WASHINGTON — Impulse Space, which launched its first orbital transfer vehicle last year, has unveiled plans for a larger vehicle for transporting satellites to geostationary and other orbits.
The company, based in Redondo Beach, California, announced Jan. 17 it is working on Helios, a kick stage using an engine fueled by liquid oxygen and methane propellants. Helios can serve as a transfer stage for transporting satellites weighing up to about 5,000 kilograms from low Earth orbit to geostationary orbit in less than a day.
Tom Mueller, chief executive of Impulse Space and one of the founding employees of SpaceX, said Helios wants to extend the capabilities of vehicles like SpaceX’s Falcon 9 to higher orbits. “SpaceX really got the party started by opening up access to LEO,” he said in an interview. “What Impulse wants to do is what SpaceX did for LEO, but for everything else, all the other high-energy orbits.”
Helios would serve as an additional stage for the Falcon 9. “It’s sized to max out the capability of a Falcon 9,” transporting satellites to GEO in less than 24 hours. “It’s basically giving you two-thirds of the capability of a [Falcon] Heavy without having to throw away a core and for much less money.”
The stage will be powered by an engine called Deneb, producing 15,000 pounds-force of thrust. Mueller said the engine components have passed a preliminary design review, and the company is on track to begin engine tests in the summer.
The first flight of Helios is planned for early 2026, with initial plans to fly the vehicle four to six times a year. Impulse has a letter of intent with an undisclosed customer and positive conversations with other potential users, he said: “This is the right product at the right time.”
Martin Halliwell, former chief technology officer of satellite operator SES and an adviser to Impulse, said in a statement that the ability to get to GEO in hours, rather than weeks or months, “changes the mission value proposition significantly” for satellite customers, allowing their satellites to enter service faster while reducing radiation exposure and payload mass. “Helios will open new opportunities for MEO and GEO operators beyond today’s limited mission choice criteria,” he said.
Helios is designed to be compatible with a wide range of launch vehicles. “Any medium-sized vehicle that could carry this would greatly improve its performance,” Mueller said. “Even on a vehicle that has awesome performance, like Vulcan, this will increase its capabilities.”
Impulse sees Helios as complementary to Mira, a smaller transfer vehicle it launched for the first time last November on SpaceX’s Transporter-9 rideshare mission. That vehicle, flying a mission called LEO Expess-1, successfully deployed a cubesat and is testing its thrusters.
“Now we’re getting ready to do longer burns and some big orbital changes,” Mueller said. The vehicle already has performed one maneuver to avoid a close approach with what he described as a defunct cubesat.
He said the company plans to keep flying Mira, with a second LEO Express mission planned for October. The interest in Mira comes from both customers looking for some ability to modify their orbits as well as others interested in hosted payloads, such as qualifying components.
The company, with nearly 100 employees, raised $45 million in a Series A round in July 2023. Mueller said the company was now working on a Series B round to support work on Helios. “We’ll need just one more round to get to profitability with this vehicle and with the Mira business that we have,” he said.
