RKLB
A hot-fire, not a hot mess
Rocket Lab just checked a pretty important box for Neutron: its Archimedes Vacuum engine finished a full-duration burn on Monday. That's the kind of milestone that sounds nerdy until you remember rockets are basically very expensive coffee makers with trust issues.
The company says the vacuum variant will power Neutron's second stage, and it matters because the whole rocket depends on these pieces playing nicely together. AVac reportedly has about 1.2 times the thrust of the first-stage Archimedes engine, and it stands roughly 2.5 meters taller thanks to that long nozzle built for the vacuum of space. In other words: same family, different gym routine.
Why investors care
Neutron is Rocket Lab's shot at the medium-lift market, with plans to carry up to 13,000 kilograms to low Earth orbit and eventually land and reuse its first stage. If that sounds familiar, it's because the launch market has become a reusable-rocket cage match.
Rocket Lab had already pushed Neutron's debut to late 2026 after a propellant tank ruptured during a January pressure test. So this hot-fire test is more than a science fair ribbon; it's evidence the company is moving past the earlier setback and keeping the timeline alive.
The bigger launch race
Rocket Lab is trying to build momentum at a time when the competition already has a serious head start:
- SpaceX has logged more than 600 booster landings and is basically treating reusability like a subscription service.
- Blue Origin has been recovering boosters too, which means the bar for "launch company" is now closer to "rocket gymnast."
Rocket Lab also says its broader mission slate is still building credibility, including the fast-turnaround Victus Haze work for the U.S. Space Force. Big picture: the engine test doesn't guarantee a smooth Neutron debut, but it does keep Rocket Lab in the conversation—and in a sector where one bad test can turn into months of delay, that matters.