Delayed Again! Rocket Lab (RKLB.US) Neutron rocket's maiden flight postponed to 2027, after-hours stock price plunged more than 9%

According to Jinse Finance APP, Rocket Lab Corp. (RKLB.US) has once again postponed the maiden flight of its new heavy-lift rocket, Neutron, delaying its inaugural launch until 2027.

This marks the latest in a series of delays for the Neutron project. As the company approached the launch preparation stage, it discovered new issues in the manufacture of the rocket’s fuel tank, prompting this postponement.

“I’ve said before that we won’t take unnecessary risks by rushing to launch. Projects like Neutron are inherently challenging,” Rocket Lab CEO Peter Beck explained in a video addressing the latest delay. “Recently, we encountered such a problem, which has postponed Neutron’s first flight until next year.”

As a result of this news, Rocket Lab’s share price dropped by more than 9% in after-hours trading. Before Wednesday's announcement, its stock price had already fallen by about 15% so far this year.

It is understood that Rocket Lab had previously aimed to complete Neutron’s maiden flight by the end of 2026. However, in August, the company hinted that achieving a first launch this year would be quite challenging.

Rocket Lab’s current primary operational rocket is Electron, which focuses on launching small satellites into orbit. Neutron, on the other hand, is positioned as a significantly upgraded launch vehicle, capable of carrying heavier payloads and directly competing with SpaceX’s (SPCX.US) dominant Falcon 9 rocket.

Neutron has already seen multiple delays during its development cycle. When Rocket Lab first announced the rocket in 2021, the plan was for a maiden flight in 2024; however, this timeline was repeatedly pushed back—first to 2025, then to this year.

But 2026 has been a turbulent year for Neutron’s development. In January, a Neutron propellant tank ruptured during testing, with the company attributing the accident to defects from a third-party manufacturer. Afterward, the company switched to a completely new manufacturing process and made design changes, only to encounter a new issue: bubbles forming inside the tank’s dome.

Beck noted that the team has successfully replicated this fault and added new steps to the production process to prevent bubbles from forming again. However, troubleshooting and implementing the fix consumed substantial time, ultimately leading to the launch being postponed until next year.