GOLD

Animation depicting GOLD on the SES-14 satellite in transit to geostationary orbit. Credit: NASA GSFC/CIL/Chris Meaney || The Global-scale Observations of the Limb and Disk (GOLD) mission is part of the NASA Explorers Program. GOLD is at the forefront of exploring and understanding near-Earth space, which is home to astronauts, radio signals used to guide airplanes and ships, and satellites that provide our communications and GPS systems. The more we understand about this region, the more we can protect our assets in space. GOLD is the first NASA mission to fly as a hosted payload on a commercial communications satellite. GOLD is onboard on the SES-14 satellite.Launch date: January 25, 2018Launch location: Guiana Space Center in Kourou, French GuianaLaunch vehicle: Arianespace Ariane 5 rocketMission target: Earth’s ionosphere and thermosphereMission duration: 2-year nominal mission at geostationary orbit; extended mission possible ||

The Global-scale Observations of the Limb and Disk, or GOLD, instrument launches aboard a commercial communications satellite in January 2018 to inspect the dynamic intermingling of space and Earth’s uppermost atmosphere. Together, GOLD and another NASA mission, Ionospheric Connection Explorer spacecraft, or ICON, will provide the most comprehensive of Earth’s upper atmosphere we’ve ever had.Above the ozone layer, the ionosphere is a part of Earth’s atmosphere where particles have been cooked into a sea of electrically-charged electrons and ions by the Sun’s radiation. The ionosphere is co-mingled with the very highest — and quite thin — layers of Earth’s neutral upper atmosphere, making this region an area that is constantly in flux undergoing the push-and-pull between Earth’s conditions and those in space. Increasingly, these layers of near-Earth space are part of the human domain, as it’s home not only to astronauts, but to radio signals used to guide airplanes and ships, and satellites that provide our communications and GPS systems. Understanding the fundamental processes that govern our upper atmosphere and ionosphere is crucial to improve situational awareness that helps protect astronauts, spacecraft and humans on the ground.GOLD, in geostationary orbit over the Western Hemisphere, will build up a full-disk view of the ionosphere and upper atmosphere every half hour, providing detailed large-scale measurements of related processes — a cadence which makes it the first mission to be able to monitor the true weather of the upper atmosphere. GOLD is also able to focus in on a tighter region and scan more quickly, to complement additional research plans as needed. ||

Closeup view of Earth from the perspective of the GOLD instrument. This version interpolates the IRI model to a higher time cadence for a smoother animation. || A view of Earth from the point-of-view of the GOLD (Global-scale Observations of the Limb and Disk) instrument in geostationary orbit. This mission will conduct measurements of ionospheric composition to better understand the connection between space weather and its terrestrial impacts.ICON (Ionospheric Connections Explorer) orbits much closer to Earth. The colors over Earth represent model data from the IRI (International Reference Ionosphere) model of the density of the singly-ionized oxygen atom at an altitude of 350 kilometers. Red represents high density. The ion density is enhanced above and below the geomagnetic equator (not perfectly aligned with the geographic equator) on the dayside due to the ionizing effects of solar ultraviolet radiation combined with the effects of high-altitude winds and the geomagnetic field. This ion density decreases at night as the ions recombine with free electrons. At the limb of Earth, we present a cross-sectional profile of the density enhancement. ||

The GOLD instrument orbits Earth in a geostationary orbit over the western hemisphere. || The GOLD instrument will be riding as a passenger instrument onboard a commercial communications satellite positioned in geostationary orbit.GOLD will scan the disk and limb of Earth with an ultraviolet imaging spectrograph to measure the response of Earth's ionosphere to the various forcings in the Sun-Earth system. ||

Visualization of GOLD orbiting Earth with image scanning. This version presents the singly-ionized oxygen density from the IRI model. || A basic view of the orbit for GOLD (Global-scale Observations of the Limb and Disk). This mission will conduct measurements of ionospheric composition and ionization better understand the connection between space weather and its terrestrial impacts.In this visualization, we present GOLD in geostationary orbit around Earth. The colors over Earth represent model data from the IRI (International Reference Ionosphere) model of the density of the singly-ionized oxygen atom at an altitude of 350 kilometers. Red represents high density. The ion density is enhanced above and below the geomagnetic equator (not perfectly aligned with the geographic equator) on the dayside due to the ionizing effects of solar ultraviolet radiation combined with the effects of high-altitude winds and the geomagnetic field.In the latter half of the visualization, the viewing fields of the GOLD instrument are displayed. GOLD has an imaging spectrometer (green) that periodically scans the disk of Earth with additional higher-resolution scans of the dayside limb. ||

Music credit: Foxy Trot by Luis Enriquez Bacalov Complete transcript available.Watch this video on the NASA Goddard YouTube channel. || Learn about the features of the ionosphere! This little-explored region exists between space and Earth. It is home to the aurora, the international space station, a variety of satellites, and radio communication waves. We know it is sensitive to weather from Earth and conditions in space, called space weather. Join us as we venture to this interface to space! ||

This visualization presents data on the concentration of the singly-ionized oxygen atom (rainbow color table, red is highest concentration), the low-latitude geomagnetic field (gold field lines) and the ionospheric winds at two altitude levels, 100km (white) and 350 km (violet). || This visualization presents several 'Reference models' for studying Earth's ionosphere. It presents a close-up view of Earth's limb and ionospheric data-driven models, over a fixed geographic location - off the Atlantic coast of South America.Reference models are used to define well-established knowledge and facilitate mapping out areas for future exploration. The models might be described as semi-empirical, in that they are generated using many measurements at a varietly of locations, and those measurements are used to constrain a theoretical model which is used to estimate measurements at locations where an actual measurement is not available.Three models important in ionospheric physics are presented in this visualization.International Reference Ionosphere (IRI)This model provides parameters such as electron temperature and density, ion temperature and the densities of various ions (O+, H+, He+, NO+, O2+). In this visualization, we display the atomic oxygen positive ion (a single atom ion) density at an altitude of 350 kilometers. On the limb of Earth, we present a vertical cross-section of the model, illustrating how the density varies with altitude and providing an altitude scale for comparison. This dataset exhibits two notable characteristics.Daily variation: The oxygen ion density increases during the day and then decreases after nightfall. This is due to photoionization by solar ultraviolet light, which increases with sunrise to a maximum at local noon, and then decreases towards evening.Appleton Anomaly: One of the more striking features of the ion density is the daytime enhancement is split into two regions, distributed symmetrically above and below the magnetic equator. This feature was discovered by Edward Appleton in 1946. It is now understood to be an effect of the interaction of Earth's geomagnetic field with upper atmosphere electric fields, and often referred to as the 'fountain effect,' explained in 1965. The electric fields lift ions and electrons upward by E-cross-B drift (Plasma Zoo). At higher altitudes, the upward drift decreases and the geomagnetic field and gravity dominate the motion, guiding the charged particles earthward.Horizontal Wind Model (HWM)This model provides speed and direction of horizontal (parallel to Earth's surface) winds constructed from over 70 million ground-based and satellite measurements. Two altitude levels are displayed in this visualization: 350 kilometers (same altitude as the IRI oxygen ion data) in violet glyphs, and 100 kilometers (white glyphs). This model only extends to 60 degrees latitude, so there are gaps around the poles in this visualization.One of the most notable characteristics in this dataset, particularly the 350 kilometer data, is how the winds are driven by the daily solar heating cycle. As the sun rises, the upper atmosphere is heated by solar ultraviolet light. This creates a high-pressure region which drives the atmosphere away from direct sunlight; westward in the morning and eastward in the afternoon. As the sun sets and the atmosphere cools, we see the wind reverse, filling in the now cooler and lower-pressure region.International Geomagnetic Reference Field-12 (IGRF-12)This model provides the structure of Earth's magnetic field which is a dominant influence on the motion of electrons and ions in the ionosphere. The geomagnetic field changes very slowly over decades. For this visualization, we display only a few field lines (golden wire-like structures) near the geomagnetic equator. As we observe the daily variation of the data, particularly the oxygen ions, we see the Appleton anomaly is hedged in by the low-latitude geomagnetic field.ReferencesNOAA/National Geophysical Data Center. International Geomagnetic Reference FieldErwan Thebault, Christopher C. Finlay, et al. International Geomagnetic Reference Field: the 12th generation. Earth, Planets and Space 67:79 (2015)Dieter Bilitza. The International Reference Ionosphere - Status 2013. Advances in Space Research, Volume 55, p. 1914-1927 (2015)Douglas P. Drob, John T. Emmert, et al. An update to the Horizontal Wind Model (HWM): The quiet time thermosphere. Earth and Space Science, vol. 2, issue 7, pp. 301-319Edward V. Appleton. Two Anomalies in the Ionosphere. Nature, Volume 157, pp. 691 (1946)E. N. Bramley and M. Peart. Diffusion and electromagnetic drift in the equatorial F2-region. Journal of Atmospheric and Terrestrial Physics, vol. 27, pp. 1201-1211 (1965)R.J. Moffett & W.B. Hanson. Effect of Ionization Transport on the Equatorial F-Region. Nature 206, pp705-706 (1965) ||

A view of the singly-ionizing oxygen atom on the dayside of Earth. This represents the variation of the enhancments due to variation in the geomagnetic field. This version interpolates the IRI model to a higher time cadence for a smoother animation. || The colors over Earth represent model data from the IRI (International Reference Ionosphere) model of the density of the singly-ionized oxygen atom at an altitude of 350 kilometers. Red represents high density. The ion density is enhanced above and below the geomagnetic equator (not perfectly aligned with the geographic equator) on the dayside due to the ionizing effects of solar ultraviolet radiation combined with the effects of high-altitude winds and the geomagnetic field. This ion density decreases at night as the ions recombine with free electrons. ||

Oxygen ion enhancements at 350km altitude, ionospheric winds at altitudes of 100 km (white) and 350 km (violet) and the low-latitude geomagnetic field. || This visualization presents several 'reference models' for studying Earth's ionosphere. It opens with a full-disk view of Earth, then zooms-in to a close-up view of Earth's limb and ionospheric data-driven models, over a fixed geographic location - off the Atlantic coast of South America.Reference models are used to define well-established knowledge and facilitate mapping out areas for future exploration. The models might be described as semi-empirical, in that they are generated using many measurements at a varietly of locations, and those measurements are used to constrain a theoretical model which is used to estimate measurements at locations where an actual measurement is not available.Three models important in ionospheric physics are presented in this visualization.International Reference Ionosphere (IRI)This model provides parameters such as electron temperature and density, ion temperature and the densities of various ions (O+, H+, He+, NO+, O2+). In this visualization, we display the atomic oxygen positive ion (a single atom ion) density at an altitude of 350 kilometers. On the limb of Earth, we present a vertical cross-section of the model, illustrating how the density varies with altitude and providing an altitude scale for comparison. This dataset exhibits two notable characteristics.Daily variation: The oxygen ion density increases during the day and then decreases after nightfall. This is due to photoionization by solar ultraviolet light, which increases with sunrise to a maximum at local noon, and then decreases towards evening.Appleton Anomaly: One of the more striking features of the ion density is the daytime enhancement is split into two regions, distributed symmetrically above and below the magnetic equator. This feature was discovered by Edward Appleton in 1946. It is now understood to be an effect of the interaction of Earth's geomagnetic field with upper atmosphere electric fields, and often referred to as the 'fountain effect,' explained in 1965. The electric fields lift ions and electrons upward by E-cross-B drift (Plasma Zoo). At higher altitudes, the upward drift decreases and the geomagnetic field and gravity dominate the motion, guiding the charged particles earthward.Horizontal Wind Model (HWM)This model provides speed and direction of horizontal (parallel to Earth's surface) winds constructed from over 70 million ground-based and satellite measurements. Two altitude levels are displayed in this visualization: 350 kilometers (same altitude as the IRI oxygen ion data) in violet glyphs, and 100 kilometers (white glyphs). This model only extends to 60 degrees latitude, so there are gaps around the poles in this visualization.One of the most notable characteristics in this dataset, particularly the 350 kilometer data, is how the winds are driven by the daily solar heating cycle. As the sun rises, the upper atmosphere is heated by solar ultraviolet light. This creates a high-pressure region which drives the atmosphere away from direct sunlight; westward in the morning and eastward in the afternoon. As the sun sets and the atmosphere cools, we see the wind reverse, filling in the now cooler and lower-pressure region.International Geomagnetic Reference Field-12 (IGRF-12)This model provides the structure of Earth's magnetic field which is a dominant influence on the motion of electrons and ions in the ionosphere. The geomagnetic field changes very slowly over decades. For this visualization, we display only a few field lines (golden wire-like structures) near the geomagnetic equator. As we observe the daily variation of the data, particularly the oxygen ions, we see the Appleton anomaly is hedged in by the low-latitude geomagnetic field.ReferencesNOAA/National Geophysical Data Center. International Geomagnetic Reference FieldErwan Thebault, Christopher C. Finlay, et al. International Geomagnetic Reference Field: the 12th generation. Earth, Planets and Space 67:79 (2015)Dieter Bilitza. The International Reference Ionosphere - Status 2013. Advances in Space Research, Volume 55, p. 1914-1927 (2015)Douglas P. Drob, John T. Emmert, et al. An update to the Horizontal Wind Model (HWM): The quiet time thermosphere. Earth and Space Science, vol. 2, issue 7, pp. 301-319Edward V. Appleton. Two Anomalies in the Ionosphere. Nature, Volume 157, pp. 691 (1946)E. N. Bramley and M. Peart. Diffusion and electromagnetic drift in the equatorial F2-region. Journal of Atmospheric and Terrestrial Physics, vol. 27, pp. 1201-1211 (1965)R.J. Moffett & W.B. Hanson. Effect of Ionization Transport on the Equatorial F-Region. Nature 206, pp705-706 (1965) ||

The photographs used to make this video were taken on September 17, 2011 from 17:22:27 to 17:37:21 GMT from the International Space Station (ISS). This image sequence begins over the Indian Ocean halfway between Madagascar and Antarctica. Aurora Australis is present for the first 2/3rds of the video, then Australis comes into view. Yellow lights near the coast show the presence of cities, while interior oragne lights indicate brush fires.http://eol.jsc.nasa.gov || Time lapse photos of Aurora Australis ||

Visualization of ICON and GOLD orbiting Earth with image scanning. This version presents several geospace models, including the singly-ionized oxygen density, the low-latitude geomagnetic field, and the high-altitude winds (100km and 350km altitudes). || A basic view of the orbits for ICON (Ionospheric Connections Explorer) and GOLD (Global-scale Observations of the Limb and Disk). These missions will conduct measurements of ionospheric composition, ionization, and winds to better understand the connection between space weather and its terrestrial impacts.In this visualization, we present GOLD (in geostationary orbit around Earth) and ICON (in low Earth orbit). The colors over Earth represent model data from the IRI (International Reference Ionosphere) model of the density of the singly-ionized oxygen atom at an altitude of 350 kilometers. Red represents high density. The ion density is enhanced above and below the geomagnetic equator (not perfectly aligned with the geographic equator) on the dayside due to the ionizing effects of solar ultraviolet radiation combined with the effects of high-altitude winds and the geomagnetic field.In the latter half of the visualization, the viewing fields of the various instruments are displayed. ICON has an EUV (Extreme Ultraviolet) and FUV (Far Ultraviolet) cameras (violet colored frustrums directed from spacecraft) pointing perpendicular to the orbit direction for detecting ionospheric emissions. Two Doppler interferometer cameras (blue) are directed at 45 degrees from this camera to detect ionospheric wind velocities.GOLD has an imaging spectrometer (green) that periodically scans the disk of Earth with additional higher-resolution scans of the dayside limb. ||

Music credit: Design Principle by Wayne RobertsComplete transcript available. || NASA's Ionospheric Connection Explorer, or ICON launches in fall 2018. It orbits above the upper atmosphere, through the bottom edge of near-Earth space. From this vantage point, ICON observes both the upper atmosphere and a layer of charged particles called the ionosphere, which extends from about 50 to 360 miles above the surface of Earth. Processes in the ionosphere also create bright swaths of color in the sky, known as airglow. ICON will observe how interactions between Earth's weather and the ionosphere create such shimmering airglow as well as other changes in the space environment. Find more views of the ionosphere from the International Space Station at The Crew Earth Observations Video Page ||

The Global-scale Observations of the Limb and Disk, or GOLD, mission is designed to explore the nearest reaches of space. Capturing never-before-seen images of Earth’s upper atmosphere, GOLD explores in unprecedented detail our space environment — which is home to astronauts, radio signals used to guide airplanes and ships, as well as satellites that provide communications and GPS systems. On January 25, 2018, the mission will launch as NASA's first-ever hosted payload.Speakers for the January 24, 2018 media telecon about the mission include:Richard Eastes, Principal Investigator, Laboratory for Atmospheric and Space Physics at the University of Colorado BoulderElsayed Talaat, Heliophysics Chief Scientist, NASA HeadquartersSusan Batiste, Systems Engineer, LASP/CUKatelynn Greer, Research Scientist, LASP/CUReplay information will be available until January 31, 2018 noon ET, via: Toll free, from within the U.S.: 1-866-469-5761 
Toll: 203-369-1460 ||

Going for GOLD: Exploring the Interface to Space || NASA's newest mission to explore our interface to space. The Global-scale Observations of the Limb and Disk, or GOLD, mission is designed to explore the nearest reaches of space. Capturing never-before-seen images of Earth's upper atmosphere, GOLD explores in unprecedented detail our space environment[Facebook Live Event 1-4-18 Air Date] || GOLD Launch Coverage 1-25-18 ||