VIENNA, Austria – September 29, 2026 – Tumbleweed and the French rocket builder SIRIUS Space Services have signed a Memorandum of Understanding (MoU) to examine flying Tumbleweed’s Pod payload containers on SIRIUS launch vehicles. The first assessment targets S1B, SIRIUS’s suborbital ballistic demonstrator, with orbital missions on the wider SIRIUS launcher family to follow.
The two companies solve opposite halves of the same problem.
Tumbleweed takes away the certification barrier. Pod is a fault-isolated, pre-certified box that holds its contents at normal air pressure and room temperature, with built-in power, data, compute and sensing. The experiment inside never has to be qualified for spaceflight on its own, making access to microgravity 10x cheaper and 5x faster than the conventional route to space. The company’s first orbital mission, Oasis Alpha, launched in July 2026, carrying four customer payloads ranging from protein manufacturing to advanced materials research.
SIRIUS takes away the launch barrier, building a European family of reusable vehicles for small satellites.
Step one: assessing a flight on S1B
Sirius S1 Ballistic (S1B) is SIRIUS’s suborbital demonstrator, designed to validate key launcher technologies under real flight conditions and, on the way, to provide access to microgravity, something Europe is short of.
Under the MoU, Tumbleweed and SIRIUS will evaluate the technical compatibility of Tumbleweed’s Pod payload containers with the S1B mission, covering payload interfaces, operational constraints and the microgravity conditions the flight would offer researchers.
“Pod gives you zero gravity without worrying about how to get there, and that is the whole point of it,” said Guillaume Brault, CTO and Co-founder of Tumbleweed. “We take care of fitting it on to a launch vehicle, and making sure it works in flight. With S1B, we get a great opportunity to demonstrate our new generation of Pods, take more payloads to space, and build a collaboration with SIRIUS that could turn into many more flights.”
Step two: orbit
The second half of the agreement looks further out. As SIRIUS brings its launcher family online (SIRIUS-1, SIRIUS-13 and SIRIUS-15), the two companies will look at how Pods could reach orbit on those vehicles, and on what timelines.
“This agreement reflects the role we want SIRIUS to play in the European space ecosystem: providing a pathway from early suborbital missions and microgravity testing to future access to orbit. With Tumbleweed, we want to turn this first opportunity on S1B into concrete missions and build the foundations for future launch services on our orbital vehicles,” said Antoine Fourcade, CEO, SIRIUS Space Services.
What happens next
Work starts with the S1B compatibility assessment. Tumbleweed continues building Oasis Beta, the return-capable successor to Oasis Alpha, which flew in July 2026.
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About Tumbleweed
Tumbleweed makes access to space as easy as mailing a package. The company sells microgravity to researchers, manufacturers and R&D teams through Pod, a modular payload container that handles power, data and certification, and Oasis, the free-flying orbital platform that hosts Pods and returns them to Earth. Founded in 2024 and now counting a team of more than 20 experts across Vienna and Delft, Tumbleweed leverages rapid hardware development and transparent pricing to get commercial partners from idea to space faster than ever before.
More at: tumbleweed.com
About SIRIUS Space
Founded in 2020, SIRIUS Space Services develops launch solutions dedicated to small satellites, with the ambition of making access to space more sustainable and strengthening European sovereignty through competitive launch services.
Its family of reusable launch vehicles — SIRIUS-1, SIRIUS-13 and SIRIUS-15 — is designed to deploy satellites weighing up to 1,100 kg into Low Earth Orbit (SSO, 600 km).
SIRIUS Space Services is a two-time winner of the French France 2030 “Mini and Micro Launchers” call for projects.
More at: www.sirius-space.com