Impulse Space raises $500M Series D at $4.26B valuation
What's the deal? Impulse Space, the orbital transfer vehicle startup founded by former SpaceXDealroom has a profile for this one. Try Dealroom → first employee Tom MuellerDealroom has a profile for this one. Try Dealroom →, has raised $500M in a Series D at a $4.26B valuation. The round was co-led by 137 Ventures and Banner VCDealroom has a profile for this one. Try Dealroom →, with participation from existing backers including Peter ThielDealroom has a profile for this one. Try Dealroom →'s Founders Fund, Lux Capital, and Linse CapitalDealroom has a profile for this one. Try Dealroom →. The deal brings Impulse's total funding to roughly $1B since its founding in 2021, just one year after a $300M Series C.
Mueller is the propulsion engineer who led development of the Merlin and Raptor engines that power every Falcon 9 and Starship flight. The company he founded after leaving SpaceX is now worth $4.26B on its own.
Why now? Rockets get satellites into space, but precise final-orbit placement is a separate, expensive problem. Most launch vehicles deposit payloads into a standard low Earth orbit or transfer orbit, leaving satellites to burn their own fuel to reach the destination — shortening their operational lifespan. Impulse builds vehicles that act as orbital taxis, deploying satellites, hosting payloads, and manoeuvring within orbits. Its Mira spacecraft has flown three missions, the most recent in November 2025. A larger vehicle, Helios, is under development to move heavier payloads from low Earth orbit to geostationary orbit and beyond; rideshare missions are planned for 2027.
Impulse is also working with AndurilDealroom has a profile for this one. Try Dealroom → on prototypes of space-based interceptors for the Trump administration's Golden Dome missile defence shield — a programme expected to generate tens of billions of dollars in procurement over the next decade. For a company already disclosing hundreds of millions in customer contracts, defence could become its largest revenue category.
The company now employs around 500 people with roughly 200 open roles, has more than doubled its headcount in the past year, and has opened new offices in Washington, DC, and Boulder, Colorado — the former signalling its growing engagement with government and defence customers. The $500M will fund team expansion, manufacturing capacity, and the development of mission-specific propulsion systems.
The signal: Impulse's $4.26B valuation reflects a broader bet that the space economy needs an infrastructure layer between launch and operations. With SpaceX dominating launch and constellations like Starlink, Amazon's Kuiper, and dozens of smaller operators building the applications, Impulse is targeting what sits between them — the logistics of moving hardware to the right place in orbit. The Founders Fund backing, the SpaceX pedigree, and a Golden Dome contract all point to a company investors see as essential infrastructure for both commercial and military space operations.
Read more: TNW
