Who are Sassie Duggleby and Andrew Duggleby? Houston couple behind America's first rotating detonation rocket engine raised $91 million; what is their Mach 4 jet dream?

Houston-based startup Venus Aerospace announced a $91 million Series B funding round on July 8, 2026. The round was led by Mercury Fund, a Houston-based venture capital firm. Lockheed Martin Ventures also participated, alongside MESH, PEAK6, Draper Associates, Starboard Star Venture Capital, Green Sands Equity and other investors. The funding was aimed to help the company move its Rotating Detonation Rocket Engine (RDRE) from a successful flight demonstration towards a scalable, manufacturable propulsion system.

Venus co-founder Sassie Duggleby called the funding "an important step." According to Space.com, Duggleby said, "We are advancing that capability with American engineering and manufacturing talent to strengthen US defense, expand space access and support the future of high-speed flight." The investment followed its successful 2025 flight demonstration, which attracted interest from potential customers.

Who are the Houston couple behind the company?

Venus Aerospace was founded in 2020 by husband-and-wife team Sassie Duggleby and Andrew Duggleby. They established the company with an ambitious idea. It was to develop a new propulsion system that could make extremely fast passenger aircraft commercially viable.


They spent several years working on the technical challenge on making the engine withstand the extreme heat generated by rotating detonation.

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What is the couple's dream?

The company's original long-term ambition is to develop an aircraft called the Stargazer M4. The end goal is a reusable, hypersonic passenger aircraft built to cruise at Mach 4. At that speed, the aircraft could theoretically travel at around 4,900 kmph. Everything notably depends on altitude and atmospheric conditions.

Venus Aerospace has previously discussed the possibility of travelling between Los Angeles and Tokyo in around two hours.

The proposed aircraft would use the RDRE for initial acceleration after taking off from a runway. Once it reaches supersonic speeds, it would transition to a second propulsion system: a detonation-based ramjet.

The company has previously discussed conducting its first uncrewed Stargazer flight test in the early 2030s. However, the aircraft is still a development ambition. It has not entered commercial production or passenger service.