Rocket Lab conducts a launch simulation of its Neutron rocket from Launch Complex 3 at the Mid-Atlantic Regional Spaceport within NASA’s Wallops Flight Facility in Virginia. Image: Rocket Lab

Rocket Lab’s anticipated debut of its medium-lift Neutron rocket may end up slipping beyond this year and into 2027.

In a filing to the U.S. Securities and Exchange Commission (SES) ahead of is second quarter 2026 earnings call with investors on Tuesday, the company noted that it’s working through various qualification testing and made “significant milestones across the Neutron program.”

“Production of the Stage 1 tank is currently aligned with the target delivery of Neutron to the launch pad in Q4 2026,” the company wrote in its filing. “While the window for an end-of-year launch date is narrowing, we are balancing the schedule of the first launch with entering Neutron into service as a system ready for full-scale production and high-cadence launch beyond flight one.

“Exact launch timing will also depend on the outcome of first stage qualification and other critical tests occurring later in 2026.”