https://techcrunch.com/2020/11/24/complete-success-rocket-labs-booster-recovery-is-a-big-step-towards-reusability/

Rocket Lab has successfully recovered the first stage of an Electron launch vehicle after it made a controlled splashdown in the Atlantic, marking a major milestone in the company’s quest for a reusable rocket. CEO Peter Beck, speaking to press shortly after the operation, called the mission “a complete success” — and it raised $286,092 for charity to boot.

This was the first major test of Rocket Lab’s improved Electron, which has a modified interstage (above the first stage booster but below the second stage, which takes the payload into orbit) that allows the booster to make a controlled descent after detaching.