As Relativity Space’s flight controllers at the Cape ran through their first real countdown in March 2023, the poll arrived at Isabel Sheff, the engineer responsible for stage one of the Terran 1 rocket.
“I was the person who gave the go call for flight,” Sheff said. “That I knew enough to say, ‘Yes, these engines are ready for flight,’ encompassed everything that I learned up until that point.”
The rocket got off the ground and into space before a second-stage anomaly ended the mission. It was still a major milestone for Relativity and for Sheff, a senior manager for engine systems and test, who helped build the 3D printed methalox Aeon engine for Terran 1.
Now, she’s leading (and hiring) the 20-person team developing engines for Relativity’s next-generation rocket, Terran R—a team that’s expected to double next year.
Fire away: Relativity is working its way through engine design ahead of qualification, with plans to ramp the production for flight-ready engines next year. “A lot of people are development people or production people,” Sheff said. “I really like the transition. It’s super fun to take an engine that you’re learning about—it’s not working, you make it work.”
As an engineer, Sheff is an optimizer—sometimes, she admits, too much in her personal life. But at work, that instinct is key: “I talk a ton of metrics for my team, and watching the number of days an engine spends on the test stand for an acceptance test kick down from, you know, double digits, our first engine, down to like, five days…that’s the most rewarding thing for me.”
Mentor master: Sheff credits mentors from early jobs for her quick rise in the industry. As an intern at Virgin Orbit, she recalled a senior engineer, Muaritz deRidder, who gave her a liquid propulsion textbook and let her quiz him about engine cycles each morning.
Now she tries to link up new employees with potential advisors and makes sure her own work when hiring and managing prioritizes a diverse workplace where people can grow.
“The impact that I want to leave on this industry is less about developing the best rocket engine there ever was, although I want to do that too, and more about making sure the industry is more diverse, more inclusive, and more equitable,” Sheff said.
