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#30. The SHARP cannon
#31. Nuclear spaceflight

(30a) The HARP Project and the Martlet

 HARP Gun (Photo by Peter
  Millman on front cover of
 Sky and Telescope)

    HARP, for High Altitude Research Project, was a study of the upper atmosphere by instruments shot from a cannon. The project was conducted in the 1960s by scientists of the McGill University in Montreal, who named their vehicle the "Martlet", an old name for the martin bird; the shield of the McGill University in Montreal displays three red martlets.

    The cannon which propelled the Martlet to the high atmosphere was the creation of Gerald Bull, a Canadian engineer who specialized in the design of cannon. From the US Navy Bull obtained two cannon of the type used by battleships, with a 16-inch (40 cm) caliber, and combined them end-to-end to create a single tube of nearly twice the length. The cannon was mounted on the island of Barbados and fired nearly vertically, over the ocean.

    To reduce air resistance, the 200-lb Martlet vehicle was given a smaller diameter than 16 inches, with wooden blocks filling the space between it and the barrel. Because the payload and attachments were about 10 times lighter than the regular 16-inch shell, the acceleration was much larger, about 25,000 g: electric circuits had to be encased in plastic to resist the great forces. The peak altitude was extended (by 4 miles), by pumping out most of the air in the gun barrel before the shot. When the cannon fired--its loud bang was heard all over Barbados--the airtight cover over the muzzle was blown away and the Martlet rose into the high atmosphere, to altitudes of 80-90 miles.

    Unfortunately, cannons are also instruments of war, and Bull's specialization ultimately led to his death. He was assassinated in March 1990 at his home in Brussels, Belgium, apparently by agents of Israel, who had learned that he was helping Iraq build a "super-cannon" to use against Israel (still formally in war with Iraq, though the two share no border), some 300 miles away. Eight pieces of the barrel of that gun, ordered by Iraq in Europe and labeled as chemical industry components, were intercepted in Britain a few weeks afterwards, and other parts were seized by customs officials in Greece and Turkey. Following the "Desert Storm" war of 1991, the allies discovered in Iraq the site of the cannon itself. It was still incomplete, and it pointed towards Israel.

The Paris Siege Gun

    An earlier "supercannon" was built by Germany in World War 1, to hit the French Capital Paris from behind the German front lines. Like Gerald Bull, the German designers started with a big cannon designed for a battleship, but then they inserted in it a narrower barrel, of caliber 210 mm or about 9". Its shells caused some damage in Paris and killed hundreds of people, but because they were relatively small, the gun's fire too inaccurate for military use and (because of its huge powder charge) its barrel wore out after less than 100 shots. For more details, see

    Officially the cannon was named for the German Kaiser (emperor). Now and then it is referred to as "Big Bertha"--in German "Dicke Bertha" (Fat ("thick") Bertha). Actually the cannon which soldiers unofficially called by that name (Bertha was the daughter of the armament manufacturer Krupp from whose factory both guns came) was a giant mortar, a short-range siege gun capable of hurling 420-mm shells weighing close to a ton.

Further reading:

"Big Gun on Barbados" by Peter M. Millman, Sky and Telescope, August 1966, p.64.

"Development of Gun Launched Vertical Probes for Upper Atmosphere Studies" by G. V. Bull, Canadian Aeronautics and Space Journal 10, p.236, 1964.

"The Development of Large Bore Gun Launched Rockets" by F. W. Eyre, Canadian Aeronautics and Space Journal 12, p. 143-149, 1966.

A review of the above two articles by Bruce Dunn.

"Bull's Eye--the assassination and life of supergun inventor Gerald Bull" by James Adams, 317 pp. , NY Times Books 1992.

Another book: "Arms and the Man" by William Lowther, Presidio Press 1991.

Article fromThe Magazine of Fantasy and Science Fiction

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Last updated: 9-24-2004