Project HARP

right|thumb|HARP gun at its test site in [[Barbados (Coordinates: )]]

Project HARP, for high altitude research project, was a joint venture 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 and collecting upper atmospheric data for research. Unlike conventional space launching methods that rely on rockets, HARP instead used very large guns to fire projectiles into the atmosphere at extremely high speeds.

A HARP gun operated by the U.S. Army's Ballistic Research Laboratory (now called the U.S. Army Research Laboratory) at Yuma Proving Ground currently holds the world record for the highest altitude that a gun-fired projectile has achieved: , well above the Kármán line conventionally marking the beginning of outer space.

History

Preparations

Project HARP originated as the brainchild of Gerald Bull, a renowned but controversial ballistic engineer specializing in high-velocity guns and gun propulsion systems. In theory, a sabot would protect the payload during firing and later fall away as the satellite inside emerges.

During the late 1950s, Bull conducted preliminary launch experiments at the CARDE (now known as Defence Research and Development Canada – Valcartier, or DRDC Valcartier) using guns as small as 76mm. These experiments soon caught the attention of the U.S. Army's Ballistic Research Laboratory and the U.S. Army's Chief of Army Research and Development, Lieutenant general Arthur Trudeau. At the time, aircraft engineers needed more information on the atmosphere's upper regions to design better jet planes. However, launching rockets into the air to collect data was generally considered costly and inefficient.

In 1961, Bull resigned from CARDE and McGill University hired him as a professor. Working together with Donald Mordell, the university's Dean of Engineering, Bull moved forward with his space gun project and requested funding from various sources. He received a $200,000 loan from McGill University's board of governors. He was given a verbal promise for a $500,000 grant from the Canadian Department of Defence Production (CDDP), which was later reportedly denied due to bureaucratic opposition. In October 1961, Bull met with Charles Murphy, the head of the Ballistic Research Laboratory, to pitch his project for a supergun and was met with overwhelming support. The U.S. Army provided Bull with substantial financial backing and two 16-inch naval gun barrels complete with a land mount and surplus powder charges, a heavy-duty crane, and a $750,000 radar tracking system. economically.

Construction

In 1962, Bull and Mordell established a McGill University research station on Barbados (then still a British colony and part of the West Indies Federation) as HARP's main base of operations for its 16-inch super gun. The site location was first suggested by Mordell, who believed that a launch site closer to the equator would allow the projectile to procure extra velocity from the Earth's rotation to reach higher altitudes. In addition, the site's close proximity to the Atlantic Ocean made for the safe impact of re-entry projectiles. HARP reportedly received enthusiastic support from the Barbados government due to expectations that the island nation would become heavily involved in space exploration research. Hundreds of people from Barbados were employed to transport the two 140-ton gun tubes from the coast to the designated emplacement 2 miles from the beach using a temporary purpose-built railway. Inside the gun barrel, the Martlet was surrounded by a sabot. This machined wooden casing protected the projectile as it traveled through the barrel by absorbing the combustive energy and then splitting apart in the air after the Martlet exited the barrel. The Martlets also carried payloads of metallic chaff, chemical smoke, or meteorological balloons to gather atmospheric data as well as telemetry antennas for tracking the missile's flight. designed several telemetry systems used in the HARP program. The firing of these Martlet missiles was always accompanied by a huge explosion that shook the houses within close proximity, leading to cracks in several areas. Since the Barbados government refused to recognize householders' damage claims, HARP fell into ill favor by much of the Barbados population. The new results from HARP convinced the U.S. Army to increase the annual funding of the project from $250,000 to $1.5 million per year. By March 1964, Canada's Department of Defence Production (DDP) agreed to provide joint funding for the HARP program for a total of $3 million per year. In September 1964, a ten-calibers extension was added to the 16-inch gun based on BRL's experiment with the 5-inch gun. However, while increased velocity and altitude was recorded for test flights, the extension failed in December after the eleventh shot was fired. In 1965, a successful extension of the 16-inch gun was established after enlarging the gun pit to accommodate the equipment's large size. The extension almost doubled the length of the gun to 120 feet and weighed nearly 200 tons, making the 16-inch Barbados gun the largest operational artillery piece in the world at the time.

By the end of 1965, Project HARP had fired more than one hundred missiles at heights over 80 km high into the ionosphere.

By 1966, the HARP program had established several different launch sites around the United States and Canada, including a second 16-inch HARP gun at the Highwater Range in Quebec and a third 16-inch HARP gun at Yuma Proving Ground, Arizona.

Closure

thumb|Abandoned HARP gun in BarbadosThroughout 1966, the HARP program experienced a series of funding delays caused by immense opposition from critics in the Canadian government and growing bureaucratic pressures.

{| class="wikitable"

|+HARP Funding receipts by McGill University In addition to the High Altitude Research Laboratory at Barbados, a 16-inch HARP gun was constructed at the Highwater Range in Quebec and at Yuma Proving Ground in Arizona. Smooth-bore 5-inch and 7-inch guns were set up at several different test sites, including Fort Greely, Alaska, Wallops Island, Virginia, Aberdeen Proving Ground, Maryland, and White Sands Missile Range, New Mexico. The data collected from the projectiles fired from these gun systems were measured by radar chaff, aluminized balloons, trimethylaluminum trails, and sensors ranging from sun sensors to magnetometers. This initial design for the 5-inch HARP gun reached an altitude of 130,000 ft when tested in 1961. The 5-inch gun was deemed successful as a low-cost launch system, costing only around $300 to $500 per launch. The 7-inch HARP gun also incorporated the use of gun-boosted rockets to increase payload and altitude capacity. Unlike the 5-inch HARP guns, all vertical high-performance flights for the 7-inch HARP guns were conducted at NASA's Wallops Island facility, where 34 vehicles were launched by May 1966.

Highwater Range

The 16-inch HARP gun at Highwater Range was established in 1964 near McGill University to conduct flight tests and other general research on the HARP guns without traveling all the way to the launch site at Barbados. Although the Highwater 16-inch gun was only capable of horizontal test flights and could not be elevated higher than 10 degrees, it was frequently used to test new and experimental launch vehicles and gun systems under each gun loads and in free flight. The Highwater 16-inch gun was primarily used for missile-sabot structural integrity tests, charge development, rocket grain tests, and for testing vehicle performance inside the gun and during the critical muzzle exit. In 1965, the barrel of the Highwater 16-inch gun was extended to a length of 176 ft, holding the record for the longest big-bore artillery piece in the world.

{| class="wikitable sortable" style="text-align:right;"

|+Performance Test of Yuma 16-inch HARP gun in 1966

!Mass (lb)

!Muzzle velocity (ft/s)

!Apogee (thousands of feet)

!Apogee (kilometers)

|June 7

|001 (W)

|700

|3360

|No track

|June 8

|002 (W)

|800

|3190

|No track

|June 13

|003 (W)

|660

|4810

|No track

|June 13

|004

|760

|5930

|415

|126.5

|June 13

|005

|780

|5810

|398

|121.3

|June 14

|006

|780

|6060

|400

|121.92

|June 14

|007

|800

|6270

|Damaged

|June 15

|008

|760

|5630

|375

|114.3

|June 15

|009

|780

|5850

|410

|125

|Oct. 25

|010

|1095

|5250

|310

|94.5

|Oct. 26

|011

|1225

|5950

|410

|125

|Oct. 26

|012

|920

|6800

|540

|164.6

|Oct. 27

|013 (L)

|900

|7100

|No track

|Oct. 27

|014

|1275

|5900

|415

|126.5

|Oct. 27

|015

|920

|6780

|535

|163

|Oct. 27

|016

|950

|7040

|Damaged

|Nov. 16

|017

|1290

|5900

|396

|120.7

|Nov. 16

|018

|1292

|5900

|395

|120.4

|Nov. 16

|019

|1296

|5850

|415

|126.5

|Nov.17

|020

|1296

|5950

|415

|126.5

|Nov. 17

|021

|1290

|NA

|Damaged

|Nov. 18

|022

|1263

|5900

|400

|122

|Nov. 18

|023

|1263

|5850

|410

|125

|Nov. 18

|024

|922

|6650

|510

|155.5

|Nov. 18

|025

|880

|6400

|490

|150.3

|Nov. 19

|026

|910

|6650

|530

|131

|Nov. 19

|027

|1270

|5850

|400

|122

|Nov. 19

|028

|960

|7000

|590

|180

|Nov. 19

|029

|1270

|NA

|Damaged

|Nov. 19

|030

|960

|6350

|480

|146.3

|Nov. 19

|031

|1270

|5650

|367

|112

|Nov. 19

|032

|1270

|5650

|370

|113

|Nov. 19

|033

|880

|6750

|550

|167.6

Martlet projectiles

Several models of test projectiles were fired or designed during Project HARP: These projectiles were fired on the island of Barbados and some were fired by the US Army's Ballistic Research Lab.

Martlet 3B

The Martlet 3B was similar to the Martlet 3A but using steel casings and attempting to solve some of the 3A model's other problems. The casings survived , but the propellant failed at . This was solved for later rockets by filling the propellant cavity with liquid, but only after developing the 3B model had ended.

History

Preparations

Construction

Closure

Highwater Range

Martlet projectiles

Martlet 3B

Further reading

See also

References

External links