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Rocket Lab announces another delay for its medium-lift Neutron rocket
Rocket Lab announced the Neutron rocket in 2021, aiming for a first flight in 2024.
Rocket Lab announced Wednesday that its Neutron launch vehicle won’t fly until 2027, citing an issue discovered during manufacturing of the rocket’s carbon composite structures.
The announcement was public confirmation of what nearly everyone inside Rocket Lab and the wider space industry already knew. The most recent official update from Rocket Lab in August suggested the company still held hope of delivering the first Neutron rocket to its launch pad at Wallops Island, Virginia, before the end of this year, a schedule that would have almost certainly pushed the first flight into 2027.
But Rocket Lab’s statement Wednesday about Neutron’s schedule suggests the company is still struggling with manufacturing the rocket’s large booster stage. Neutron’s reusable first stage is made of carbon composite structures, which offer low weight, high strength, and corrosion resistance. But carbon composites in aerospace are generally harder to manufacture than metallic structures.
Peter Beck, Rocket Lab’s founder and CEO, identified a manufacturing defect as the reason for Neutron’s latest schedule slip. The problem lies in the dome sections at the ends of the rocket’s first stage propellant tanks.
“Recently, we identified an issue with the manufacturing process for the propellant domes specifically, and this caused us to delay production and investigate further,” Beck said in a video released by Rocket Lab.
Engineers discovered voids, or air pockets, between layers of carbon fiber that make up the domes’ composite structure. Carbon composite manufacturing involves laying down carbon fiber layers in a mold, then curing, or heating, the material to bind the fibers together. But this is a tricky process, especially for large structures that won’t fit into an autoclave, a high-pressure thermal curing chamber common in modern aerospace factories.
The Neutron rocket’s first stage is the “largest pressurized structure ever made out of carbon composite,” Beck said. “Because of its scale, we’ve had to develop new out-of-autoclave processes to build Neutron, and this includes custom cure cycles for the very large pieces, like the forward and aft domes for the propellant tanks on Stage One.”
Inspections revealed voids in a newly cured forward dome, defects that could affect the structure’s strength, durability, and reliability, Beck said. “They don’t necessarily mean that the dome would fail in flight, but our practice is to proceed only when we believe the system has the appropriate margins.”
Engineers traced the voids to a recent design change intended to strengthen the rocket’s structure. Rocket Lab introduced the design change after a Neutron propellant tank unexpectedly ruptured during a hydrostatic pressure test in January, a failure blamed on a manufacturing defect at a “critical join” in the tank.