"In terms of orbital rockets, only NASA's space shuttle and SpaceX's Falcon 9 vehicles have demonstrated the capability of re-flying an engine. With Rutherford, Rocket Lab has now also flown a rocket engine that landed in the ocean for the first time."
https://arstechnica.com/space/2023/08/rocket-lab-joins-spacex-in-re-flying-a-rocket-engine-to-space/