Rocket Lab Neutron Reusable Space Rocket Tests Continue to Challenge SpaceX's Falcon 9

During the month of May, the New Zealand-American company Rocket Lab continued the development of the reusable space rocket Neutron, which is currently scheduled for its debut launch at the end of 2026, although a further delay with the launch possibly at the beginning of 2027 is possible. Earlier in the month, some ignition tests of the Archimedes engines were conducted at NASA's Stennis Space Center.

According to reports, Rocket Lab pushed the engines to maximum power while also performing Thrust Vector Control maneuvers. Neutron will have 9 Archimedes throttles at the base of the first stage that operate with liquid methane and liquid oxygen. The second stage, on the other hand, uses a single Archimedes engine optimized for vacuum.

Another test session focused on stage separation. The company is validating the procedure that sees the second stage exit the fairings attached to the first stage via a test structure. Unlike other rockets, the second stage is more similar to an OTV (Orbital Transfer Vehicle) with no visible structures on the outside until the moment of separation.

Successful stage separation test campaign ✅ We're validating stage separation for Neutron, one of the most novel rocket separation systems ever designed. From sep system design, component testing and qualification, GSE design, manufacturing, commissioning, and operations Image

In the second half of May, some photographers observed test hardware related to Neutron built from composite material with noticeable cracks. This raised concerns about a structural issue and potential delays in the development program. However, Rocket Lab responded to these speculations by indicating that the interstage was first subjected to a load test equal to 125% of what the space rocket will actually experience during flight and subsequently taken to failure to gather further useful data.

According to the company, the design of the reusable space rocket Neutron has been correctly developed, with Rocket Lab already producing new hardware for tests, adding that "currently, no impact on the program is expected".

Neutron will not compete with SpaceX's Starship, but will rather be a competitor to the Falcon 9 (albeit with a completely different design) and similar space rockets. The dimensions will be 43 meters tall with a maximum width of 7 meters (and fairings of 5 meters). The rocket will be able to carry up to 13 tons to low Earth orbit (LEO) and will be partially reusable, considering that the second stage will need to be replaced with each launch, as is currently the case with the Falcon 9.