Project HARP

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Project HARP is not to be confused with the HAARP Project.

Project HARP, short for High Altitude Research Project, was a joint project of the United States Department of Defense and Canada's Department of National Defence created with the goal of studying ballistics of re-entry vehicles at low cost; whereas most such projects used expensive (and failure-prone) rockets, HARP used a very large gun to fire the models to high altitudes and speeds.

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[edit] Background

Started in 1961, it was created largely due to lobbying from Gerald Bull, a controversial but highly successful ballistics engineer who went on to head the project. Bull had developed the high-speed gun technique while working on anti-ballistic missile (ABM) research at CARDE in the 1950s, shooting models of high-speed interceptor missiles from guns as opposed to building supersonic wind tunnels, which would be much more expensive. The ABM project eventually ended without delivering a working system, but Bull was convinced the rocket systems he had developed had potential and started looking for other ways to use the technology.

HARP was such a development. The U.S. was in the process of testing newer ICBM systems and required repeated tests of newer re-entry vehicles. Bull suggested that the program could be run for considerably less money if the test vehicles were lofted from a large gun, as opposed to using rockets. This would also allow the test program to be greatly sped up, as repeated firing was easy to arrange in comparison to setting up rockets. The key concept was the use of an oversized gun firing an undersized vehicle mounted in a sabot, allowing it to be fired with relatively high acceleration. Test electronics were potted in a mix of sand and epoxy, proving more than capable of withstanding the rigors of launch.

The project was based on a flight range of the Seawell Airport in Barbados, from which shells were fired eastward toward the Atlantic Ocean. Using an old U.S. Navy 16 inch (406 mm) 50 caliber gun (20 m), later extended to 100 caliber (40 m), the team was able to fire a 180 kilogram slug at 3600 meters per second, reaching an altitude of 180 kilometers. The program was cancelled shortly after this. The politics of the Vietnam War (then in its fifth year) and soured Canada/U.S. relations played their role in the projects cancellation. The project received just over 10 million dollars during its lifetime.

Bull's ultimate goal was to fire a payload into space from a gun, and many have suggested that the ballistics study was offered up simply to gain funding. While the speed was not nearly enough to reach orbit (just 32% of Earth's 11.2 km/s escape velocity), it was a major achievement at much lower cost than most ballistic missile programs.

[edit] Project Babylon

Bull never gave up on the idea of building a gun-fired satellite, but was forced to turn to other work. Through the 1970s and 80s he developed a new artillery piece that dramatically outperformed anything in the world. His design, the GC 45, attracted wide attention. Looking for customers, Bull happily sold the gun to South Africa (then under the Apartheid system) and then to Iraq. He was arrested and jailed in the U.S. for the sales to South Africa, and left Canada after his release to take up residence in Brussels.

He then resumed work with Iraq, convincing them to build a new satellite launcher gun, Project Babylon. Saddam Hussein agreed to fund the project, but only if Bull helped with their efforts to re-design the re-entry vehicle of the SCUD missiles in order to improve range. Bull agreed, immediately making him an enemy of Israel, the intended target of the longer-range missiles. The March 1990 assassination of Bull (allegedly at the hands of the Mossad or the Iranian VEVAK intelligence agency) in his Brussels apartment, and the 1991 Gulf War ended the project partway through development.

[edit] Martlet projectiles

There were several models of test projectile fired or designed during Project HARP.

  • Martlet 1 - The first test projectile. 16 inch (40.6 cm) gun bore, projectile weighed 450 lb, was 6.6 inches in diameter and 70 inches long. Only four manufactured. Two were fired on Jan 21 and Feb 1, 1962.
  • Martlet 2 - Primary 16 inch test projectiles. Around 200 fired, of various weights and configurations. Most carried research payloads studying upper atmosphere and near space conditions. About half the weight of the typical Martlet 2 series projectile was in the pusher plate and centering sabot.
  • Martlet 2G - A more advanced projectile, which had nearly all of its total 160 kg weight in the projectile. The Martlet 2G utilized a sabot system very similar to modern antitank Kinetic energy penetrators.
  • Martlet 2G-1 - A proposed space launch vehicle variant of Martlet 2G, which had a solid rocket motor in the projectile. The followon 2G-2 would have had a second rocket motor and been able to place the second stage in orbit, though with little or no payload.
  • Martlet 3 - A series of more advanced rocket propelled projectiles in the HARP project.
  • Martlet 3A - Intended to be a 16 inch diameter, gun fired rocket projectile able to reach 500 km altitude. The rocket motors' solid propellant deformed during firing and the design was never successful, despite several test firings.
  • Martlet 3B - Similar to the Martlet 3A, using steel casings and attempting to solve some of the 3A model's problems. Unsuccessful.
  • Martlet 3D - This model was going to be a suborbital test rocket, using the first stage of the Martlet 4 solid rocket version. As Martlet 4 was never built, no Martlet 3Ds were produced either.
  • Martlet 3E - A suborbital solid rocket designed to be fired from a smaller, seven inch cannon used in the HARP project.
  • Martlet 4 - Two versions of full scale orbital launch vehicle projectiles were proposed in the Martlet 4 series. The first used three solid rocket motor stages and was planned to orbit about 50 pounds of payload. The second used liquid rocket motors and was planned to have orbited 200 pounds of payload. Both were about 28 feet long and 16 inches in diameter, weighing about 1,300 kilograms at launch. No Martlet 4 vehicles were built; the project halted before the design was completed.

[edit] Further reading

  • Gerald V. Bull, Charles H. Murphy, Paris Kanonen: The Paris Guns (Wilhelmgeschutze) and Project HARP, E. S. Mittler, Herford, 1988.

[edit] External links

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