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14101–14150 of 16426 results (0.015 seconds)

Data Sets and Information
• instrument : Differential Long Base Line Interferometer for PIONEER VENUS LARGE PROBE
  This experiment involved applying differential long-baseline interferometry techniques to the radio signals from the entry probes and bus in order to infer or place upper limits on wind speeds in the lower atmosphere. These results were used in modeling the circulation patterns of Venus' atmosphere. As the four probes descended, the Pioneer Venus Probe Bus followed a well-defined ballistic trajectory above the atmosphere that was accurately known with respect to the planet's surface. Probe velocities were measured relative to the Bus. Additionally, four ground stations on Earth simultaneously tracked the four probes. These were the 64-meter dish Goldstone and Canberra Deep Space Network (DSN) stations, and the 9-meter dish Santiago (Chile) and Guam Spaceflight Tracking And Data Network (STDN) stations. They covered passbands of 2291 to 2293 MHz to receive signals from all four probes and the bus simultaneously. The Doppler frequency shifts of the received 13 cm (S-band) signals gave the component of the velocity vector along the Earth-spacecraft line of sight. The differential long-baseline interferometry was used to find the other two components of the velocity vector of each probe. Measurements of the temperature and pressure taken by other instruments as the probes descended were used with the interferometry results. Data taken prior to probe entry were used, where feasible, to infer characteristics of Venus' gravity field for use with probe entry operations as well as in later scientific evaluation. Deviations of the probe trajectories from the mathematical model of their trajectories in a still atmosphere were attributed to winds. Overall uncertainties were estimated at 10 cm/s. The magnitude of the wind velocity was found to be about 1 meter/s or less near the surface of the planet and about 100 meters/s near 65-km altitude at all four probe locations. High wind shear was measured centered at altitudes of 15, 45, and 60 km. The wind velocity was uniformly directed very close to due west, except within a few km of the surface.
• instrument : Atmospheric Structure Experiment for Pioneer Venus Large Probe
  The Large Probe Atmospheric Structure Experiment (LAS) of Pioneer Venus had instruments that included a three-axis accelerometer, pressure sensors, and temperature sensors. They were based on the technology demonstrated by the PAET rocket vehicle (Planetary Atmosphere Experiment Test R7106-2001). The measurements were used to construct a profile of atmosphere state properties for the large probe trajectory from the surface to approximately 140 km altitude. They were also used to determine vertical wind velocity, horizontal wind velocity, and turbulence. By comparing atmospheric conditions along the large probe trajectory with those measured by the small probes, circulation models of the atmosphere were determined. The instruments weighed about 2.3 kg and consumed about 4.9 W of power.
• instrument : Cloud Particle Size Spectrometer for Pioneer Venus Large Probe
  The Large Probe Cloud Particle Size Spectrometer (LCPS) of Pioneer Venus was an instrument with the objective to measure Venus' cloud particle sizes and concentrations. The LCPS comprised of a laser, spectrometers, a sapphire window, a system of prisms and lenses, array detectors, and electronics. The 2 mW He-Ne ruggedized Coherent 80-2T laser was used to illuminate cloud particles. The spectrometers are an Optical Array Spectrometer (OAS) that covers 5 to 500 microns particle range, and a Scattering Subrange Spectrometer (SSR), which covers a particle size range from 0.5 to 5 microns. Optical lenses imaged the particle shadows on arrays of detectors. The particle shadows were used to determine particle size and concentration. For low-rate channels, output data were registered to an 8-bit counter, while for high-rate channels it was a log compressed counter. The flight sensor was similar to those flown in aircraft and balloons.
• instrument : Gas Chromatograph for Pioneer Venus Large Probe
  The Large Probe Gas Chromatograph (LGC) of Pioneer Venus was an instrument with the objective to determine the composition of Venus' lower atmosphere. From these measurements, deductions were made of the gaseous sources of infrared opacity, the degree of differentiation of Venus' interior, the degree of similarity between the solid bodies of earth and Venus, and evolution of Venus' atmosphere. Gases the LGC was designed to detect and measure included oxygen (O2), carbon monoxide (CO), carbon dioxide (CO2), nitrogen (N2), water vapor (H2O), and sulfur dioxide (SO2). Two gas chromatograph columns were used to analyze samples of the atmosphere during probe descent. The long column, which was used for gases with mass range from neon to carbon dioxide, was kept at a temperature of 18.3 degrees C, and was made up of two 1585 cm long packed bifilarly wound columns, with 1.1 mm internal diameter. The short column, used for gases with masses between carbon dioxide and sulfur dioxide, was made up of two 213 cm long bifilarly wound columns (as well as an internal diameter of 1.1 mm), and operated at a temperature of 62.0 degrees C.
• instrument : Infrared Radiometer for Pioneer Venus Large Probe
  The Large Probe Infrared Radiometer (LIR) of Pioneer Venus was used to measure the atmosphere thermal flux profile, detect cloud layers and infer their composition, and estimate the atmospheric water vapor content. The instrument, comprised of a six-channel calibrated radiometer, measured the radiance difference at plus/minus 45 degrees to the horizontal. It operated in the wavelength range from 3 to 50 microns. Two internal blackbodies were used to allow absolute measurements of the flux in each channel. The instrument weighed about 2 kg and used about 3 W of power.
• instrument : Nephelometer for Pioneer Venus Large Probe
  The Large Probe Nephelometer (LN) of Pioneer Venus was an instrument that measured the energy backscattered from cloud particles, at around a wavelength of 900 nm. It used a solid-state pulsed gallium arsenide laser light emitting diode (LED) and detectors to illuminate the clouds. These detectors were made of three solid state photodiodes to allow the detection of the backscattering, ultraviolet background, and visible background. The altitude history of the backscattered signal indicated the presence and vertical extent of clouds along the trajectory. Comparisons with the measurements from the small probes indicated the spatial variability of the cloud structure. The experiment weighed about 0.5 kg and used about 1.3 W of power.
• instrument : Neutral Mass Spectrometer for Pioneer Venus Large Probe
  The Large Probe Neutral Mass Spectrometer (LNMS) of Pioneer Venus has a mass of 10.9 kg, a volume of 10650 cubic cm, and uses 14 W power. The instrument comprises a miniature magnetic sector-field mass analyzer, a gas inlet and pumping system, and an electronics (microprocessor) package all mounted on a 31 x 36 cm baseplate. It also had a noble gas enrichment cell, the Isotope Ratio Measurement Cell (IRMC), which collected an atmospheric sample at the beginning of instrument operation at around 62 km altitude. This sample was purged of carbon dioxide using sorption and getter pumping during the descent to enrich the inert gases in the cell, and then introduced the into the mass spectrometer just before parachute jettison. The inlet system consisted of a primary microleak (conductance of 0.0001 cubic mm per second) and a secondary microleak (0.001 cubic mm per second), which was only used in the upper atmosphere where the pressure was lower. The single focusing magnetic sector-field mass spectrometer consisted of the electron bombardment ion source, with selectable electron energies of 70 eV, 30 eV, or 22 eV, a magnetic momentum analyzer and a detector system, which had two electron multiplier-counter channels, one covering 1 - 16 amu and the other covering 15 - 208 amu. It also had two calibration gases containing 136Xe+, 136Xe++, and CH3+ producing peaks at 135.907, 67.954, and 15.035 amu.
• instrument : Solar Flux Radiometer for Pioneer Venus Large Probe
  The Large Probe Solar Flux Radiometer (LSFR) of Pioneer Venus was used to determine the regions in Venus' atmosphere where solar energy is deposited. To measure the intensity of scattered solar light, narrow-field-of-view detectors were used, covering the spectral range from 0.4 to 1.8 microns. As the probe descended through the atmosphere, the LSFR continuously measured the difference in atmospheric radiance above and below the horizon of the probe as a function of altitude, which allows the determination of how much sunlight was absorbed by the clouds and how much reached the surface. This approach provides more accurate radiation balance modeling of the atmosphere and will provide information on the role of the greenhouse effect on the heating of the Venus atmosphere. The instrument consisted of five 3-mm diameter fused silica lenses, with focal length of 11.45 mm and focal ratio of F/3.8, pointing in different directions: zenith (27 degrees), nadir (142 degrees), and 3 lenses at roughly azimuthally (60, 83, and 102 degrees).
• instrument : Differential Long Base Line Interferometer for PIONEER VENUS SMALL PROBE (DAY)
  This experiment involved applying differential long-baseline interferometry techniques to the radio signals from the entry probes and bus in order to infer or place upper limits on wind speeds in the lower atmosphere. These results were used in modeling the circulation patterns of Venus' atmosphere. As the four probes descended, the Pioneer Venus Probe Bus followed a well-defined ballistic trajectory above the atmosphere that was accurately known with respect to the planet's surface. Probe velocities were measured relative to the Bus. Additionally, four ground stations on Earth simultaneously tracked the four probes. These were the 64-meter dish Goldstone and Canberra Deep Space Network (DSN) stations, and the 9-meter dish Santiago (Chile) and Guam Spaceflight Tracking And Data Network (STDN) stations. They covered passbands of 2291 to 2293 MHz to receive signals from all four probes and the bus simultaneously. The Doppler frequency shifts of the received 13 cm (S-band) signals gave the component of the velocity vector along the Earth-spacecraft line of sight. The differential long-baseline interferometry was used to find the other two components of the velocity vector of each probe. Measurements of the temperature and pressure taken by other instruments as the probes descended were used with the interferometry results. Data taken prior to probe entry were used, where feasible, to infer characteristics of Venus' gravity field for use with probe entry operations as well as in later scientific evaluation. Deviations of the probe trajectories from the mathematical model of their trajectories in a still atmosphere were attributed to winds. Overall uncertainties were estimated at 10 cm/s. The magnitude of the wind velocity was found to be about 1 meter/s or less near the surface of the planet and about 100 meters/s near 65-km altitude at all four probe locations. High wind shear was measured centered at altitudes of 15, 45, and 60 km. The wind velocity was uniformly directed very close to due west, except within a few km of the surface.
• instrument : Atmosphere Structure Experiment for Pioneer Venus Small Probe (Day)
  The Small Probe (Day) Atmosphere Structure Experiment (SAS) of Pioneer Venus included a single-axis accelerometer, pressure sensors, and temperature sensors. They were based on the technology demonstrated by the PAET rocket vehicle (Planetary Atmosphere Experiment Test R 7106-2001). The measurements were used to construct a profile of atmospheric state properties for the trajectory from the surface to approximately 140 km altitude. They were also used to determine vertical wind velocity, horizontal wind velocity, and turbulence. By comparing atmospheric conditions along this trajectory with those measured by the other Probes, circulation models of the atmosphere were determined. The instruments weighed about 1.2 kg and consumed about 4.8 W of power.
• instrument : Nephelometer for Pioneer Venus Small Probe (Day)
  The Small Probe (Day) Nephelometer (SN) of Pioneer Venus was an instrument with the objectives to measure the energy backscattered from cloud particles, at around a wavelength of 900 nm. To illuminate the clouds, it used a solid-state pulsed gallium arsenide laser light emitting diode (LED) and detectors. These detectors were made of three solid state photodiodes to allow the detection of the backscattering, ultraviolet background, and visible background. The altitude history of the backscattered signal indicated the presence and vertical extent of clouds along the trajectory. When comparing the measurements from other probes, indications of the spatial variability of the cloud structure were found. The experiment weighed about 0.6 kg and used about 1.3 W of power.
• instrument : Net Flux Radiometer for Pioneer Venus Small Probe (Day)
  The Small Probe (Day) Net Flux Radiometer (SNFR) of Pioneer Venus was an instrument with the objectives to locate regions of radiative convergence and divergence as a function of altitude and to indicate the height at which solar energy is absorbed by the atmosphere of Venus, measured within the spectral range of 0.2 to 50 microns with a resolution of 1km. This experiment used a small net flux radiometer on the Probe targeted to the dayside of Venus to measure the net solar flux in the 0.2 to 4 micron region. The two probes targeted to the nightside of the planet carried net infrared flux sensors covering the 1 to 25 micron region. The SNFR was made of two modules, with the electronics module comprised of five circuit boards inside a gold plated titanium box. The modules contained amplifier, voltage controlled oscillator, max/min electronics, digital electronics, heater and solenoid drivers, power conversion unit, and temperature monitors. Two measurement periods were used by SNFR. When the probe’s altitude was roughly above 30 km, it used 8 second measurements, while below this altitude, it obtained maximum, minimum, and average flux difference measurements.
• instrument : Differential Long Base Line Interferometer for PIONEER VENUS SMALL PROBE (NIGHT)
  This experiment involved applying differential long-baseline interferometry techniques to the radio signals from the entry probes and bus in order to infer or place upper limits on wind speeds in the lower atmosphere. These results were used in modeling the circulation patterns of Venus' atmosphere. As the four probes descended, the Pioneer Venus Probe Bus followed a well-defined ballistic trajectory above the atmosphere that was accurately known with respect to the planet's surface. Probe velocities were measured relative to the Bus. Additionally, four ground stations on Earth simultaneously tracked the four probes. These were the 64-meter dish Goldstone and Canberra Deep Space Network (DSN) stations, and the 9-meter dish Santiago (Chile) and Guam Spaceflight Tracking And Data Network (STDN) stations. They covered passbands of 2291 to 2293 MHz to receive signals from all four probes and the bus simultaneously. The Doppler frequency shifts of the received 13 cm (S-band) signals gave the component of the velocity vector along the Earth-spacecraft line of sight. The differential long-baseline interferometry was used to find the other two components of the velocity vector of each probe. Measurements of the temperature and pressure taken by other instruments as the probes descended were used with the interferometry results. Data taken prior to probe entry were used, where feasible, to infer characteristics of Venus' gravity field for use with probe entry operations as well as in later scientific evaluation. Deviations of the probe trajectories from the mathematical model of their trajectories in a still atmosphere were attributed to winds. Overall uncertainties were estimated at 10 cm/s. The magnitude of the wind velocity was found to be about 1 meter/s or less near the surface of the planet and about 100 meters/s near 65-km altitude at all four probe locations. High wind shear was measured centered at altitudes of 15, 45, and 60 km. The wind velocity was uniformly directed very close to due west, except within a few km of the surface.
• instrument : Atmosphere Structure Experiment for Pioneer Venus Small Probe (Night)
  The Small Probe (Night) Atmosphere Structure Experiment (SAS) of Pioneer Venus included a single-axis accelerometer, pressure sensors, and temperature sensors. They were based on the technology demonstrated by the PAET rocket vehicle (Planetary Atmosphere Experiment Test R 7106-2001). The measurements were used to construct a profile of atmospheric state properties for the trajectory from the surface to approximately 140 km altitude. They were also used to determine vertical wind velocity, horizontal wind velocity, and turbulence. By comparing atmospheric conditions along this trajectory with those measured by the other Probes, circulation models of the atmosphere were determined. The instruments weighed about 1.2 kg and consumed about 4.8 W of power.
• instrument : Nephelometer for Pioneer Venus Small Probe (Night)
  The Small Probe (Night) Nephelometer (SN) of Pioneer Venus was an instrument with the objectives to measure the energy backscattered from cloud particles, at around a wavelength of 900 nm. To illuminate the clouds, it used a solid-state pulsed gallium arsenide laser light emitting diode (LED) and detectors. These detectors were made of three solid state photodiodes to allow the detection of the backscattering, ultraviolet background, and visible background. The altitude history of the backscattered signal indicated the presence and vertical extent of clouds along the trajectory. When comparing the measurements from other probes, indications of the spatial variability of the cloud structure were found. The experiment weighed about 0.6 kg and used about 1.3 W of power.
• instrument : Net Flux Radiometer for Pioneer Venus Small Probe (Night)
  The Small Probe (Night) Net Flux Radiometer (SNFR) of Pioneer Venus was an instrument with the objectives to locate regions of radiative convergence and divergence as a function of altitude and to indicate the height at which solar energy is absorbed by the atmosphere of Venus, measured within the spectral range of 0.2 to 50 microns with a resolution of 1km. This experiment used a small net flux radiometer on the Probe targeted to the dayside of Venus to measure the net solar flux in the 0.2 to 4 micron region. The two probes targeted to the nightside of the planet carried net infrared flux sensors covering the 1 to 25 micron region. The SNFR was made of two modules, with the electronics module comprised of five circuit boards inside a gold plated titanium box. The modules contained amplifier, voltage controlled oscillator, max/min electronics, digital electronics, heater and solenoid drivers, power conversion unit, and temperature monitors. Two measurement periods were used by SNFR. When the probe’s altitude was roughly above 30 km, it used 8 second measurements, while below this altitude, it obtained maximum, minimum, and average flux difference measurements. The instrument weighed about 0.4 kg and used 2.2 W of power.
• instrument : Differential Long Base Line Interferometer for PIONEER VENUS SMALL PROBE (NORTH)
  This experiment involved applying differential long-baseline interferometry techniques to the radio signals from the entry probes and bus in order to infer or place upper limits on wind speeds in the lower atmosphere. These results were used in modeling the circulation patterns of Venus' atmosphere. As the four probes descended, the Pioneer Venus Probe Bus followed a well-defined ballistic trajectory above the atmosphere that was accurately known with respect to the planet's surface. Probe velocities were measured relative to the Bus. Additionally, four ground stations on Earth simultaneously tracked the four probes. These were the 64-meter dish Goldstone and Canberra Deep Space Network (DSN) stations, and the 9-meter dish Santiago (Chile) and Guam Spaceflight Tracking And Data Network (STDN) stations. They covered passbands of 2291 to 2293 MHz to receive signals from all four probes and the bus simultaneously. The Doppler frequency shifts of the received 13 cm (S-band) signals gave the component of the velocity vector along the Earth-spacecraft line of sight. The differential long-baseline interferometry was used to find the other two components of the velocity vector of each probe. Measurements of the temperature and pressure taken by other instruments as the probes descended were used with the interferometry results. Data taken prior to probe entry were used, where feasible, to infer characteristics of Venus' gravity field for use with probe entry operations as well as in later scientific evaluation. Deviations of the probe trajectories from the mathematical model of their trajectories in a still atmosphere were attributed to winds. Overall uncertainties were estimated at 10 cm/s. The magnitude of the wind velocity was found to be about 1 meter/s or less near the surface of the planet and about 100 meters/s near 65-km altitude at all four probe locations. High wind shear was measured centered at altitudes of 15, 45, and 60 km. The wind velocity was uniformly directed very close to due west, except within a few km of the surface.
• instrument : Atmosphere Structure Experiment for Pioneer Venus Small Probe (North)
  The Small Probe (North) Atmosphere Structure Experiment (SAS) of Pioneer Venus included a single-axis accelerometer, pressure sensors, and temperature sensors. They were based on the technology demonstrated by the PAET rocket vehicle (Planetary Atmosphere Experiment Test R 7106-2001). The measurements were used to construct a profile of atmospheric state properties for the trajectory from the surface to approximately 140 km altitude. They were also used to determine vertical wind velocity, horizontal wind velocity, and turbulence. By comparing atmospheric conditions along this trajectory with those measured by the other Probes, circulation models of the atmosphere were determined. The instruments weighed about 1.2 kg and consumed about 4.8 W of power.
• instrument : Nephelometer for Pioneer Venus Small Probe (North)
  The Small Probe (North) Nephelometer (SN) of Pioneer Venus was an instrument with the objectives to measure the energy backscattered from cloud particles, at around a wavelength of 900 nm. To illuminate the clouds, it used a solid-state pulsed gallium arsenide laser light emitting diode (LED) and detectors. These detectors were made of three solid state photodiodes to allow the detection of the backscattering, ultraviolet background, and visible background. The altitude history of the backscattered signal indicated the presence and vertical extent of clouds along the trajectory. When comparing the measurements from other probes, indications of the spatial variability of the cloud structure were found. The experiment weighed about 0.6 kg and used about 1.3 W of power.
• instrument : Net Flux Radiometer for Pioneer Venus Small Probe (North)
  The Small Probe (North) Net Flux Radiometer (SNFR) of Pioneer Venus was an instrument with the objectives to locate regions of radiative convergence and divergence as a function of altitude and to indicate the height at which solar energy is absorbed by the atmosphere of Venus, measured within the spectral range of 0.2 to 50 microns with a resolution of 1km. This experiment used a small net flux radiometer on the Probe targeted to the dayside of Venus to measure the net solar flux in the 0.2 to 4 micron region. The two probes targeted to the nightside of the planet carried net infrared flux sensors covering the 1 to 25 micron region. The SNFR was made of two modules, with the electronics module comprised of five circuit boards inside a gold plated titanium box. The modules contained amplifier, voltage controlled oscillator, max/min electronics, digital electronics, heater and solenoid drivers, power conversion unit, and temperature monitors. Two measurement periods were used by SNFR. When the probe’s altitude was roughly above 30 km, it used 8 second measurements, while below this altitude, it obtained maximum, minimum, and average flux difference measurements. The instrument weighed about 0.4 kg and used 2.2 W of power.
• instrument : Orbiter Atmospheric Drag (OAD) for Pioneer Venus
  The Orbiter Atmospheric Drag (OAD) experiment utilized S-band and X-band radio signals from a spacecraft to gather data on the Venusian atmosphere. Its objectives included measuring the diurnal variation of thermospheric density, understanding the impact of solar wind on atmospheric density, examining the effects of solar extreme UV radiation, and investigating phenomena like semi-annual variations and super-rotation. The experiment analyzed Doppler shifts in radio transmissions to calculate spacecraft acceleration and drag coefficients, which, when combined with atmospheric models, helped estimate atmospheric density. The changing periapsis altitude allowed for sampling different atmospheric depths, contributing to studies on atmospheric variations and dynamics.
• instrument : Pioneer Venus Cloud Photopolarimeter
  The Cloud Photopolarimeter (OCPP) used a simplified version of the Imaging Photopolarimeter (IPP) flown on Pioneers 10 and 11 to provide low-resolution, four-color maps of the Venusian cloud cover with a high-resolution imaging capability near apocenter. The principal objective of this investigation was to determine the properties of the clouds and haze (both vertical and horizontal particle distribution), cloud particle size and refractive index, the cloud-top height, and the number density of particles. The instrument consists of a 3.7 cm Cassegrain telescope with a 15.7 cm focal length, backed by a 16 position filter wheel. The imaging mode has a 365-nm filter, a 0.4 x 0.45 mrad aperture field of view, and a single detector that feeds into the imaging channel. It can provide scan lines containing 1016 8-bit measurements of intensity (radiance), with a resolution of 30 km at the subspacecraft point. Approximately 3.5 hours are required to image the full planetary disk, or five full images in the roughly 18 hours of the orbit centered on apoapsis. The channel is sampled every 0.488 ms (0.610 ms low sample rate), absolute radiometric accuracy is 5%. The photopolarimetry mode uses four passband filters centered at 270 nm (far ultraviolet), 365 nm (ultraviolet), 550 nm (visible), and 935 nm (near infrared), with three half-wave retarder positions on the filter wheel for each of these. The field of view is 6.5 x 8 mrad, giving a resolution of 250 - 500 km at the subsatellite point. A Wollaston prism splits the output into two detectors, which are sampled simultaneously every 9.52 ms (28.6 ms low sample rate), with 11 bit a/d conversion, and an absolute radiometric accuracy of 5%. The limb-scan mode, used at the orbiter’s periapsis, uses a 690 nm filter with a 0.3 x 0.35 mrad field of view aperture and a single detector that feeds into the limb-scan channel, with a sampling every 0.310 ms (0.397 ms low sample rate) with 8 bit conversion, absolute radiometric accuracy is 5%. There is a calibration lamp for periodic calibration checks, which can view 0 to 145 degrees from the spacecraft spin axis by using the 5 rpm spin of the spacecraft. It uses a first in/first out 8192 bit memory (3072 bit section for photopolarimetry mode). The data format is 56 bits of status information followed by 8136 bits of data.
• instrument : Electric Field Detector (OEFD) for Pioneer Venus
  The Electric Field Detector (OEFD) for Pioneer Venus plasma wave instrument is a modified version of the Pioneer 8 and 9 experiments, designed to measure VLF electric fields at Venus across four narrow-band channels centered at 100, 730, 7350, and 30,000 Hz. Its goal is to analyze electric field interactions between the solar wind and Venus's plasma, as well as investigate plasma instabilities affecting heat flux and ion behavior. The instrument features a self-contained balanced V-type antenna and a 4-channel spectrum analyzer, with a total mass of 0.55 kg, and is capable of conducting spectral scans based on varying telemetry rates. The report outlines its design and in-flight performance.
• instrument : Electron Temperature Probe (OETP) for Pioneer Venus
  The Pioneer Venus Orbiter Electron Temperature Probe (OETP) is an instrument designed for in-situ measurements of electron temperature and plasma density in Venus' ionosphere. Utilizing cylindrical Langmuir probes, the OETP features adaptive voltage circuitry that continuously adjusts to changing conditions, enabling the collection of high-resolution data despite limited telemetry rates. The system includes independent amplifiers for each probe, adaptive sweep voltage circuits, and onboard data storage, facilitating the transmission of key ionospheric parameters to Earth. The probe has completed over 250 successful passes through Venus' nightside ionosphere, demonstrating robust performance in capturing crucial plasma characteristics.
• instrument : Gamma Ray Burst Detector (OGBD) for Pioneer Venus
  The Gamma Ray Burst Detector (OGBD) was an omnidirectional gamma-ray detector designed to observe high-energy gamma-ray bursts from astronomical sources, operating from 1978 to 1992. It utilized two Phoswich scintillation spectrometers sensitive to photon energies ranging from 0.1 to 2.0 MeV, enabling rapid data collection upon detecting gamma events. The instrument featured a full sky field of view and was capable of achieving source location accuracy of under one arc minute by leveraging long-distance data from Earth to Venus. With a total mass of 2.8 kg and power consumption of 1.3 W, the OGBD included multiple energy channels and utilized a pretrigger memory to capture transient data. Its data was compared with other satellite experiments for valid event confirmation.
• instrument : Ion Mass Spectrometer (OIMS) for Pioneer Venus
  The Pioneer Venus Orbiter Ion Mass Spectrometer (OIMS) was used to analyze the composition and concentration of thermal positive ions in Venus's ionosphere. This data helped interpret solar wind interactions with Venus, upper atmosphere photochemistry, and atmospheric mass and heat transport. The OIMS, designed similarly to instruments on previous missions, operates within a mass range of 1-56 amu and utilizes a Bennett radio-frequency mass spectrometer. Comprising an analyzer tube and an electronics package, the instrument weighs 3.0 kg and functions using 1.5 W of power for data processing and telemetry. The analyzer tube includes tungsten mesh grids and can measure 16 common ion masses. The instrument operates in 6.3-second cycles, alternating between an explore phase (measuring the selected masses) and an adapt phase (repeated measurements of detected ions).
• instrument : Infrared Radiometer (OIR) for Pioneer Venus
  The Orbiter Infrared Radiometer (OIR) was an advanced instrument designed for vertical temperature sounding of the atmosphere from cloud tops to 150 km on Venus, as well as for cloud morphology studies, including water vapor mapping. Based on Nimbus satellite technologies, the OIR operated for only 72 orbits before failing on February 14, 1979. The instrument featured eight channels, each focused on different wavelengths, which helped measure temperatures, cloud structures, total solar reflected intensity, and water vapor distribution. The OIR had dimensions of 24.8 x 17.5 x 25.1 cm, weighed 5.9 kg, and consumed 5.2 W of power, achieving a temperature sensitivity of better than 0.5 K. During its operation, it collected around 800,000 temperature profiles of the upper atmosphere.
• instrument : Fluxgate Magnetometer (OMAG) for Pioneer Venus
  The Fluxgate Magnetometer (OMAG) for Pioneer Venus operates with two ring-core sensors at the end of a 4.7-meter magnetometer boom and an additional sensor oriented at 45 degrees, is built upon the successful engineering principles utilized in previous Apollo missions. The primary objectives are to elucidate the presence of planetary and remnant magnetic fields, investigate the configuration and intensity of the ionospheric current system, analyze the energy and mass distribution in Venus's upper atmosphere, and explore solar wind interactions. Additionally, the instrument aims to characterize the Venusian near-wake region and the structure of the bow shock, as well as to assess the solar wind perturbations in the vicinity of Venus at different astronomical units (AU). The magnetometer architecture integrates three units: an electronics unit, an inboard sensor assembly, and an outboard sensor assembly, achieving a total mass of 2 kg with advanced operational capabilities. The magnetometers leverage a feedback-controlled triaxial fluxgate mechanism, enabling measurement resolution down to 1/16 gamma and accommodating varying sampling rates—critical during different mission phases. This research yields essential data, contributing to the fundamental understanding of Venus's space environment and the broader dynamics of solar system interactions, culminating in significant findings up to the last full orbital data collection on October 16, 1988.
• instrument : Orbiter Neutral Mass Spectrometer (ONMS) for Pioneer Venus
  The Neutral Mass Spectrometer (ONMS) is designed to measure the concentration of neutral atoms and molecules in Venus's upper atmosphere, ranging from 150 km to 500 km in altitude. The instrument is housed in a compact tube and includes a cylindrical chamber for ion source operations. It employs a quadrupole mass spectrometer with multiple ion-source modes to measure both noble gases in open mode and chemically active gases in closed mode, as well as a "flip-flop" mode for alternate measurements. The instrument can accurately analyze gas particles based on their mass, with a resolution of 0.0001 for mass readings from 1 to 46 amu. After being activated, the ONMS successfully detected and measured density variations of key atmospheric constituents including helium, oxygen, carbon dioxide, and nitrogen, contributing to a better understanding of Venus's atmospheric dynamics, chemistry, and thermal state.
• instrument : Solar Wind Plasma Analyzer (OPA) for Pioneer Venus
  The Solar Wind Plasma Analyzer (OPA) is a quadrispherical electrostatic analyzer designed to measure solar wind conditions such as velocity, density, flow direction, and temperature in various locations around Venus. It weighs 3.9 kg and operates on 5 W of power. The instrument features a pair of spherical plates with an entrance aperture that allows charged particles to pass through, eventually striking one of five current collectors. It can vary the voltage between the plates from 50 V to 8000 V for ions and from 3 V to 250 V for electrons, covering an extensive energy/charge range. It has a detection capability of particle flux in a 360-degree azimuth range and +/-85 degrees in elevation. The OPA operates in two modes: a command able scan mode to identify peak particle fluxes and a step mode for specific flux measurements.
• instrument : Surface Radar Mapper (ORAD) for Pioneer Venus
  The Pioneer Venus Orbiter's radar altimeter (ORAD) was designed to gather data on Venus's altitude, surface temperature, and radar properties to infer its topography and geological characteristics. Operating with a 38 cm antenna, ORAD emitted low-power S-band pulses to measure surface heights with an accuracy of 150 meters and derived data on electrical conductivity and surface roughness. The instrument weighed 9.7 kg and required 18 W of power, functioning when the spacecraft was below 4700 km altitude. ORAD conducted various measurements during each 12-second rotation of the spacecraft, including multiple altimetry measurements, radiometric assessments, and calibrations, aiming for high signal-to-noise ratios. The data collected ranged from December 5, 1978, to March 23, 1981, allowing detailed profiling of the Venusian surface.
• instrument : Orbiter Retarding Potential Analyzer (ORPA) for Pioneer Venus
  The Retarding Potential Analyzer (ORPA) is a Langmuir-probe retarding-potential analyzer designed to measure various characteristics of the ionosphere, including electron concentration, temperature, major ion concentrations, and ion drift velocities. An adaptation from an instrument flown on the German Aeros satellite in 1972, it has two sensor heads and operates in electron, ion, or photoelectron modes. The investigation aims to enhance understanding of ionic reactions in the Venusian ionosphere, plasma transport processes, and the interaction between the ionosphere and solar wind.The ORPA weighs 2.8 kg and operates on 2.4 W of power. It features an offset axis for alignment with the spacecraft's velocity vector and utilizes multiple collector grids to selectively funnel ionospheric particles. It operates in three modes: Langmuir probe, ion, and photoelectron, with varying voltage settings for different measurements. Scans are performed every 12 seconds while the spacecraft is in the ionosphere, allowing for numerous measurements and sampling data on concentrations, temperatures, and drift velocities of ions and electrons at specified intervals. A specific operational mode can measure total ion concentration over a 1-meter sampling distance along the spacecraft's trajectory.
• instrument : Pioneer Venus Orbiter Radio Science Experiment
  The Pioneer Venus Orbiter Radio Science Experiment was designed to use the spacecraft’s radio signal to study Venus’s atmosphere, ionosphere, gravity field, and surface properties. By analyzing changes in the frequency and phase of the spacecraft’s radio waves as they passed through the Venusian atmosphere, scientists could infer temperature, pressure, and density profiles. The experiment also provided data on the planet’s gravitational field by measuring tiny shifts in the spacecraft’s trajectory, helping to improve models of Venus’s internal structure. Additionally, the radio signals were used to study the solar corona when the spacecraft was in line with the Sun.
• instrument : Turbulence Experiment for Pioneer Venus Orbiter
  The Pioneer Venus Orbiter Turbulence Experiment (OTUR) used S- and X-band radio signals to measure turbulence intensity variations with altitude; planetary latitude and longitude; and atmospheric scale size distribution. It was designed to observe turbulence of scale sizes smaller than 10 km in the Venus atmosphere above 34 km for studying global patterns, and to measure ionospheric electron density variations.
• instrument : Pioneer Venus Orbiter Ultraviolet Spectrometer
  The Orbiter Ultraviolet Spectrometer (OUVS), or Airglow Ultraviolet Spectrometer, on Pioneer Venus was designed to map and make spectroscopic analyses of ultraviolet light scattered and emitted by the clouds and gases in the Venus atmosphere, in order to detect and measure airglow, scattered sunlight, and hydrogen Lyman-alpha emissions in the thermosphere, mesosphere, and exosphere of Venus. These measurements are used to establish and map the composition, temperature, and photochemistry of the thermosphere and ionosphere, to determine the pressure at and above the visible cloud tops, and to establish the distribution and escape rate of atomic hydrogen. The OUVS used a 250 mm Cassegrain telescope on a 125 mm focal length Ebert-Fastie monochromator with a programmable grating drive. The instrument operated in the 1100-3400 A region. The telescope had a lightshade assembly and a 5 cm aperture. It had a 1.83 x 0.16 degree field of view, 60 degrees from the spin axis. and focused the incoming light onto the Ebert-Fastie monochromator had a 3600 line/mm diffraction grating, with 15 Angstrom spectral resolution and 4.4 angstrom grating steps. It had two exit slits, which passed the dispersed light to two photomultiplier tubes, to convert the light into electrical impulses. One tube was sensitive to UV wavelengths from 1100 to 1900 Angstroms, while the other one covered wavelengths from 1900 to 3600 angstroms. Counting could be done up to 2 Hz, it could store up to 256 words of data, and an integration period of 4, 8, 16, or 32 ms, determined by ground command. The instrument had three primary modes of operation: spectral, wavelength, and, Lyman-Alpha.
• instrument : Butterfield Wind Tunnel, Whitehead Aeronautical Laboratory, Queen Mary University of London, UK
  The Butterfield Wind Tunnel is an open circulation, suction-style wind tunnel with length of 3 m and cross-sectional area of 0.16 by 0.16 m. Graeme Butterfield was associated with the Department of Geography and with Aerospace Engineering at Queen Mary and Westfield College, University of London, merged in 1989 to be Queen Mary University of London, UK.
• instrument : NASA Reflectance Experiment Laboratory Nicolet 740 FT-IR Spectrometer
  The NASA Reflectance Experiment Laboratory (RELAB) Nicolet 740 Fourier-Transform infrared spectrometer with a biconical diffuse reflectance accessory was manufactured by SpectraTech. Using a globar IR light source, NIR range (1.5-4 um) is measured with PbSe detector and Mid-IR range (2-25 um) with DTGS detector, both using KBr beam splitter. Spectrometer interior and sample compartment can be purged with dry air. In addition to its built-in sample compartment, an environmental chamber built by William Patterson and Janice Bishop is attached, allowing Mars-like environment a small, yellow-color dome containing just one sample. The standard reference material is typically diffuse gold. The instrument has been decommissioned.
• instrument : NASA Reflectance Experiment Laboratory Thermo Nexus 870 FT-IR Spectrometer
  The NASA Reflectance Experiment Laboratory (RELAB) Thermo Nexus 870 Fourier-Transform infrared spectrometer with an off-axis biconical diffuse reflectance accessory was manufactured by PIKE Technology. The incidence and emergence beams are reflected on a large gold mirror with large unknown cone angle footprints, including some grazing angle beams. The NIR range (1-4 um) is measured with a halogen-tungsten lamp, CaF2 beam splitter, and either DTGS (TE-cooled) or InSb (liquid N2 cooled) detecter, Mid-IR range (2-25 um) with a globar, KBr beam splitter, and DTGS detector, and Far-IR range (14-100 um) with a globar, a solid-state beam splitter, and DTGS detector. The standard reference material is usually diffuse gold.
• instrument : NASA Reflectance Experiment Laboratory Bidirectional Visible and Near Infrared Spectrometer
  The NASA Reflectance Experiment Laboratory (RELAB) highly bidirectional (8-degree cone angle on the detector side) reflectance spectrometer was built originally by Lockheed at NASA Johnson Space Center for returned lunar samples by Apollo 11 and later missions. Both the incidence and emergence angles can be independently changed up to about 70 degrees. The incidence arm is integrated with a lamp unit, a chopper, a monochromater, an order sorting filter wheel, and a scrambler lens, and the emergence arm is integrated with apertures, a telescope, and detectors. Halogen-Tungsten and Xenom lamps are used for UV and Vis-NIR ranges, and PMT and InSb (liquid N2 cooled) are used for UV-Vis and NIR ranges, respectively. The standard reference material was typically pressed halon until March 2018, and was switched to Spectralon manufactured by Labsphere after that date. Wavelength coverage is 0.3-2.6 um.
• instrument : The Alpha Particle X-Ray Spectrometer (APXS) for the Rosetta Philae Lander
  The design of the APXS instrument was based on the interaction of alpha particles and X-rays with matter. It has two operational modes: Alpha mode, which measured Rutherford backscattering; and X-ray mode, which measure alpha-particle and x-ray induced x-ray backscattering.
• instrument : The Comet Nucleus Infrared and Visual Analyser (CIVA) for the Rosetta Philae Lander
  The CIVA experiment comprised a suite of cameras (CIVA-P) to take panoramic images of the surface of comet 67P/Churyumov-Gerasimenko, as well as an optical microscope with a near-infrared microscops hyperspectral imager (CIVA-M) to study surface and subsurface samples in detail.
• instrument : The Comet Nucleus Sounding Experiment by Radiowave Transmission (CONSERT) for the Rosetta Philae Lander
  The CONSERT experiment was designed to obtain tomography of the comet nucleus through instruments mounted both on the Philae lander and on the orbiter. The CONSERT system would have acted as a time domain transponder betweed one module on the lander and another on the orbiter.
• instrument : The Cometary Sampling and Composition Experiment (COSAC) for the Rosetta Philae Lander
  The COSAC experiment comprised two instruments: A gas chromatograph with eight columns, each with a thermal conductivity detector; and a time-of-flight mass spectrometer with a multi-sphere plate detector.
• instrument : The Multi Purpose Suite for Surface and Subsurface Science (MUPUS) for the Rosetta Philae Lander
  The MUPUS experiment consisted of a penetrator equipped with 16 thermal sensors, an infrared radiometer, and thermal and accelerometer sensors located in the harpoons the Philae lander would use to anchor itself to the comet surface.
• instrument : The Ptolemy Gas Chromatograph Isotope Ratio Mass Spectrometer for the Rosetta Philae Lander
  The Ptolemy instrument detector was an ion trap mass spectrometer. It was one of two (the other being the COSAC experiment) evolved gas analyzers on the Philae Lander.
• instrument : The Rosetta Lander Imaging System (ROLIS) Descent and Closeup Imager for the Philae
  The ROLIS consisted of a miniature CCD imager pointing downwards from the Philae Lander, with an array of light-emitting diodes (LEDs) raditing in four spectral bands in the visible and near-infrared to illuminate the comet surface after landing. ROLIS was also used for imaging the comet surface as the lander descended to the comet surface.
• instrument : Rosetta Magnetometer and Plasma Monitor (ROMAP) for the Rosetta Philae Lander
  The ROMAP experiment included a fluxgate magnetometer, an electrostatis analyzer, and a Faraday cup. It could measure the magnetic field (0 - 32Hz), ions (up to 8.0 keV), and electrons (up to 4.2 keV). Two additional pressure sensors were also included in the ROMAP configuration.
• instrument : The Sampling, Drilling and Distribution (SD2) Subsystem for the Rosetta Philae Lander
  The SD2 subsystem included a drill, carousel, volume checker, and electronics. The SD2 was to collect samples from the surface of the comet, record the details of the collection, verify the volume collected, and distribute the samples to the CIVA and COSAC experiments.
• instrument : The Surface Electric Sounding and Acoustic Monitoring Experiment for the Rosetta Philae Lander
  The SESAME experiment contained three parts: The Comet Acoustic Surface Sounding Experiment (CASSE); the Dust Impact Monitor (DIM); and the Permitivity Probe (PP). CASSE consisted of accelerometers and Piezo stacks mounted on the bottom of the Philae lander's feet to record and generate vibrations in the audible frequency range. DIM was a piezoelectric detector and analyzer for the impacts of cometary dust particles. PP used a quadrupole configuration of sensors on various parts of the Philae lander, with metal meshes on the feet of the lander touching the comet surface and three transmitters located on the lander, to measure the permissivity of the surface material on the comet nucleus.
• instrument : The Alice Spectrometer for the Rosetta Orbiter
  The ALICE instrument was a Roland Circle style imaging spectrograph designed to perform far-UV spectroscopy in the range 700-2050 angstroms with a spectral resolution of 8 - 12 angstroms. Light passed through a concave, toroidal, holographic reflection grating used in first order. The detector was a microchannel plate with 1024 pixels in the wavelength dimension.

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