The Prince Albert Radar Laboratory (PARL) was a radar research facility operated by the Defence Research Telecommunications Establishment (DRTE), part of the Canadian Defence Research Board. Its primary purpose was to test long-range radio propagation and radar techniques in the presence of the aurora borealis. This was part of a greater ABM effort being carried out in concert with the United States Air Force, and PARL operated along with two similar instruments at the Rome Air Development Centre and MIT Lincoln Laboratory. The site continues to operate today, used as a satellite downlink station known as the Prince Albert Satellite Station (PASS).
Radar is a detection system that uses radio waves to determine the range, angle, or velocity of objects. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, weather formations, and terrain. A radar system consists of a transmitter producing electromagnetic waves in the radio or microwaves domain, a transmitting antenna, a receiving antenna and a receiver and processor to determine properties of the object(s). Radio waves from the transmitter reflect off the object and return to the receiver, giving information about the object's location and speed.
An anti-ballistic missile (ABM) is a surface-to-air missile designed to counter ballistic missiles. Ballistic missiles are used to deliver nuclear, chemical, biological, or conventional warheads in a ballistic flight trajectory. The term "anti-ballistic missile" is a generic term conveying a system designed to intercept and destroy any type of ballistic threat, however it is commonly used for systems specifically designed to counter intercontinental ballistic missiles (ICBMs).
The United States Air Force (USAF) is the aerial and space warfare service branch of the United States Armed Forces. It is one of the five branches of the United States Armed Forces, and one of the seven American uniformed services. Initially formed as a part of the United States Army on 1 August 1907, the USAF was established as a separate branch of the U.S. Armed Forces on 18 September 1947 with the passing of the National Security Act of 1947. It is the youngest branch of the U.S. Armed Forces, and the fourth in order of precedence. The USAF is the largest and most technologically advanced air force in the world. The Air Force articulates its core missions as air and space superiority, global integrated intelligence, surveillance, and reconnaissance, rapid global mobility, global strike, and command and control.
The original study that led to PARL came about as the side effect of questions about the effects of the aurora on radar systems. There was some concern that the aurora could shield incoming reentry vehicles from observation until they were too low to be effectively attacked by the long range interceptor missiles then being designed (Nike Zeus). The United States Air Force sent a request to Peter Forsyth for further information. Forsyth had done extensive research on the aurora while earning his PhD at the University of Saskatchewan, Saskatoon, including the first observations using radar.
Nike Zeus was an anti-ballistic missile (ABM) system developed by the US Army during the late 1950s and early 1960s that was designed to destroy incoming Soviet intercontinental ballistic missile warheads before they could hit their targets. It was designed by Bell Labs' Nike team, and was initially based on the earlier Nike Hercules anti-aircraft missile. The original, Zeus A, was designed to intercept warheads in the upper atmosphere, mounting a 25 kiloton W31 nuclear warhead. During development, the concept changed to protect a much larger area and intercept the warheads at higher altitudes. This required the missile to be greatly enlarged into the totally new design, Zeus B, given the tri-service identifier XLIM-49, mounting a 400 kiloton W50 warhead. In several successful tests, the B model proved itself able to intercept warheads, and even satellites.
The University of Saskatchewan is a Canadian public research university, founded on March 19, 1907, and located on the east side of the South Saskatchewan River in Saskatoon, Saskatchewan, Canada. An "Act to establish and incorporate a University for the Province of Saskatchewan" was passed by the provincial legislature in 1907. It established the provincial university on March 19, 1907 "for the purpose of providing facilities for higher education in all its branches and enabling all persons without regard to race, creed or religion to take the fullest advantage". The University of Saskatchewan is the largest education institution in the Canadian province of Saskatchewan. The University of Saskatchewan is one of Canada’s top research universities and is a member of the U15 Group of Canadian Research Universities.
Saskatoon is the largest city in the Canadian province of Saskatchewan. It straddles a bend in the South Saskatchewan River in the central region of the province. It is located along the Trans-Canada Yellowhead Highway, and has served as the cultural and economic hub of central Saskatchewan since it was founded in 1882 as a Temperance colony.
Forsyth was invited to a meeting at Rome, the outcome eventually led to an agreement whereby two radars would be sent to Canada, one would be placed in Churchill, Manitoba where the aurora is often at its maximum, while another would be located a distance away at a lower "grazing angle" in order to compare the returns from two different locations. Finding a suitable location was not difficult; they wanted a site near Saskatoon so travel from the University would not be onerous, but one that would have line-of-sight visibility of Churchill. [1] At first a site outside Dundurn was considered, but eventually Prince Albert was selected instead. This may have had a lot to do with Prince Albert being in the home riding of the Prime Minister, John Diefenbaker.
Churchill is a town in northern Manitoba, Canada, on the west shore of Hudson Bay, roughly 110 kilometres from the Manitoba–Nunavut border. It is most famous for the many polar bears that move toward the shore from inland in the autumn, leading to the nickname "Polar Bear Capital of the World" that has helped its growing tourism industry.
Prince Albert is the third-largest city in Saskatchewan, Canada, after Saskatoon and Regina. It is situated near the centre of the province on the banks of the North Saskatchewan River. The city is known as the "Gateway to the North" because it is the last major centre along the route to the resources of northern Saskatchewan. Prince Albert National Park is located 51 km (32 mi) north of the city and contains a huge wealth of lakes, forest, and wildlife. The city itself is located in a transition zone between the aspen parkland and boreal forest biomes. Prince Albert is bordered by the Rural Municipality of Prince Albert No. 461 and the Rural Municipality of Buckland No. 491.
John George Diefenbaker was the 13th prime minister of Canada, serving from June 21, 1957 to April 22, 1963. He was the only Progressive Conservative party leader after 1930 and before 1979 to lead the party to an election victory, doing so three times, although only once with a majority of seats in the House of Commons of Canada.
After a visit to Millstone Hill Observatory, where the Lincoln Lab was developing what would become the BMEWS radar, a suitable lab for the Prince Albert site was selected. The Millstone Hill site used a prefab steel building, but a Canadian equivalent was selected in its place, and construction on the "silo" for the radar started while the buildings arrived and were assembled.
The BMEWS radar operated on a frequency of 448 MHz with a peak design power of 2.5 MW and maximum average power of 100 kW. The output was fed via waveguide to an 84 foot parabolic reflector mounted on an altazimuth mount. It was equipped with a conical scanning feed, providing higher resolution and making automatic tracking easier. [2]
An altazimuth or alt-azimuth mount is a simple two-axis mount for supporting and rotating an instrument about two perpendicular axes – one vertical and the other horizontal. Rotation about the vertical axis varies the azimuth of the pointing direction of the instrument. Rotation about the horizontal axis varies the altitude of the pointing direction.
Conical scanning is a system used in early radar units to improve their accuracy, as well as making it easier to steer the antenna properly to point at a target. Conical scanning is similar in concept to the earlier lobe switching concept used on some of the earliest radars, and many examples of lobe switching sets were modified in the field to conical scanning during World War II, notably the German Würzburg radar. Antenna guidance can be made entirely automatic, as in the American SCR-584. Potential failure modes and susceptibility to deception jamming led to the replacement of conical scan systems with monopulse radar sets. They are still used by the Deep Space Network for maintaining communications links to space probes. The spin-stabilized Pioneer 10 and Pioneer 11 probes used onboard conical scanning maneuvers to track Earth in its orbit.
Limited operations started in 1959. The official opening was on June 6, 1959, by John Diefenbaker. For this event, a recorded message by U.S. President Dwight D. Eisenhower was to be broadcast from the Millstone Hill site, reflected off the Moon, and received at PARL. After some tense debugging prior to the attempt, the "trick" went off without a hitch. [3]
Dwight David "Ike" Eisenhower was an American army general and statesman who served as the 34th president of the United States from 1953 to 1961. During World War II, he was a five-star general in the United States Army and served as supreme commander of the Allied Expeditionary Forces in Europe. He was responsible for planning and supervising the invasion of North Africa in Operation Torch in 1942–43 and the successful invasion of France and Germany in 1944–45 from the Western Front.
The Moon, also known as Luna, is an astronomical body that orbits planet Earth and is Earth's only permanent natural satellite. It is the fifth-largest natural satellite in the Solar System, and the largest among planetary satellites relative to the size of the planet that it orbits. The Moon is after Jupiter's satellite Io the second-densest satellite in the Solar System among those whose densities are known.
The main purpose of the instrument was radar observation of the aurora, which started in January 1960 and were carried out for some time. Rockets fired from the Churchill Rocket Research Range, often Black Brants, were tracked by PARL at angles similar to those that the BMEWS radar would be tracking over-pole missile launches from its sites in Alaska and Greenland. PARL also tracked Arcas rockets fired from Cold Lake. In order to support this work, an experimental computer built at the DRTE in Ottawa, known only as the DRTE Computer, was adapted to create the Digital Analyzer and Recorder, or DAR.
The site was also used as a space radar system, starting a satellite tracking program in February 1960. The radar was used to track the decay of several satellites, including Sputnik 3, 4 and 5, Delta 2, and Epsilon 2. [2] Sputnik 4 was the first test of the Vostok spacecraft; after launch its orbital period was 91.27 minutes, but on May 19 the PARL staff noted that the period was 94.26 minutes and it had been joined by seven new objects. It is assumed this was due to an explosion. PARL also used the Echo 1 satellite in a repetition of the earlier Moon-bounce experiments.
After being operational only a short time, on January 31, 1961 a major fire broke out that destroyed the buildings. Contrary to the findings of the government, the "equivalent" building did not have nearly the same fireproofing as the US design, and the fire proved unstoppable. Some of the equipment was saved, and replacements forthcoming, and the radar was soon in operation again. DAR was one of the instruments lost in the 1961 fire, and a replacement had to be built, arriving in 1962.
PARL later served a number of roles. For some time it was the major Canadian ground receiving station for satellite communications, both for US satellites, and the Canadian Alouette 1. The DRTE Computer was used in this role too, calculating the path of the satellite over the PARL site, allowing the radar dish to be steered into the proper location to receive the signals from the quickly moving source. In 1968 the distance from the Algonquin Radio Observatory to the PARL site was measured to 2,143 km +/- 20 m. [4]
Today the Prince Albert Satellite Station is operated by Canada Centre for Remote Sensing a branch of Natural Resources Canada as a ground station for the following satellites: [5]
