(Bloomberg) -- Relativity Space Inc. postponed the first test flight of its mostly 3D-printed rocket, the Terran 1, on Wednesday at the company’s launch site in Cape Canaveral, Florida. The company said it scrubbed the planned test mission, which it called “Good Luck, Have Fun,” because of issues with the rocket’s propellant.

Relativity’s launch had garnered significant attention because this would be the first-ever flight for the buzzy startup. Despite only testing the Terran 1 on the ground, executives are optimistic it will reach orbit on its first launch, something no commercial company has done before on a debut.

If successful, it would also be the first rocket that is almost entirely 3D printed to reach orbit, and the first to get there on methane-based fuel — innovations the company says could dramatically reduce production cost and boost the reusability of its future vehicles.

The company said in a tweet on Wednesday that temperature issues with the rocket’s propellant pushed it to scrub the launch. The next launch attempt is slated for Saturday afternoon.

Ahead of the scrubbed launch, Chief Executive Officer Tim Ellis, a former engineer at Blue Origin LLC who co-founded Relativity in 2016, was optimistic about Relativity’s ability to reach orbit. He said the company wants to prove its 3D-printed vehicle can handle Max Q — a moment during the first few minutes of flight when the rocket experiences the maximum amount of forces and stress.

The ground test “actually does technically prove it, and the engineering proves it,” Ellis said in an interview. “But I think doing it in flight is definitely a lot more visceral and a lot more exciting to the world to see.”

Without ever launching a rocket, the closely held company from Long Beach, California, has created some big hype. Relativity has raised at least $1.3 billion and was last valued at $4.2 billion in June 2021. It’s also secured various partnerships with NASA to use the agency’s facilities for engine testing. The company claims to have invented the world’s largest metal 3D printer to create its vehicles and says it’s already sold future Terran 1 trips, priced at roughly $12 million per flight. 

Relativity hopes to later scale its Terran 1 into the commercial workhorse Terran R, announced in 2021. That rocket would be able to carry as much as 20,000 kilograms, or 44,000 pounds, and is aimed at competing against other heavy hitters like SpaceX’s Falcon 9 rocket. Relativity has already signed a combined $1.7 billion in launch contracts for Terran R, Ellis said.

Terran 1 is capable of carrying as much as 1,250 kilograms to low Earth orbit, the company said.

Grand Ambitions

By 3D printing the majority of its rockets, Relativity says it can be more agile throughout the design process while cutting down on labor and the overall cost of making the vehicle.

85% of Terran 1 is 3D printed, according to the company. Nearly all of the visible parts are 3D printed, Ellis said, referring to the nose cone, the rocket body, the internal propellant tanks and the majority of its Aeon engines. The electrical circuits and computers, and movable parts like rubber seals, are not. 

Not everyone sees the need for creating a fully 3D-printed rocket. Peter Beck, the CEO of Rocket Lab USA Inc., has said there’s “zero sense” in making simple traditional structures for rockets with 3D printing.

“3D printing is incredible for highly complex parts, generally when multiple parts have been combined into one,” Beck said in a tweet last month. “This is when real savings are made.”

Ellis said Relativity’s goal is to eventually create a rocket that is 95% 3D-printed. 

As a nod to how far the company’s 3D printing technology has come, the rocket will be carrying Relativity’s first failed 3D printed part, from nearly six and a half years ago. “We actually found the part in a pelican case, dug it out from the factory, and I’ve been saving it the whole time,” Ellis said. “I thought that would be something very cool to send on the first rocket.”

A Methane Future

No rocket running on methane fuel has yet achieved orbit.

A Chinese company called LandSpace was poised to capture that title in December during its first test launch, but the launch failed. Other next-generation vehicles like Space Exploration Technologies Corp.’s Starship rocket and United Launch Alliance’s Vulcan use methane engines but have yet to launch to space. The question now is whether Relativity will actually be first to do so after Wednesday’s postponement.

Though methane is less efficient than the alternative hydrogen, meaning it requires more propellant to achieve the same amount of thrust, it’s become a popular rocket fuel choice because it doesn’t need to be as cold to operate, requiring less complex machinery. It’s also less prone to leakage, since hydrogen is a much smaller molecule.

“Hydrogen fuel rocket engines are like the Ferraris of the rocket engine,” said Martin Ross, an atmospheric scientist at the nonprofit Aerospace Corp. “They’re very complex, difficult to manufacture, difficult to reuse. But they’ve got great performance.”

Perhaps the biggest benefit of methane is that it burns more cleanly, producing less soot than another alternative fuel, kerosene. That means less waste during a launch, and less soot to clean out of an engine, making it easier to reuse again. That’s important for Relativity as it wants to make the Terran R fully reusable, with plans to land the vehicle propulsively after launch, as SpaceX does. The Terran 1 launch Wednesday is a non-reusable rocket.

“I think any serious rocket company that is really pursuing reuse is using [methane] at this point,” Ellis said.

Relativity and SpaceX have each said they want to build industrial bases on Mars, in part for the promise of creating methane fuel by breaking apart the Martian atmosphere into the necessary components. That way a rocket bound for the Red Planet doesn’t need to bring all of the fuel for the return journey home. Methane can also be more easily synthesized here on Earth than kerosene, Ross said.

“You have to pull it out of the ground and refine it to get rocket-grade kerosene,” Ross said. “But methane is so simple. You can make it in the laboratory and you can make it in a factory presumably with renewable electricity. So with methane we could be moving to a regime where rocket fuels are sustainable.”

Methane first needs to get a rocket to space. Ellis, while cautious, is optimistic about Relativity’s chances to reach orbit. “I think there’s a real shot that we do actually achieve that,” he said. “This is not a kind of prototype rocket or a development rocket; this is an honest-to-god orbital class rocket that could make it.”

(Updates with rescheduled launch date in fourth paragraph.)

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