If you want to move through space fast you strap a rocket engine onto something. That’s exactly what we’re doing here.”
— Tom Mueller, Founder & CEO
The space economy needs to move: far, fast, and affordably. Our Helios spacecraft is designed to meet that need, providing same-day delivery to distant orbits for commercial, civil, and government missions.
Some of the most critical infrastructure in space, like communications and GPS satellites, are located in Medium Earth Orbit (MEO) and Geostationary Earth Orbit (GEO). For operators seeking to reach these orbits (or beyond), they have historically been faced with a combination of technical complexity, slow transportation, supply constraints, and steep cost. They can either:
- Take a heavy-lift rocket that can directly deliver their payloads to MEO or GEO — but for a hefty launch fee and limited launch availability. Or,
- Take a medium-lift rocket to a transfer orbit, then spend 6 to 9 months orbit raising, through a high-radiation environment, toward MEO or GEO with electric propulsion — saving on launch costs but delaying time to mission operations and exposing their spacecraft to risk.
Helios introduces a meaningfully better, third option.
The Kick Stage Unlocking the Orbital Economy
The Helios kick stage is a highly-customizable platform, capable of transporting dedicated, shared, Caravan rideshare, and other mission configurations to high-energy orbits.
Helios is a high-energy kick stage capable of taking up to 4,000 kg of payload from LEO to GEO in less than 24 hours. Flying as a payload on a medium-lift launch vehicle, Helios ignites its engine after deployment in LEO to carry satellites directly to their final orbit.
Designed to be launch vehicle agnostic, Helios expands the capability of any medium-lift launch vehicle it flies with — unlocking greater performance and enabling mission profiles that would otherwise require larger rockets or longer transit times.
The Most Efficient Hydrocarbon Engine Ever Designed
Deneb engine development underway at Impulse’s Mojave, CA test facilities.
At the center of Helios is Deneb: a powerful liquid-fed rocket engine purpose-built for high-energy missions. Deneb features:
- 67 kN (15,000 lbf) of vacuum thrust
- 380+ seconds Isp (specific impulse)
- Liquid oxygen and liquid methane propellants
- Ox-rich staged combustion cycle, for high efficiency
- Restart capability for multi-burn missions
End to end, our spacecraft and propulsion systems are purpose built to deliver fast, affordable in-space mobility.
Why Operators Choose Helios
Helios can be used across a wide range of commercial, civil, and government missions.
Time-Savings
Helios uses chemical propulsion to reduce a 6 to 9 month orbit raising process (via electric propulsion) to the span of a single workday. Reaching orbit sooner means gaining months of additional operational revenue for customers’ payloads and earlier mission starts.
Additionally, instead of waiting for limited heavy-lift opportunities, operators can launch Helios on higher-cadence medium-lift flights — unlocking reliable, frequent access to MEO, GEO and beyond.
Cost-Savings
Helios delivers heavy-lift performance at medium-lift cost, saving operators tens of millions of dollars in launch fees before the mission even leaves the ground. And, with Helios dramatically shortening the time to transit between orbits, operators can design for the destination rather than the journey — unlocking more economical satellite manufacturing by reducing the need for onboard propulsion, complex systems, and radiation hardening.
Flexible Mission Profiles
Helios delivers standardized capability across multiple mission configurations, including:
- Dedicated missions (single customer)
- Shared missions (primary and secondary customers)
- Caravan missions (Impulse-led dedicated rideshare program)
Flight Heritage
Many of the systems used on Helios build on technologies that have established flight heritage on our highly maneuverable Mira missions — including core avionics and star trackers. Leveraging proven systems is core to Impulse’s development model, allowing our team to execute quickly while maintaining reliability.
Expanding the Mission Envelope
Helios expands what spacecraft can do once they reach MEO and GEO. Operators can apply the onboard propellant and system resources that would otherwise be spent on orbit-raising to the real mission. This extends a satellite’s lifespan and capabilities on orbit. It also opens high-energy orbits to smaller satellites, lowering the barrier to entry for GEO missions.
Orbit-raising is also one of the riskiest phases of a mission. Reaching GEO requires traversing the radiation-heavy Van Allen Belts, where spacecraft can spend months exposed to conditions that degrade systems. By shortening that journey from months to hours, Helios reduces exposure and improves overall mission reliability.
The Team Enabling the Future of Space
Behind Helios is a team of deeply experienced engineers and mission operators working across vertically integrated facilities to design, build, and test spacecraft at speed. We move faster than the industry norm while maintaining high standards of reliability for our products. Helios is currently progressing well through integrated testing, as the team advances toward its first flights beginning in 2027.
Expanding access to high-energy orbits will unlock new missions, new markets, and entirely new possibilities in space — just as expanded access to LEO did before it.
Helios is designed to make that future possible.
Want to help unlock a true space age? Join our team.
