Encyclopedia Astronautica
Martlet 2G-1

Martlet 2G1
Martlet 2G-1 vehicle. Orbital 2G-2 would have added a second stage.
Canadian gun-launched orbital launch vehicle. The Martlet 2G-1 was the absolute minimum gun-launched satellite vehicle. Conceived when the HARP project was under threat, it was a seven-inch diameter, two-stage solid propellnat vehicle that would be sabot-launched from the HARP 16 inch gun. Its total payload in orbit would have been just two kilogrammes - ideal for today's planned nano-satellites. Unfortunately even this minimum orbital launch vehicle could not be demonstrated before the program was shut down.

During the last year of the HARP program, when it became clear that further funding was not forthcoming, and that the goals of the Martlet 4 program were not to be realised, full efforts were diverted to developing a Martlet 2G-1 orbital vehicle (GLO-1A). It was felt that if a satellite - any satellite, no matter now small - could be successfully gun-launched, that it then would be possible to encourage further funding, either public or private, which would permit the orbital goals of the HARP program to be realised. Unfortunately time and fate were against HARP and the project was closed down on June 30 1967, only a few months before an orbital 2G-1 could be flown.

LEO Payload: 2.00 kg (4.40 lb) to a 185 km orbit at 13.00 degrees.

Stage Data - Martlet 2G-1

  • Stage 0. 1 x HARP Gun. Gross Mass: 450 kg (990 lb). Empty Mass: 1.00 kg (2.20 lb). Thrust (vac): 127,000.000 kN (28,550,000 lbf). Isp: 365 sec. Burn time: 0.0100 sec. Isp(sl): 43 sec. Diameter: 0.42 m (1.37 ft). Span: 0.42 m (1.37 ft). Length: 36.59 m (120.04 ft). Propellants: Guncotton. No Engines: 1. Engine: 16 in gun. Status: Out of production. The HARP gun, a converted 16 inch naval gun, was used during the 1960's to launch the Martlet series of rocket-launched space probes. Using 450 kg of M8M propellant, with optimum web size, and a maximum muzzle pressure of 4100 atmospheres, the gun had the following performance:

    • 250 kg projectile accelerated at 13,000 peak G's to 2,300 m/s muzzle velocity
    • 500 kg projectile accelerated at 9,000 peak G's to 1,900 m/s muzzle velocity
    • 750 kg projectile accelerated at 6,500 peak G's to 1,680 m/s muzzle velocity
    • 1,000 kg projectile accelerated at 5,000 peak G's to 1,550 m/s muzzle velocity
    'Specific impulse' indicated here is effective specific impulse for a 750 kg projectile. Due to muzzle dynamics, value differs for other masses of projectile. Diameter and length are that for the gun bore.
  • Stage 1. 1 x Martlet 2G1-1. Gross Mass: 130 kg (280 lb). Empty Mass: 21 kg (46 lb). Diameter: 0.29 m (0.95 ft). Span: 0.45 m (1.47 ft). Length: 3.21 m (10.53 ft). Propellants: Solid. Status: Study 1963.
  • Stage 2. 1 x Martlet 2G1-2. Gross Mass: 41 kg (90 lb). Empty Mass: 7.00 kg (15.40 lb). Diameter: 0.29 m (0.95 ft). Span: 0.29 m (0.95 ft). Length: 0.53 m (1.73 ft). Propellants: Solid. Status: Study 1963.

Status: Development ended 1966.
Gross mass: 500 kg (1,100 lb).
Payload: 2.00 kg (4.40 lb).
Height: 4.29 m (14.07 ft).
Diameter: 0.30 m (0.98 ft).
Apogee: 185 km (114 mi).

More... - Chronology...

Associated Countries
See also
  • Gun-launched Artillery dominated military ballistics from the earliest use of gunpowder. In 1865 Jules Verne could only realistically consider a cannon for a moon launch in his influential novel. Even after the rocket established its primacy as a method of accessing space, Canadian Gerald Bull began a life-long struggle to use guns for cheap access to space. His successes could not generate funding to continue. Others since then have pursued the technology, convinced it was the only way for low-cost delivery of payloads to orbit. More...
  • Martlet In 1962-1967 Canada's Gerard Bull led development of the Martlet system for gun-launched access to space. The program was cancelled before the objective of gun launch to orbit was attained. More...

Associated Manufacturers and Agencies
  • Bull Canadian manufacturer of rockets, spacecraft, and rocket engines. Bull, Canada. More...

Associated Stages
  • HARP Gun Guncotton propellant rocket stage. Loaded/empty mass 450/1 kg. Thrust 127,000.00 kN. Vacuum specific impulse 365 seconds. The HARP gun, a converted 16 inch naval gun, was used during the 1960's to launch the Martlet series of rocket-launched space probes. More...

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