First Light for a Space Weather Satellite

June 5, 2000 -- "First-light" pictures from NASA's Imager for Magnetopause to Aurora Global Exploration (IMAGE) spacecraft have revealed the global ebb and flow of hot, electrified gas (plasma) around the Earth in response to the solar wind. Severe disturbances in this region controlled by the Earth's magnetic field (the magnetosphere) are capable of disrupting satellites, telephone and radio communications, and power systems.

"IMAGE is the first weather satellite for space storms," said Dr. James L. Burch, Principal Investigator for IMAGE at Southwest Research Institute, San Antonio, Texas. "This revolutionary spacecraft makes these invisible storms visible. In a sense, IMAGE allows us to view the Earth through plasma-colored glasses. We eagerly anticipate the arrival of severe solar weather associated with solar maximum, which we are now entering."

Above: This picture, recorded by IMAGE's Extreme Ultraviolet Imager, shows solar ultraviolet radiation scattered from ionized helium in the Earth's extended atmosphere. The ionized helium envelope is 2 to 3 times the size of the Earth. Irregularities at the fringe of the image (upper left) indicate magnetic storm activity. This is the first time such features have been imaged. This is a selected frame from a sequence which is available as a 1.6 Mb Quicktime movie.

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Previous spacecraft explored the turbulent magnetosphere by detecting particles and fields in the immediate vicinity of the spacecraft. This technique limited their vision to small portions of this vast and dynamic region, which extends beyond the Moon on the Earth's night side.

"The old way of tracking magnetic storms is like trying to understand severe thunderstorms in the Midwest by driving around with a rain gauge out the window," said Dr. Thomas Moore, IMAGE Project Scientist at NASA's Goddard Space Flight Center, Greenbelt, Md. "With IMAGE, we will see the big picture, just like entire storm systems appear on the evening news with weather satellites."

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The first pictures from IMAGE were presented at a press conference during the spring meeting of the American Geophysical Union May 31 in Washington, D.C.

"These first images are an enticing glimpse at the spectacular results expected from IMAGE once we encounter really heavy weather in space," said Dr. James Green, Deputy Project Scientist for IMAGE at Goddard.

All spacecraft systems have been successfully deployed and are operating normally. All scientific instruments are operating as expected and are returning images.

The Radio Plasma Imager instrument provides a three-dimensional view of the plasmasphere by sounding it with radio pulses, like an ultrasound image of the human body. To accomplish this, it uses the longest antennas ever deployed in space, longer than the height of the Empire State Building.

Left: The Radio Plasma Imager (RPI) on IMAGE is the first-of-its-kind instrument designed to study the dynamics of the magnetosphere by using radar techniques. In order to generate very low frequency radio waves and to receive the resulting echoes, RPI uses very long dipole antennas. IMAGE has 2 spin-plane dipole antennas (along the spacecraft X and Y axis) and one spin-axis dipole antenna (along the spacecraft Z axis). The X and Y axis antennas are 1647 ft or 500 meters tip-to-tip each. These antennas are 182 ft longer than the height of the Empire State Building, making the IMAGE spacecraft the largest dipole antenna system currently in space. This is a selected frame from a sequence which is available as a 100 kb Quicktime movie.

A suite of three Neutral Atom Imaging instruments is recording the glow of fast atoms coming from throughout the Earth's magnetic field. This reveals the shape and motion of the clouds of plasma that make up a magnetic storm.

The Far Ultraviolet Imaging instrument is collecting the first-ever images from space of the Earth's proton aurora. The aurora, commonly known as the northern and southern lights, is a ghostly light show seen most often at high latitudes of Earth. The dance of lights that is visible from the ground is caused by electrons striking and lighting up the atmosphere much like electricity lights up a television screen. The proton aurora is invisible to the naked eye and has never been viewed from space; from the ground, it is visible only in far-ultraviolet wavelengths.

Right: Aurora are caused by the interaction of precipitating charged particles (electrons and ions) with the neutral gases of our atmosphere. Light from the Earth's aurora occur principally in two oval-shaped bands lying between ~65 and 75 degrees magnetic latitude and centered on the northern (aurora borealis) and southern (aurora australis) magnetic poles. IMAGE observes the aurora in several important wavelengths and has captured its first geomagnetic substorm (pictured above). These observations are caused by precipitating electrons. This is a selected frame from a sequence which is available as a 145 kb Quicktime movie.

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The Extreme Ultraviolet Imager is capturing the first global images of the plasmasphere, which is the tenuous extension of the Earth's electrically charged upper atmosphere, or ionosphere. The plasmasphere extends about 12,500 miles (20,000 kilometers) into space. Images from this region will provide a sensitive indicator of the onset of magnetic storm activity.

Southwest Research Institute manages the IMAGE project and leads the IMAGE science investigation. The IMAGE Principal Investigator is James L. Burch.

Web Links

IMAGE First Light Movies and Pictures - from NASA/GSFC

IMAGE home page - from the Southwest Research Institute

IMAGE home page - from NASA/GSFC

More Science@NASA stories about IMAGE:

Innovative Space Weather Mission Nears Launch -- Feb. 24, 2000

The RADAR Cop in Space -- March 24, 2000

Space Weather Satellite Blasts Off -- March 27, 2000

Instruments on IMAGE include:

The Radio Plasma Imager. The RPI will use radar echoes in the frequency range 3 kHz to 3 MHz to detect and monitor ionized gas (plasma) inside the magnetosphere.
Far Ultraviolet Imager. The FUI will take pictures and spectra of the entire Earth along with the auroral oval at ultraviolet wavelengths. The 3 instruments that combine to form the FUI instrument package (GEO, SI and WIC) will provide almost constant monitoring of auroral activity from above our planet. The Earth is surrounded by a cloud of neutral atoms and molecules that is largely invisible from the ground. The so-called 'geocorona' is an extension of Earth's atmosphere into space. It is mostly made up of hydrogen, because it's the lightest element. GEO will also be used to detect these neutral atoms, measure their energy and map their distribution.
Neutral Atom Imagers. The neutral atom cameras will detect neutral atoms created by ring current ions and escaping auroral ions that collide and exchange charge with the cold, geocoronal hydrogen gas. This will allow scientists to indirectly monitor and explore the ring current and auroral ion fountains.
Extreme Ultraviolet Imager. The EUVI will detect ultraviolet photons from the Sun that are scattered by helium ions in the plasmasphere, a torus of cold dense plasma surrounding the Earth in the inner magnetosphere. A sophisticated deconvolution technique will be used to translate the photon counts into images of the plasmasphere.

IMAGE First Light

NASA's IMAGE mission, a unique satellite dedicated to space storms, has returned its first pictures of electrified gas surrounding our planet.

Instruments on IMAGE include: