Announced on 1 March 2021, the vehicle is designed to be capable of delivering a payload of 13,000 kg (28,700 lb) to low Earth orbit in a partially reusable configuration,[3] and will focus on the growing megaconstellation satellite delivery market.

[4][6] On 2 December 2021, Rocket Lab unveiled a revised design for Neutron, featuring a tapered shape with a maximum diameter of 7 m (23 ft).

[3] Rocket Lab abandoned plans for landing Neutron on a floating platform, instead opting for a return-to-launch-site reusability profile.

[9][10] On 28 February 2022, Rocket Lab announced that Neutron will launch from the Mid-Atlantic Regional Spaceport (MARS) within NASA's Wallops Flight Facility on the eastern coast of Virginia.

[7] Test firing of Neutron's Archimedes engine occurred at NASA's Stennis Space Center in Hancock County, Mississippi.

Rocket Lab also intends the design to be able to support constellation deployment, deep space missions, and eventually human spaceflight.