What if everything we thought we knew about building rockets was incorrect?
An ambitious young team of former SpaceX and Blue Origin employees is setting out to prove
Elon Musk and Jeff Bezos wrong by 3D printing a commercial, reusable rocket in under 60
days.
Will it all go up in smoke?
Or can Relativity Space’s bleeding-edge tech hand it’s investors a license to print
money?
Join us today for a sneak peek at the 3D printer that can build rockets.
New-minted rocket maker Relativity Space is in many ways your classic Californian startup.
It even started life in a Seattle WeWork space.
Co-founders Tim Ellis from Blue Origin and Jordan Noone from SpaceX, get this, hustled
their first half-million bucks by cold-emailing billionaire Mark Cuban with a message cheekily
headed ‘Space is sexy: 3D printing an entire rocket’.
Now based in – where else – Long Beach, the firm has steadily raised $1.3bn in venture
capital, and counts 30 Seconds To Mars lead singer Jared Leto among its most vocal backers.
The company’s big idea?
To upend 60 years of rocket-building orthodoxy by 3D printing rockets, and ultimately establishing
a 3D-printed rocket factory on the Martian surface.
So what’s the next step?
All being well, the company will launch its first 3D printed rocket, the Terran 1, early
next year.
After that they’ll build a medium-lift fully-reusable commercial rocket intended to rival SpaceX’s
workhorse Falcon 9, hopefully blasting into orbit by the middle of this decade.
To make that happen, the Relativity Space team is betting big on its fresh, high-concept
approach.
Traditional rocket builders all adhere to what might be termed a ‘subtractive’ design
philosophy.
That is to say, the likes of Elon Musk and NASA first order in great chunks of raw material,
like steel.
Then they cut and craft that material into the required forms for assembly.
There’s no denying it’s an effective way of building spacecraft.
It got mankind to the moon after all.
But is it still the best way, six decades on?
Relativity Space is developing an ‘additive’ approach, employing two distinct species of
3D printer to build – and, crucially, adapt and iterate – their own rocket components,
from the engines to the fairings.
A conventional, subtractive rocket builder – again, let’s say Elon Musk – has no
choice but to invest in expensive fixed tooling, hampering innovation and slowing his iteration
process.
But the team at Relativity can tweak and refine, say, the length of a nozzle or the girth of
a hose straightforwardly, to a superfine degree, using CAD software.
And do it again and again, every time they launch a prototype.
So how does it actually work?
Complex rocket parts, like the company’s in-house developed Aeon 1 engine, are created
in a printing process called ‘direct metal laser sintering’.
This involves fusing together particles of metal powder with a highly-focussed laser
beam, building elaborate mechanical structures layer by layer.
Instead of multiple expensive, complex, awkward-to-reconfigure mechanical tooling systems, the exact same
printer can be used to produce the engine’s combustion chamber, injector or nozzles.
The only difference between these parts, as far as the printer is concerned, is the software
instruction it’s given.
Over which Relativity engineers have complete proprietary control, and the power to tweak
endlessly based on experimental observations.
Soon, Relativity reckons, its engineers may even be able to print an entire rocket engine
in one go.
The other kind of printer made by the company is the enticingly named ‘Stargate’.
Stargate works on an entirely different principle, called ‘directed energy deposition’, and
is said to be the largest 3D metal printer in the world.
Whereas the sintering print, used on those Aeon engines, inevitably leads to wasted powder,
Stargate uses three buff robotic arms to lay sophisticated proprietary alloys exactly where
they’re needed.
Less metal – developed in-house by Relativity Space’s own metallurgy team – is wasted.
A powerful laser melts a blob of it, again building up the printed part, layer by layer.
Although less useful for the fiddly stuff, Stargate is great for big, simple components
like fuel tanks.
And while it does have limitations – those arms can only reach so far, and must never
collide with the printed structure – Relativity Space’s design philosophy means the printer
can reconfigure for different jobs fast.
So it could build a 3 metre wide pressure vessel one day, then a two metre tank the
next, without disruptive retooling.
Most excitingly, the printer can whip up single components almost ten metres tall – the
height limit in their million-square-foot ex-Boeing factory home.
What all this means in practice is a much simpler rocket design.
The Terran 1, set for launch early next year, has only 730 parts.
That’s around a 100 times fewer than a conventional rocket, and a long way off the 2.5 million
or so individual components that made up the Space Shuttle.
Conceptual Silicon Valley types in every way, Relativity Space is fond of saying this approach
reduces the ‘cognitive overhead’ involved in building modern spacecraft.
Cultivating an innovation friendly corporate climate is as important to Relativity Space
as nailing the rocket design itself.
As Zach Dunn, another former SpaceX alumnus put it in an interview:
‘We have our engineering offices literally like two steps from our engineering area,’
he said.
‘The ability to go from your computer and analysis tools, then go out and see the hardware,
means we have a super tight iteration loop’.
CEO Tim Ellis likes to boast his company will soon be able to make a working rocket, from
raw materials, in about 60 days.
‘And 60 days later,’ he enthuses,’we’ll be able to do a better version.’
So does it actually work?
Until Terran 1 launches it’s hard to say.
But Relativity is already testing engines quicker than regular rocket companies, who
usually take a year or more per iteration.
Relativity Space says it has tested five versions of the Aeon engine in just 14 months, firing
them 100 times.
The company has a permanent lease at Stennis Space Centre for firing, and has already poached
staff from Stennis, a widely-respected hub of rocket testing.
For a good illustration of how this additive approach is not only quicker, but straight-up
superior to conventional subtractive methods, let’s look at one rocket system in particular.
Most modern rocket engines reduce overheating through a technique known as ‘regenerative
cooling’.
To accomplish regenerative cooling, liquid fuel is pumped along narrow channels that
coil around the combustion chamber, drawing out excess heat.
Conventionally, to engineer this, thick pieces of copper are machine moulded then spun at
high speed by dedicated tools.
Another tool’s job is to mill intricate cooling channels on the outside of these structures,
before a sturdy outer bracket is brazed onto the outside of that structure with a fuel-inlet
manifold welded on
for good measure.
That’s a lot of joins, a lot of welds, and a lot of potential for errors to creep in.
On a Relativity Space Aeon engine, all those bits can be created in one step.
Better still, because it’s 3D printed, even more cooling channels can be incorporated
than the old-fashioned way, meaning the engine is ultimately safer and more efficient.
Reducing the number of tools required to do all this naturally shrinks the factory footprint,
meaning Relativity can cram even more productive space into their workshops.
Ultimately – after the launch of Terran 1, and later the Terran R, a 100% 3D printed,
216 foot high rocket the company hopes will go toe-to-toe with Falcon 9 – the ambition
is to transplant the whole enterprise to mars.
As Tim Ellis puts it, ‘We really see this factory as the prototype – in a potentially
crude but very important way – of what a Mars factory looks like.
‘Eventually we want to shrink the footprint of the factory, so the amount of tooling and
machines and things that you will need would go down to where you could just launch an
entire factory to Mars on one launch vehicle.’
Here’s hoping Relativity Space succeed.
Mars is a long way to go for the IT guy if the printer jams.
What do you think?
Is Relativity Space already making SpaceX look obsolete?
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