TRW Inc. was an American corporation involved in a variety of businesses aerospace and credit reporting. It was a pioneer in multiple fields including electronic components, integrated circuits, computers and systems engineering. TRW built many spacecraft, including Pioneer 1, Pioneer 10, several space-based observatories, it was #57 on the 1986 Fortune 500 list, had 122,258 employees. In 1958 the company was called Thompson Ramo Wooldridge, after three prominent leaders; this was shortened to TRW. The company's roots were founded in 1901, it lasted for more than a century until being acquired by Northrop Grumman in 2002, it helped create a variety of corporations, including Pacific Semiconductors, the Aerospace Corporation, Bunker-Ramo, TRW Automotive, now part of ZF Friedrichshafen. People coming from TRW were important to building up corporations like SpaceX. In 1953, the company was recruited to lead the development of the United States' first ICBM. Starting with the initial design by Convair, the multi-corporate team launched Atlas in 1957.
It flew its full range in 1958, was adapted to fly the Mercury astronauts into orbit. TRW led development of the Titan missile, adapted to fly the Gemini missions; the company served the US Air Force as systems engineers on all subsequent ICBM development efforts, but TRW never produced any missile hardware because of the conflict of interest. In 1960, Congress spurred the formation of the non-profit Aerospace Corporation to provide systems engineering to the US government, but TRW continued to guide the ICBM efforts. TRW originated in 1901 with the Cleveland Cap Screw Company, founded by David Kurtz and four other Cleveland residents, their initial products were bolts with heads electrically welded to the shafts. In 1904, a welder named Charles E. Thompson adapted their process to making automobile engine valves, and, by 1915, the company was the largest valve producer in the United States. Charles Thompson was named general manager of the company, which became Thompson Products in 1926, their experimental hollow sodium-cooled valves aided Charles Lindbergh's solo flight across the Atlantic.
In 1937, Thompson Motor Products bought J. A. Drake and Sons; the company made high-performance valves that were used in many racing engines of the day, including the Miller Offy. Dale Drake bought the Offy engine design with his partner Louis Meyer in 1946 and won the Indianapolis 500 twenty-seven times, more than any other engine design. During the period leading up to World War II, through the end of the Korean war, Thompson Products was a key manufacturer of component parts for aircraft engines, including aircraft valves; the TAPCO plant, owned by the US government but operated by Thompson Products, extended for a mile along Cleveland's Euclid Avenue. It employed over 16,000 workers at the peak of WW II production; as jet aircraft replaced piston-engined aircraft, Thompson Products became a major manufacturer of turbine blades for jet engines In 1950, Simon Ramo and Dean Wooldridge while working for Hughes Aircraft, led the development of the Falcon radar-guided missile, among other projects.
They grew frustrated with Howard Hughes' management, formed the Ramo-Wooldridge Corporation in September 1953, with the financial support of Thompson Products. The detonation of a thermonuclear bomb by the Soviet Union spurred Trevor Gardner to form the Teapot Committee in October 1953. Chaired by John von Neumann, its purpose was to study the development of ballistic missiles, including ICBMs. Ramo and Wooldridge were committee members, Ramo-Wooldridge Corp. became the lead contractor of the resulting ICBM development effort, reporting to the United States Air Force. With continued backing from Thompson Products, Ramo-Wooldridge diversified into computers and electronic components, founding Pacific Semiconductors in 1954, they produced scientific spacecraft such as Pioneer 1. Thompson Products and Ramo-Wooldridge merged in October 1958 to form Thompson Ramo Wooldridge Inc. unofficially known as "TRW". In February 1959, Jimmy Doolittle became Chairman of the Board of Space Technology Laboratories, the division which continued to support the Air Force ICBM efforts.
Other aerospace companies challenged that TRW's Air Force advisory role granted it unfair access to its competitors' technology, in September 1959 the United States Congress issued a report recommending that STL be converted to a non-profit organization. With nearly half of STL's employees, The Aerospace Corporation was formed in June 1960, which headed the Atlas conversion for Mercury, Titan conversion for Gemini, provides ongoing systems engineering support for the United States government; the Air Force continued its ICBM work with TRW. Dean Wooldridge retired in January 1962 to become a professor at California Institute of Technology. Simon Ramo became President of the Bunker-Ramo Corp in January 1964, a company jointly owned by TRW and Martin Marietta for the production of computers and computer monitors. Thompson Ramo Wooldridge became TRW Inc. in July 1965. Free of anti-competitive restrictions except regarding ICBM hardware, STL was renamed TRW Systems Group in July 1965. In 1968, the company entered the credit reporting industry by purchasing Credit Data Corporation and renaming it TRW Information Systems and Services Inc. a subsidiary of the company.
The Credit Data group was formed in 1970 to compete with Dun & Bradstreet, from the combination of TRWISS and ESL, acquired in 1978, specializing in technical strategic reconnaissance. TRW Information Systems and Services Division was spun off in 1996 to form Experian. TRW acquired LucasVarity in 1999 sold Lucas Diesel Systems to Delphi Automotive, L
Pioneer 4 was an American spin-stabilized unmanned spacecraft launched as part of the Pioneer program on a lunar flyby trajectory and into a heliocentric orbit making it the first probe of the United States to escape from the Earth's gravity. It carried a payload similar to Pioneer 3: a lunar radiation environment experiment using a Geiger–Müller tube detector and a lunar photography experiment, it passed within 58,983 km of the Moon's surface. However, Pioneer 4 did not come close enough to trigger its photoelectric sensor; the spacecraft was still in solar orbit as of 1969. It was the only successful lunar probe launched by the U. S. in 12 attempts between 1958–63. After the Soviet Luna 1 probe conducted the first successful flyby of the Moon on January 3, 1959, the pressure felt by the US to succeed with a lunar mission was enormous since American mission failures were public while the Soviet failures were kept a secret. Pioneer 4 was 23 cm in diameter at its base; the cone was composed of a thin fiberglass shell coated with a gold wash to make it electrically conducting and painted with white stripes to maintain the temperature between 10 and 50 degrees Celsius.
At the tip of the cone was a small probe which combined with the cone itself to act as an antenna. At the base of the cone a ring of mercury batteries provided power. A photoelectric sensor protruded from the center of the ring; the sensor was designed with two photocells which would be triggered by the light of the Moon when the probe was within about 30,000 km of the Moon. At the center of the cone was a voltage supply tube and two Geiger–Müller tubes; the Laboratory's Microlock system, used for communicating with earlier Explorer satellites, did not have sufficient range to perform this mission. Therefore a new radio system called TRAC Communication was designed. TRAC was an integral part of the Goldstone Deep Space Communications Complex. A transmitter with a mass of 0.5 kilograms delivered a phase modulated signal of 0.1 W at a frequency of 960.05 MHz. The modulated carrier power was 0.08 W and the total effective radiated power 0.18 W. A despin mechanism consisted of two 7 gram weights which spooled out to the end of two 150 cm wires when triggered by a hydraulic timer 10 hours after launch.
The weights were designed to slow the spacecraft spin from 400 rpm to 6 rpm, weights and wires were released. Pioneer 4 received a few small modifications over its predecessor, namely added lead shielding around the Geiger tubes and modifications to the telemetry system to improve its reliability and signal strength; the probe had S/N #4, with probe #3 recalled from launch due to technical issues. Pioneer 4 was launched with a Juno II launch vehicle, which launched Pioneer 3. Juno II resembled the Juno I vehicle that launched Explorer 1, its first stage was a 19.51 m elongated Jupiter IRBM missile, used by the U. S. Army. On top of the Jupiter propulsion section was a guidance and control compartment that supported a rotating tub containing the rocket stages 2, 3 and 4. Pioneer 4 was mounted on top of stage 4. At 12:10 AM EST on the night of March 2-3 of 1959, Pioneer 4 lifted from LC-5; this time, the booster performed perfectly so that Pioneer 4 achieved its primary objective, returned radiation data and provided a valuable tracking exercise.
A longer than nominal second stage burn however was enough to induce small trajectory and velocity errors, so that the probe passed within 60,000 km of the Moon's surface on 4 March 1959 at 22:25 UT at a speed of 7,230 km/h. The distance was not close enough to trigger the photoelectric sensor; the probe continued transmitting radiation data for 82.5 hours, to a distance of 409,000 miles, reached perihelion on 18 March 1959 at 01:00 UT. The cylindrical fourth stage casing went into orbit with the probe; the communication system had worked well, it was estimated that signals could have been received out to 680,000 miles had there been enough battery power. Luna 1 – a similar Soviet space program mission launched January 2, 1959, several weeks before Pioneer 4. NASA JPL Pioneer 3 and 4 NSSDC Master Catalog: Spacecraft Pioneer 4
Pioneer 5 was a spin-stabilized space probe in the NASA Pioneer program used to investigate interplanetary space between the orbits of Earth and Venus. It was launched on March 11, 1960 from Cape Canaveral Air Force Station Launch Complex 17A at 13:00:00 UTC with an on-orbit dry mass of 43 kg, it was a 0.66 m diameter sphere with 1.4 m span across its four solar panels and achieved a solar orbit of 0.806 × 0.995 AU. Data was received until April 30, 1960. Among other accomplishments, the probe confirmed the existence of interplanetary magnetic fields. Pioneer 5 was the most successful probe in the Pioneer/Able series; the original mission plan was for a launch in November 1959 where Pioneer 5 would conduct a flyby of Venus, but technical issues prevented the launch from occurring until early 1960 by which time the Venus window for the year had closed. Since it was not possible to send the probe to Venus, it would instead investigate interplanetary space and an actual mission to the planet would have to wait another three years.
The spacecraft was a 0.66 m diameter sphere with four solar panels. It was equipped with four scientific instruments: A triple coincidence omnidirectional proportional counter telescope to detect solar particles and observe terrestrial trapped radiation, it could detect photons with E > 75 MeV and electrons with E > 13 MeV. A rotating search coil magnetometer to measure the magnetic field in the distant field of the Earth, near the geomagnetic boundary, in interplanetary space, it was capable of measuring fields from 1 microgauss to 12 milligauss. It consisted of a single search coil, mounted on the spacecraft in such a way that it measured the magnetic field perpendicular to the spin axis of the spacecraft, it could output its measurements in a digital format. A Neher-type integrating ionization chamber and an Anton 302 Geiger-Müller tube to measure cosmic radiation, it was mounted normal to the spin axis of the spacecraft. A micrometeorite momentum spectrometer that consisted of two microphone combinations.
It was used to measure the momentum of these particles. Booster performance during launch was overall excellent considering the numerous earlier difficulties with the Thor-Able vehicle. There were some minor anomalies with the second stage flight control system that resulted in unplanned pitch and roll motions, however they were not enough to endanger the mission; the spacecraft returned data collected by the magnetometer on the magnetic field and it measured that the median undisturbed interplanetary field was 5 γ ± 0.5 γ in magnitude. The spacecraft measured solar flare particles, cosmic radiation in the interplanetary region; the micrometeorite counter failed to operate as the data system saturated and failed to operate properly. The recorded digital data were transmitted at 1, 8, 64 bit/s, depending on the distance of the spacecraft from Earth and the size of the receiving antenna. Weight limitations on the solar cells prevented continuous operation of the telemetry transmitters. About four operations of 25 min duration were scheduled per day with occasional increases during times of special interest.
A total of 138.9 h of operation was completed, over three megabits of data were received. The major portion of the data was received by the Lovell radio telescope at Jodrell Bank Observatory and the Hawaii Tracking Station because their antennas provided grid reception. Data was received until April 30, 1960, after which telemetry noise and weak signal strength made data reception impossible; the spacecraft's signal was detected by Jodrell Bank from a record distance of 36.2 million km on June 26, 1960, although it was much too weak by to acquire data. In common with Explorer 6, Pioneer 5 used the earliest known digital telemetry system used on spacecraft, codenamed "Telebit". Which was a tenfold improvement in channel efficiency on previous generation "Microlock" analog systems in use since Explorer 1 and the biggest single improvement in signal encoding on western spacecraft; the spacecraft received the uplink carrier at 401.8 MHz and converted it to a 378.2 MHz signal using a 16/17 coherent oscillator circuit.
The telemetry system phase modulated a 512 Hz subcarrier, in turn amplitude modulated at 64, 8, or 1bit/s. The spacecraft was unable to aim its antennas, so had no high-gain dish antenna common on spacecraft. Instead, the system could introduce a 150W amplifier into its 5W transmitter circuit, it was powered by a battery of 28 F-size NiCd cells recharged by the solar paddles, allowing up to eight minutes of high power communications before risking damage to the batteries. Each hour of 5W communications or five minutes of 150W communications required ten hours of recharging the batteries. Unlike interplanetary spacecraft, this spacecraft did not use the Deep Space Network, not yet available, but a somewhat ad hoc Space Network called SPAN consisting of the 76m Lovell Telescope, a 26-meter radio telescope in Hawaii, a small helical array in Singapore. Pioneer program Timeline of artificial satellites and space probes Mariner 2 Pioneer 5 Profile by NASA's Solar System Exploration Space Technology Laboratories Documents Archive
Pioneer Venus Multiprobe
The Pioneer Venus Multiprobe known as Pioneer Venus 2 or Pioneer 13 was a spacecraft launched in 1978 to explore Venus as part of NASA's Pioneer program. This part of the mission included a spacecraft Bus, launched from Earth carrying one large and three smaller probes, which after separating penetrated the Venusian atmosphere at a different location, returning data as they descended into the planet's thick atmosphere; the entry occurred on December 9, 1978. There was an orbiter launched this year, part of the overall Pioneer Venus project along with this entry probe mission. Whereas the probes entered the atmosphere in 1978, the orbiter would stay in orbit throughout the 1980s and the early 1990s; the next major mission was the Magellan spacecraft, an orbiter capable mapping Venus by seeing through its opaque clouds with radar. Another NASA entry probe mission was the Galileo probe, for planet Jupiter; the Pioneer Venus Multiprobe bus was constructed by the Hughes Aircraft Company, built around the HS-507 bus.
It was cylindrical in shape, with a mass of 290 kilograms. Unlike the probes, which did not begin making direct measurements until they had decelerated lower in the atmosphere, the bus returned data on Venus' upper atmosphere; the bus was targeted to enter the Venusian atmosphere at a shallow entry angle and transmit data until destruction by the heat of atmospheric friction. The objective was to study the structure and composition of the atmosphere down to the surface, the nature and composition of the clouds, the radiation field and energy exchange in the lower atmosphere, local information on atmospheric circulation patterns. With no heat shield or parachute, the bus made upper atmospheric measurements with two instruments: BIMS - an ion mass spectrometer to determine the origin and long-term development of the Venusian atmosphere, the dynamics of the upper atmosphere layers, its energy balance and the effect of solar radiation and interplanetary space on those layers; this instrument used 6 W of power and weighed 5 kilograms.
BNMS - a neutral mass spectrometer. This made measurements of the interaction between the solar wind and Venus, the photochemistry of the upper layers of and heat distribution in the Venusian atmosphere, it had a range of 1 to 60 u, weighed 1 kilogram, used ~1W of power. The spacecraft operated down to an altitude of about 110 km before disintegrating; the spacecraft carried one large and three small atmospheric probes, designed to collect data as they descended into the atmosphere of Venus. The probes did not carry photographic instruments, were not designed to survive landing – the smaller probes were not equipped with parachutes, the larger probe's parachute was expected to detach as it neared the ground. All four probes continued transmitting data until impact; the Large probe carried seven experiments, contained within a sealed spherical pressure vessel. The science experiments were: LNMS - neutral mass spectrometer to measure the atmospheric composition LGC - gas chromatograph to measure the atmospheric composition LSFR - solar flux radiometer to measure solar flux penetration in the atmosphere LIR - infrared radiometer to measure distribution of infrared radiation LCPS - cloud particle size spectrometer to measure particle size and shape LN - nephelometer to search for cloud particles temperature and acceleration sensorsThis pressure vessel was encased in a nose cone and aft protective cover.
After deceleration from initial atmospheric entry at about 11.5 kilometres per second near the equator on the night side of Venus, a parachute was deployed at 67 km altitude. The large probe was about 150 centimetres in diameter and the pressure vessel itself was 73.2 centimeters in diameter. Three identical small probes, around 0.8 metres in diameter, were deployed. These probes consisted of spherical pressure vessels surrounded by an aeroshell, but unlike the large probe, they had no parachutes and the aeroshells did not separate from the probes; the science experiments were: a neutral mass spectrometer to measure the atmospheric composition a gas chromatograph to measure the atmospheric composition SNFR - solar flux radiometer to measure solar flux penetration in the atmosphere an infrared radiometer to measure distribution of infrared radiation MTUR - cloud particle size spectrometer to measure particle size and shape SN - nephelometer to search for cloud particles SAS - temperature and acceleration sensorsThe radio signals from all four probes were used to characterize the winds and propagation in the atmosphere.
The small probes were each were named accordingly. The North probe entered the atmosphere at about 60 degrees north latitude on the day side; the Night probe entered on the night side. The Day probe entered well into the day side, was the only one of the four probes which continued to send radio signals back after impact, for over an hour; the Pioneer Venus Multiprobe was launched by an Atlas SLV-3D Centaur-D1AR rocket, which flew from Launch Complex 36A at the Cape Canaveral Air Force Station. The launch occurred at 07:33 on August 8, 1978, deployed the Multiprobe into heliocentric orbit for its coast to Venus. Prior to the Multiprobe reaching Venus, the four probes were deployed from the main bus; the large probe was released on November 16, 1978, the three small probes on November 20. All four probes and the bus reached Venus on December 9, 1978; the large probe was the first to enter the atmosphere, at 18:45:32 UTC, followed over the next 11 minutes by the other t
In geometry, a frustum is the portion of a solid that lies between one or two parallel planes cutting it. A right frustum is a parallel truncation of a right right cone. In computer graphics, the viewing frustum is the three-dimensional region, visible on the screen, it is formed by a clipped pyramid. In the aerospace industry, a frustum is the fairing between two stages of a multistage rocket, shaped like a truncated cone. If all the edges are forced to be identical, a frustum becomes a uniform prism; each plane section is a base of the frustum. Its axis if any, is that of the original pyramid. A frustum is circular; the height of a frustum is the perpendicular distance between the planes of the two bases. Cones and pyramids can be viewed as degenerate cases of frusta, where one of the cutting planes passes through the apex; the pyramidal frusta are a subclass of the prismatoids. Two frusta joined at their bases make a bifrustum; the volume formula of a frustum of a square pyramid was introduced by the ancient Egyptian mathematics in what is called the Moscow Mathematical Papyrus, written in the 13th dynasty: V = 1 3 h. where a and b are the base and top side lengths of the truncated pyramid, h is the height.
The Egyptians knew the correct formula for obtaining the volume of a truncated square pyramid, but no proof of this equation is given in the Moscow papyrus. The volume of a conical or pyramidal frustum is the volume of the solid before slicing the apex off, minus the volume of the apex: V = h 1 B 1 − h 2 B 2 3 where B1 is the area of one base, B2 is the area of the other base, h1, h2 are the perpendicular heights from the apex to the planes of the two bases. Considering that B 1 h 1 2 = B 2 h 2 2 = B 1 B 2 h 1 h 2 = α,the formula for the volume can be expressed as a product of this proportionality α/3 and a difference of cubes of heights h1 and h2 only. V = h 1 α h 1 2 − h 2 α h 2 2 3 = α 3 By factoring the difference of two cubes one gets h1−h2 = h, the height of the frustum, α/3. Distributing α and substituting from its definition, the Heronian mean of areas B1 and B2 is obtained; the alternative formula is therefore V = h 3. Heron of Alexandria is noted for deriving this formula and with it encountering the imaginary number, the square root of negative one.
In particular, the volume of a circular cone frustum is V = π h 3 where π is 3.14159265... and r1, r2 are the radii of the two bases. The volume of a pyramidal frustum whose bases are n-sided regular polygons is V = n h 12 cot π n where a1 and a2 are the sides of the two bases. For a right circular conical frustum Lateral surface area = π s = π
The ionization chamber is the simplest of all gas-filled radiation detectors, is used for the detection and measurement of certain types of ionizing radiation. Conventionally, the term "ionization chamber" is used to describe those detectors which collect all the charges created by direct ionization within the gas through the application of an electric field, it only uses the discrete charges created by each interaction between the incident radiation and the gas, does not involve the gas multiplication mechanisms used by other radiation instruments, such as the Geiger counter or the proportional counter. Ion chambers have a good uniform response to radiation over a wide range of energies and are the preferred means of measuring high levels of gamma radiation, they are used in the nuclear power industry, research labs, radiography and environmental monitoring. An ionization chamber measures the charge from the number of ion pairs created within a gas caused by incident radiation, it consists of a gas-filled chamber with two electrodes.
The electrodes may be in the form of parallel plates, or a cylinder arrangement with a coaxially located internal anode wire. A voltage potential is applied between the electrodes to create an electric field in the fill gas; when gas between the electrodes is ionized by incident ionizing radiation, ion-pairs are created and the resultant positive ions and dissociated electrons move to the electrodes of the opposite polarity under the influence of the electric field. This generates an ionization current, measured by an electrometer circuit; the electrometer must be capable of measuring the small output current, in the region of femtoamperes to picoamperes, depending on the chamber design, radiation dose and applied voltage. Each ion pair created deposits or removes a small electric charge to or from an electrode, such that the accumulated charge is proportional to the number of ion pairs created, hence the radiation dose; this continual generation of charge produces an ionization current, a measure of the total ionizing dose entering the chamber.
However, the chamber cannot discriminate between radiation types and cannot produce an energy spectrum of radiation. The electric field enables the device to work continuously by mopping up electrons, which prevents the fill gas from becoming saturated, where no more ions could be collected, by preventing the recombination of ion pairs, which would diminish the ion current; this mode of operation is referred to as "current" mode, meaning that the output signal is a continuous current, not a pulse output as in the cases of the Geiger–Müller tube or the proportional counter. Referring to the accompanying ion pair collection graph, it can be seen that in the "ion chamber" operating region the collection of ion pairs is constant over a range of applied voltage, as due to its low electric field strength the ion chamber does not have any "multiplication effect"; this is in distinction to the Geiger–Müller tube or the proportional counter whereby secondary electrons, multiple avalanches amplify the original ion-current charge.
The following chamber types are used. This is a chamber open to atmosphere, where the fill gas is ambient air; the domestic smoke detector is a good example of this, where a natural flow of air through the chamber is necessary so that smoke particles can be detected by the change in ion current. Other examples are applications where the ions are created outside the chamber but are carried in by a forced flow of air or gas; these chambers are cylindrical and operate at atmospheric pressure, but to prevent ingress of moisture a filter containing a desiccant is installed in the vent line. This is to stop moisture building up in the interior of the chamber, which would otherwise be introduced by the "pump" effect of changing atmospheric air pressure; these chambers have a cylindrical body made of plastic a few millimetres thick. The material is selected to have an atomic number similar to that of air so that the wall is said to be "air equivalent" over a range of radiation beam energies; this has the effect of ensuring the gas in the chamber is acting as though it were a portion of an infinitely large gas volume, increases the accuracy by reducing interactions of gamma with the wall material.
The higher the atomic number of the wall material, the greater the chance of interaction. The wall thickness is a trade-off between maintaining the air effect with a thicker wall, increasing sensitivity by using a thinner wall; these chambers have an end window made of material thin enough, such as mylar, so that beta particles can enter the gas volume. Gamma radiation enters both through the side walls. For hand-held instruments the wall thickness is made as uniform as possible to reduce photon directionality though any beta window response is highly directional. Vented chambers are susceptible to small changes in efficiency with air pressure and correction factors can be applied for accurate measurement applications; these are similar in construction to the vented chamber but are sealed and operate at or around atmospheric pressure. They contain a special fill gas to improve detection efficiency as free electrons are captured in air-filled vented chambers by neutral oxygen, electronegative, to form negative ions.
These chambers have the advantage of not requiring a vent and desiccant. The beta end window limits the differential pressure from atmospheric pressure that can be tolerated, common materials are stainless steel or titanium with a t