Reusable rocket engines have become all the rage lately, even as NASA's continually delayed Artemis I mission attempts to launch with non-reusable technology. Realistically, the only way to significantly lower launch costs is to reuse the engines rather than build them from scratch every time. Another small start-up company, RocketLab, has successfully retested a rocket that has flown in space.

SpaceX famously has flown several of its Raptor engines into space multiple times already, making headlines along the way. But it's not the only company with ambitions for reusing its rockets. RocketLab, which makes a much smaller rocket called the Electron, has also been eyeing this milestone for a while now.

The company made headlines back in May when it made a spectacular show of catching its rocket stage out of the air with a helicopter.