Prime (rocket)

The Prime rocket is a future British light launch vehicle under development by Orbex. Its booster (first stage) is planned to be reusable.^[1][2] The rocket's diameter is 1.45 m (4 ft 9 in),^[3] and will use a non-toxic bi-propellant consisting of liquid oxygen and propane. First stage reuse is planned to be achieved by a combination of a parachute and four 'petals' which will fold out prior to atmospheric reentry to induce drag and passively reorient the vehicle.^[4] It will be capable of launching payloads up to 150 kilograms (330 lb) to a standard 500 km Sun-synchronous orbit (SSO).^[5][2]

Prime

Second stage engineering prototype of the Prime orbital rocket
Function	Small payloads to low Earth orbit
Manufacturer	Orbex
Country of origin	United Kingdom
Size
Height	19 m (62 ft)
Diameter	1.45 m (4 ft 9 in)
Mass	18,000 kg (40,000 lb)
Stages	2
Capacity
Payload to SSO (500 km or 310 mi)
Mass	180 kg (400 lb)
Associated rockets
Comparable	Shavit 2, Kaituozhe-1, Unha, Electron, Miura 5
Launch history
Status	Under development
Launch sites	SaxaVord Spaceport Sutherland spaceport (proposed) Azores spaceport (proposed)
First flight	2025 (planned)
First stage
Diameter	1.45 m (4 ft 9 in)
Powered by	6
Propellant	LOX / bioLPG
Second stage
Diameter	1.45 m (4 ft 9 in)
Powered by	1
Propellant	LOX / bioLPG

Propellants

One cited advantage of using propane is that it remains liquid at cryogenic temperatures, which enables a design where a central carbon-fibre tank of propane is surrounded by an outer tank of liquid oxygen, creating a light structural mass.^[5]

Flights

In 2022, the maiden flight of Prime was expected to occur in late 2025, subject to the availability of SaxaVord Spaceport and a Civil Aviation Authority launch licence,^[6] for Surrey Satellite Technology Ltd.^[7] As of 2025, the first flight is planned for early 2026.^[8] Orbex also announced it was chosen by nanosatellite company Astrocast to launch their communications satellites^[9][10][11] and by Italian in-orbit logistics company D-Orbit for two other launches.^[12]

See also

• European Launcher Challenge – Space launch vehicle development programme of the European Space Agency
• Other orbital launchers under development in Europe:
  • Ariane Next – Orbital recoverable launch vehicle of the European company ArianeGroup
  • Maia – French orbital reusable rocket of the company MaiaSpace
  • Miura 5 – European orbital recoverable rocket of the company PLD Space
  • Miura Next – European orbital recoverable rocket of the company PLD Space
  • RFA One – Space launch vehicle in development
  • Spectrum – Two-stage small launch vehicle