UK rocket startup is on a mission to make satellite launches sustainable

“This funding round was about launching and taking the product into space,” Orbex CEO Chris Larmour tells IE in an interview. “It allows us to build the team by about a third, adding 50 people, and then we move to the operation of the vehicle late next year.”

The road to the rocket pad has included some ingenious engineering that will reduce carbon emissions dramatically and prevent the Orbex Prime from leaving space debris in orbit, all aided by Europe’s largest 3D printer, Larmour explains.

Bio-propane powers efficient, sustainable Orbex Prime

The Orbex Prime is a two-stage 62ft-tall (19m) rocket that will launch small satellite payloads of up to 396 lbs (180 kg) from Space Hub Sutherland, the UK’s first spaceport, located on the northern coast of Scotland.

While that’s fairly small compared to the likes of SpaceX’s 50,000 lbs (23,000 kg) payload capacity for Falcon 9, it’s not too far behind Rocket Lab’s 661 lb (300 kg) Electron. Unlike those two rockets, Larmour explains, Prime’s technology could be a vital step forward for sustainability within the rocket industry.

Orbex’s rocket will be reusable and fly using renewable, ultra-low-carbon bio-propane as a fuel. Last year, a University of Exeter study showed that the fuel and the rocket’s design would allow it to have a carbon footprint between 90 and 96 percent lower than that of similar launch systems. Rather than complicating the development process, Orbex says Prime’s environmental design goes hand in hand with the company’s ambition of building an efficient, commercially feasible small satellite launcher.

“The problem with small rockets is they're not very efficient,” Larmour says. “Mega rockets can contain more volume of fuel per unit of surface area than smaller rockets, so that's a core problem with smaller rockets. They're inefficient as a class, but that was the engineering challenge we set out to solve, and the way we did it was to pick a different fuel.”

Ultimately, Orbex picked propane, which is “quite overlooked” as a rocket propellant, Larmour says, because it allowed them to “make the rocket much more efficient”. SpaceX favors methane because it hopes to source the hydrocarbon from Mars’s atmosphere eventually and other rocket firms use a highly refined form of kerosene as a propellant. Propane, though, “has a unique physical property for a hydrocarbon,” Larmour explains. Namely, “it doesn't freeze when you chill it to the same temperature as liquid oxygen. And it's the only hydrocarbon that has that property.”

“So we can package the fuel and the liquid oxygen in a clever new way, which we’ve patented, in a system called coaxial tanks,” Larmour continues. The Orbex CEO compares the coaxial tank system to Russian dolls as it “uses tanks inside tanks”, meaning “the propane is actually embedded in a jacket of liquid oxygen.” That in itself has allowed Orbex “to cut about 30 percent of the mass of the vehicle and massively increase the efficiency of that small rocket just by choosing propane as the fuel,” Larmour says.

Cutting rocket carbon emissions before they reach global aviation levels

Orbex used bio-propane, in part, thanks to a fellow student who was also a housemate of Larmour’s while attending French business school INSEAD. By “complete coincidence”, Larmour says, he shared a house with Fulco van Lede, now the former CEO of SHV Energy, the “largest propane company on the planet”, according to Larmour.

Through van Lede’s guidance and their interest in climate change solutions, Larmour and his team found that merely using fossil propane gives you a carbon emission reduction of approximately 40 percent compared to other hydrocarbons such as kerosene or methane. “If you then use the bio variant of it, you reduce that by another 80 percent,” Larmour says. “So you get a 90% reduction on the carbon emissions of a fossil fuel rocket just by choosing bio propane.”

This reduction is vital, Larmour argues, given that “the emissions from space rockets over the next decade could be as high as the entire global aviation fleet because of black carbon.”

A June study, published in the Journal of Geophysical Research: Atmospheres, detailed how rockets release tons of black carbon molecules into the stratosphere. As rocket companies globally increase their launch cadence, an accumulation of black carbon could result in a warmer stratosphere and a thinner ozone layer, the study explained. Some scientists refer to this effect as the black umbrella since black carbon particles can stay in the atmosphere for roughly four years.

So “the biggest improvement [with Prime] is that propane burns clean and doesn’t produce black carbon,” Larmour explains. “Just solving that part of it was a massive win for us in the environmental solution equation.”

Europe’s largest 3D printer helps tackle space debris and reusability

Orbex’s sustainability philosophy runs through its entire operations, with Larmour stating that, after all the work that went into making Prime sustainable, they didn’t want “a spaceport that's going to blow that all out of the water” or a “recovery technology that's going to delete all those results and make it even worse.”

Space Hub Sutherland has publicly committed to the goal of being carbon-neutral during both its construction and its operational phases. As for the reusability technology, Orbex is yet to reveal much in the way of specifications, though Larmour says Prime’s first stage will be recovered after a controlled splash down in the ocean, using some as-yet-undisclosed technology. Meanwhile, the 330 lbs (150-kg) second stage will contain enough fuel and control mass to enable it to deorbit soon after payload deployment — preventing it from becoming space junk.

All this work is aided by an AMCM M4K 3D printer, the largest high-precision metal 3D printer in Europe. It is the only one currently operated by a European space company, and it allows Orbex to build “what we believe are currently the world's largest monobody rocket engines,” the company explains on its website.

Other companies, such as SpinLaunch and GreenLaunch, are also building revolutionary technologies to make small satellite launches more sustainable — the former aims to catapult payloads into space using a kinetic launch system, and the latter will literally shoot them out of a “space cannon”. However, those experimental technologies are likely some way off from going operational. Orbex, meanwhile, could launch to orbit for the first time next year, and it aims to start launching 12 times a year soon after.

How confident does Larmour feel ahead of launch? “I always say we’re targeting next year, but it’s the one date I might get wrong. It’s just the nature of the beast,” he says, adding that so many moving parts need to come together. “There’s no point in an on-time failure,” he says, adding, "we’ll be ready when we’re ready”.

It wouldn’t be a space company if the launch date weren’t moved back at least a few times before finally taking to the skies.