Editing Project HARP (section)

=== Operations ===
The projectiles fired by the 16-inch HARP gun on Barbados belonged to a family of cylindrical, finned missiles called Martlets, named after the [[Martin (bird)|martin bird]] that appeared on the McGill University crest.<ref name=":12">{{Cite web|url=https://www.daviddarling.info/encyclopedia/H/HARP.html|title=HARP (High Altitude Research Project)|website=David Darling|access-date=February 11, 2020}}</ref><ref name=":13">{{Cite web|url=https://apgdiscovery.com/stories-from-apg/now-thats-a-big-gun/|title=Now that's a big gun!|last=Deutsch|first=Elliot|website=APG Discovery Center|access-date=February 11, 2020}}</ref> 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.<ref name=":5" /><ref name=":13" /> The [[Harry Diamond Laboratories]]<ref>{{Cite journal|last=Finger|first=Daniel|title=Telemetry for 250,000-G Gun Environment|url=https://repository.arizona.edu/bitstream/handle/10150/578489/ITC_1965_65-14-3.pdf?sequence=1&isAllowed=y|format=PDF|journal=International Telemetering Conference Proceedings|via=The University of Arizona University Libraries}}</ref> 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.<ref name=":10" /><ref name=":12" />

From late January to early February 1963, the 16-inch gun on Barbados conducted its first test series using the Martlet 1, the first of which flew for 145 seconds and reached an altitude of 26&nbsp;km. It was the first Martlet flight to feature a radio transmitter beacon that tracked the vehicle's flight. The second test series was conducted in April 1963 with the new Martlet 2 missiles, which set the world's new gun-launched altitude record of 92&nbsp;km. Around the same time, development for the Martlet 3A began in the spring, with test launches commencing in September.<ref name=":3" /><ref name=":10" /> By the end of 1963, approximately 20 Martlet 2 missiles were launched and regularly reached altitudes of 80&nbsp;km. From these tests, researchers obtained a significant amount of atmospheric data as well as the internal ballistics of the 16-inch gun and the flight performance of the Martlet 2, 3A, and 3B. Impressed with the HARP program's initial results, the U.S. Army agreed to provide $250,000 per year in funding.<ref name=":3" />

In 1964, the HARP gun on Barbados continued to primarily launch Martlet 2 missiles that carried a wide variety of payloads. Part of the reason was its low cost, since the firing of the Martlet 2 cost from $2500 to $3000 and took only half an hour to load.<ref name=":3" /><ref>{{Cite web|url=https://yarchive.net/space/project_harp.html|title=Re: Cannon Launch? (Very cheap access to space)|last=Dunn|first=Bruce|date=July 26, 1996|website=Usenet Archives|access-date=February 11, 2020}}</ref> 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.<ref name=":3" /><ref name=":8" /><ref name=":11" /> However, HARP funding reportedly faced several obstacles in the form of bureaucratic sabotage due to opposition in the Canadian government.<ref name=":3" /> The funding promised by the DDP for July 1, 1964, to June 30, 1965, did not arrive until May 1965. During this period, McGill University covered the funds to the best of its ability, although changes had to be made to the original plan. For each subsequent funding periods, the DDP repeatedly delayed HARP funding late into the fiscal year.<ref name=":11" />

The first attempts to improve the performance of the 16-inch gun at Barbados were made in 1964, primarily by increasing the barrel's length.<ref name=":3" /> In 1962, the Ballistic Research Laboratory increased the barrel length of a 5-inch gun system by welding a second section of barrel to the first barrel's muzzle, lengthening the barrel to 8.9 meters. The resulting gun system demonstrated a higher muzzle velocity at the muzzle exit. The longer barrel allowed the propellant gases to push on the projectile for a longer period of time.<ref name=":3" /><ref name=":6" /><ref name=":14">{{cite report|url=https://www.governmentattic.org/3docs/3DugwayReports_1953-1966.pdf|title=Review of the High Altitude Research Program (HARP)|last1=Murphy|first1=Charles|last2=Bull|first2=Gerald|date=July 1966|publisher=Ballistic Research Laboratory|id=AD645284|via=Government Attic}}</ref> 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.<ref name=":3" /><ref name=":9" /><ref name=":12" /><ref>{{Cite news|url=http://www.slate.com/blogs/atlas_obscura/2013/07/03/project_harp_a_giant_space_gun_in_barbados_is_now_abandoned.html|title=Abandoned Space Gun Rusting Away in the Barbados Jungle|date=July 3, 2013|work=Slate|access-date=February 11, 2020}}</ref>

By the end of 1965, Project HARP had fired more than one hundred missiles at heights over 80&nbsp;km high into the [[ionosphere]].<ref name=":5" /><ref name=":12" /> At this point, the project starting planning the launch of the Martlet 4, a projectile that used rocket jets that would ignite mid-flight to send the missile into orbit.<ref name=":5" /> For this endeavor, BRL designed the telemetry system that utilized [[Sun sensor]]s to determine the projectile's altitude. This telemetry system would serve as an early precursor to the U.S. Army's Aeroballistic Dynamic Fuze (DFuze).<ref>{{Cite journal|last1=Decker|first1=Ryan|last2=Yakimenko|first2=Oleg|last3=Hollis|first3=Michael|last4=Sweeney|first4=Patrick|date=May 2011|title=On the Development of the Artillery Flight Characterization Electronics Rescue Kit|url=https://calhoun.nps.edu/bitstream/handle/10945/45465/Decker_Artillery_Flight_Characterization.pdf?sequence=1|format=PDF|journal=Proceedings of the 21st AIAA Aerodynamic Decelerator Systems Technology Conference|pages=2|via=Calhoun: The NPS Institutional Archive}}</ref>

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.<ref name=":3" /><ref name=":14" />

On November 18, 1966, the HARP gun operated by BRL at Yuma Proving Ground launched an 84-kg Martlet 2 missile at 2,100&nbsp;m/s, sending it briefly into space and setting a world altitude record of 179&nbsp;km. This feat has remained the world altitude record for any fired projectile.<ref name=":5" /><ref name=":12" /><ref>{{Cite news|last=Patel|first=Neel|url=https://www.inverse.com/article/16735-a-history-of-space-guns-from-isaac-newton-to-nazis-in-paris-and-project-harp|title=A History of Space Guns from Isaac Newton to Nazis in Paris and Project HARP|date=June 14, 2016|work=Inverse|access-date=February 11, 2020}}</ref>