops Island, Virginia.