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Rocket engines haven't changed fundamentally since the Apollo missions. Sassie and Andrew Duggleby, co-founders of Venus Aerospace, set out to change that paradigm by building an engine efficient enough to reshape what's possible in defense, space, and eventually commercial aviation. On top of that, they are building a modern advanced manufacturing company in the Era of AI.
“The idea of detonation-based propulsion isn't new; researchers have chased it for decades. What's new is the Venus Aerospace team in Houston who got it to fly,” said Mercury Fund Managing Partner, and Venus Aerospace Board Member, Blair Garrou. “The combination of innovation timing - specifically advances in additive manufacturing, Generative AI, and design software - with a world-class aerospace team who saw the problem through a fundamentally different lens, has created one of the most remarkable engineering advances in a generation.”
Here's their story, in their own words.
What were you doing right before you started this company, and what finally made you pull the trigger and go all in on this idea?
"We were working at Virgin Orbit, launching rockets off the wings of a 747. While we were there, Andrew got deployed to Japan for the Navy reserves. We were sitting on our balcony one night, talking about flying back for my grandmother's birthday. It's 13 hours to get back to the US, the jetlag is brutal, and that's when Andrew turned to me and said if the RDRE ever got proven out, we could put it on a plane and get home in an hour. I laughed at him. But we flew that engine last year.
By the time we got back to California, about a year and a half had passed. Andrew came home one day and said a university had proven the RDRE was more efficient than a standard liquid rocket engine. As soon as we got Virgin Orbit to its first demo launch, we quit our jobs to start Venus."
Tell us what you're building, what problem you're solving, and how you think about the market.
"We build rotating detonation rocket engines, RDREs, which use controlled detonation waves instead of traditional combustion to generate thrust. The result is a simpler engine that burns fuel faster and more efficiently.
Propulsion efficiency shapes what vehicles and systems can actually do. A more efficient engine means more speed, more range, more payload, more operational flexibility, without being boxed in by the tradeoffs that have defined legacy propulsion for decades.
The opportunity spans multiple domains. In defense, hypersonic munitions and drones represent a market of over $30 billion in 2026 alone, and it's growing fast. In space, our engine solves propulsion challenges across launch, orbital transfer vehicles, and landers, a combined $25 billion market in 2026 that keeps expanding. And in the medium term, we're positioned to power a $40 billion global market for supersonic commercial aviation. Our efficiency, our low cost of production, and our scalable design give us a real edge across all three."
Tell us a little bit about your fundraising process, and what you wish you knew going into fundraising that you know now.
"We closed our seed round in January 2021, when the market was red hot, and immediately raised extra capital. We spent the next year building, then closed our Series A. Then the market turned, and fundraising got hard for the next few years. But once we flew our engine last May, everything changed. Proving we could build and fly an RDRE told a different story than any pitch deck could."
What's the one thing you'd tell a founder who's about to raise their first round?
"Be very intentional about who you let lead your round and join your board. This is a long-term process. You want the right people at the table with you for the long haul."
What made Mercury Fund the right relationship for that stage?
"A world-class Houston-based fund backing a world-changing Houston-based company. It doesn't get much better than that. Once we got to really know Blair and the Mercury team, it's been a true joy."
If you weren't building this, what would you be doing instead?
Sassie: "Investing in and supporting other women deep tech founders and builders. There aren't enough of us."
Andrew: "Pursuing another PhD. Sassie already says I have enough, but I love learning."
What's something about you that would surprise people? What's one thing we wouldn't know about you by looking at your resume?
"We're both musicians. We both play the piano. Andrew even played as an accompanist in college and earned a scholarship for it."
Is there anything else about you or what you're building that we should know?
"We're proud of the technology we've built. But we're just as proud of the team and the culture we've built as a company."
Last May's flight test wasn't just a milestone for Venus, it was proof that a Houston-based team can out-build the legacy players in one of the hardest engineering problems in aerospace. We couldn't be more proud to back them.
