Skyrora XL
Dropping the Skylark prefix, Skyrora XL will be the company’s first orbital-class launcher and could yet become the first UK-built orbital-class rocket to be launched from UK soil.
While the various Skylark vehicles were each intended to inform the next in an iterative approach, the XL has been partially developed over the last eight years. “Because the vehicles have been delayed by a couple of years, the whole aim was that all the information we got back would affect any changes we would make, but we’ve had to take that on the chin and move forward”, Harris elaborates.
Render of the Skyrora XL in orbit (Credit: Skyrora)
The company released a video in 2020 showing a test of the 3.5 kilonewton third-stage vacuum engine — a reignitable pressure-fed engine with a specific impulse of 305 seconds. Harris recollects the team spending Christmas Eve in a container performing these engine restart tests.
The second stage’s Skyforce engine was then static fired in 2021 at Machrihanish, west of Glasgow, on the Scottish coast. This regeneratively cooled engine incorporates advanced turbopump technology and has a thrust in vacuum of 85 kilonewtons.
Skyrora XL measures 22.7 m in height and 2.2 m wide, and sits in size between two other European vehicles, which are also intended to launch from the SaxaVord site. It stands taller and wider than Orbex’s Prime launcher (19 m tall), while shorter but a little wider than Rocket Factory Augsburg’s RFA One (30 m tall). For a more familiar comparison, the vehicle is almost 20% taller and twice as wide as Rocket Lab’s Electron, similarly using carbon composites, sporting nine engines on its first stage, and offering a similar payload to orbit.
The vehicle can carry 315 kg into Sun-synchronous or polar orbits up to around 500 km altitude, according to Harris. “That will be the main workhorse for us when it comes to the demonstrator”, he notes, adding that the delays to Skylark L have pushed this from the last quarter of 2026 and into early 2027 now.
Illustration of the Skyrora XL launching. (Credit: Skyrora)
Fairings for the vehicle have been made and are currently undergoing testing, while the nine 3D-printed Skyforce engines for the first stage have almost completed their testing campaign. “We’ve got one or two tests on the last engine,” Harris adds, “and then some destructive and non-destructive testing on the first stage tanks. Then we can move into integration of those and head towards a first-stage static test.”
These engines have a combined thrust at sea-level of 70 kilonewtons and are arranged in a 3×3 grid pattern — a geometric layout which is also utilized on Spectrum’s first stage. “We’ve pushed them to that, and above by quite a bit, so we know what we’re quoting is actually under what they can hit”, adds Harris, “so we know we’ve got room to maneuver.”
A third kick-stage can act as a space tug, delivering small satellites to their destination orbits, from smaller payloads on potential rideshares to constellations. Skyrora has performed vacuum testing in the UK, restarting the engine at least 20 times, according to Harris. Scotland already builds more satellites than any other European country, and, with the likes of Spire, Clyde Space, and Alba Orbital on their doorstep, there are plenty of potential launch contracts to be won that could keep the company busy for many years.
Illustration of Skyrora XL’s second and upper stages in orbit. (Credit: Skyrora)
Future designs
The company has come far from the original team of five people in a small office roughly eight years ago. With a headcount of 85 now, plus a handful of contractors, Skyrora aims to rise to around 300 permanent staff once it has moved into commercial launches.
The company has been diversifying from the beginning and, with the UK an unexplored supply chain when it came to building rockets, developed its own SkyPrint 3D printer that can print an area as large as 2 m square.
A second head allows subtraction as well as addition. “We can actually machine and print on the same machine, which saves you [from] taking the part off”, Harris points out. “It’s one of the biggest in Europe, possibly in the world.” Like the container-based approach for the launch infrastructure, the printer was born from necessity, which has made the company stronger and more innovative, he adds.
Skyrora’s SkyPrint 3D Printer at work. (Credit: Skyrora)
A Skyforce-2 engine design is in the wings, which the propulsion team has been working on in the background. The turbo pump is already designed, and prototypes are ready for a series of iterations and testing.
Harris predicts it could be three to five years after the vehicle launches before the new designs might take flight. “The problem is, if you start to switch engines on the vehicle, you then need to apply for a new license, and no one really wants to wait for that long. That’s why you need XL to be running while you apply for those new engines on the vehicle.”
For now, Skylark L waits ready in Glasgow, as Skyrora considers its next move.
(Lead image: Illustration of the Skyrora XL and its launch tower. Credit: Skyrora)
