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NASA Wants Aerojet Rocketdyne to Make More Rocket Engines with 3D-Printed Parts

On its first launch, NASA‘s uncrewed Space Launch System (SLS) mega-rocket will go on a trip around the Moon as part of the initial test flight for the Artemis 1 mission. It will mark the beginning of one of the most talked-about space programs this year, Artemis, an ongoing government-funded crewed spaceflight initiative with the goal of landing the first woman and the next man on the Moon by 2024, particularly, on the lunar south pole region. The most powerful rockets ever built, the SLS is in turn powered by four super engines that are designed to handle some of the most extreme temperatures as they move massive amounts of propellants to generate enough energy for the rocket to escape Earth’s gravity.

As part of a years-long working relationship with NASA, Aerojet Rocketdyne of Sacramento, California, will be building a total of 24 RS-25 rocket engines to support as many as six SLS flights for a total contract value of almost $3.5 billion. Originally slated to produce six new RS-25 engines, the company has recently been awarded a $1.79 billion contract modification to build 18 additional RS-25 rocket engines to support future deep space exploration missions.

“This contract allows NASA to work with Aerojet Rocketdyne to build the rocket engines needed for future missions,” said John Honeycutt, the SLS program manager at NASA’s Marshall Space Flight Center in Huntsville, Alabama. “The same reliable engines that launched more than 100 space shuttle missions have been modified to be even more powerful to launch the next astronauts who will set foot on the lunar surface during the Artemis missions.”

Although the Space Shuttle Endeavour is now at a museum exhibit at the California Science Center in Los Angeles, its engines—along with those that used to power space shuttles Discovery and Atlantis—have been maintained for SLS. However, unlike the shuttles, SLS will not reuse its engines. Once the core stage falls away at around eight minutes after launch, the engines will disintegrate during reentry. There are currently 16 RS-25 engines remaining from NASA’s Space Shuttle Program that Aerojet Rocketdyne has upgraded, tested, and that are ready to support the first four SLS missions. Yet, with more SLS missions expected to launch well into the end of the decade, Aerojet Rocketdyne has been asked to build more engines; actually, six new expendable RS-25 engines are already being assembled using advanced manufacturing techniques, including 3D printing, that reduces both the cost and time for manufacturing each engine.

The additional 18 engines will continue to leverage supply chain optimization and the incorporation of additive manufacturing (AM) techniques that were already introduced in the initial SLS engine production.

Initial SLS Configuration, powered by RS-25 rocket engines (Credits: NASA)

Employing AM technology to reduce costs and improve the efficiency of its engines is among the top priorities of the aerospace and defense company. Aerojet Rocketdyne’s senior engineer on the Additive Manufacturing team, Alan Fung, told 3DPrint.com that hundreds of people have been working on the design, development, and manufacture of the engines which relies mainly on laser powder bed fusion technology to additively manufacture at least 35 parts on each engine. 

“Our primary focus is to make reliable, robust printed parts, that will work 100 percent of the time. We started designing some of these pieces a couple of years ago to make sure they were tested and certified for NASA’s space program, which is crucial to the safety of the upcoming crewed missions,” said Fung. 

AM Team at Aerojet Rocketdyne, from left to right: Bryan Webb, Ivan Cazares, and Alan Fung (Credit: Aerojet Rocketdyne)

With the delivery of these new engines scheduled to begin in 2023, the team is not wasting any time. Fung said that “part of the big quest in the first round was to work with NASA closely on developing the certification processes.” Revealing that “we now have a process to make parts using AM that we know is safe and it is exactly what we need to make sure that our parts will work on the engines that will power future SLS missions.”

3D printing simplifies the production of several RS-25 parts and components, making the engine more affordable to produce while increasing reliability. With fewer part welds, the structural integrity of the engine increases. This is a very manual, complex manufacturing process. In fact, rocket engines are so complicated to build, that only a handful of countries have been able to manufacture them.

“That’s where AM really shined for us. We were able to get rid of many welding joints and just incorporate the processes automatically, getting down the part count and reducing the load across the engine,” said Fung.

One of the largest 3D-printed components of the engine was the critical “Pogo” accumulator assembly. Roughly the size of a beach ball, the complex piece of hardware acts as a shock absorber to reduce oscillations caused by propellants as they flow between the vehicle and the engine. Fung described the 3D-printed component as a critical part of the engine because it helps smooth the ride for astronauts and the vehicle ensuring a safe flight. Moreover, he explained that the Pogo used to demand more than 100 weld joints that had to be done manually and took almost four years to make, while the 3D-printed Pogo developed at Aerojet Rocketdyne’s factory in Los Angeles, brought the welds down to just three, and was finished in less than a year.

Some of these modified components have already been tested during engine tests that replicate the conditions of flight. For example, during a 400-second test at NASA’s Stennis Space Center, Aerojet Rocketdyne was able to successfully evaluate the performance of the 3D printed Pogo accumulator assembly.

“We expect that more and more engines will be additively manufactured in the future, leaving behind a lot of traditional rocket engine manufacturing processes that are very difficult, and allowing us to print more engines. Eventually, the time to build is going to go down even more, especially as the industry gears towards incorporating more lasers and bigger machines; which is good for us, because our engines keep getting a little bit bigger than the last ones. So, when those machines get to be bigger, use more lasers, and print parts faster, then that’s when we will see a really big shift in the way we make rocket engines,” went on Fung. 

Artemis I RS-25 Engines (Credits: Aerojet Rocketdyne)

Working with NASA, Aerojet has implemented a plan to reduce the cost of the engines by more than 30% on future production when compared to the versions that flew on the Space Shuttle, all thanks to more advanced manufacturing techniques, like AM, that help the engineers modify some of the rocket components.

During the flight, the four engines will provide the SLS with around two million pounds of thrust to send the heavy-lift rocket to space. The rocket engines are mounted at the base of a 212-foot-tall core stage, which holds more than 700,000 gallons of propellant and provides the flight computers that control the rocket’s flight.

The AM team at Aerojet is using GE Concept Laser and EOS machines for its selective laser melting requirements. Fung said they were using superalloys, mostly nickel-based for the engine parts being 3D printed, due to its outstanding corrosion resistance, high strength, and ability to resist hydrogen embrittlement due to the hydrogen fuels found in most of Aerojet Rocketdyne’s liquid propellant rocket engines.

“These new RS-25 engines are an upgrade from the Space Shuttle engines, which were already some of the most reliable engines made in history. Engineers spent 40 years making the shuttle engines as reliable, safe and high performance as possible; but with additive manufacturing we thought we could also try to get the cost down. This technology will revolutionize the way we build engines” 

With so many challenges ahead, having certified rocket engines to take the next lunar explorers to orbit feels like a stepping stone for the journey that lies ahead. After all, the SLS rocket is part of NASA’s backbone for deep space exploration and will prepare humans for long-duration space travel and the eventual journey to Mars.

Space Launch System (SLS) (Credits: NASA)

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Interview with Lockheed: “Orion Spacecraft Has 200 3D Printed Components”

In 2006, NASA selected Lockheed Martin to design, develop, and build Orion, set to embark on both manned and unmanned missions, it is the agency’s newest deep space exploration spaceship that will eventually carry astronauts from the Earth to the Moon, and back. As part of a plan to extend a sustained human presence beyond low Earth orbit (LEO), advance commerce and science in space, the Artemis program is the next step in human space exploration and a part of NASA’s broader Moon to Mars approach. In 2022, the Orion crew capsule is expected to take astronauts on a ride beyond LEO, to the Moon and back, and in five years it will transport the next people to a lunar orbital post.

NASA’s Orion spacecraft has been using additive manufacturing technologies exponentially. Lockheed Martin and NASA recently announced the completion of the Orion crew and service module being developed for the uncrewed Artemis I mission, which used 100 3D printed parts. While the spacecraft for the Artemis II mission has Lockheed developing close to 200 3D printed parts.

The Orion crew module for Exploration Mission 1 that will launch atop NASA’s Space Launch System rocket on its first uncrewed integrated flight (Image credit: NASA)

Last September, NASA, and Lockheed finalized a contract for the production and operations of six Orion spacecraft missions with an option to order up to 12 in total. The agency’s Orion Production and Operations Contract (OPOC) is an indefinite-delivery, indefinite-quantity (IDIQ) contract for NASA to issue both cost-plus-incentive-fee and firm-fixed-price orders. Initially, NASA has ordered three Orion spacecraft for Artemis missions III through V for $2.7 billion. Then in 2022, the agency plans to order three additional Orion spacecraft for Artemis missions VI through VIII for $1.9 billion. Up to six additional Orion spacecraft may be ordered under the IDIQ contract through 2030, leveraging spacecraft production cost data from the previous six missions to enable the lowest possible unit prices.

During an interview with Lockheed Martin Space’ specialists Brian Kaplun, Manager of the Additive Manufacturing Lab, and Colin Sipe, Orion Crew Systems Senior Manager, 3DPrint.com delved into the makings of America’s next spacecraft for a new generation of explorers.

How has additive manufacturing helped in the creation of more efficient spacecraft?

“One of the tenants of advanced manufacturing is to increase the cost and the schedule efficiency for any of our platforms, including Orion, and doing so in a way that, at the very least, maintains parity from a technical perspective but in many cases enhances that. So a lot of the work we’ve done with Orion was targeted to allow for a more efficiently reusable, cost-competitive and faster time to delivery spacecraft that will have a better technical performance. For example our docking hatch covers were printed in a cost and schedule effective manner; additionally, thanks to a new ESD compliant polymer (a type of no-static plastic) we provided more technical performance as well,” suggested Kaplun. “AM is one tool in the advance manufacturing toolbox that really allows us to hit all three of those valuable points. The plan is to continue creating AM components that we already utilized and look at increasing the number.”

While Colin Sipe explained that “we do a lot of parts that would be traditionally difficult to produce, such as structural components and brackets, different parts to channel airflow, or fuel containers, like hydrogen fuel tanks. Moreover, on the seats that the astronauts will use on Orion, we 3D printed different spacers (parts that go between the edge of the seat and the hip of the astronaut) and those come in various sizes based on the astronaut using it. We have to be able to accommodate from 1 to 99th percentile of the average American size individual.”

Do 3D printed parts withstand some of the harshest conditions in space?

“We fully qualify any of our spacecraft and platforms, and it is a qualification born of many years of doing this. On 2011 we launched the first-ever 3D printed part going to outer space on our Juno mission and right now those parts are orbiting the gas giant. So just as rigorous as we did in 2011, here in the last throes of 2019 we have to go through and really qualify any of the Orion parts. Even more so, with future manned missions, we are going to further stress those qualifications. Its a challenge that we are very experienced in and really believe we are up for,” claimed Kaplun. “Experience in any way, shape or form is going to be a competitive advantage for Lockheed.”

How do you choose the design for the 3D printed parts?

“We have produced many different parts for our customers that almost have an organic shape to them and so if you look at some of the new designs where you are optimizing for strength in terms of weight and producibility, you will observe that they mimic the bones in your arm like a very evolved and efficient method of support. If we look at some of the structural brackets that we have done, they almost have a tree or a skeletal structure look to them, that is a very unique mindset or would have been a unique mindset when we were looking at the substractive and traditional manufacturing. But now that people are being trained for AM, we notice that there are a lot more technically complex designs. Some of the ESD parts that we made for Orion would be virtually imposible ot make any other way,” revealed Kaplun. “Now, we are able to combine a large number of other parts into one piece and eliminate a lot of the fasteners and the weight that otherwise would have been a parasitic load, providing greater opportunities to put payloads and scienitic instruments onto our platforms.”

In what way does 3D printing drive down spacecraft costs?

“We try for a really ambitious cost reduction, aiming at 50%. Over the last year, we printed roughly 6,500 parts across our entire space division. Recently we even used AM technology to develop mockups for tests, such as the toilet that will be used on Orion, called the UWMS,” proposed Sipe. “We were concerned about one area of interference so we printed the entire mockup of the toilet and put it into the flight vehicle to verify that we could reach and access the bolts. The size of that toilet is probably two feet in diameter and three feet tall, so it was a very large piece to produce.”

How does Lockheed factor in sustainability when 3D printing its pieces?

Kaplun indicated that at Lockheed, engineers are “very proud of how sustainable our technology is. Our polymer builds can be recycled and reused if needed, the powder bed processes are extremely efficient and the industry as a whole is considered very sustainable and cost-efficient from a materials perspective. Some of the waste for our additive processes can be lower than five percent. When you compare that to some of the subtractive and traditional manufacturing applications, those numbers flip completely, producing 90% waste.” 

Would you be able to convey how many AM parts were used for Orion?

“We made 200 components for the Artemis II Orion spacecraft. While the Artemis I had over 100 printed pieces and the previous version had only four 3D printed parts. This reveals that only one spacecraft generation later, we were able to double the amount of 3D printed parts,” reported Sipe. 

A 3D printed titanium part for NASA’s Orion spacecraft (Image credit: Lockheed Martin)

What can we expect to see during the Artemis II mission scheduled for late 2020?

“Our next mission will launch Orion on a Space Launch System (SLS) rocket, which will be the largest rocket ever built as far as liftoff power. Next year we can expect an unmaned service module to travel to the lunar orbit where it will stay for a month, carry out significant checkouts of all of our modules and will be the first launch on the new rocket. Once it returns to Earth, we will recover it, take it apart, see what we can reuse, what we need to make some improvements on, and at the same time, we’ll be getting ready for our Artemis II mission, with the first astronauts flying on 2022. Then, Artemis III in 2024, will take astronauts to Gateway, a small space station in the lunar orbit, and from there to a human landing system that will put the first woman and next man on the Moon surface. This will be the first of many missions to the Moon’s south pole, where bases and moon mining will begin,” said Sipe.

Are there more engineers interested in AM technology applications?

According to Kaplun, there has been much interest in AM: “we are witnessing a lot of students and scholars contributing to the design space, coming into our engineering and production ranks with a lot of previous work in the field, with new ideas and new abilities to utilize the tools that we can now offer.” 

As an engineer, how do you change your mindset to produce something from a subtractive standpoint to an additive one?

“We are starting to corrupt the threshold as we are beginning to design parts that can only be made via the additive route, whereby in the past we would sort of take something that was designed for a normal conventional machine and then transition it to the additive world,” told Sipe. “Today we are generating designs that we know the only way they can be made is through AM. There are certain parts of the spacecraft that couldn’t be done with other technologies, such as hollow, organically grown on the printer parts that create new opportunities for us.” 

3D printed Orion docking hatch cover (Image credit: Lockheed Martin)

What 3D printing technologies are being used at Lockheed?

“We have a very large gamut of different types of technologies to make the 3D printed parts for Orion, the docking hedge covers were made on Stratasys FDM printers, but we also use a lot of metal powder bed technologies in various forms as well as different polymer technologies,” the experts proposed. 

3D printed Orion docking hatch cover made of PEKK thermoplastic (Image credit: Lockheed Martin)

So what lays ahead for the aerospace company?

“We just got into a long term production contract with NASA for the six upcoming spacecraft missions, so I believe it is our goal to make even more 3D printed parts for spacecraft. A big focus of the contract was to dramatically reduce per-vehicle costs and the major ways of doing that was by having reusable Orion crew modules and systems, using advanced manufacturing technologies, material and component bulk buys and an accelerated mission cadence. I consider that AM is a large part of reducing the cost and increasing the cadence of how often we fly,” enlightened Kaplun.

Both Kaplun and Sipe consider that the “Orion spacecraft is part of NASA’s backbone for deep space exploration.”

The completed Orion spacecraft crew module at the NASA Kennedy Space Center (Image credit: Lockheed Martin)

 

With work well underway on both the Artemis I and II rockets, with core stage assembly nearly complete at Michoud, Orion will leave Lockheed for testing at NASA’s Stennis Space Center near Bay St. Louis, in Mississippi.

Sipe concluded that: “In 1981, NASA wanted to move back into deep space so since 1981 we were flying the space shuttle, and physically could not go outside the Earth’s orbit, the Apollo was the last spacecraft that physically could leave the gravity of the Earth and move into deep space, and NASA had a desire for mankind to return. Orion is the only spacecraft development that is a true exploration class spacecraft. It’s not like any other, it has unique capabilities never before seen and even though the capsule is a heritage of the Apollo mission, its actually far superior.” 

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Lockheed Martin 3D Prints Large Titanium Domes for Satellite Fuel Tanks

Global security and aerospace company Lockheed Martin has made many significant contributions to its industry through the use of 3D printing, from propulsion tanks and spacecraft parts to missile components and fuel tanks. The company, which received three Edison Awards this year for ground-breaking innovations in autonomy, directed energy, and satellite technology, has been invested in the innovative technology for quite some time, and recently completed the largest 3D printed parts it’s ever created…so far.

In order to hold up under difficult launch conditions and decade-long missions in the zero gravity conditions of outer space, satellite fuel tanks need to be both lightweight and strong. Titanium is an obvious choice of material, but it can take over a year to acquire 4-foot-diameter, 4-inch-thick titanium forgings, which also increases the overall cost of the tank. Additionally, if traditional manufacturing methods are used to fabricate these forgings, over 80% of the material is wasted.

This infographic shows the scale of the 3D printed domes, their placement on the tank, and overall location within an LM 2100 satellite.

That’s why Lockheed Martin chose to employ 3D printing to create a record-setting, 46-inch-diameter titanium dome for its satellite fuel tanks.

“Our largest 3-D printed parts to date show we’re committed to a future where we produce satellites twice as fast and at half the cost. And we’re pushing forward for even better results,” Rick Ambrose, the Executive Vice President of Lockheed Martin Space, explained. “For example, we shaved off 87 percent of the schedule to build the domes, reducing the total delivery timeline from two years to three months.”

The new fuel tank for Lockheed Martin’s largest satellites have 3D printed domes integrated into the body to cap them off.

The tank is made up of a traditionally manufactured, variable-length titanium cylinder, which is capped by two 3D printed domes; these three pieces are then welded together to make up the final product. Technicians at Lockheed Martin’s Denver facility fabricate the domes using Electron Beam Additive Manufacturing (EBAM) technology on a large 3D printer.

By 3D printing the domes, there is no longer any material waste, and the titanium is available to use with no wait time, which lowers the delivery time of the satellite tank from two years to just three months. This in turn helps the company cut its satellite schedule and costs by 50%.

“We self-funded this design and qualification effort as an investment in helping our customers move faster and save costs. These tanks are part of a total transformation in the way we design and deliver space technology,” said Ambrose. “We’re making great strides in automation, virtual reality design and commonality across our satellite product line. Our customers want greater speed and value without sacrificing capability in orbit, and we’re answering the call.”

These 3D printed tank domes are far bigger in size for the company’s qualified 3D printing materials – previously, its largest part was an electronics enclosure for the Advanced Extremely High Frequency satellite program that was only the size of a toaster. That makes these domes, which are large enough to hold nearly 75 gallons of liquid, a pretty big leap.

A Lockheed Martin engineer inspects one of the 3D printed dome prototypes at the company’s space facility in Denver.

The final rounds of quality testing for the satellite fuel tank and its 3D printed domes were completed earlier this month, which finally ends a multi-year development program with the goal of successfully creating giant, high-pressure tanks to carry fuel on satellites. Lockheed Martin technicians and engineers spared nothing on their quest to ensure that the tanks would meet, and even exceed, the reliability and performance required by NASA, as even the tiniest of flaws or leaks could spell disaster for a satellite’s operations.

The structure of the vessel was “rigorously evaluated,” according to a release, and the company’s techs ran it through an entire suite of tests in order to demonstrate its repeatability and high tolerances. Lockheed Martin is now offering the large satellite fuel tank, complete with its two 3D printed domes, as one of the standard product options for its 2100 satellite buses.

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[Images: Lockheed Martin]