Encyclopedia Astronautica
HARP 7-2

HARP 7 & 5 in probes
From left to right: HARP 7-1, 7-2, 5-1, and 5-3.
HARP 7 inch Gun
Canadian earth atmosphere probe. Study 1961. The Harp 7-2 vehicle was an optimized version of the 7-1 vehicle. The 7-2 had a body diameter of 76 mm a length of 1410 mm a flight weight of 18.2 kg and a payload volume of 2048 cc.

The 7-2 prove was designed with a much-improved streamlined shape and exhibited far cleaner aerodynamics. The smaller 7-2 probe was capable of reaching altitudes of 105 km which allowed it to carry payloads through the D-layer and into the lower E-layer of the ionosphere - the very edge of space itself.

The 7-2 probe was used for a multitude of payloads including the standard ejectable chaff flown in the 5-1 probes. Of note was the 7-2 probe's ability to carry chemical payloads such as cesium nitrate, which was used to create artificial electron clouds, and to carry Langmuir probes with associated radio telemetry.

The 7 inch HARP gun system proved to be a valuable atmospheric research tool with some 60 operational flights over a 3 year period. Perhaps the least recognized gun system of the HARP program, the 7 inch HARP guns were poised to prove just how versatile and valuable a research tool they could have been when, in 1967, the HARP project abruptly ended leaving their true potential unfulfilled.

by Richard K Graf

Gross mass: 18 kg (40 lb).
Height: 1.41 m (4.62 ft).
Span: 0.18 m (0.58 ft).

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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...

Associated Launch Vehicles
  • 7 inch HARP Gun Canadian gun-launched sounding rocket. The highly successful 5 inch HARP gun had demonstrated the immense versatility of small portable gun systems for atmospheric exploration. The 7 inch HARP gun system represented the 5 inch system scaled up to the largest barrel size practical, while still remaining portable. More...

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

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