Iteration vs Reusability – A Race to Mars

Contributions from: Louis Brasington, Intern

Interview with Tim Ellis, CEO of Relativity Space

Launching rockets has never been cheaper. Technological advances and new business models are shaking up the industry, and private investments are soaring. But while all eyes are on the ‘Falcon Heavy’ – currently being tested in Cape Canaveral – and SpaceX’s successful recovery of rockets, a few companies have chosen another path to drive down costs and improve the economics of space launch: 3D printing.

Companies like Rocket Lab and Relativity Space are aiming to disrupt traditional rocket manufacturing by setting up highly automated, flexible facilities using standardized additive manufacturing (AM) to accelerate production and slash costs. Iteration, rather than reusability, is the chosen panacea.

We spoke to Tim Ellis, Co-Founder of Relativity Space (which recently emerged from stealth mode), to get a better understanding of the value proposition of 3D printing for the space industry, and describe what has happened since the company’s launch.

Additive Manufacturing for Lightweight Designs

As we’ve covered in the December edition of CTG Insights, additive manufacturing – a process that creates a three-dimensional product by successively adding layers of material according to a digital design – has made rapid improvements in the past decade. While the early industrial deployment of the technology focused on rapid prototyping, trailblazers are now taking the technology to high value markets coalescing around the importance of lightweight design, specifically in the automotive and aerospace industries. It is no surprise then, to see similar applications for AM in the space sector.

As the printed object is created directly from a digital file, there are virtually no constraints to possible shapes and geometries, and designs can reach a degree of complexity unobtainable with subtractive manufacturing, with fewer parts and less material. In an industry where weight translates directly into fuel consumption, and every supplementary kilo adds thousands of dollars to the launch cost, 3D-printing in space could therefore provide significant savings.

While this manufacturing technique is no secret to the likes of SpaceX, Blue Origin or the United Launch Alliance – which entered a partnership with 3D printing heavyweight Stratasys last year – Rocket Lab and Relativity Space are taking the lead in making it the core case of their business models.

Rocket Lab’s Electron

In May 2017, Rocket Lab successfully launched its Electron rocket from New Zealand with an engine that was almost entirely 3D-printed. The US-based company, founded in 2007 by Peter Beck, raised a $75 million growth equity from investors such as Bessemer Venture Partners, Khosla Ventures and Data Collective just weeks before the successful launch. Contrary to the strategy of SpaceX,Vector Space Systems or PLD Space, rockets are not recovered, reused and refurbished, but instead are manufactured in high volumes, with the ultimate goal of making space more affordable through the frequency of launches.

The Stargate Printer

Relativity Space Facilities

Relativity Space, founded in 2015 by Tim Ellis and Jordan Noone (who have both worked on additive manufacturing at Blue Origin and SpaceX, respectively), is taking a different approach. Although no rocket has yet taken off, Relativity is hoping to push AM’s potential even further and to not only print the engine, but the entire rocket. The company has raised an initial $10 million Series A round in July 2016 from Social Capital, and received direct investments from the University of Southern California and Stanford University. Y Combinator and Mark Cuban are also both investors of the company.

As most 3D printers are focused on small-sized products (under 30cm3), size constraint remains one of the prevalent challenges of AM. To combat this, Relativity Space has developed an in-house 3D printer, fittingly named Stargate, to be able to produce something as big as a rocket. The printer is 18 feet tall, making it the largest metal 3D printer in the world – even larger than GE’s recently unveiled ATLAS laser-powder printer. Stargate uses three separate robotic printing arms steered by a custom control system that work collaboratively using laser deposition technology and capable of layering about eight inches’ worth of metal per second.

While most larger components are built using Stargate, the printer works in conjunction with off the shelf, smaller metal 3D printing technologies for certain vehicle components. Desktop Metal, GE, SLM, EOS and Concept Laser are suppliers are these types of systems. According to Tim, this effectively allows them to print everything from the ground up, excluding only electronics, circuit boards, silicon seals and similar parts that are unsuitable for AM.

Similar to what we’ve heard from other players, such as Carbon and GE Additive, Tim emphasized that one of the biggest opportunities for innovation lies on the material side – developing new composite materials and alloys with superior mechanical and chemical properties, which allow a stronger design and higher reliability. To this end, Relativity has built an in-house metallurgy and material characterization lab.

Terran 1

The Aeon 1 Engine

Relativity Space’s first rocket, Terran 1, is a 90-foot high, 7-foot wide system constructed from the company’s own printable metal alloy and designed for satellite constellation deployment and resupply. By reducing the number of components within the entire rocket from 100,000 seen in other rockets systems to around 1,000, Relativity Space is hoping for a low earth orbit (LEO) price per payload of $1100 per kg, at around $10 million per launch, according to Tim. This compares to around $164 million dollars ($20,000/kg of payload) for the United Launch Alliance’s rocket Atlas V, or $62 million ($2719/kg) for SpaceX’s Falcon 9.

The team of 14 is currently working through iterations of an important piece of the puzzle – the engine, Aeon 1. Traditionally the engine design is a highly complex task, designed for maximum precision due to the high pressures and speeds they work in. Any flaws in welding points can be catastrophic. Not only does 3D printing simplify this process, it also creates new opportunities for aerodynamic optimization, fluid flow, heat transport, leakage and so on. The oxygen and methane based propellant system will be fully 3D-printed and comprised of less than 100 components, compared to other current rocket engines, which have in the area of 2,500 separate components.

Space Race to Mars

According to Tim, once fully developed, the Stargate printer will be able to turn raw material into a flight-ready rocket in 60 days, compared to the current standard of 12-18 months. This shorter time to market is enabled by both the printing itself and the digitalization, automation, and customization of the entire production line. Having a fully autonomous and flexible additive factory means having an agile setup with exponential learning curve. Once the core infrastructure is fully functioning, any changes and improvements in the rocket design can be implemented almost instantly, through the simple uploading of a new digital file.

To quote Tim directly: “It is important to work from the ground up and get the basic principles in place, down to material choice. Customisability will be key in the rocket industry, and as more and more businesses come into the field in the future, we need to be able to adapt rapidly for progressive changes in rocket design and development.”

Reusable rockets are still in Relativity’s pipeline, but it isn’t a short-term goal for current systems. Iteration and agility, according to Tim, have to be the first steps.

With additive manufacturing already proving invaluable for design optimization and for driving down the weight and cost of rocket components, it is likely to create lasting opportunities in the space industry. Certainly, the simplification of rocket science is an attractive value proposition that will enable new businesses to gain cheaper access to space in a much shorter time frame. For now, SpaceX’s reusable rocket model largely dominates this sector, and with grants and contracts from the likes of NASA, it’s hard to see a change in direction anytime soon. There will ultimately be a point in the coming years, however, when reusability and reiterative design will cross paths and will open up far more opportunities than just the initial mars-shot idea, and serve our expansion towards an interplanetary society.