1) SOFIA is a joint US-German airborne observatory consisting of a 2.5-meter telescope mounted in a modified Boeing 747. It will observe in the infrared and submillimeter wavelengths between 0.3-1600 microns.
2) Nine instruments are under development to cover this wavelength range with both imaging and spectroscopic capabilities at resolutions from narrow bands to high resolution spectroscopy.
3) Key early science goals include studying the interstellar medium of galaxies using fine structure lines, measuring the interstellar deuterium abundance using HD lines, and conducting spectral surveys to identify new spectral lines.
The Stratospheric Observatory for Infrared Astronomy (SOFIA) is an airborne observatory consisting of a 2.7-meter telescope mounted in a modified Boeing 747-SP aircraft. Funded by NASA and the German Aerospace Agency, SOFIA is scheduled to begin science flights in late 2005 operating at altitudes around 41,000 feet. SOFIA will allow astronomers to make infrared observations of astronomical sources with unprecedented angular resolution and sensitivity. The aircraft and telescope were developed through the collaboration of US and German government, academic, and industry partners.
This document provides an introduction to microwave remote sensing, including an overview of microwave instrumentation, frequency channels, and applications. It discusses how microwave sensing complements other methods by providing vertical atmospheric profiles and observing through non-precipitating clouds. Examples are given of products like total precipitable water, cloud liquid water, and wind speed that are derived from combining microwave channel measurements.
Hyperspectral remote sensing uses narrow, contiguous bands across the electromagnetic spectrum to characterize vegetation. It is useful for studying species composition, crop/vegetation type, biophysical properties like leaf area index and biomass, biochemical properties like chlorophyll and moisture, and stress factors. Hyperspectral data comes from airborne, ground, and spaceborne sensors, with spaceborne providing global continuous coverage but at lower spatial resolution than airborne sensors. Hyperspectral data cubes contain hundreds of bands providing detailed spectral signatures to distinguish vegetation.
Microwave sensing systems use sensors that operate in the microwave portion of the electromagnetic spectrum between 1 mm and 1 m wavelengths. These sensors include radars and radiometers that can image outside the visible and infrared regions. Microwaves can penetrate haze, clouds, smoke and pollution, allowing these sensors to image in all weather conditions unlike visible and infrared sensors. Common microwave remote sensing platforms include synthetic aperture radar, scatterometers and radar altimeters.
TU2.L10 - ACCURATE MONITORING OF TERRESTRIAL AEROSOLS AND TOTAL SOLAR IRRADIA...grssieee
The Glory mission aims to better understand the role of aerosols and solar irradiance in climate change through two instruments: the Aerosol Polarimetry Sensor (APS) and the Total Irradiance Monitor (TIM). APS will make more accurate measurements of aerosols using polarization to reduce uncertainties in aerosol properties. TIM will extend the 30-year record of total solar irradiance measurements with improved accuracy and stability. The NASA Glory spacecraft carrying these instruments is scheduled to launch in November 2010.
This document provides an introduction to radio astronomy, including its history and key discoveries. It discusses how radio astronomy works and some of the tools used, such as radio telescopes, receivers, and interferometers. Important figures who contributed to the field are also mentioned, such as Maxwell, Jansky, and Reber. Current large radio astronomy projects and arrays are summarized. In conclusion, radio astronomy is used to learn about the universe through radio wave observations and produce images where light cannot be seen.
1) SAR data from missions like DESDynI can be used to map ionospheric properties with unprecedented spatial resolution due to SAR's ability to detect Faraday rotation and dispersion effects.
2) Techniques for ionospheric mapping from SAR include Faraday rotation analysis and dispersion analysis, which have been demonstrated on L-band data to achieve TEC mapping accuracy of 1 TECU or better.
3) Case studies of SAR data over Alaska and Brazil have shown SAR can image fine-scale structures in the auroral oval and map equatorial scintillation patterns, providing new insights into these ionospheric phenomena.
This document provides an overview of microwave remote sensing and microwave sensors. It discusses how microwaves can penetrate clouds, smoke, and haze, allowing sensors to operate during day and night. Microwave sensors are either active sensors, which provide their own electromagnetic source, like SAR and SLAR, or passive sensors, which detect natural radiation from the Earth's surface. The document also covers radar fundamentals like polarization, wavelength effects, and imaging geometry.
The Stratospheric Observatory for Infrared Astronomy (SOFIA) is an airborne observatory consisting of a 2.7-meter telescope mounted in a modified Boeing 747-SP aircraft. Funded by NASA and the German Aerospace Agency, SOFIA is scheduled to begin science flights in late 2005 operating at altitudes around 41,000 feet. SOFIA will allow astronomers to make infrared observations of astronomical sources with unprecedented angular resolution and sensitivity. The aircraft and telescope were developed through the collaboration of US and German government, academic, and industry partners.
This document provides an introduction to microwave remote sensing, including an overview of microwave instrumentation, frequency channels, and applications. It discusses how microwave sensing complements other methods by providing vertical atmospheric profiles and observing through non-precipitating clouds. Examples are given of products like total precipitable water, cloud liquid water, and wind speed that are derived from combining microwave channel measurements.
Hyperspectral remote sensing uses narrow, contiguous bands across the electromagnetic spectrum to characterize vegetation. It is useful for studying species composition, crop/vegetation type, biophysical properties like leaf area index and biomass, biochemical properties like chlorophyll and moisture, and stress factors. Hyperspectral data comes from airborne, ground, and spaceborne sensors, with spaceborne providing global continuous coverage but at lower spatial resolution than airborne sensors. Hyperspectral data cubes contain hundreds of bands providing detailed spectral signatures to distinguish vegetation.
Microwave sensing systems use sensors that operate in the microwave portion of the electromagnetic spectrum between 1 mm and 1 m wavelengths. These sensors include radars and radiometers that can image outside the visible and infrared regions. Microwaves can penetrate haze, clouds, smoke and pollution, allowing these sensors to image in all weather conditions unlike visible and infrared sensors. Common microwave remote sensing platforms include synthetic aperture radar, scatterometers and radar altimeters.
TU2.L10 - ACCURATE MONITORING OF TERRESTRIAL AEROSOLS AND TOTAL SOLAR IRRADIA...grssieee
The Glory mission aims to better understand the role of aerosols and solar irradiance in climate change through two instruments: the Aerosol Polarimetry Sensor (APS) and the Total Irradiance Monitor (TIM). APS will make more accurate measurements of aerosols using polarization to reduce uncertainties in aerosol properties. TIM will extend the 30-year record of total solar irradiance measurements with improved accuracy and stability. The NASA Glory spacecraft carrying these instruments is scheduled to launch in November 2010.
This document provides an introduction to radio astronomy, including its history and key discoveries. It discusses how radio astronomy works and some of the tools used, such as radio telescopes, receivers, and interferometers. Important figures who contributed to the field are also mentioned, such as Maxwell, Jansky, and Reber. Current large radio astronomy projects and arrays are summarized. In conclusion, radio astronomy is used to learn about the universe through radio wave observations and produce images where light cannot be seen.
1) SAR data from missions like DESDynI can be used to map ionospheric properties with unprecedented spatial resolution due to SAR's ability to detect Faraday rotation and dispersion effects.
2) Techniques for ionospheric mapping from SAR include Faraday rotation analysis and dispersion analysis, which have been demonstrated on L-band data to achieve TEC mapping accuracy of 1 TECU or better.
3) Case studies of SAR data over Alaska and Brazil have shown SAR can image fine-scale structures in the auroral oval and map equatorial scintillation patterns, providing new insights into these ionospheric phenomena.
This document provides an overview of microwave remote sensing and microwave sensors. It discusses how microwaves can penetrate clouds, smoke, and haze, allowing sensors to operate during day and night. Microwave sensors are either active sensors, which provide their own electromagnetic source, like SAR and SLAR, or passive sensors, which detect natural radiation from the Earth's surface. The document also covers radar fundamentals like polarization, wavelength effects, and imaging geometry.
This document provides an overview of thermal remote sensing. It begins with an introduction to remote sensing and defines thermal remote sensing as measuring electromagnetic radiation in the thermal infrared region. It describes the atmospheric windows and fundamental radiation laws governing thermal remote sensing. Applications discussed include surface temperature detection, fire detection, and volcano monitoring. The document concludes with the advantages of being able to detect true temperatures and limitations such as difficulty maintaining sensor temperatures.
This document provides an introduction to thermal remote sensing. It discusses the principles, including that thermal remote sensing measures electromagnetic radiation in the infrared region. It describes common thermal sensors like those used on Landsat and how thermal data can be used for applications like detecting surface temperatures, fires, drought monitoring, and more. Thermal remote sensing principles are explained, including the relationship between temperature and emitted radiation, and how emissivity of different materials affects thermal signatures.
The document provides an overview of remote sensing techniques used in civil engineering projects. It discusses (1) the electromagnetic spectrum used for remote sensing, including microwave and radar bands; (2) active and passive microwave sensing methods such as SAR; and (3) applications like flood mapping, soil moisture monitoring, and landslide prediction. The document is a useful primer on how remote sensing and GIS technologies can support infrastructure and environmental monitoring.
Basic Concepts, Explanation, and Application. Fundamental Remote Sensing; Advantage/ disadvantages, Imaging/non Imaging sensors, RAR and SAR, SAR Geometry, Resolutions in the microwave, Geometric Distortions in SAR, Polarization in SAR, Target Interaction, SAR Interferometry
1. The document discusses amateur radio astronomy, proposing areas of work accessible to amateur experimenters, such as receiving very low frequency electromagnetic phenomena induced by the ionosphere or solar/astronomical events.
2. It describes feasible amateur radio astronomy projects and the necessary equipment, such as antennas, receivers, and data acquisition systems, to conduct successful observations across different frequency bands.
3. The document provides examples of electronic modules with software that allow amateurs to build instruments for radio astronomy applications and contribute to the diffusion of this discipline.
1) Advances in radar techniques have allowed for continuous observation of the Earth's atmosphere from the lower to upper atmosphere. 2) The latest techniques include active phased array radars like the MU radar in Japan which can rapidly scan beams to accurately measure wind velocity. 3) Atmospheric radars provide high resolution continuous data on winds and have revealed processes like gravity wave propagation, saturation and their influence on mean flows.
Overview of hyperspectral remote sensing of impervious surfaceszhengspace
This document discusses the use of hyperspectral data for monitoring impervious surfaces. It begins with an overview of hyperspectral data characteristics compared to multispectral data. It then provides examples of previous studies that have used hyperspectral data and spectral features to classify and detect urban materials like asphalt, concrete, and rooftops. The document concludes that while hyperspectral data has potential for improved urban classification, more work is needed to develop robust spectral features and validation methods.
Radio beacon for ionspheric tomography RaBITKarlos Svoboda
This document presents preliminary results from the Radio Beacon for Ionospheric Tomography (RaBIT) payload onboard the YOUTHSAT satellite. RaBIT transmits signals at 150 and 400 MHz that are received by ground stations in India to generate tomographic images of the ionosphere. The first tomograms obtained using RaBIT data during the beginning of solar cycle 24 are shown, demonstrating its ability to investigate large-scale ionospheric structures over the Indian region like the equatorial ionization anomaly. RaBIT improves upon previous experiments by providing improved temporal coverage of the ionosphere from its orbit onboard YOUTHSAT.
This document describes the development of an airborne lidar instrument called A-LISTS to demonstrate technologies for a proposed spaceborne lidar mission called LIST. LIST aims to map global topography at 5m resolution to study Earth's surface and changes over time. A-LISTS will test a multi-beam laser transmitter, high sensitivity detectors, and data processing to achieve LIST measurement capabilities from an aircraft. Its first flight in September 2011 will collect lidar data over various terrain to evaluate performance. Key challenges for LIST that A-LISTS helps address include detecting ground returns through vegetation canopies and developing efficient, lightweight instruments.
This document provides a review of synthetic aperture radar (SAR) engineering. It begins with an introduction to SAR and its uses in remote sensing and defense. It then discusses designs for SAR systems and antennas. The document reviews recent literature on SAR, including works discussing antenna mask design to optimize SAR performance, polarimetric SAR for mapping terrain changes, and using SAR to monitor cryospheric regions. It concludes that SAR is a useful technique for achieving good image quality through optimized antenna design.
The document discusses radar remote sensing. It begins by defining radar as radio detection and ranging, where distances are inferred from the time elapsed between signal transmission and reception of the returned signal. It describes two main types of radar: non-imaging radar such as Doppler radar for speed detection, and imaging radar which provides high spatial resolution images. Key applications of non-imaging radar mentioned are traffic radar and satellite altimeters, while side-looking airborne radar is used for imaging. The document also discusses various radar imaging concepts such as range and azimuth resolution, backscatter, polarization, shadowing and layover effects.
WE4.L10.3: THE EVOLUTION OF THE US SATELLITE IR SOUNDING PROGRAM – FROM THE ...grssieee
1. The document discusses the evolution of infrared sounding instruments for measuring atmospheric temperature and water vapor profiles from space, beginning with the Nimbus program in the 1960s.
2. Key developments included increasing spectral resolution and coverage, from early spectrometers to current instruments like AIRS, IASI, and CrIS. Aircraft instruments like HIS helped prove the value of high-resolution measurements.
3. The Cross-track Infrared Sounder (CrIS) for NPP/JPSS will provide high-resolution profiling with much smaller size, power and data requirements than previous instruments, demonstrating readiness for operational use.
The shape radio_signals_wavefront_encountered_in_the_context_of_the_uhecr_rad...Ahmed Ammar Rebai PhD
"Uploaded only for Authors copyrights 9/9/2014. All rights reserved"
Ultra high energy cosmic rays are the most extreme energetic subatomic particles
in nature. Coming from the outer space, these particles initiate extensive air showers (EAS) in
the Earth’s atmosphere. The generated EAS produce elusive radio-transients in the MHz frequency
band measured by sensitive antenna arrays and radio telescopes. Theoretical developments indicate
that the EAS radio wavefront shape depends on the shower longitudinal development, it is waited
that the wavefront curved shape provides information to answer many fundamental questions about
UHECR nature and origins. In the first part of this paper, we report on an investigation in the
wavefront shape, based on an already published sample of events collected between November
2006 and January 2010 at the CODALEMA II experiment located in the radioastronomy facility at
Nançay in France. We find that measurements of individual air showers have been conclusive for
a non-planar shape which could be hyperbolical (further analysis are needed). By cons and in the
second part of this paper, a spherical shape of the wavefront for the anthropic radio-sources has been
proposed. Many studies have shown the strong dependence of the solution of the radio-transient
sources localization problem (the radio wavefront time of arrival on antennas TOA), such solutions
are purely numerical artifacts. Based on a detailed analysis of some published results of radio-
detection experiments around the world like : CODALEMA III in France, AERA in Argentina,
TREND in China and LUNASKA in Australia, we demonstrate the ill-posed character of this
problem in the sense of Hadamard. To support the mathematical studies, a comparison between the
experimental results and the simulations have been made.
This document provides an overview of remote sensing including:
1. The history of remote sensing from early aerial photography to modern satellite systems.
2. The principles of electromagnetic radiation and how different sensors capture radiation in various parts of the spectrum to analyze objects.
3. The various types of remote sensing platforms, sensors, and resolutions including spatial, spectral, temporal, and radiometric and how they provide information.
4. Common applications of remote sensing like land use mapping, change detection, environmental monitoring, and more.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Propagation Effects for Radar&Comm SystemsJim Jenkins
This three-day course examines the atmospheric effects that influence the propagation characteristics of radar and communication signals at microwave and millimeter frequencies for both earth and earth-satellite scenarios. These include propagation in standard, ducting, and subrefractive atmospheres, attenuation due to the gaseous atmosphere, precipitation, and ionospheric effects. Propagation estimation techniques are given such as the Tropospheric Electromagnetic Parabolic Equation Routine (TEMPER) and Radio Physical Optics (RPO). Formulations for calculating attenuation due to the gaseous atmosphere and precipitation for terrestrial and earth-satellite scenarios employing International Telecommunication Union (ITU) models are reviewed. Case studies are presented from experimental line-of-sight, over-the-horizon, and earth-satellite communication systems. Example problems, calculation methods, and formulations are presented throughout the course for purpose of providing practical estimation tools.
Remote sensing and GIS are useful tools for civil engineering projects. The Global Positioning System (GPS) uses 24 satellites that orbit the earth to provide location and time information to GPS receivers. It has three segments: space (satellites), control (monitoring stations), and user (receivers). GPS works by precisely measuring the time it takes signals from multiple satellites to reach a receiver, allowing the device to triangulate its position. Its applications include navigation, mapping, precision agriculture, and more. Other global satellite systems include GLONASS, Galileo, BeiDou, and future systems like Compass.
The document discusses advances in radar remote sensing techniques for observing Earth's atmosphere. It describes the structure of the atmosphere and the basic principles of radar techniques. Recent radar systems like the MU radar in Japan can measure atmospheric parameters like wind velocity with high temporal and altitude resolution. Radars have been used to study dynamics in the upper, middle, and lower atmosphere. Atmospheric gravity waves observed by radar modulate wind profiles and transport momentum, affecting atmospheric structure. Range imaging techniques allow reconstruction of time series and Doppler spectra at any height within the radar observation volume.
The document describes the FAST (Fluorescence detector Array of Single-pixel Telescopes) project. FAST aims to measure ultra-high energy cosmic rays above 1019.5 eV using an array of single-pixel telescopes to detect air fluorescence. Each FAST station would have 12 telescopes covering a 30°×360° field of view. With 500 stations spaced 20 km apart over 150,000 km2, FAST could detect over 5,000 events per year above 57 EeV and 650 above 100 EeV. Prototype FAST telescopes have been installed and observed laser shots and cosmic ray air showers in coincidences with the Telescope Array fluorescence detector.
Beyond the disk: EUV coronagraphic observations of the Extreme Ultraviolet Im...Sérgio Sacani
Most observations of the solar corona beyond 2 R consist of broadband visible light imagery carried out with coronagraphs.
The associated diagnostics mainly consist of kinematics and derivations of the electron number density. While the measurement of the
properties of emission lines can provide crucial additional diagnostics of the coronal plasma (temperatures, velocities, abundances,
etc.), these types of observations are comparatively rare. In visible wavelengths, observations at these heights are limited to total
eclipses. In the ultraviolet (UV) to extreme UV (EUV) range, very few additional observations have been achieved since the pioneering
results of the Ultraviolet Coronagraph Spectrometer (UVCS).
Aims. One of the objectives of the Full Sun Imager (FSI) channel of the Extreme Ultraviolet Imager (EUI) on board the Solar Orbiter
mission has been to provide very wide field-of-view EUV diagnostics of the morphology and dynamics of the solar atmosphere in
temperature regimes that are typical of the lower transition region and of the corona.
Methods. FSI carries out observations in two narrowbands of the EUV spectrum centered on 17.4 nm and 30.4 nm that are dominated,
respectively, by lines of Fe ix/x (formed in the corona around 1 MK) and by the resonance line of He ii (formed around 80 kK in the
lower transition region). Unlike previous EUV imagers, FSI includes a moveable occulting disk that can be inserted in the optical path
to reduce the amount of instrumental stray light to a minimum.
Results. FSI detects signals at 17.4 nm up to the edge of its field of view (7 R), which is about twice further than was previously
possible. Operation at 30.4 nm are for the moment compromised by an as-yet unidentified source of stray light. Comparisons with
observations by the LASCO and Metis coronagraphs confirm the presence of morphological similarities and differences between the
broadband visible light and EUV emissions, as documented on the basis of prior eclipse and space-based observations.
Conclusions. The very-wide-field observations of FSI out to about 3 and 7 R, without and with the occulting disk, respectively, are
paving the way for future dedicated instruments.
This document describes the design and implementation of a directional object sensing and ranging system. It uses an ultrasonic range sensor mounted on a stepper motor to detect objects within a 2.5m radius as the motor rotates continuously. When an object is detected, the microcontroller records the angle of the stepper motor and distance to the object, displaying it on an LCD. The system differs from stationary detectors by providing directional detection capabilities through the rotational motion of the sensors.
ALMA Observations of the Extraordinary Carina Pillars: A Complementary SampleSérgio Sacani
We present a study of six dusty and gaseous pillars (containing the HH 1004 and HH 1010 objects)
and globules (that contain the HH 666, HH 900, HH 1006, and HH 1066 objects) localized in the Carina
nebula using sensitive and high angular resolution (∼0.3′′) Atacama Large Millimeter/Sub-millimeter
Array (ALMA) observations. This is a more extensive study that the one presented in Cortes-Rangel
et al. (2020). As in this former study, we also analyzed the 1.3 mm continuum emission and C18O(2−1),
N2D+(3−2) and 12CO(2−1) spectral lines. These new observations revealed the molecular outflows
emanating from the pillars, the dusty envelopes+disks that are exciting them, and the extended HH
objects far from their respective pillars. We reveal that the masses of the disks+envelopes are in a
range of 0.02 to 0.38 M⊙, and those for the molecular outflows are of the order of 10−3 M⊙, which
suggests that their exciting sources might be low- or intermediate-mass protostars as already revealed
in recent studies at infrared and submillimeter bands. In the regions associated with the objects HH
900 and HH 1004, we report multiple millimeter continuum sources, from where several molecular
outflows emanate.
This document provides an overview of thermal remote sensing. It begins with an introduction to remote sensing and defines thermal remote sensing as measuring electromagnetic radiation in the thermal infrared region. It describes the atmospheric windows and fundamental radiation laws governing thermal remote sensing. Applications discussed include surface temperature detection, fire detection, and volcano monitoring. The document concludes with the advantages of being able to detect true temperatures and limitations such as difficulty maintaining sensor temperatures.
This document provides an introduction to thermal remote sensing. It discusses the principles, including that thermal remote sensing measures electromagnetic radiation in the infrared region. It describes common thermal sensors like those used on Landsat and how thermal data can be used for applications like detecting surface temperatures, fires, drought monitoring, and more. Thermal remote sensing principles are explained, including the relationship between temperature and emitted radiation, and how emissivity of different materials affects thermal signatures.
The document provides an overview of remote sensing techniques used in civil engineering projects. It discusses (1) the electromagnetic spectrum used for remote sensing, including microwave and radar bands; (2) active and passive microwave sensing methods such as SAR; and (3) applications like flood mapping, soil moisture monitoring, and landslide prediction. The document is a useful primer on how remote sensing and GIS technologies can support infrastructure and environmental monitoring.
Basic Concepts, Explanation, and Application. Fundamental Remote Sensing; Advantage/ disadvantages, Imaging/non Imaging sensors, RAR and SAR, SAR Geometry, Resolutions in the microwave, Geometric Distortions in SAR, Polarization in SAR, Target Interaction, SAR Interferometry
1. The document discusses amateur radio astronomy, proposing areas of work accessible to amateur experimenters, such as receiving very low frequency electromagnetic phenomena induced by the ionosphere or solar/astronomical events.
2. It describes feasible amateur radio astronomy projects and the necessary equipment, such as antennas, receivers, and data acquisition systems, to conduct successful observations across different frequency bands.
3. The document provides examples of electronic modules with software that allow amateurs to build instruments for radio astronomy applications and contribute to the diffusion of this discipline.
1) Advances in radar techniques have allowed for continuous observation of the Earth's atmosphere from the lower to upper atmosphere. 2) The latest techniques include active phased array radars like the MU radar in Japan which can rapidly scan beams to accurately measure wind velocity. 3) Atmospheric radars provide high resolution continuous data on winds and have revealed processes like gravity wave propagation, saturation and their influence on mean flows.
Overview of hyperspectral remote sensing of impervious surfaceszhengspace
This document discusses the use of hyperspectral data for monitoring impervious surfaces. It begins with an overview of hyperspectral data characteristics compared to multispectral data. It then provides examples of previous studies that have used hyperspectral data and spectral features to classify and detect urban materials like asphalt, concrete, and rooftops. The document concludes that while hyperspectral data has potential for improved urban classification, more work is needed to develop robust spectral features and validation methods.
Radio beacon for ionspheric tomography RaBITKarlos Svoboda
This document presents preliminary results from the Radio Beacon for Ionospheric Tomography (RaBIT) payload onboard the YOUTHSAT satellite. RaBIT transmits signals at 150 and 400 MHz that are received by ground stations in India to generate tomographic images of the ionosphere. The first tomograms obtained using RaBIT data during the beginning of solar cycle 24 are shown, demonstrating its ability to investigate large-scale ionospheric structures over the Indian region like the equatorial ionization anomaly. RaBIT improves upon previous experiments by providing improved temporal coverage of the ionosphere from its orbit onboard YOUTHSAT.
This document describes the development of an airborne lidar instrument called A-LISTS to demonstrate technologies for a proposed spaceborne lidar mission called LIST. LIST aims to map global topography at 5m resolution to study Earth's surface and changes over time. A-LISTS will test a multi-beam laser transmitter, high sensitivity detectors, and data processing to achieve LIST measurement capabilities from an aircraft. Its first flight in September 2011 will collect lidar data over various terrain to evaluate performance. Key challenges for LIST that A-LISTS helps address include detecting ground returns through vegetation canopies and developing efficient, lightweight instruments.
This document provides a review of synthetic aperture radar (SAR) engineering. It begins with an introduction to SAR and its uses in remote sensing and defense. It then discusses designs for SAR systems and antennas. The document reviews recent literature on SAR, including works discussing antenna mask design to optimize SAR performance, polarimetric SAR for mapping terrain changes, and using SAR to monitor cryospheric regions. It concludes that SAR is a useful technique for achieving good image quality through optimized antenna design.
The document discusses radar remote sensing. It begins by defining radar as radio detection and ranging, where distances are inferred from the time elapsed between signal transmission and reception of the returned signal. It describes two main types of radar: non-imaging radar such as Doppler radar for speed detection, and imaging radar which provides high spatial resolution images. Key applications of non-imaging radar mentioned are traffic radar and satellite altimeters, while side-looking airborne radar is used for imaging. The document also discusses various radar imaging concepts such as range and azimuth resolution, backscatter, polarization, shadowing and layover effects.
WE4.L10.3: THE EVOLUTION OF THE US SATELLITE IR SOUNDING PROGRAM – FROM THE ...grssieee
1. The document discusses the evolution of infrared sounding instruments for measuring atmospheric temperature and water vapor profiles from space, beginning with the Nimbus program in the 1960s.
2. Key developments included increasing spectral resolution and coverage, from early spectrometers to current instruments like AIRS, IASI, and CrIS. Aircraft instruments like HIS helped prove the value of high-resolution measurements.
3. The Cross-track Infrared Sounder (CrIS) for NPP/JPSS will provide high-resolution profiling with much smaller size, power and data requirements than previous instruments, demonstrating readiness for operational use.
The shape radio_signals_wavefront_encountered_in_the_context_of_the_uhecr_rad...Ahmed Ammar Rebai PhD
"Uploaded only for Authors copyrights 9/9/2014. All rights reserved"
Ultra high energy cosmic rays are the most extreme energetic subatomic particles
in nature. Coming from the outer space, these particles initiate extensive air showers (EAS) in
the Earth’s atmosphere. The generated EAS produce elusive radio-transients in the MHz frequency
band measured by sensitive antenna arrays and radio telescopes. Theoretical developments indicate
that the EAS radio wavefront shape depends on the shower longitudinal development, it is waited
that the wavefront curved shape provides information to answer many fundamental questions about
UHECR nature and origins. In the first part of this paper, we report on an investigation in the
wavefront shape, based on an already published sample of events collected between November
2006 and January 2010 at the CODALEMA II experiment located in the radioastronomy facility at
Nançay in France. We find that measurements of individual air showers have been conclusive for
a non-planar shape which could be hyperbolical (further analysis are needed). By cons and in the
second part of this paper, a spherical shape of the wavefront for the anthropic radio-sources has been
proposed. Many studies have shown the strong dependence of the solution of the radio-transient
sources localization problem (the radio wavefront time of arrival on antennas TOA), such solutions
are purely numerical artifacts. Based on a detailed analysis of some published results of radio-
detection experiments around the world like : CODALEMA III in France, AERA in Argentina,
TREND in China and LUNASKA in Australia, we demonstrate the ill-posed character of this
problem in the sense of Hadamard. To support the mathematical studies, a comparison between the
experimental results and the simulations have been made.
This document provides an overview of remote sensing including:
1. The history of remote sensing from early aerial photography to modern satellite systems.
2. The principles of electromagnetic radiation and how different sensors capture radiation in various parts of the spectrum to analyze objects.
3. The various types of remote sensing platforms, sensors, and resolutions including spatial, spectral, temporal, and radiometric and how they provide information.
4. Common applications of remote sensing like land use mapping, change detection, environmental monitoring, and more.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Propagation Effects for Radar&Comm SystemsJim Jenkins
This three-day course examines the atmospheric effects that influence the propagation characteristics of radar and communication signals at microwave and millimeter frequencies for both earth and earth-satellite scenarios. These include propagation in standard, ducting, and subrefractive atmospheres, attenuation due to the gaseous atmosphere, precipitation, and ionospheric effects. Propagation estimation techniques are given such as the Tropospheric Electromagnetic Parabolic Equation Routine (TEMPER) and Radio Physical Optics (RPO). Formulations for calculating attenuation due to the gaseous atmosphere and precipitation for terrestrial and earth-satellite scenarios employing International Telecommunication Union (ITU) models are reviewed. Case studies are presented from experimental line-of-sight, over-the-horizon, and earth-satellite communication systems. Example problems, calculation methods, and formulations are presented throughout the course for purpose of providing practical estimation tools.
Remote sensing and GIS are useful tools for civil engineering projects. The Global Positioning System (GPS) uses 24 satellites that orbit the earth to provide location and time information to GPS receivers. It has three segments: space (satellites), control (monitoring stations), and user (receivers). GPS works by precisely measuring the time it takes signals from multiple satellites to reach a receiver, allowing the device to triangulate its position. Its applications include navigation, mapping, precision agriculture, and more. Other global satellite systems include GLONASS, Galileo, BeiDou, and future systems like Compass.
The document discusses advances in radar remote sensing techniques for observing Earth's atmosphere. It describes the structure of the atmosphere and the basic principles of radar techniques. Recent radar systems like the MU radar in Japan can measure atmospheric parameters like wind velocity with high temporal and altitude resolution. Radars have been used to study dynamics in the upper, middle, and lower atmosphere. Atmospheric gravity waves observed by radar modulate wind profiles and transport momentum, affecting atmospheric structure. Range imaging techniques allow reconstruction of time series and Doppler spectra at any height within the radar observation volume.
The document describes the FAST (Fluorescence detector Array of Single-pixel Telescopes) project. FAST aims to measure ultra-high energy cosmic rays above 1019.5 eV using an array of single-pixel telescopes to detect air fluorescence. Each FAST station would have 12 telescopes covering a 30°×360° field of view. With 500 stations spaced 20 km apart over 150,000 km2, FAST could detect over 5,000 events per year above 57 EeV and 650 above 100 EeV. Prototype FAST telescopes have been installed and observed laser shots and cosmic ray air showers in coincidences with the Telescope Array fluorescence detector.
Beyond the disk: EUV coronagraphic observations of the Extreme Ultraviolet Im...Sérgio Sacani
Most observations of the solar corona beyond 2 R consist of broadband visible light imagery carried out with coronagraphs.
The associated diagnostics mainly consist of kinematics and derivations of the electron number density. While the measurement of the
properties of emission lines can provide crucial additional diagnostics of the coronal plasma (temperatures, velocities, abundances,
etc.), these types of observations are comparatively rare. In visible wavelengths, observations at these heights are limited to total
eclipses. In the ultraviolet (UV) to extreme UV (EUV) range, very few additional observations have been achieved since the pioneering
results of the Ultraviolet Coronagraph Spectrometer (UVCS).
Aims. One of the objectives of the Full Sun Imager (FSI) channel of the Extreme Ultraviolet Imager (EUI) on board the Solar Orbiter
mission has been to provide very wide field-of-view EUV diagnostics of the morphology and dynamics of the solar atmosphere in
temperature regimes that are typical of the lower transition region and of the corona.
Methods. FSI carries out observations in two narrowbands of the EUV spectrum centered on 17.4 nm and 30.4 nm that are dominated,
respectively, by lines of Fe ix/x (formed in the corona around 1 MK) and by the resonance line of He ii (formed around 80 kK in the
lower transition region). Unlike previous EUV imagers, FSI includes a moveable occulting disk that can be inserted in the optical path
to reduce the amount of instrumental stray light to a minimum.
Results. FSI detects signals at 17.4 nm up to the edge of its field of view (7 R), which is about twice further than was previously
possible. Operation at 30.4 nm are for the moment compromised by an as-yet unidentified source of stray light. Comparisons with
observations by the LASCO and Metis coronagraphs confirm the presence of morphological similarities and differences between the
broadband visible light and EUV emissions, as documented on the basis of prior eclipse and space-based observations.
Conclusions. The very-wide-field observations of FSI out to about 3 and 7 R, without and with the occulting disk, respectively, are
paving the way for future dedicated instruments.
This document describes the design and implementation of a directional object sensing and ranging system. It uses an ultrasonic range sensor mounted on a stepper motor to detect objects within a 2.5m radius as the motor rotates continuously. When an object is detected, the microcontroller records the angle of the stepper motor and distance to the object, displaying it on an LCD. The system differs from stationary detectors by providing directional detection capabilities through the rotational motion of the sensors.
ALMA Observations of the Extraordinary Carina Pillars: A Complementary SampleSérgio Sacani
We present a study of six dusty and gaseous pillars (containing the HH 1004 and HH 1010 objects)
and globules (that contain the HH 666, HH 900, HH 1006, and HH 1066 objects) localized in the Carina
nebula using sensitive and high angular resolution (∼0.3′′) Atacama Large Millimeter/Sub-millimeter
Array (ALMA) observations. This is a more extensive study that the one presented in Cortes-Rangel
et al. (2020). As in this former study, we also analyzed the 1.3 mm continuum emission and C18O(2−1),
N2D+(3−2) and 12CO(2−1) spectral lines. These new observations revealed the molecular outflows
emanating from the pillars, the dusty envelopes+disks that are exciting them, and the extended HH
objects far from their respective pillars. We reveal that the masses of the disks+envelopes are in a
range of 0.02 to 0.38 M⊙, and those for the molecular outflows are of the order of 10−3 M⊙, which
suggests that their exciting sources might be low- or intermediate-mass protostars as already revealed
in recent studies at infrared and submillimeter bands. In the regions associated with the objects HH
900 and HH 1004, we report multiple millimeter continuum sources, from where several molecular
outflows emanate.
The document discusses radio astronomy and Nigeria's 25m radio telescope project. It provides background on radio astronomy research and education in Nigeria. It describes the key components and functions of radio telescopes, including how they collect radio waves from space using large parabolic dishes to form images, which are then recorded. The 25m radio telescope will allow Nigeria to conduct frontline space research.
Wallops Flight Facility conducts frequent low-cost rocket and balloon missions supporting NASA science and technology research. Sounding rockets and scientific balloons are used for over 20 missions annually across various fields like heliophysics, astrophysics, and planetary physics. Wallops is developing new balloon and small satellite technologies and will support upcoming missions like LADEE and HS-3.
Fluorescence detector Array of Single-pixel Telescopes (FAST) projectToshihiro FUJII
This document discusses the history and development of fluorescence detection techniques for ultra-high energy cosmic rays (UHECR). It proposes a new concept called the Fluorescence detector Array of Single-pixel Telescopes (FAST) project. FAST aims to develop an optimized and economical fluorescence detector array to observe UHECRs above 1019.5 eV over a large area. The document outlines the design of FAST stations and reports on an initial test using the EUSO-TA prototype that successfully detected laser pulses and UHECR signals. It concludes by discussing plans to construct a new full-scale FAST prototype and the potential for FAST to increase UHECR exposure and help resolve questions about their origin.
Proceedings of the space surveillance workshop volume 1Clifford Stone
- The Maui Space Surveillance Site has used 23 bright reference stars for infrared calibration over 12 years. Observations were made with the Advanced Multicolor Tracker sensor on a 1.2-meter telescope.
- Light curves and period analyses were presented for 4 stars, showing variability in some. Care must be taken to choose non-variable stars for calibration.
- Over 250 stars in stellar classification Autoclass 23/delta 0 are mostly constant and suitable for infrared calibration standards. Future observations will add to the database of calibration stars.
The document describes Project ELSA, which aims to design and construct a low-cost spherical probe called the NeoPod to collect and transmit scientific data from the surface of Europa. A team of undergraduate students designed the NeoPod over 8 months to fit within a 25cm diameter sphere and weigh less than 10kg. The NeoPod integrates two sensors (a magnetometer and Geiger counter), an avionics package with an FPGA, a communications system, and a power system to operate for 100 hours. Simulation results show the NeoPod could transmit up to 301MB of data if located at Europa's poles. The project aims to demonstrate the feasibility of using low-cost probes to explore Europa and other planetary
First light of VLT/HiRISE: High-resolution spectroscopy of young giant exopla...Sérgio Sacani
A major endeavor of this decade is the direct characterization of young giant exoplanets at high spectral resolution to determine the composition of
their atmosphere and infer their formation processes and evolution. Such a goal represents a major challenge owing to their small angular separation
and luminosity contrast with respect to their parent stars. Instead of designing and implementing completely new facilities, it has been proposed
to leverage the capabilities of existing instruments that offer either high contrast imaging or high dispersion spectroscopy, by coupling them using
optical fibers. In this work we present the implementation and first on-sky results of the HiRISE instrument at the very large telescope (VLT),
which combines the exoplanet imager SPHERE with the recently upgraded high resolution spectrograph CRIRES using single-mode fibers. The
goal of HiRISE is to enable the characterization of known companions in the H band, at a spectral resolution of the order of R = λ/∆λ = 100 000,
in a few hours of observing time. We present the main design choices and the technical implementation of the system, which is constituted of three
major parts: the fiber injection module inside of SPHERE, the fiber bundle around the telescope, and the fiber extraction module at the entrance
of CRIRES. We also detail the specific calibrations required for HiRISE and the operations of the instrument for science observations. Finally, we
detail the performance of the system in terms of astrometry, temporal stability, optical aberrations, and transmission, for which we report a peak
value of ∼3.9% based on sky measurements in median observing conditions. Finally, we report on the first astrophysical detection of HiRISE to
illustrate its potential.
Lidar uses laser light to measure distances by illuminating targets. It is an active remote sensing method. The document discusses remote sensing concepts like platforms, sensors, data collection using electromagnetic radiation, and data interpretation techniques. It provides examples of Indian remote sensing satellites like Resourcesat and Cartosat, and describes their sensors and applications in areas like agriculture, mapping, and disaster management. Visual interpretation of remote sensing images involves analyzing tone, shape, size, pattern, texture, shadows, and associations of targets.
Lidar uses laser light to measure distances by illuminating targets. It is an active remote sensing method. The document discusses remote sensing concepts like platforms, sensors, data collection using electromagnetic radiation, and data interpretation techniques. It provides examples of Indian remote sensing satellites like Resourcesat and Cartosat, and describes their sensors and applications in areas like agriculture, mapping, and disaster management. Visual interpretation of remote sensing images involves analyzing tone, shape, size, pattern, texture, shadows, and associations of targets.
Remote sensing involves acquiring information about objects through analysis of sensor data without physical contact. The document discusses various aspects of remote sensing including:
- Platforms that carry sensors like satellites, aircraft, and space shuttles at different altitudes.
- Sensors detect electromagnetic radiation in different wavelength bands from ultraviolet to radio. Common sensors include cameras, scanners, and radar.
- Factors like the atmosphere, wavelength, and sensor design impact remote sensing. Atmospheric windows allow transmission of certain wavelengths.
- Imaging systems include push-broom scanners that use linear detector arrays and opto-mechanical scanners that use oscillating mirrors to build up images.
SOFIA is a flying observatory built into a Boeing 747SP aircraft that allows astronomers to make infrared observations from around the world above most of the atmosphere. It uses a 2.5-meter reflector telescope with a parabolic primary mirror and hyperbolic secondary mirror that looks out of a door near the tail. NASA provides 80% of funding, the German Aerospace Center provides 20% of funding and the telescope, and the Universities Space Research Association manages the program. SOFIA replaces the earlier Kuiper Observatory and was first proposed in 1984, with costs split between NASA and Germany, and the modified aircraft began operations in 2007 from Palmdale, California.
Sean Casey presented on the Stratospheric Observatory for Infrared Astronomy (SOFIA). SOFIA is a 2.7 meter telescope mounted on a Boeing 747 aircraft that allows astronomers to make observations in the infrared region of the electromagnetic spectrum from an altitude of 37,000-45,000 feet. Casey discussed SOFIA's construction, its expected science return across topics like star and planet formation, and provided examples of early science instruments like FORCAST and GREAT. SOFIA had its first flight in 2010 and will allow flexible infrared observations of the sky for at least 20 years.
The Large Interferometer For Exoplanets (LIFE): the science of characterising...Advanced-Concepts-Team
Studying the atmospheres of a statistically significant number of rocky, terrestrial exoplanets - including the search for habitable and potentially inhabited planets - is one of the major goals of exoplanetary science and possibly the most challenging question in 21st century astrophysics. However, despite being at the top of the agenda of all major space agencies and ground-based observatories, none of the currently planned projects or missions worldwide has the technical capabilities to achieve this goal. In this talk we present new results from the LIFE Mission initiative, which addresses this issue by investigating the scientific potential of a mid infrared nulling interferometer observatory. Here we will focus on the mission's yield estimates, our simulator software as well as various exemplary science cases such as observing Earth- and Venus-twins or searching for phosphine in exoplanetary atmospheres.
GOALS-JWST: Unveiling Dusty Compact Sources in the Merging Galaxy IIZw096Sérgio Sacani
We have used the Mid-InfraRed Instrument (MIRI) on the James Webb Space Telescope (JWST) to obtain the first
spatially resolved, mid-infrared images of IIZw096, a merging luminous infrared galaxy (LIRG) at z = 0.036.
Previous observations with the Spitzer Space Telescope suggested that the vast majority of the total IR luminosity
(LIR) of the system originated from a small region outside of the two merging nuclei. New observations with
JWST/MIRI now allow an accurate measurement of the location and luminosity density of the source that is
responsible for the bulk of the IR emission. We estimate that 40%–70% of the IR bolometric luminosity, or
3–5 × 1011 Le, arises from a source no larger than 175 pc in radius, suggesting a luminosity density of at least
3–5 × 1012 Le kpc−2
. In addition, we detect 11 other star-forming sources, five of which were previously
unknown. The MIRI F1500W/F560W colors of most of these sources, including the source responsible for the
bulk of the far-IR emission, are much redder than the nuclei of local LIRGs. These observations reveal the power
of JWST to disentangle the complex regions at the hearts of merging, dusty galaxies.
This document discusses the ionosphere and its effects on radio systems. It begins with an introduction to the ionosphere, its layers, and how it can reflect radio signals. It then discusses space weather events like solar flares and coronal mass ejections that impact the ionosphere. The document outlines ionospheric monitoring efforts in Cyprus using instruments like ionosondes and GPS receivers. It presents results on topics like modeling the ionosphere, detecting scintillations, and using radio occultations to study the topside ionosphere. The document emphasizes how understanding the ionosphere is important for radio communications and navigation systems.
The document describes an imaging Fourier transform spectrometer (IFTS) intended to provide atmospheric measurements of the Arctic region from a highly elliptical orbit. The IFTS would measure pressure, temperature, and concentrations of gases like O2, CH4, and CO2 to improve understanding of climate change, methane hydrate releases, and air quality in the Arctic. A balloon mission is planned to test the instrument at a technology readiness level of 7. The IFTS design uses a commercial Michelson interferometer with a diode laser, beam splitter, and double-axis mirror pointing system to collect interferograms at 100 frames per second with 0.25 cm-1 spectral resolution across two wavelength channels.
La red de telescopios robóticos BOOTES y el proyecto GLORIAcampusmilenio
Bootes es el primer observatorio astronómico robótico ubicado en España para complementar desde Tierra la observación de fuentes celestes estudiadas en altas energías (rayos X y gamma) desde el espacio. En 1998 comienza a funcionar en Huelva, en 2001 en Málaga, y en 2009 se produce la internacionalización del proyecto con Bootes-3 en Nueva Zelanda.
Ponente: Alberto Castro Tirado (España) es licenciado en Físicas por la Universidad de Granada Doctor en Astrofísica por la Universidad de Copenhague. Es Investigador Científico del C.S.I.C desde 2007 y es el Investigador Principal del proyecto Bootes en el Instituto de Astrofísica de Andalucía (IAA). Es miembro de la IAU y ha publicado más de 190 artículos en revistas especializadas como Nature, Science, de divulgación sobre Astronomía y prensa.
This document discusses the potential for nanotechnology to enable and enhance space exploration technologies. It envisions nanoscale sensors and instrumentation that can enhance existing space mission capabilities and enable new missions. Some key areas that could benefit include remote sensing, vehicle health monitoring, astrobiological research, and manned spaceflight. Realizing this potential will require continued fundamental research and strategic development over the next 10-15 years, with a focus on enabling critical mission technologies like novel sensors, standardized integration techniques, and compact biological research labs. Major challenges include refining nanomaterial production, developing manipulation and lithography techniques, and addressing issues like toxicity and reliability in networked sensor systems.
The document discusses the need for the National Virtual Observatory (NVO) to provide a unified architecture for accessing and analyzing astronomical data from various sources. It argues that NASA should lead efforts to federate different university, government, and industry programs and offices under the NVO to maximize scientific returns. The NVO would establish standards and clear communication channels between different phases of astrophysical research like data collection, analysis, and new missions. This would create an efficient "marketplace" for astrophysical research that benefits scientists, educators, and the public.
Team FREDNET is an open source nonprofit organization competing in the Google Lunar X PRIZE by developing systems to land a spacecraft on the Moon, transmit images and video, and have a rover travel 500 meters on the lunar surface. They plan to complete the mission using commercial launch partners SpaceX and Masten Space Systems, and open source ground and flight systems developed by volunteers at Hacker Dojo for under $30 million. They are seeking additional volunteers to help with development and flight tests in 2011-2012 leading up to their 2013 mission.
10 01-01 team cheese-final report_lunar landing gearSean Casey, USRA
Team Cheese, a group of mechanical engineering students, designed a lunar landing gear system for Team FREDNET, which is competing in the Google Lunar X Prize. The report documents Team Cheese's conceptual design of an impact absorption system and supporting structure to dampen the shock of an unmanned vehicle landing on the moon within the 10G acceleration constraint set by Team FREDNET. The design incorporated crushable cartridges in secondary struts and analysis to optimize the structure and size of struts, foot pads, and joints.
This document provides an overview and analysis of the potential disruptiveness of the CubeSat market. It examines CubeSats through the lens of Christensen's disruptive innovation model. While CubeSats show some characteristics of a disruptive technology, the document concludes that there is still not enough data to determine if CubeSats will disrupt the traditional satellite market. Specifically, CubeSats have yet to demonstrate commercial customers or a clear initial market. Additionally, aspects of the value network like launches and components may still pose barriers to the full development of CubeSats. The document raises questions around whether standardization itself, not just CubeSats, could be the true disruptive innovation if applied more broadly
This document provides an overview of a project to design the system and network architecture for an open source lunar lander. A team of students at the University of Virginia worked with the organization Team FREDNET, which is competing in the Google Lunar X Prize, to address the software needs of the lunar lander. The team developed several software packages over several months to control sensors, engines, and other systems. The packages could run independently but also together in a simulation. The simulation was later integrated with a spaceflight simulator for additional testing capabilities. The project achieved its goals of revising the initial specifications and creating a viable demonstration system through simulation.
Team FREDNET aims to land a robot on the moon by 2012 to demonstrate open source space exploration. It has three teams: an open source development team that creates space technologies; an open participation mission team that plans the lunar mission; and a business development team that promotes and funds the organization. The overall goal is to establish open source as a viable approach to space exploration and development.
Team FREDNET aims to win the Google Lunar X Prize by landing a spacecraft on the moon that carries a payload, broadcasts HD video, and roams at least 500 meters. The team plans to launch a small lunar lander aboard a Falcon 1e rocket from Kwajalein Atoll. The lander would follow a direct descent trajectory to the lunar surface, where it would operate for up to two days. Team FREDNET is an open source effort involving students, professionals, and universities from around the world collaborating online to develop the design.
1. SOFIA: An Observatory for THz Science and Technology
Eric E. Becklin*a
, Sean C. Casey a
, and Xander Tielens b
a
Universities Space Research Association, NASA MS 211-3, Moffett Field, CA 94035-1000
b
Code SST, NASA Ames Research Center, MS 245-1, Moffett Field, CA 94035-1000
ABSTRACT
The Stratospheric Observatory for Infrared Astronomy (SOFIA) is the next generation of airborne
astronomical observatories. Funded by the U.S. and German space agencies with an expected operational
lifetime of 20 years, SOFIA is scheduled for science flights beginning in late-2009. The observatory consists
of a 747-SP aircraft modified to accommodate a 2.5-meter infrared telescope within an open port cavity.
Academic and government laboratories spanning both the U.S. and Germany are developing science
instruments for SOFIA. With an evolving suite of state-of-the-art technologies, SOFIA will explore the
emission of astronomical sources with an unprecedented level of angular resolution (θ[arc-seconds] = 0.1 x
wavelength [μm]) and spectral line sensitivity over a core frequency range of 1 – 10 THz (i.e. wavelengths of
30 – 300 microns). On April 26, 2007, the first test flight of the heavily modified SOFIA aircraft was
achieved in Waco, Texas. The current status of SOFIA is available from the observatory web site at
http://sofia.arc.nasa.gov and is updated frequently.
Keywords: SOFIA, airborne astronomy, far-infrared, instruments
1. INTRODUCTION
The Stratospheric Observatory For Infrared Astronomy (SOFIA) along with the Spitzer and Herschel
observatories are the U.S. and European premier astronomical programs for infrared and submillimeter
astronomy. SOFIA, a joint project of NASA and the German Space Agency (DLR) is a 2.5-meter telescope
in a Boeing 747-SP aircraft designed to make sensitive infrared measurements of a wide range of
astronomical objects (Erickson and Davidson 1995, Becklin 1997, Casey 2004). It will fly at and above 12.5
km, where the telescope will collect radiation in the wavelength range of 0.3 μm to 1.6 mm. The SOFIA
science program is being developed and operated for NASA and DLR by the Universities Space Research
Association (USRA).
The telescope and 20% of operations will be supplied by Germany through contracts with DLR. In
Germany, the University of Stuttgart has been awarded the contract to run the Deutsches SOFIA Institut
(DSI). Science communities in the U.S. and Germany have the responsibilities for the development of the
science instruments to be installed on the SOFIA telescope. In the U.S., science instrument teams are
selected and funded through an a peer review and ranking of the proposals received.
2. SCIENCE OPERATIONS
SOFIA will see first light in 2009, and is planned to make more than 120 scientific flights per year of at
least 8 to 10 hours in duration. SOFIA is expected to operate for at least 20 years, primarily from NASA’s
Dryden Flight Research Center in Edwards, California, but occasionally from other bases around the world,
especially in the Southern Hemisphere. SOFIA will fly above 12.5 km, where the typical precipitable water
*
contact: ebecklin@sofia.usra.edu; telephone: (650)604-2114; NASA MS 211-3, Moffett Field, CA 94035-1000
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2. column depth is less than 10 μm. A graphic comparison of the typical transmission at mountaintop and
aircraft altitudes is shown in Figure 1. It is clear that, except for a few very narrow bands in the mid-infrared
that are completely blocked by telluric CO2, the atmosphere at aircraft altitudes is mostly transparent at
infrared and submillimeter wavelengths. In particular, THz frequencies (30 – 300 microns) are strongly
blocked at typical Mauna Kea-type water vapor values (ZH2O ~ 1 mm).
The SOFIA Science and Mission Operations Center (SSMOC) will be located at NASA’s Ames
Research Center in Moffett Field, CA and is currently operated by USRA under contract to NASA. The
SOFIA Program expects to support approximately 50 investigation teams per year through a peer reviewed
proposal process.
In early-1997, NASA acquired the SOFIA aircraft, the ‘Clipper Lindbergh’, from United Airlines. The
telescope and support structure was developed by DLR and delivered to NASA in late-2002. The first
ground-based observations with the SOFIA telescope were in mid-2004. The first flight of the modified
aircraft was on April 26, 2007 and is shown in Figure 2. With most U.S. and German science instruments
nearing completion, the first science flights are expected in early-2009.
Figure 2. The first test flight of the SOFIA
aircraft occurred on April 26, 2007 in Waco,
Texas after nearly ten years of development.
Open door test flight are expected in 2008 with
science flights beginning in 2009.
Figure 1. The comparison of atmospheric
transmission at THz frequencies between ground
based and airborne facilities. Note that THz
observations (1 – 10 THz) are completely blocked
by the effects of atmospheric water vapor.
3. SOFIA’S TELESCOPE AND FIRST GENERATION INSTRUMENTS
Mounted in the aft section of the aircraft, the SOFIA telescope is stabilized in-flight by a three-axis
gyroscope package coupled to a magneto-torque motor drive via a tuned servo-system. Guide camera and
strain gauges provide low frequency corrections for close-loop tracking on celestial sources. The primary
mirror is finished to provide quality images at optical wavelengths. The portside telescope cavity door is
typically closed for take-off and landings so as the keep the aluminized mirror surface as clean as possible
(and of moderately low emissivity). The door is opened at altitude and is articulated to track the telescope’s
range of motion in elevation (20 – 60 degrees). A secondary mirror drive provides both chopping and
scanning motions. The top-level characteristics for SOFIA are listed in Table 1.
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3. Table 1. SOFIA Characteristics
Nominal Operational Wavelength Range 0.3 to 1600 microns
Primary Mirror Diameter 2.7 meters
System Clear Aperture Diameter 2.5 meters
Nominal System f-ratio 19.6
Primary Mirror f-ratio 1.28
Telescope’s Unvignetted Elevation Range 20 – 60 degrees
Unvignetted Field-of-view Diameter 8 arc-minutes, 13 arc-minutes at optimum focus
Maximum Chop Throw on Sky ± 4 arc minutes (unvignetted)
Diffraction-Limited Wavelengths > 15 microns
Recovery Air and Optical Temperature in Cavity 240 K
Image Quality of Telescope Optics (at 0.6 microns) 1.0” on-axis (80% encircled energy)
Optical Configuration Bent Cassegrain, chopping secondary
and flat folding tertiary
Chopper Frequencies 1 to 20 Hertz for 2-point square-wave chop
Pointing Stability < 2.0” rms for first-light
Pointing Accuracy = 0.5” if on-axis Focal Plane tracking
= 3” if on-axis Fine-Field tracking
Total Emissivity of Telescope (goal) 15% at 10 microns with dichroic tertiary
10% at 10 microns with aluminized tertiary
Chopped Image Quality due to
coma for ± 4’ chop throw
= 9.1” for 80% encircled energy diameter
= 5.8” for 50% encircled energy diameter
A total of nine instruments have been
selected and are now under development.
SOFIA's first generation instruments cover the
full wavelength range from the visible to the
near, mid, and far-infrared and submillimeter
and, in spectral resolution terms, range from
imagers with narrow photometric bands, to
moderate resolution spectrometers geared
towards studies of broad dust and molecular
features, to high resolution instruments capable
of velocity-resolved gas phase line studies. The
discovery space of SOFIA’s first generation
instrument suite is illustrated in Figure 3.
Figure 3. The phase space of wavelength coverage
versus spectral resolution for SOFIA's first
generation instrument suite. The instruments
GREAT, CASIMIR, and SAFIRE are discussed in
this symposium.
The operational parameters of the first
generation instruments are listed in Table 2
below. SOFIA science instruments are either
principal investigator class or facility class. In
particular, the current suite includes three
Facility Class Science Instruments (FSI):
HAWC, FORCAST, and FLITECAM. Facility class instruments are maintained and operated by the science
staff of the SSMOC for the general science community. In addition, there are six Principal Investigator
Class (PI) Science Instruments, which will be maintained and operated by the PI teams at their home
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4. institutions. General investigators will be able to propose for these instruments in collaboration with the PI
teams. Two of the PI Class instruments (FIFI-ls and GREAT) are being developed in Germany.
Table 2: SOFIA First Light Instruments
PI Institution Name Type of instrument
E. Dunham Lowell Observatory HIPO High-speed Imaging Photometer for Occultations
0.3-1.1 μm
I. McLean UCLA FLITECAM Near-IR Camera 1-5 μm; GRISM R = 2,000
J. Lacy Univ. of Texas EXES Echelon spectrometer
5-28μm; R = 105
, 104
, or 3,000
T. Herter Cornell Univ. FORCAST Mid IR Camera 5-40 μm
D. A. Harper Univ. of Chicago HAWC Far IR Bolometer Camera 50-240 μm
A. Poglitsch MPE, Garching FIFI-LS Field Imaging Far IR Line Spectrometer
4-210 μm; R ≅ 2,000
S. Moseley NASA GSFC SAFIRE Imaging Fabry-Perot Bolometer Array
Spectrometer 145-655 μm; R = 1,000-2,000
R. Güsten MPIfR, KOSMA GREAT Heterodyne Spectrometer 60-200 μm
R = 104
-108
J. Zmuidzinas Caltech CASIMIR Heterodyne Spectrometer 200-600 μm
R = 104
-108
An obvious disadvantage of an airborne mission compared to a space-based mission is the much higher
background. Nevertheless, SOFIA will be about an order of magnitude more sensitive than the IRAS space
mission and of course will have a factor >5 better spatial resolution due to its larger telescope aperture. At
high spectral resolution, SOFIA will match or be more sensitive than the ISO space mission. In addition, no
space-based mission is presently envisioned with a spectral resolution exceeding 3,000 in the "home" (the 3
to 150 μm range) of many of the important atomic and ionic fine structure lines as well as ro-vibrational
transitions of many simple molecules, including H2O, CH4, and C2H2.
However, a great strength of an airborne astronomy program is that science instruments can be regularly
exchanged between flight opportunities. In addition, compared to space-based missions, much larger and
more massive instruments can be flown. Likewise, mission constraints such as heat dissipation or power
consumption are of less concern for airborne platforms than for satellites. The SOFIA instrument program
takes full advantage of these differences. SOFIA’s first generation instrumentation is technically very
diverse.1
Another advantage of an airborne observatory, as compared to a space-based mission, is the ability to
rapidly incorporate improvements in technology and other instrument upgrades. In this way, instrumentation
can quickly react to the latest technological innovations. At frequencies of 1 – 10 THz (30 – 300 microns),
technology is still rapidly improving and major advances in detector sensitivity and array size can be
expected over SOFIA’s 20-year lifetime. The SOFIA program plans to support a technology development
and new instrumentation program that will essentially provide an entirely new instrument complement (and
thus an entirely new mission) every ~10 years. Given the cost of new space-based instrumentation and the
1
Details on all SOFIA science instrument are available from:
http://www.sofia.arc.nasa.gov/Science/instruments/sci_instruments.html .
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5. rapidly evolving capability at THz frequencies, a modest level of funding for new SOFIA instruments
expects to yield a bountiful science return to NASA, DLR, and the at-large astronomical community.
4. THZ SCIENCE WITH SOFIA
As illustrated in Figure 4, SOFIA will be
able to contribute to a wide variety of science
topics. These focus on the formation of stars and
planetary systems, the characteristics of dwarf-
planets at the edge of our Solar System and what
they tell us about the origin and evolution of the
solar system, the death of stars and the
enrichment of galaxies by their ashes, the black
hole in the center of our galaxy, and the role of
star formation and black hole activity in the
nuclei of starburst galaxies. Below, we discuss
in more detail some of the first THz science that
may be done with SOFIA.
Figure 4. An overlay of SOFIA science with
the phase space of the observatory's first
generation instrument suite.
4.1.The ISM of Galaxies
The interstellar medium (ISM) plays a
central role in the evolution of galaxies as the
birthsite of new stars and the repository of old stellar ejecta. The formation of new stars slowly consumes the
ISM, locking it up for millions to billions of years. As these stars age, the winds from low mass, asymptotic
giant branch stars (AGB) and high mass, red supergiants (RSG), and supernova explosions inject
nucleosynthetic products of stellar interiors into the ISM, slowly increasing its metallicity. This constant
recycling and associated enrichment drives the evolution of a galaxy's visible matter and changes its
emission characteristics. To understand this recycling, we have to study the physical processes of the ISM,
the formation of new stars, the injection of mass by evolved stars, and their relationships on a galaxy-wide
scale. Dust and gas play a major role in these processes and hence SOFIA with its wide wavelength coverage
and high spectral resolution capabilities is destined to play a dominant role in this field.
Of specific importance are the atomic fine structure lines of [OI] at 63 and 145 μm and of [CII] at
158μm. These lines are bright in regions illuminated or shocked by massive stars and their outflows. The
GREAT instrument on SOFIA will be the only means to resolve these lines at the sub-km/s level and hence
probe in detail the physical conditions in these regions as well as their kinematics.
4.2.The Interstellar Deuterium Abundance
Deuterium was formed in the Big Bang; its abundance provides strong constraints on the physical
conditions during the first few minutes of the universe's expansion. As stars form, deuterium is lost due to
nucleosynthesis when material is cycled through stellar interiors in the course of galactic chemical evolution.
Deuterium is thus potentially a key element for probing the origin and evolution of the universe as well as the
star formation history of the universe. The 3 THz (100 μm) channel on GREAT is designed to measure the
ground state transition of HD, the main reservoir of deuterium in molecular clouds, at sub-km/s resolution.
HD will be seen in emission in the warm gas associated with photodissociation regions and interstellar
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6. shocks, and in absorption toward bright background sources. Observations of a wide sample of sources will
probe the cosmologically important D abundance and its astration by nuclear burning in stars throughout the
galaxy. SOFIA is the only observatory with the appropriate wavelength coverage and spectral resolution
required for this study (see Güsten 2005).
4.3. THz (Far-Infared and Submillimeter) Surveys
Following the spectral studies of ISO (e.g. van Dishoeck and Tielens, 2001) and Spitzer (e.g. Watson et
al, 2004), and in line with the spectral surveys proposed for Herschel (e.g. Schilke et al, 1997), SOFIA will
likely also develop its own spectral surveys program. Using the first light heterodyne instruments, spectral
line surveys can be made to reveal many new lines in the broad atmospheric window of SOFIA not covered
by Herschel. With spectral line sensitivities similar to the CSO, many new lines should be observed for the
first time in the 1.3 - 1.5 THz region and the 2 - 5 THz region
5. SUMMARY
The Stratospheric Observatory for Infrared Astronomy (SOFIA) will be the premier platform from
which to make astronomical observations at THz frequencies for the next twenty years. With the ability to
deploy new and updated instruments, the observatory will play an important role in addressing a variety of
astrophysical problems well into the 21st
century.
6. ACKNOWLEDGMENTS
We thank the entire SOFIA team for much tireless and continued work on the SOFIA project. We
would especially like to thank Tom Greene, Rolf Güsten, John Lacy, and Matt Richter for putting together
parts of several of the science cases described in this paper.
7. REFERENCES
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ESA Symposium "The Far Infrared And Submillimetre Universe", pp. 201-206, ESA SP-401, Grenoble,
France, August 1997.
Casey, S. C., “The SOFIA program: astronomers return to the stratosphere”, in Advances in Space Research,
p 560 – 567, 34, 2004.
Erickson, E. F. and Davidson, J. A., “SOFIA: The Future of Airborne Astronomy”, in Proceedings of the
Airborne Astronomy Symposium on the Galactic Ecosystem: From Gas to Stars to Dust, edited by M.
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Güsten, R., The Interstellar Deuterium Abundance,
http://www.sofia.usra.edu/Science/science_cases/index.html, 2005.
Schilke, P., Phillips, T. G., and Mehringer, D. M. First Wide Band Submillimeter Line Surveys, in: Wilson,
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van Dishoeck, E. F. and Tielens, A. G. G. M. Space-borne Observations of the Life Cycle of Interstellar Gas
and Dust, in: Bleeker, J. A. M., Geiss, J., and Huber, M. C. E. (Eds.), The Century of Space Science, pp.
607-646, 2001.
Watson, D. M. et al. Mid-infrared spectra of class I protostars in Taurus. Astrophys. J. Supplement Series
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