On June 3, 2026, Impulse Space, the Redondo Beach, California-based leader in orbital transfer vehicles and in-space mobility, announced a massive $500 million Series D funding round. Co-led by 137 Ventures and BANNER VC, with participation from existing investors including Founders Fund and Linse Capital, the round values the company at $4.26 billion and brings its total capital raised to over $1 billion since its founding in 2021. The announcement was published on the company’s official updates page.
This latest infusion – following a $300 million Series C on June 3, 2025 that had already pushed the total to $525 million – underscores explosive investor confidence in Impulse’s technology, execution track record, and the surging demand for reliable, rapid, and affordable movement of satellites and payloads between orbits.
“We’re building more than spacecraft: we’re building the economic and technical engine that will power humanity’s expansion into space,” said founder and CEO Tom Mueller. “From Earth orbit to the Moon and beyond, the ability to move quickly, precisely, and affordably on orbit is the fundamental capability that will unlock a true space age.”
Impulse Space was founded in 2021 by Tom Mueller, widely regarded as one of the world’s foremost propulsion experts. As employee number one and former CTO of Propulsion at SpaceX, Mueller led development of the Merlin engines for Falcon 1, Falcon 9, and Falcon Heavy, as well as the Draco thrusters for Dragon – technologies that dramatically lowered the cost of access to space.
Having helped solve the “getting to space” problem, Mueller turned his attention to the next bottleneck: mobility within space. Satellites launched into low Earth orbit often need to reach higher orbits, perform precise station-keeping, deploy constellations, conduct responsive maneuvers, or support defense and scientific missions. Traditional approaches are slow, expensive, or inflexible. Impulse aims to change that with purpose-built orbital transfer vehicles, often called space tugs.
The company emphasizes vertical integration – designing, building, and testing the majority of its vehicles in-house (including proprietary engines like the Saiph and Deneb) – to ensure reliability, accelerate timelines, and control costs. Facilities span Redondo Beach headquarters, a Mojave test site, expanding operations in Boulder, Colorado, and a new Washington, D.C. office. More details are available on the company’s About page.
Impulse’s product lineup addresses different segments of the in-space mobility market.
Mira is the agile, high-thrust spacecraft for last-mile delivery, payload hosting, constellation deployment, and responsive maneuvers across low Earth orbit, medium Earth orbit, geostationary orbit, cislunar, and beyond. It offers up to 300 kg payload capacity with eight Saiph thrusters using non-toxic nitrous oxide and ethane bipropellant. Mira has demonstrated record-setting orbital maneuvers, autonomous rendezvous and proximity operations, collision avoidance, and precise payload deployment. The vehicle has completed three successful LEO Express missions and is flight-proven with a 12-month lead time. Full specifications and capabilities are detailed on the Mira vehicle page.
Helios is the high-energy kick stage for rapid, heavy-lift transfers from low Earth orbit to geostationary orbit, medium Earth orbit, cislunar, or beyond. It is designed for same-day or under-one-day delivery of large payloads using the restartable Deneb liquid oxygen and methane engine. Helios offers substantial payload volume and is compatible with a wide range of launch vehicles. The vehicle is in production, with first flight targeted for 2027 as part of the Caravan series. Details appear on the Helios vehicle page.
Impulse also offers a Rideshare and Caravan program for economical shared missions to geostationary orbit and other destinations, providing schedule reliability through dedicated or rideshare configurations.
Impulse has raised capital efficiently and at increasing scale as milestones were achieved:
- Seed round in 2022 supported initial development and first launches.
- Series A in 2023 enabled product development and scaling.
- Series B of $150 million in October 2024, led by Founders Fund, supported team growth, production ramp for Mira and Helios, and preparation for the first Helios flight.
- Series C of $300 million on June 3, 2025, led by Linse Capital with participation from DFJ Growth and returning investors, was a preemptive round driven by surging customer demand. Funds supported production scaling, hiring, facility expansion, and research and development into electric propulsion.
- Series D of $500 million on June 3, 2026, co-led by 137 Ventures and BANNER VC, brings total capital to over $1 billion. Primary uses include hiring up to 200 additional engineers and staff – the company has already more than doubled headcount in the past year – expanding manufacturing capacity, and scaling infrastructure to meet demand. More than 200 open roles exist in propulsion, avionics, autonomy, manufacturing, and operations.
Investor perspectives highlight the strategic importance. Justin Fishner-Wolfson, Managing Partner at 137 Ventures, noted that Tom Mueller helped transform access to space at SpaceX and is now tackling in-space mobility, which will define the next phase of the space economy. Adam Ramada, Managing Partner at BANNER VC, stated that as activity in orbit increases, in-space mobility becomes foundational and Impulse is building the infrastructure that enables the next layer of growth.
The full details of the Series D announcement are available on the company’s official updates page.
Impulse has flown three missions with Mira, executing record-setting orbit changes and complex in-space operations including autonomous rendezvous and proximity operations. The company holds hundreds of millions of dollars in customer contracts across commercial operators, the U.S. Space Force, NASA opportunities, and defense partners. Demand signals remain strong from both commercial satellite operators and national security priorities around space control and mobility.
President and COO Eric Romo emphasized that the new funding allows Impulse to scale without compromising quality and speed of execution while addressing exceptionally high demand for in-space mobility.
With the new capital, Impulse plans to accelerate production of Mira and Helios vehicles, advance electric propulsion technologies for extended missions, expand its operational footprint and team significantly, execute more complex missions including autonomous operations, and support national security priorities. Helios first flight remains scheduled for 2027.
The company has already demonstrated it can move fast: from founding in 2021 to multiple successful orbital missions, a robust backlog, and a clear roadmap from low Earth orbit agility to high-energy geostationary orbit and cislunar transfers.
As satellite deployments accelerate and the boundaries of the space economy push outward, the ability to maneuver reliably and affordably on orbit becomes foundational infrastructure. Impulse Space, backed by one of the strongest teams and investor syndicates in the industry and now capitalized at over $1 billion, is aggressively building that infrastructure. The $500 million Series D is a clear signal that the market believes in-space mobility is a critical enabler of the next era of space activity.
For the latest updates, visit the Impulse Space website. The careers page lists active hiring across engineering and operations roles.
