Advancing the Neutron Launch Program

Rocket Lab has reached a significant milestone in the development of its next-generation Neutron rocket. The aerospace company recently concluded a successful full-duration test of its proprietary Archimedes engine, bringing the vehicle closer to its anticipated debut.

While Rocket Lab maintains a steady cadence of launches with its Electron rocket, development of the larger, more powerful Neutron has been moving forward steadily behind the scenes. This latest test marks a crucial step in preparing the propulsion system for integration with the main vehicle.


Testing at NASA’s Stennis Space Center

The firing occurred at Rocket Lab's Archimedes Test Complex, located at NASA’s Stennis Space Center in Mississippi. During the test, the engine sustained a full-duration burn lasting nearly 5.5 minutes, effectively simulating the conditions and requirements of a real-world flight. The company heralded the success as a «critical preparation for Neutron's first flight.»


Performance and Design Innovations

The Neutron rocket is designed to compete in the heavy-lift market, utilizing eight Archimedes engines on its first stage to generate approximately 1.5 million pounds of thrust. The performance of these engines is comparable to the Merlin 1D engines used on the SpaceX Falcon 9. Much like the Falcon 9, Neutron is engineered for partial reusability, allowing the first stage to return to Earth for vertical landings.

The design of the second stage features several unique technical innovations:

  • The "Hungry Hippo" Fairing: Unlike traditional rockets that jettison fairings, Neutron features a clam-shell style opening system that remains attached to the vehicle.
  • Vacuum-Optimized Engines: A single Archimedes (AVac) engine powers the second stage. This variant is equipped with an extended nozzle, standing roughly 2.5 meters taller than its first-stage counterpart, to maximize efficiency in space.

During the recent ground-based test, engineers utilized a shorter, sea-level variant skirt on the AVac engine. This was done to prevent flow separation and structural instability that could occur if the full-length vacuum-optimized nozzle were fired in the dense atmosphere near the ground.


Looking Toward the Future

While the company initially targeted a 2025 launch for the Neutron, the timeline has shifted to the first half of 2026. This adjustment follows several developmental challenges, including a structural failure of a main stage tank during a pressure test at the Wallops, Virginia facility earlier this year.

Despite these setbacks, Rocket Lab CEO Peter Beck has remained steadfast in his commitment to prioritize technical readiness and safety over aggressive deadline chasing. The company remains focused on ensuring the vehicle is fully prepared before its maiden voyage to orbit.