3D-printed rocket engines are powering the commercial space age
3D printing technology is revolutionizing trial-and-error rocket development
Add rocket fuel
The key to fast engine development is to reduce the number of parts, which reduces the time it takes to assemble the engine and the disruption caused by supply chain delays. The easiest way to do this is to change manufacturing processes. Space companies are now moving away fromsubtractive manufacturing processes– which remove material to shape a part – toadditive manufacturing processesthat build up a part by adding material to it bit by bit.
That means 3D printing. Increasingly, engineers are favoring a process calledselective laser sinteringto 3D-print rocket engine parts in an additive process. It works by first laying down a layer of metal powder, before melting shapes into the powder with lasers. The metal binds where it’s melted, and remains powder where it’s not. Once the shape has cooled, another layer of powder is added, and the part is built uplayer by layer. For rocket engines, an Inconel copper super alloy powder is used, because it can withstand very high temperatures.
Selective laser sintering allows for multiple components to be printed in-house, as one unified part, in a matter of days. When an RUD occurs and the fault is found, engineers can create a fix using 3D modelling software, integrating highly complex parts into new rocket engines for test firing a few days later.
Using 3D printing also helps manufacturers reduce the weight of the complete rocket, as fewer nuts, bolts and welds are required to produce their complex structure. 3D printing is especially useful in manufacturing an engine’s complexregeneratively cooled nozzle, which routes cool fuel around the hot engine to simultaneously cool the engine walls and preheat the cold fuel before combustion.
A redesign of the Apollo F-1 engines using 3D printing reduced the number of partsfrom 5,600 to just 40. No company has yet to reduce this number down to one, but it’s undeniable that 3D printing has brought about a new age of fast, responsive rocket engine development.
Business viable
That matters for private space enterprises. Building a rocket isn’t cheap. Investors may get flighty as the RUD scrap heap begins to mount. Companies vying to launch payloads into space take a public relations knock whenever they’re forced to push back their launch schedules on account of faulty rockets.
Virtually all new rocket companies and space startups are adopting 3D metal-printing technology. It accelerates their development phase, helping them survive the crucial years before they manage to get anything into space. Of note areRocket Lab, which uses its 3D-printed engine to launch rockets from New Zealand, andRelativity Spacewhich is 3D printing its entire rocket. In the UK there’s,SkyroraandOrbex. The latter aims to launch a rocket using a 3D-printed engine as early as 2022.
It remains to be seen whether an entire rocket, including its engine, can be 3D-printed in once piece. But that’s clearly the direction of travel for an industry in which light-weight, complex, in-house manufacturing will define which payloads enter orbit – and which end up rapidly dissembling at an inopportune moment.
Article byOliver Hitchens, PhD Candidate, Department of Electrical and Electronic Engineering,University of Surrey
This article is republished fromThe Conversationunder a Creative Commons license. Read theoriginal article.
Story byThe Conversation
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