Rocket Lab Electron and Neutron: The Small-Sat Specialist Goes Big

Rocket Lab is the most successful small-satellite launch company in history. Its Electron rocket has flown more than 60 missions, making it the second-most-flown U.S.-made orbital rocket. Now Rocket Lab is scaling up with Neutron — a partially reusable medium-lift rocket aimed directly at the smaller end of the Falcon 9 market.

Electron specifications

Height

18 m (59 ft)

Diameter

1.2 m (4 ft)

Liftoff mass

13,000 kg fueled

First-stage engines

9 Rutherford (electric pump-fed)

Second-stage engine

1 Rutherford Vacuum

Payload to LEO

320 kg

Payload to SSO (500 km)

200 kg

Reusability

Partial (sea recovery)

The electric-pump Rutherford engine

Electron's Rutherford engines were the first electric-pump-fed engines to reach orbit. Instead of using a complex turbopump driven by combustion gas, Rutherford uses brushless DC motors and lithium-polymer batteries to feed propellants. The engines are also largely 3D-printed — Rocket Lab can produce a full Electron set in days.

Neutron — the medium-lift reusable

Height

43 m (141 ft)

Diameter

7 m (23 ft) at base

Engines

9 Archimedes (LOX/LCH₄)

Payload to LEO (reusable)

13,000 kg

Payload to LEO (expendable)

15,000 kg

Reusability

First stage returns to launch site

Neutron's defining feature is the integrated payload fairing — the "hungry hippo" — which opens like jaws to deploy the payload, then closes for first-stage reentry. The first stage stays attached to the fairing throughout flight; only the upper stage and the payload separate. Neutron flies its inaugural mission in 2026.

What Rocket Lab launches

• Commercial smallsats (radar imaging, IoT, weather)
• NASA CAPSTONE — sent to lunar orbit on a custom Photon upper stage
• NRO and DoD smallsat launches
• Constellation deployments for Synspective, BlackSky, and others