Sounding rocket
A sounding rocket or rocketsonde, sometimes called a research rocket or a suborbital rocket, is an instrument-carrying rocket designed to take measurements and perform scientific experiments during its sub-orbital flight. The rockets are often used to launch instruments from above the surface of the Earth, the altitude generally between weather balloons and satellites; the maximum altitude for balloons is about, and the minimum for satellites is approximately.
Due to their suborbital flight profile, sounding rockets are often much simpler than their counterparts built for orbital flight. Certain sounding rockets have an apogee between, such as the Black Brant X and XII. Sounding rockets may be flown to altitudes as high as to allow observing times of around 40 minutes to provide geophysical observations of the magnetosphere, ionosphere, thermosphere, and mesosphere.
Etymology
The origin of the term comes from nautical vocabulary to sound, which is to throw a weighted line from a ship into the water to measure the water's depth. The term itself has its etymological roots in the Romance languages word for probe, of which there are nouns like sonda and sonde and verbs like sondar, which means "to do a survey or a poll." Sounding in the rocket context is equivalent to "taking a measurement."Design
The basic elements of a modern sounding rocket are a solid-fuel rocket motor and a science payload. In certain sounding rockets, the payload may even be nothing more than a smoke trail as in the Nike Smoke, which is used to determine wind directions and strengths more accurately than may be determined by weather balloons. A sounding rocket, such as the Nike-Apache may deposit sodium clouds to observe very high altitude winds. Larger, higher altitude rockets have multiple stages to increase altitude and payload capability.A flight of a sounding rocket has several parts. During the boost phase, the rocket burns its fuel to accelerate upwards, nearly vertically. Once the motor burns all of its fuel, the rocket may fall away to allow the payload to coast along a ballistic trajectory. The path of the rocket in nearly parabolic, being influenced only by gravity and small wind resistance at high altitudes. The speed decreases near the highest point of the flight, the apogee, allowing the payload to linger around this point for a few minutes. Lastly, the rocket descends, sometimes deploying a drag source such as a small balloon or a parachute. The average flight time is less than 30 minutes; usually between 5 and 20 minutes.
Sounding rockets have used balloons, aeroplanes, and artillery as first stages. Project Farside used a rockoon composed of a balloon, lifting a four-stage rocket. Sparoair was launched in the air from Navy F4D and F-4 fighters. Sounding rockets can also be launched from artillery guns, such as Project HARP's guns, sometimes having additional rocket stages.
Development history
The earliest sounding rockets used liquid propellant, such as the WAC Corporal, Aerobee, and Viking. The German V-2 was used in both the US and the USSR immediately after World War II. Starting in the 1950s, inexpensive surplus military boosters such as those used by the Nike, Talos, Terrier, and Sparrow were used. Since the 1960s, most sounding rockets have been specifically designed for the purpose, such as the Black Brant.The earliest attempts at developing sounding rockets were in the Soviet Union. While all of the early rocket developers were concerned with developing the ability to launch rockets, some had the objective of investigating the atmosphere. The first All-Union Conference on the Study of the Stratosphere was held in Leningrad in 1934. The conference primarily dealt with balloon Radiosondes, however, there was a small group of rocket developers who sought to develop "recording rockets" to explore the upper atmosphere. Sergey Korolev, who later became the leading figure of the Soviet space program, gave a presentation in which he called for "the development of scientific instruments for high-altitude rockets to study the upper atmosphere."
V. V. Razumov, of the Leningrad Group for the Study of Jet Propulsion, had a specific interest in sounding rocket design. A. I. Polyarny, who worked in a special group within the Society for Assistance to the Defence, Aviation and Chemical Construction of the USSR in Moscow, designed the R-06, which eventually flew, but not in the meteorological role.
The early Soviet efforts to develop a sounding rocket ultimately failed before WWII. P. I. Ivanov built a three-stage rocket which flew in March 1946. At the end of summer 1946, development ended because it lacked sufficient thrust to lift a research payload.
The first successful sounding rocket was created at the California Institute of Technology, where, before World War II there was a group of rocket enthusiasts led by Frank Malina, under the leadership of Theodore von Kármán, known as the "Suicide Squad". Their immediate goal was to explore the upper atmosphere, which required developing the means of lofting instruments to high altitude and recovering the results. After the start of WWII, the rocketry enthusiasts found themselves involved in a number of defense programs, one of which was intended to produce a guided missile, the Corporal. Eventually known as the MGM-5 Corporal it became the first guided missile deployed by the US Army.
During WWII, the Signal Corps created a requirement for a sounding rocket to carry of instruments to or higher. To meet that goal, Malina proposed a small liquid-propellant rocket to provide the necessary experience to develop the Corporal missile. Malina with Tsien Hsue-shen, wrote "Flight analysis of a Sounding Rocket with Special Reference to Propulsion by Successive Impulses." As the Signal Corps rocket was being developed for the Corporal project, it lacked any guidance mechanism. Thus it was named the WAC Corporal for "without attitude control." The WAC Corporal served as the foundation of Sounding Rocketry in the US. The WAC Corporal was developed in two versions, the second of which was much improved. After the war, the WAC Corporal was in competition for sounding mission funding with the much larger captured V-2 rocket being tested by the US Army. The WAC Corporal was overshadowed at its job of cost-effectively lifting experiments to high altitudes, thus it effectively became obsolete. WAC Corporals were later modified to become the upper stage of the first two-stage rocket the RTV-G-4 Bumper.
Captured V-2s dominated American sounding rockets and other rocketry developments during the late 1940s. The Aerobee was developed by the Aerojet Corporation to meet a requirement of the Applied Physics Laboratory and the Naval Research Laboratory. Over 1,000 Aerobees were flown between 1947 and 1985. One engine produced for the Aerobee ultimately powered the second stage of the Vanguard rocket, which was the first purpose-built satellite launch vehicle. The AJ10 engine used by many Aerobees eventually evolved into the AJ10-190 which formed the orbital maneuvering system of the Space Shuttle.
The Viking rocket was designed by the US Navy to not only replace the V-2, but to also advance guided missile technology. The Viking was controlled by a multi-axis guidance system with gimbled XLR10-RM-2 engines. The Viking was developed through two major versions. After the United States announced it intended to launch a satellite in the International Geophysical Year the Viking was chosen as the first stage of the Vanguard Satellite Launch Vehicle. The last two Vikings were fired as Vanguard Test Vehicle 1 and 2.
During the post-WWII era, the USSR also pursued V-2-based sounding rockets. The last two R-1As were flown in 1949 as sounding rockets. They were followed between July 1951 and June 1956 by four R-1Bs, two R-1Vs, three R-1Ds, five R-1Es, and one R-1E. The improved V-2 descendant, the R-2A, could reach altitudes of and was flown between April 1957 and May 1962. Fifteen R-5Vs were flown from June 1965 to October 1983. Two R-5 VAOs were flown in September 1964 and October 1965. The first solid-fueled Soviet sounding rocket was the M-100. Some 6640 M-100 sounding rockets were flown from 1957 to 1990.
Other early users of sounding rockets were Britain, France, and Japan.
Great Britain developed the Skylark series and the Skua for the International Geophysical Year.
France had begun the design of a Super V-2 but that program had been abandoned in the late 1940s due to the inability of France to manufacture all of the necessary components. Development of the Veronique began in 1949, but it was not until 1952 that the first full-scale Veronique was launched. Veronique variants were flown until 1974. The Monica family was all solid-fueled, and a number of versions were built. These were later replaced by the ONERA series.
Japan used the Kappa rocket, and also pursued Rockoons.
The People's Republic of China was the last nation to launch a new liquid-fueled sounding rocket, the T-7. It was first fired from a very primitive launch site, where the "command center" and borrowed power generator were in a grass hut separated from the launcher by a small river. There was no communications equipment, not even a telephone between the command post and the rocket launcher. The T-7 led to the T-7M, T-7A, T-7A-S, T-7A-S2 and T-7/GF-01A. The T-7/GF-01A was used in 1969 to launch the FSW satellite technology development missions. Thus the I-7 led to the first Chinese satellite, the Dong Fang Hong 1, launched by a DF-1. Qian Xuesen was vital to the development of Chinese rocketry, and the Dong Feng-1. He had worked with Theodore von Kármán and the California Institute of Technology "Suicide Squad", creating the first successful sounding rocket, the WAC Corporal.
By the early 1960s, the sounding rocket was considered established technology.