REDONDO BEACH — Impulse Space announced it has raised $500 million in a Series D funding round to accelerate development of its Helios spacecraft and expand its workforce. The company said the capital will support hiring and the advancement of new vehicles and services.

Impulse Space, founded five years ago by SpaceX veteran Tom Mueller, has raised more than $1 billion in total funding since its inception. The latest round was led by 137 Ventures and BANNER VC, with participation from Founders Fund, Lux Capital, and Linse Capital.

The company is developing Helios, a kick stage designed to fly atop a two-stage Falcon 9 rocket, with its debut expected in 2025 on a rideshare mission called “Caravan” that will deliver smaller spacecraft directly to geostationary orbit. The Caravan mission is fully booked, and Impulse Space plans to offer additional opportunities in 2028.

Following the Helios announcement, the company saw higher-than-anticipated demand from commercial customers. It also believes it can provide landing services in the “1-ton-class” to NASA for its Moon Base initiative, aligning with the agency’s “Phase 2” plans to deliver larger rovers and infrastructure for human habitation starting in 2029.

Eric Romo, president and chief operating officer of Impulse Space, said in a podcast interview, “It’s all happening now. And I think that’s going to continue, and the market’s going to continue to find exciting new things. No one was talking about data centers in space a year ago, right? And so who knows what we’re talking about this time next year.” He also said, “If you put a Helios on top of that same Falcon 9, and an optimized lander around it, you can get more like one or two tons. So you’re totally 10x-ing the amount of mass that you get off the same launch vehicle. Launch vehicles are a pretty expensive part of the whole thing, so you’re not quite 10x-ing a reduction in the cost of mass to the Moon, but it’s in that ballpark, and that’s where we think the sweet spot is.”

The company, based in Redondo Beach, California, has more than 500 employees and 200 open positions. It recently opened an office in Colorado to access aerospace talent. Impulse Space has flown three missions with its Mira spacecraft, first launched in 2023 with a propulsion system powered by nitrous oxide and ethane. Tom Mueller said, “Timing is everything,” in reference to the new funding round.

No independent assessment of Impulse Space’s claims was available.