Spaceport

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https://en.wikipedia.org/wiki/Spaceport

The Baikonur Cosmodrome (Gagarin's Start launch pad)

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Spaceflight

A spaceport or cosmodrome is a site for launching or receiving spacecraft, by analogy to a seaport for ships or an airport for aircraft. The word spaceport, and even more so cosmodrome, has traditionally been used for sites capable of launching spacecraft into orbit around Earth or on interplanetary trajectories. However, rocket launch sites for purely sub-orbital flights are sometimes called spaceports, as in recent years new and proposed sites for suborbital human flights have been frequently referred to or named "spaceports". Space stations and proposed future bases on the Moon are sometimes called spaceports, in particular if intended as a base for further journeys.

The term rocket launch site is used for any facility from which rockets are launched. It may contain one or more launch pads or suitable sites to mount a transportable launch pad. It is typically surrounded by a large safety area, often called a rocket range or missile range. The range includes the area over which launched rockets are expected to fly, and within which some components of the rockets may land. Tracking stations are sometimes located in the range to assess the progress of the launches.

Major spaceports often include more than one launch complex, which can be rocket launch sites adapted for different types of launch vehicles. (These sites can be well-separated for safety reasons.) For launch vehicles with liquid propellant, suitable storage facilities and, in some cases, production facilities are necessary. On-site processing facilities for solid propellants are also common.

A spaceport may also include runways for takeoff and landing of aircraft to support spaceport operations, or to enable support of HTHL or HTVL winged launch vehicles.

History

The age of crewed rocket flight was initiated by Fritz von Opel who piloted the world's first rocket-propelled flight on 30 September 1929; von Opel was the co-designer and financier of the visionary project which led to actual space flights.

Peenemünde, Germany – where the "V-2", the first rocket reaching space in June 1944 was launched

The first rockets to reach space were V-2 rockets launched from Peenemünde, Germany in 1944 during World War II. After the war, 70 complete V-2 rockets were brought to White Sands for test launches, with 47 of them reaching altitudes between 100 km and 213 km.

The world's first spaceport for orbital and human launches, the Baikonur Cosmodrome in southern Kazakhstan, started as a Soviet military rocket range in 1955. It achieved the first orbital flight (Sputnik 1) in October 1957. The exact location of the cosmodrome was initially held secret. Guesses to its location were misdirected by a name in common with a mining town 320 km away. The position became known in 1957 outside the Soviet Union only after U-2 planes had identified the site by following railway lines in the Kazakh SSR, although Soviet authorities did not confirm the location for decades.

The Baikonur Cosmodrome achieved the first launch of a human into space (Yuri Gagarin) in 1961. The launch complex used, Site 1, has reached a special symbolic significance and is commonly called Gagarin's Start. Baikonur was the primary Soviet cosmodrome, and is still frequently used by Russia under a lease arrangement with Kazakhstan.

In response to the early Soviet successes, the United States built up a major spaceport complex at Cape Canaveral in Florida. A large number of uncrewed flights, as well as the early human flights, were carried out at Cape Canaveral Space Force Station. For the Apollo programme, an adjacent spaceport, Kennedy Space Center, was constructed, and achieved the first crewed mission to the lunar surface (Apollo 11) in July 1969. It was the base for all Space Shuttle launches and most of their runway landings. For details on the launch complexes of the two spaceports, see List of Cape Canaveral and Merritt Island launch sites.

The Guiana Space Centre in Kourou, French Guiana, is the major European spaceport, with satellite launches that benefit from the location 5 degrees north of the equator.

In October 2003 the Jiuquan Satellite Launch Center achieved the first Chinese human spaceflight.

Breaking with tradition, in June 2004 on a runway at Mojave Air and Space Port, California, a human was for the first time launched to space in a privately funded, suborbital spaceflight, that was intended to pave the way for future commercial spaceflights. The spacecraft, SpaceShipOne, was launched by a carrier airplane taking off horizontally.

At Cape Canaveral, SpaceX in 2015 made the first successful landing and recovery of a first stage used in a vertical satellite launch.

Location

Rockets can most easily reach satellite orbits if launched near the equator in an easterly direction, as this maximizes use of the Earth's rotational speed (465 m/s at the equator). Such launches also provide a desirable orientation for arriving at a geostationary orbit. For polar orbits and Molniya orbits this does not apply.

In principle, advantages of high altitude launch are reduced vertical distance to travel and a thinner atmosphere for the rocket to penetrate. However, altitude of the launch site is not a driving factor in spaceport placement because most of the delta-v for a launch is spent on achieving the required horizontal orbital speed. The small gain from a few kilometers of extra altitude does not usually off-set the logistical costs of ground transport in mountainous terrain.

Many spaceports have been placed at existing military installations, such as intercontinental ballistic missile ranges, which are not always physically ideal sites for launch.

A rocket launch site is built as far as possible away from major population centers in order to mitigate risk to bystanders should a rocket experience a catastrophic failure. In many cases a launch site is built close to major bodies of water to ensure that no components are shed over populated areas. Typically a spaceport site is large enough that, should a vehicle explode, it will not endanger human lives or adjacent launch pads.

Planned sites of spaceports for sub-orbital tourist spaceflight often make use of existing ground infrastructure, including runways. The nature of the local view from 100 km (62 mi) altitude is also a factor to consider.

Active orbital-launch spaceports in the world.

Space tourism

The space tourism industry (see List of private spaceflight companies) is being targeted by spaceports in numerous locations worldwide. e.g. Spaceport America, New Mexico.

The establishment of spaceports for tourist trips raises legal issues, which are only beginning to be addressed.

With achieved vertical launches of humans

The following is a table of spaceports and launch complexes for vertical launchers with documented achieved launches of humans to space (more than 100 km (62 mi) altitude). The sorting order is spaceport by spaceport according to the time of the first human launch.

Spaceport	Launch complex	Launcher	Spacecraft	Flights	Years
Baikonur Cosmodrome, Kazakhstan (Soviet and Russian flights)	Site 1	Vostok (r)	Vostok 1–6	6 Orbital	1961–1963
	Site 1	Voskhod (r)	Voskhod 1–2	2 Orbital	1964–1965
	Site 1, 31	Soyuz, Soyuz-U	Soyuz 1–40 †	37 Orbital	1967–1981
	Site 1, 31	Soyuz-U, Soyuz-U2	Soyuz-T 2–15	14 Orbital	1980–1986
	Site 1	Soyuz-U, Soyuz-U2	Soyuz-TM 2–34	33 Orbital	1987–2002
	Site 1	Soyuz-FG	Soyuz-TMA 1–22	22 Orbital	2002–2011
	Site 1, 31	Soyuz-FG	Soyuz TMA-M 1–20	20 Orbital	2010–2016
	Site 1, 31	Soyuz-FG	Soyuz MS 1–9, 11–13, 15	13 Orbital	2016–2019
	Site 1, 31	Soyuz-2	Soyuz MS 16–22	7 Orbital	2020–
Cape Canaveral Space Force Station, Florida, United States	LC-5	Redstone	Mercury 3–4	2 Sub-O	1961
	LC-14	Atlas	Mercury 6–9	4 Orbital	1962–1963
	LC-19	Titan II	Gemini 3–12	10 Orbital	1965–1966
	LC-34	Saturn IB	Apollo 7	1 Orbital	1968
Kennedy Space Center, Florida, United States	LC-39	Saturn V	Apollo 8–17	10 Lun/Or	1968–1972
		Saturn IB	Skylab 2–4	3 Orbital	1973–1974
		Saturn IB	Apollo–Soyuz	1 Orbital	1975
		Space Shuttle	STS 1-135‡	134 Orbital	1981–2011
		Falcon 9 Block 5	Crew Dragon	9 Orbital	2020–
Jiuquan Satellite Launch Center, China	Area 4	Long March 2F	Shenzhou 5–7, 9-16	11 Orbital	2003–
Corn Ranch, Texas, United States	Launch Site One	New Shepard	New Shepard Crew Capsule	5 Sub-O	2015–

† Three of the Soyuz missions were uncrewed and are not counted (Soyuz 2, Soyuz 20, Soyuz 34).

‡ STS-51-L (Challenger) failed to reach orbit and is not counted. STS-107 (Columbia) reached orbit and is therefore included in the count (disaster struck on re-entry).

With achieved satellite launches

The following is a table of spaceports with a documented achieved launch to orbit. The table is sorted according to the time of the first launch that achieved satellite orbit insertion. The first column gives the geographical location. Operations from a different country are indicated in the fourth column. A launch is counted as one also in cases where the payload consists of multiple satellites.

Spaceport	Location	Years (orbital)	Launches to orbit or inter- planetary	Launch vehicles (operators)	Sources
Baikonur Cosmodrome, Baikonur/Tyuratam, Kazakhstan	Kazakhstan	1957–	>1,000	R-7/Soyuz, Kosmos, Proton, Tsyklon, Zenit, Energia
Cape Canaveral Space Force Station, Florida, United States	United States	1958–	>400	Delta, Scout, Atlas, Titan, Saturn, Athena, Falcon 9
Vandenberg Space Force Base, California, United States	United States	1959–	>700	Delta, Scout, Atlas, Titan, Taurus, Athena, Minotaur, Falcon 9
Wallops Flight Facility, Virginia, United States (see also MARS below)	United States	1961–1985	19	Scout
Kapustin Yar Cosmodrome, Astrakhan Oblast, Russia	Russia	1962–2008	85	Kosmos
Hammaguir French Special Weapons Test Centre, Algeria	Algeria	1965–1967	4	Diamant A (France)	Diamant
Plesetsk Cosmodrome, Arkhangelsk Oblast, Russia	Russia	1966–	>1,500	R-7/Soyuz, Kosmos, Tsyklon-3, Rokot, Angara
San Marco platform, Broglio Space Centre, Malindi, Kenya	Kenya	1967–1988	9	Scout (ASI and Sapienza, Italy)	Broglio
Kennedy Space Center, Florida, United States	United States	1967–	187	17 Saturn, 135 Space Shuttle, 32 Falcon 9, 7 Falcon Heavy	Saturn, STS, F9
Woomera Prohibited Area, South Australia	Australia	1967, 1971	2	Redstone (WRESAT), Black Arrow (UK Prospero X-3)	WRESAT, X-3
Uchinoura Space Center (Kagoshima), Japan	Japan	1970–	31	27 Mu, 3 Epsilon, 1 SS-520-5	M, ε, S
Guyane française Space Centre, Kourou, French Guiana, France	France	1970–	318	7 Diamant, 227 Ariane, 16 Soyuz-2, 11 Vega	see 4 rockets
Jiuquan Satellite Launch Center, China	China	1970–	121	2 LM1, 3 LM2A, 20 LM2C, 36 LM2D, 13 LM2F, 3 LM4B, 5 LM4C, 3 LM11	See 8 rockets
Tanegashima Space Center, Japan	Japan	1975–	65	6 N-I, 8 N-II, 9 H-I, 6 H-II, 36 H-IIA	see 5 rockets
Satish Dhawan Space Centre (SHAR), Andhra Pradesh, India	India	1979–	88	4 SLV, 4 ASLV, 56 PSLV, 14 GSLV, 6 LVM 3, 2 SSLV	List SDSC
Xichang Satellite Launch Center, China	China	1984–	183	Long March: 6 LM2C, 5 LM2E, 11 LM3, 25 LM3A, 42 LM3B, 15 LM3C	See 6 rockets
Taiyuan Satellite Launch Center, China	China	1988–	62	Long March: 16 LM2C, 2 LM2D, 2 LM4A, 25 LM4B, 15 LM4C, 2 LM6	See 6 rockets
Palmachim Air Force Base, Israel	Israel	1988–	8	Shavit	Shavit
Various airport runways (B-52, Stargazer)	Various	1990–	39	Pegasus (Orbital Sciences Corporation)	Pegasus
Svobodny Cosmodrome, Amur Oblast, Russia	Russia	1997–2006	5	Start-1
Delta-class submarine, Barents Sea	Barents Sea	1998, 2006	2	Shtil' (Russia)	Shtil'
Odyssey mobile platform, Pacific Ocean	Pacific Ocean	1999–2014	32	Zenit-3SL (Sea Launch)	Sea Launch
Pacific Spaceport Complex (Kodiak), Alaska, United States	United States	2001–	3	1 Athena, 2 Minotaur IV	Kodiak
Yasny Cosmodrome (Dombarovsky), Orenburg Oblast, Russia	Russia	2006–	10	Dnepr	Dnepr
Mid-Atlantic Regional Spaceport (MARS), Virginia, United States	United States	2006–	12	5 Minotaur I, 6 Antares, 1 Minotaur V	MARS
Omelek, Kwajalein Atoll, Marshall Islands	Marshall Islands	2008–2009	5	5 Falcon 1 (US)	Falcon 1
Semnan Space Center, Semnan, Iran	Iran	2009–	5	Safir, Simorgh, Zuljanah	Safir
Sohae Satellite Launching Station, North Korea	North Korea	2012–	2	Unha-3	K3-U2
Naro Space Center, South Jeolla, South Korea	South Korea	2013–	2	Naro-1, Nuri	Naro-1,Nuri
Vostochny Cosmodrome, Amur Oblast, Russia	Russia	2016–	8	8 Soyuz-2	Vostochny
Wenchang Satellite Launch Center, China	China	2016–	23	Long March: 9 LM5, 12 LM7, 2 LM8	See 3 rockets
Rocket Lab Launch Complex 1, New Zealand	New Zealand	2018–	21	21 Electron	Electron (rocket)
Shahroud Space Center, Semnan Province, Iran	Iran	2020–	2	Qased

With achieved horizontal launches of humans to 100 km

The following table shows spaceports with documented achieved launches of humans to at least 100 km altitude, starting from a horizontal runway. All the flights were sub-orbital.

Spaceport	Carrier aircraft	Spacecraft	Flights above 100 km	Years
Edwards AFB, California, United States	B-52	X-15	2 flights (# 90-91)	1963
Mojave Air and Space Port, California, United States	White Knight	SpaceShipOne	3 flights (# 15P-17P)	2004

Beyond Earth

Spaceports have been proposed for locations on the Moon, Mars, orbiting the Earth, at Sun-Earth and Earth-Moon Lagrange points, and at other locations in the Solar System. Human-tended outposts on the Moon or Mars, for example, will be spaceports by definition. The 2012 Space Studies Program of the International Space University studied the economic benefit of a network of spaceports throughout the solar system beginning from Earth and expanding outwardly in phases, within its team project Operations And Service Infrastructure for Space (OASIS). Its analysis claimed that the first phase, placing the "Node 1" spaceport with space tug services in low Earth orbit (LEO), would be commercially profitable and reduce transportation costs to geosynchronous orbit by as much as 44% (depending on the launch vehicle). The second phase would add a Node 2 spaceport on the lunar surface to provide services including lunar ice mining and delivery of rocket propellants back to Node 1. This would enable lunar surface activities and further reduce transportation costs within and out from cislunar space. The third phase would add a Node 3 spaceport on the Martian moon Phobos to enable refueling and resupply prior to Mars surface landings, missions beyond Mars, and return trips to Earth. In addition to propellant mining and refueling, the network of spaceports could provide services such as power storage and distribution, in-space assembly and repair of spacecraft, communications relay, shelter, construction and leasing of infrastructure, maintaining spacecraft positioned for future use, and logistics.

Evolutionary computation

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Evolutionary_computation

In computer science, evolutionary computation is a family of algorithms for global optimization inspired by biological evolution, and the subfield of artificial intelligence and soft computing studying these algorithms. In technical terms, they are a family of population-based trial and error problem solvers with a metaheuristic or stochastic optimization character.

In evolutionary computation, an initial set of candidate solutions is generated and iteratively updated. Each new generation is produced by stochastically removing less desired solutions, and introducing small random changes. In biological terminology, a population of solutions is subjected to natural selection (or artificial selection) and mutation. As a result, the population will gradually evolve to increase in fitness, in this case the chosen fitness function of the algorithm.

Evolutionary computation techniques can produce highly optimized solutions in a wide range of problem settings, making them popular in computer science. Many variants and extensions exist, suited to more specific families of problems and data structures. Evolutionary computation is also sometimes used in evolutionary biology as an in silico experimental procedure to study common aspects of general evolutionary processes.

History

The concept of mimicking evolutionary processes to solve problems originates before the advent of computers, such as when Alan Turing proposed a method of genetic search in 1948 . Turing's B-type u-machines resemble primitive neural networks, and connections between neurons were learnt via a sort of genetic algorithm. His P-type u-machines resemble a method for reinforcement learning, where pleasure and pain signals direct the machine to learn certain behaviors. However, Turing's paper went unpublished until 1968, and he died in 1954, so this early work had little to no effect on the field of evolutionary computation that was to develop.

Evolutionary computing as a field began in earnest in the 1950s and 1960s. There were several independent attempts to use the process of evolution in computing at this time, which developed separately for roughly 15 years. Three branches emerged in different places to attain this goal: evolution strategies, evolutionary programming, and genetic algorithms. A fourth branch, genetic programming, eventually emerged in the early 1990s. These approaches differ in the method of selection, the permitted mutations, and the representation of genetic data. By the 1990s, the distinctions between the historic branches had begun to blur, and the term 'evolutionary computing' was coined in 1991 to denote a field that exists over all four paradigms.

In 1962, Lawrence J. Fogel initiated the research of Evolutionary Programming in the United States, which was considered an artificial intelligence endeavor. In this system, finite state machines are used to solve a prediction problem: these machines would be mutated (adding or deleting states, or changing the state transition rules), and the best of these mutated machines would be evolved further in future generations. The final finite state machine may be used to generate predictions when needed. The evolutionary programming method was successfully applied to prediction problems, system identification, and automatic control. It was eventually extended to handle time series data and to model the evolution of gaming strategies.

In 1964, Ingo Rechenberg and Hans-Paul Schwefel introduce the paradigm of evolution strategies in Germany. Since traditional gradient descent techniques produce results that may get stuck in local minima, Rechenberg and Schwefel proposed that random mutations (applied to all parameters of some solution vector) may be used to escape these minima. Child solutions were generated from parent solutions, and the more successful of the two was kept for future generations. This technique was first used by the two to successfully solve optimization problems in fluid dynamics. Initially, this optimization technique was performed without computers, instead relying on dice to determine random mutations. By 1965, the calculations were performed wholly by machine.

John Henry Holland introduced genetic algorithms in the 1960s, and it was further developed at the University of Michigan in the 1970s. While the other approaches were focused on solving problems, Holland primarily aimed to use genetic algorithms to study adaptation and determine how it may be simulated. Populations of chromosomes, represented as bit strings, were transformed by an artificial selection process, selecting for specific 'allele' bits in the bit string. Among other mutation methods, interactions between chromosomes were used to simulate the recombination of DNA between different organisms. While previous methods only tracked a single optimal organism at a time (having children compete with parents), Holland's genetic algorithms tracked large populations (having many organisms compete each generation).

By the 1990s, a new approach to evolutionary computation that came to be called genetic programming emerged, advocated for by John Koza among others. In this class of algorithms, the subject of evolution was itself a program written in a high-level programming language (there had been some previous attempts as early as 1958 to use machine code, but they met with little success). For Koza, the programs were Lisp S-expressions, which can be thought of as trees of sub-expressions. This representation permits programs to swap subtrees, representing a sort of genetic mixing. Programs are scored based on how well they complete a certain task, and the score is used for artificial selection. Sequence induction, pattern recognition, and planning were all successful applications of the genetic programming paradigm.

Many other figures played a role in the history of evolutionary computing, although their work did not always fit into one of the major historical branches of the field. The earliest computational simulations of evolution using evolutionary algorithms and artificial life techniques were performed by Nils Aall Barricelli in 1953, with first results published in 1954. Another pioneer in the 1950s was Alex Fraser, who published a series of papers on simulation of artificial selection. As academic interest grew, dramatic increases in the power of computers allowed practical applications, including the automatic evolution of computer programs. Evolutionary algorithms are now used to solve multi-dimensional problems more efficiently than software produced by human designers, and also to optimize the design of systems.

Techniques

Evolutionary computing techniques mostly involve metaheuristic optimization algorithms. Broadly speaking, the field includes:

• Agent-based modeling
• Ant colony optimization
• Artificial immune systems
• Artificial life (also see digital organism)
• Cultural algorithms
• Coevolutionary algorithms
• Differential evolution
• Dual-phase evolution
• Estimation of distribution algorithms
• Evolutionary algorithms
• Evolutionary programming
• Evolution strategy
• Gene expression programming
• Genetic algorithm
• Genetic programming
• Grammatical evolution
• Learnable evolution model
• Learning classifier systems
• Memetic algorithms
• Neuroevolution
• Particle swarm optimization
• Beetle Antennae Search
• Self-organization such as self-organizing maps, competitive learning
• Swarm intelligence

A through catalogue with many other recently proposed algorithms has been published in the Evolutionary Computation Bestiary. It is important to note that many recent algorithms, however, have poor experimental validation.

Evolutionary algorithms

Main article: Evolutionary algorithm

Evolutionary algorithms form a subset of evolutionary computation in that they generally only involve techniques implementing mechanisms inspired by biological evolution such as reproduction, mutation, recombination, natural selection and survival of the fittest. Candidate solutions to the optimization problem play the role of individuals in a population, and the cost function determines the environment within which the solutions "live" (see also fitness function). Evolution of the population then takes place after the repeated application of the above operators.

In this process, there are two main forces that form the basis of evolutionary systems: Recombination mutation and crossover create the necessary diversity and thereby facilitate novelty, while selection acts as a force increasing quality.

Many aspects of such an evolutionary process are stochastic. Changed pieces of information due to recombination and mutation are randomly chosen. On the other hand, selection operators can be either deterministic, or stochastic. In the latter case, individuals with a higher fitness have a higher chance to be selected than individuals with a lower fitness, but typically even the weak individuals have a chance to become a parent or to survive.

Evolutionary algorithms and biology

Main article: Evolutionary algorithm

Genetic algorithms deliver methods to model biological systems and systems biology that are linked to the theory of dynamical systems, since they are used to predict the future states of the system. This is just a vivid (but perhaps misleading) way of drawing attention to the orderly, well-controlled and highly structured character of development in biology.

However, the use of algorithms and informatics, in particular of computational theory, beyond the analogy to dynamical systems, is also relevant to understand evolution itself.

This view has the merit of recognizing that there is no central control of development; organisms develop as a result of local interactions within and between cells. The most promising ideas about program-development parallels seem to us to be ones that point to an apparently close analogy between processes within cells, and the low-level operation of modern computers. Thus, biological systems are like computational machines that process input information to compute next states, such that biological systems are closer to a computation than classical dynamical system.

Furthermore, following concepts from computational theory, micro processes in biological organisms are fundamentally incomplete and undecidable (completeness (logic)), implying that “there is more than a crude metaphor behind the analogy between cells and computers.

The analogy to computation extends also to the relationship between inheritance systems and biological structure, which is often thought to reveal one of the most pressing problems in explaining the origins of life.

Evolutionary automata, a generalization of Evolutionary Turing machines, have been introduced in order to investigate more precisely properties of biological and evolutionary computation. In particular, they allow to obtain new results on expressiveness of evolutionary computation. This confirms the initial result about undecidability of natural evolution and evolutionary algorithms and processes. Evolutionary finite automata, the simplest subclass of Evolutionary automata working in terminal mode can accept arbitrary languages over a given alphabet, including non-recursively enumerable (e.g., diagonalization language) and recursively enumerable but not recursive languages (e.g., language of the universal Turing machine).

Notable practitioners

The list of active researchers is naturally dynamic and non-exhaustive. A network analysis of the community was published in 2007.

• Kalyanmoy Deb
• Kenneth A De Jong
• Peter J. Fleming
• David B. Fogel
• Stephanie Forrest
• David E. Goldberg
• John Henry Holland
• Theo Jansen
• John Koza
• Zbigniew Michalewicz
• Melanie Mitchell
• Peter Nordin
• Riccardo Poli
• Ingo Rechenberg
• Hans-Paul Schwefel

Conferences

The main conferences in the evolutionary computation area include

• ACM Genetic and Evolutionary Computation Conference (GECCO),
• IEEE Congress on Evolutionary Computation (CEC),
• EvoStar, which comprises four conferences: EuroGP, EvoApplications, EvoCOP and EvoMUSART,
• Parallel Problem Solving from Nature (PPSN).

Telemetry

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Telemetry

An expendable dropsonde used to capture weather data. The telemetry consists of sensors for pressure, temperature, and humidity and a wireless transmitter to return the captured data to an aircraft.

A saltwater crocodile with a GPS-based satellite transmitter attached to its head for tracking

Telemetry is the in situ collection of measurements or other data at remote points and their automatic transmission to receiving equipment (telecommunication) for monitoring. The word is derived from the Greek roots tele, 'remote', and metron, 'measure'. Systems that need external instructions and data to operate require the counterpart of telemetry: telecommand.

Although the term commonly refers to wireless data transfer mechanisms (e.g., using radio, ultrasonic, or infrared systems), it also encompasses data transferred over other media such as a telephone or computer network, optical link or other wired communications like power line carriers. Many modern telemetry systems take advantage of the low cost and ubiquity of GSM networks by using SMS to receive and transmit telemetry data.

A telemeter is a physical device used in telemetry. It consists of a sensor, a transmission path, and a display, recording, or control device. Electronic devices are widely used in telemetry and can be wireless or hard-wired, analog or digital. Other technologies are also possible, such as mechanical, hydraulic and optical.

Telemetry may be commutated to allow the transmission of multiple data streams in a fixed frame.

History

The beginning of industrial telemetry lies in the steam age, although the sensor was not called telemeter at that time. Examples are James Watt's (1736-1819) additions to his steam engines for monitoring from a (near) distance such as the mercury pressure gauge and the fly-ball governor.

Although the original telemeter referred to a ranging device (the rangefinding telemeter), by the late 19th century the same term had been in wide use by electrical engineers applying it refer to electrically operated devices measuring many other quantities besides distance (for instance, in the patent of an "Electric Telemeter Transmitter"). General telemeters included such sensors as the thermocouple (from the work of Thomas Johann Seebeck), the resistance thermometer (by William Siemens based on the work of Humphry Davy), and the electrical strain gauge (based on Lord Kelvin's discovery that conductors under mechanical strain change their resistance) and output devices such as Samuel Morse's telegraph sounder and the relay. In 1889 this led an author in the Institution of Civil Engineers proceedings to suggest that the term for the rangefinder telemeter might be replaced with tacheometer.

In the 1930s use of electrical telemeters grew rapidly. The electrical strain gauge was widely used in rocket and aviation research and the radiosonde was invented for meteorological measurements. The advent of World War II gave an impetus to industrial development and henceforth many of these telemeters became commercially viable. Carrying on from rocket research, radio telemetry was used routinely as space exploration got underway. Spacecraft are in a place where a physical connection is not possible, leaving radio or other electromagnetic waves (such as infrared lasers) as the only viable option for telemetry. During crewed space missions it is used to monitor not only parameters of the vehicle, but also the health and life support of the astronauts. During the Cold War telemetry found uses in espionage. US intelligence found that they could monitor the telemetry from Soviet missile tests by building a telemeter of their own to intercept the radio signals and hence learn a great deal about Soviet capabilities.

Types of telemeter

Telemeters are the physical devices used in telemetry. It consists of a sensor, a transmission path, and a display, recording, or control device. Electronic devices are widely used in telemetry and can be wireless or hard-wired, analog or digital. Other technologies are also possible, such as mechanical, hydraulic and optical.

Telemetering information over wire had its origins in the 19th century. One of the first data-transmission circuits was developed in 1845 between the Russian Tsar's Winter Palace and army headquarters. In 1874, French engineers built a system of weather and snow-depth sensors on Mont Blanc that transmitted real-time information to Paris. In 1901 the American inventor C. Michalke patented the selsyn, a circuit for sending synchronized rotation information over a distance. In 1906 a set of seismic stations were built with telemetering to the Pulkovo Observatory in Russia. In 1912, Commonwealth Edison developed a system of telemetry to monitor electrical loads on its power grid. The Panama Canal (completed 1913–1914) used extensive telemetry systems to monitor locks and water levels.

Wireless telemetry made early appearances in the radiosonde, developed concurrently in 1930 by Robert Bureau in France and Pavel Molchanov in Russia. Molchanov's system modulated temperature and pressure measurements by converting them to wireless Morse code. The German V-2 rocket used a system of primitive multiplexed radio signals called "Messina" to report four rocket parameters, but it was so unreliable that Wernher von Braun once claimed it was more useful to watch the rocket through binoculars.

In the US and the USSR, the Messina system was quickly replaced with better systems; in both cases, based on pulse-position modulation (PPM). Early Soviet missile and space telemetry systems which were developed in the late 1940s used either PPM (e.g., the Tral telemetry system developed by OKB-MEI) or pulse-duration modulation (e.g., the RTS-5 system developed by NII-885). In the United States, early work employed similar systems, but were later replaced by pulse-code modulation (PCM) (for example, in the Mars probe Mariner 4). Later Soviet interplanetary probes used redundant radio systems, transmitting telemetry by PCM on a decimeter band and PPM on a centimeter band.

Applications

Meteorology

Telemetry has been used by weather balloons for transmitting meteorological data since 1920.

Oil and gas industry

Telemetry is used to transmit drilling mechanics and formation evaluation information uphole, in real time, as a well is drilled. These services are known as Measurement while drilling and Logging while drilling. Information acquired thousands of feet below ground, while drilling, is sent through the drilling hole to the surface sensors and the demodulation software. The pressure wave (sana) is translated into useful information after DSP and noise filters. This information is used for Formation evaluation, Drilling Optimization, and Geosteering.

Motor racing

Telemetry is a key factor in modern motor racing, allowing race engineers to interpret data collected during a test or race and use it to properly tune the car for optimum performance. Systems used in series such as Formula One have become advanced to the point where the potential lap time of the car can be calculated, and this time is what the driver is expected to meet. Examples of measurements on a race car include accelerations (G forces) in three axes, temperature readings, wheel speed, and suspension displacement. In Formula One, driver input is also recorded so the team can assess driver performance and (in case of an accident) the FIA can determine or rule out driver error as a possible cause.

Later developments include two-way telemetry which allows engineers to update calibrations on the car in real time (even while it is out on the track). In Formula One, two-way telemetry surfaced in the early 1990s and consisted of a message display on the dashboard which the team could update. Its development continued until May 2001, when it was first allowed on the cars. By 2002, teams were able to change engine mapping and deactivate engine sensors from the pit while the car was on the track. For the 2003 season, the FIA banned two-way telemetry from Formula One; however, the technology may be used in other types of racing or on road cars.

One way telemetry system has also been applied in R/C racing car to get information by car's sensors like: engine RPM, voltage, temperatures, throttle.

Transportation

In the transportation industry, telemetry provides meaningful information about a vehicle or driver's performance by collecting data from sensors within the vehicle. This is undertaken for various reasons ranging from staff compliance monitoring, insurance rating to predictive maintenance.

Telemetry is used to link traffic counter devices to data recorders to measure traffic flows and vehicle lengths and weights.

Telemetry is used by the railway industry for measuring the health of trackage. This permits optimized and focused predictive and preventative maintenance. Typically this is done with specialized trains, such as the New Measurement Train used in the United Kingdom by Network Rail, which can check for track defects, such as problems with gauge, and deformations in the rail. Japan uses similar, but quicker trains, nicknamed Doctor Yellow. Such trains, besides checking the tracks, can also verify whether or not there are any problems with the overhead power supply (catenary), where it's installed. Dedicated rail inspection companies, such as Sperry Rail, have their own customized rail cars and rail-wheel equipped trucks that use a variety of methods, including lasers, ultrasound, and induction (measuring resulting magnetic fields from running electricity into rails) to find any defects.

Agriculture

Most activities related to healthy crops and good yields depend on timely availability of weather and soil data. Therefore, wireless weather stations play a major role in disease prevention and precision irrigation. These stations transmit parameters necessary for decision-making to a base station: air temperature and relative humidity, precipitation and leaf wetness (for disease prediction models), solar radiation and wind speed (to calculate evapotranspiration), water deficit stress (WDS) leaf sensors and soil moisture (crucial to irrigation decisions).

Because local micro-climates can vary significantly, such data needs to come from within the crop. Monitoring stations usually transmit data back by terrestrial radio, although occasionally satellite systems are used. Solar power is often employed to make the station independent of the power grid.

Water management

Telemetry is important in water management, including water quality and stream gauging functions. Major applications include AMR (automatic meter reading), groundwater monitoring, leak detection in distribution pipelines and equipment surveillance. Having data available in almost real time allows quick reactions to events in the field. Telemetry control allows engineers to intervene with assets such as pumps and by remotely switching pumps on or off depending on the circumstances. Watershed telemetry is an excellent strategy of how to implement a water management system. 

Defense, space and resource exploration

Telemetry is used in complex systems such as missiles, RPVs, spacecraft, oil rigs, and chemical plants since it allows the automatic monitoring, alerting, and record-keeping necessary for efficient and safe operation. Space agencies such as NASA, ISRO, the European Space Agency (ESA), and other agencies use telemetry and/or telecommand systems to collect data from spacecraft and satellites.

Telemetry is vital in the development of missiles, satellites and aircraft because the system might be destroyed during or after the test. Engineers need critical system parameters to analyze (and improve) the performance of the system. In the absence of telemetry, this data would often be unavailable.

Space science

Telemetry is used by crewed or uncrewed spacecraft for data transmission. Distances of more than 10 billion kilometres have been covered, e.g., by Voyager 1.

Rocketry

In rocketry, telemetry equipment forms an integral part of the rocket range assets used to monitor the position and health of a launch vehicle to determine range safety flight termination criteria (Range purpose is for public safety). Problems include the extreme environment (temperature, acceleration and vibration), the energy supply, antenna alignment and (at long distances, e.g., in spaceflight) signal travel time.

Flight testing

Today nearly every type of aircraft, missiles, or spacecraft carries a wireless telemetry system as it is tested. Aeronautical mobile telemetry is used for the safety of the pilots and persons on the ground during flight tests. Telemetry from an on-board flight test instrumentation system is the primary source of real-time measurement and status information transmitted during the testing of crewed and uncrewed aircraft.

Military intelligence

Intercepted telemetry was an important source of intelligence for the United States and UK when Soviet missiles were tested; for this purpose, the United States operated a listening post in Iran. Eventually, the Russians discovered the United States intelligence-gathering network and encrypted their missile-test telemetry signals. Telemetry was also a source for the Soviets, who operated listening ships in Cardigan Bay to eavesdrop on UK missile tests performed in the area.

Energy monitoring

In factories, buildings and houses, energy consumption of systems such as HVAC are monitored at multiple locations; related parameters (e.g., temperature) are sent via wireless telemetry to a central location. The information is collected and processed, enabling the most efficient use of energy. Such systems also facilitate predictive maintenance.

Resource distribution

Many resources need to be distributed over wide areas. Telemetry is useful in these cases, since it allows the logistics system to channel resources where they are needed, as well as provide security for those assets; principal examples of this are dry goods, fluids, and granular bulk solids.

Dry goods

Dry goods, such as packaged merchandise, may be tracked and remotely monitored, tracked and inventoried by RFID sensing systems, barcode reader, optical character recognition (OCR) reader, or other sensing devices—coupled to telemetry devices, to detect RFID tags, barcode labels or other identifying markers affixed to the item, its package, or (for large items and bulk shipments) affixed to its shipping container or vehicle. This facilitates knowledge of their location, and can record their status and disposition, as when merchandise with barcode labels is scanned through a checkout reader at point-of-sale systems in a retail store. Stationary or hand-held barcode RFID scanners or Optical reader with remote communications, can be used to expedite inventory tracking and counting in stores, warehouses, shipping terminals, transportation carriers and factories.

Fluids

Fluids stored in tanks are a principal object of constant commercial telemetry. This typically includes monitoring of tank farms in gasoline refineries and chemical plants—and distributed or remote tanks, which must be replenished when empty (as with gas station storage tanks, home heating oil tanks, or ag-chemical tanks at farms), or emptied when full (as with production from oil wells, accumulated waste products, and newly produced fluids). Telemetry is used to communicate the variable measurements of flow and tank level sensors detecting fluid movements and/or volumes by pneumatic, hydrostatic, or differential pressure; tank-confined ultrasonic, radar or Doppler effect echoes; or mechanical or magnetic sensors.

See also: level sensor

Bulk solids

Telemetry of bulk solids is common for tracking and reporting the volume status and condition of grain and livestock feed bins, powdered or granular food, powders and pellets for manufacturing, sand and gravel, and other granular bulk solids. While technology associated with fluid tank monitoring also applies, in part, to granular bulk solids, reporting of overall container weight, or other gross characteristics and conditions, are sometimes required, owing to bulk solids' more complex and variable physical characteristics.

Medicine/healthcare

Telemetry is used for patients (biotelemetry) who are at risk of abnormal heart activity, generally in a coronary care unit. Telemetry specialists are sometimes used to monitor many patients within a hospital. Such patients are outfitted with measuring, recording and transmitting devices. A data log can be useful in diagnosis of the patient's condition by doctors. An alerting function can alert nurses if the patient is suffering from an acute (or dangerous) condition.

Systems are available in medical-surgical nursing for monitoring to rule out a heart condition, or to monitor a response to antiarrhythmic medications such as amiodarone.

A new and emerging application for telemetry is in the field of neurophysiology, or neurotelemetry. Neurophysiology is the study of the central and peripheral nervous systems through the recording of bioelectrical activity, whether spontaneous or stimulated. In neurotelemetry (NT) the electroencephalogram (EEG) of a patient is monitored remotely by a registered EEG technologist using advanced communication software. The goal of neurotelemetry is to recognize a decline in a patient's condition before physical signs and symptoms are present.

Neurotelemetry is synonymous with real-time continuous video EEG monitoring and has application in the epilepsy monitoring unit, neuro ICU, pediatric ICU and newborn ICU. Due to the labor-intensive nature of continuous EEG monitoring NT is typically done in the larger academic teaching hospitals using in-house programs that include R.EEG Technologists, IT support staff, neurologist and neurophysiologist and monitoring support personnel.

Modern microprocessor speeds, software algorithms and video data compression allow hospitals to centrally record and monitor continuous digital EEGs of multiple critically ill patients simultaneously.

Neurotelemetry and continuous EEG monitoring provides dynamic information about brain function that permits early detection of changes in neurologic status, which is especially useful when the clinical examination is limited.

Fishery and wildlife research and management

Main article: Wildlife radio telemetry

A bumblebee worker with a transponder attached to its back, visiting an oilseed rape flower

Telemetry is used to study wildlife, and has been useful for monitoring threatened species at the individual level. Animals under study can be outfitted with instrumentation tags, which include sensors that measure temperature, diving depth and duration (for marine animals), speed and location (using GPS or Argos packages). Telemetry tags can give researchers information about animal behavior, functions, and their environment. This information is then either stored (with archival tags) or the tags can send (or transmit) their information to a satellite or handheld receiving device. Capturing and marking wild animals can put them at some risk, so it is important to minimize these impacts.

Retail

At a 2005 workshop in Las Vegas, a seminar noted the introduction of telemetry equipment which would allow vending machines to communicate sales and inventory data to a route truck or to a headquarters. This data could be used for a variety of purposes, such as eliminating the need for drivers to make a first trip to see which items needed to be restocked before delivering the inventory.

Retailers also use RFID tags to track inventory and prevent shoplifting. Most of these tags passively respond to RFID readers (e.g., at the cashier), but active RFID tags are available which periodically transmit location information to a base station.

Law enforcement

Telemetry hardware is useful for tracking persons and property in law enforcement. An ankle collar worn by convicts on probation can warn authorities if a person violates the terms of his or her parole, such as by straying from authorized boundaries or visiting an unauthorized location. Telemetry has also enabled bait cars, where law enforcement can rig a car with cameras and tracking equipment and leave it somewhere they expect it to be stolen. When stolen the telemetry equipment reports the location of the vehicle, enabling law enforcement to deactivate the engine and lock the doors when it is stopped by responding officers.

Energy providers

In some countries, telemetry is used to measure the amount of electrical energy consumed. The electricity meter communicates with a concentrator, and the latter sends the information through GPRS or GSM to the energy provider's server. Telemetry is also used for the remote monitoring of substations and their equipment. For data transmission, phase line carrier systems operating on frequencies between 30 and 400 kHz are sometimes used.

Falconry

In falconry, "telemetry" means a small radio transmitter carried by a bird of prey that will allow the bird's owner to track it when it is out of sight.

Testing

Telemetry is used in testing hostile environments which are dangerous to humans. Examples include munitions storage facilities, radioactive sites, volcanoes, deep sea, and outer space.

Communications

Telemetry is used in many battery operated wireless systems to inform monitoring personnel when the battery power is reaching a low point and the end item needs fresh batteries.

Mining

In the mining industry, telemetry serves two main purposes: the measurement of key parameters from mining equipment and the monitoring of safety practices. The information provided by the collection and analysis of key parameters allows for root-cause identification of inefficient operations, unsafe practices and incorrect equipment usage for maximizing productivity and safety. Further applications of the technology allow for sharing knowledge and best practices across the organization.

Software

See also: Phoning home

In software, telemetry is used to gather data on the use and performance of applications and application components, e.g. how often certain features are used, measurements of start-up time and processing time, hardware, application crashes, and general usage statistics and/or user behavior. In some cases, very detailed data is reported like individual window metrics, counts of used features, and individual function timings.

This kind of telemetry can be essential to software developers to receive data from a wide variety of endpoints that can't possibly all be tested in-house, as well as getting data on the popularity of certain features and whether they should be given priority or be considered for removal. Due to concerns about privacy since software telemetry can easily be used to profile users, telemetry in user software is often user choice, commonly presented as an opt-in feature (requiring explicit user action to enable it) or user choice during the software installation process.

International standards

As in other telecommunications fields, international standards exist for telemetry equipment and software. International standards producing bodies include Consultative Committee for Space Data Systems (CCSDS) for space agencies, Inter-Range Instrumentation Group (IRIG) for missile ranges, and Telemetering Standards Coordination Committee (TSCC), an organisation of the International Foundation for Telemetering.