Impulse Space Raises $308 Million Series D Extension, Pushing Total Round to $808 Million at $5.6 Billion Valuation

Impulse Space announced a $308 million extension to its Series D funding round on Wednesday, September 16, bringing the total raised in that round to $808 million, according to Reuters. The extension values the Redondo Beach, California company at $5.6 billion, a source close to the company told Reuters. That's a jump from the $4.26 billion valuation Impulse landed just three months ago, when it closed the original $500 million tranche of the Series D in June.

The company builds spacecraft designed to move satellites and other payloads once they've reached orbit, a business known as in-space mobility. Its products include the Mira maneuvering vehicle, the Helios high-energy kick stage, and the Caravan rideshare program, plus a newer electric propulsion line called Electra, according to a company statement distributed via GlobeNewswire.

Who's Writing the Checks

Existing investors returned for the extension, including 137 Ventures, BANNER VC, DFJ Growth, Linse Capital, Lux Capital, and Valor Equity Partners, per the GlobeNewswire release. Reuters reported that investor demand stayed strong even after the original round closed, prompting the company to go back for more.

"We looked at the plan and said, well, gosh, if we raise a little bit more, it'll give us confidence that even if a pessimistic scenario happens in the future, we can hire and be a little bit ahead of the plans from customers," Impulse President and COO Eric Romo told Reuters.

Romo said the extra capital will go mainly toward accelerated hiring and manufacturing. Impulse now has more than 600 employees and over 180 open roles, and it just hired Vizio veteran Adam Townsend as its first chief financial officer, according to both Reuters and the company's own announcement.

A Strong Fundraising Environment for Space Startups

Reuters ties the fundraising environment to broader investor enthusiasm for the space sector, which has made it easier for companies like Impulse to raise money at higher valuations.

Impulse was founded by Tom Mueller, who Reuters and GlobeNewswire both identify as SpaceX's first employee and its former chief propulsion engineer. Mueller called the fundraise part of "an exciting time to be in the business of space" in the company's statement, saying Impulse is "defining the infrastructure that powers our future beyond Earth."

Government Contracts Stacking Up

Beyond the venture money, Impulse has been landing federal defense work. Its Helios spacecraft was selected for the U.S. Space Force's National Security Space Launch Phase 3 Lane 1 contract, making it the first upper-stage prime contractor awarded a slot in that program, according to the company's release. Impulse also picked up a $28 million contract extension from Space Systems Command's Space Safari Office to support the VICTUS SALO 2 and VICTUS SALO 3 missions, building on earlier awards tied to its Mira spacecraft.

On the commercial side, Romo told Reuters that Impulse has sold out its Caravan 2 and Caravan 3 Helios rideshare missions planned for 2028, plus additional dedicated flights. "The market, I think, has surprised us, if anything, to the upside as far as the reception of that product," Romo said. "We're really full on our manifest for Helios. So now we need to deliver on that for those customers."