Nasa - Solar Observation Missions

Heliophysics
"We live in the extended atmosphere of an active star. While sunlight enables and sustains life, the Sun's variability produces streams of high energy particles and radiation that can harm life or alter its evolution.

Under the protective shield of a magnetic field and atmosphere, the Earth is an island in the Universe where life has developed and flourished. The origins and fate of life on Earth are intimately connected to the way the Earth responds to the Sun's variations.

Understanding the Sun, Heliosphere, and Planetary Environments as a single connected system is the goal of the Science Mission Directorate's Heliophysics Research Program. In addition to solar processes, our domain of study includes the interaction of solar plasma and radiation with Earth, the other planets, and the Galaxy. By analyzing the connections between the Sun, solar wind, planetary space environments, and our place in the Galaxy, we are uncovering the fundamental physical processes that occur throughout the Universe. Understanding the connections between the Sun and its planets will allow us to predict the impacts of solar variability on humans, technological systems, and even the presence of life itself.

We have already discovered ways to peer into the internal workings of the Sun and understand how the Earth's magnetosphere responds to solar activity. Our challenge now is to explore the full system of complex interactions that characterize the relationship of the Sun with the solar system." ... more

Sun Missions
SOHO - RHESSI - ACRIMSAT - STEREO - Hinode - SDO - Solar Orbiter
Solar Interaction With Earth:   Cluster - Geotail - TIMED - THEMIS - TWINS-A and TWINS-B - Wind - CINDI - STEREO   Sun & Moon Interaction:   ARTEMIS
Sun & Space Activities:   Voyager - ACE

The Heliophysics Science Division
"The Heliophysics Science Division conducts research on the Sun, its extended solar-system environment (the heliosphere), and interactions of Earth, other planets, small bodies, and interstellar gas with the heliosphere. Division research also encompasses geospace -- Earth's uppermost atmosphere, the ionosphere, and the magnetosphere -- and the changing environmental conditions throughout the coupled heliosphere (solar system weather).

Scientists in the Heliophysics Science Division develop models, spacecraft missions and instruments, and systems to manage and disseminate heliophysical data. They interpret and evaluate data gathered from instruments, draw comparisons with computer simulations and theoretical models, and publish the results. The Division also conducts education and public outreach programs to communicate the excitement and social value of NASA heliophysics." ... more

Heliophysics Missions
ACE - AIM - CINDI/CNOFS - Cluster-II - BARREL (in development)

SOHO
"SOHO, the Solar & Heliospheric Observatory, is a project of international collaboration between ESA and NASA to study the Sun from its deep core to the outer corona and the solar wind.

SOHO Objectives
SOHO was designed to answer the following three fundamental scientific questions about the Sun:
          . What is the structure and dynamics of the solar interior?
          . Why does the solar corona exist and how is it heated to the extremely high temperature of about 1 000 000ºC?
          . Where is the solar wind produced and how is it accelerated?
Clues on the solar interior come from studying seismic waves that are produced in the turbulent outer shell of the Sun and which appear as ripples on its surface." ... more

SOHO was launched on December 2, 1995. The SOHO spacecraft was built in Europe by an industry team led by prime contractor Matra Marconi Space (now EADS Astrium) under overall management by ESA. The twelve instruments on board SOHO were provided by European and American scientists. Nine of the international instrument consortia are led by European Principal Investigators (PI's), three by PI's from the US. Large engineering teams and more than 200 co-investigators from many institutions supported the PI's in the development of the instruments and in the preparation of their operations and data analysis. NASA was responsible for the launch and is now responsible for mission operations. Large radio dishes around the world which form NASA's Deep Space Network are used for data downlink and commanding. Mission control is based at Goddard Space Flight Center in Maryland." ... more

ACRIMSAT
The ACRIMSAT Mission will measure Total Solar Irradiance (TSI) during its five-year mission life. The ACRIMSAT spacecraft, carrying the ACRIM III instrument, will be secondary payload on a Taurus vehicle scheduled to launch in December 1999. The instrument, third in a series of long-term solar-monitoring tools built for NASA by the Jet Propulsion Laboratory, will continue to extend the database first created by ACRIM I, which was launched in 1980 on the Solar Maximum Mission (SMM) spacecraft. ACRIM II followed on the Upper Atmosphere Research Satellite (UARS) in 1991.

The Active Cavity Radiometer Irradiance Monitor (ACRIM) I instrument was the first to clearly demonstrate that the total radiant energy from the sun was not a constant. However, the solar variability was so slight (0.1% of full scale) that continuous monitoring by state-of-the-art instrumentation was necessary. It is theorized that as much as 25% of the anticipated global warming of the earth may be solar in origin. In addition, seemingly small (0.5%) changes in the TSI output of the sun over a century or more may cause significant climatological changes on earth.

The ACRIMSAT mission is funded by NASA through the Earth Science Programs Office at Goddard Space Flight Center. The ACRIMSAT Project Office at the Jet Propulsion Laboratory (Pasadena, CA) manages the design, fabrication, and test of the ACRIM III instrument and manages the subcontract for the ACRIMSAT spacecraft being built by Orbital Sciences Corporation. The ACRIM III data products will be available through the Langley EOS Data Analysis and Archive Center." ... more

The Reuven Ramaty High Energy Solar Spectroscopic Imager
"RHESSI's primary mission is to explore the basic physics of particle acceleration and explosive energy release in solar flares. This is achieved through imaging spectroscopy in X-rays and gamma-rays with fine angular and energy resolution to reveal the locations and spectra of the accelerated electrons and ions and of the hottest plasma.

Solar flares and their associated coronal mass ejections are of great scientific interest since they are so little understood. They present severe challenges to explain how the energy equivalent of billions of megatons of TNT is released in the solar atmosphere on time scales of minutes, and how so many electrons, protons and heavier ions are accelerated to such high energies. These super-energetic solar eruptive events are the most extreme drivers of space weather and present significant dangers in space and on Earth.

RHESSI's New Approach
Researchers believe that much of the energy released during a flare is used to accelerate, to very high energies, electrons (emitting primarily X-rays) and protons and other ions (emitting primarily gamma rays). The new approach of the RHESSI mission is to combine, for the first time, high-resolution imaging in hard X-rays and gamma rays with high-resolution spectroscopy, so that a detailed energy spectrum can be obtained at each point of the image.

This new approach will enable researchers to find out where these particles are accelerated and to what energies. Such information will advance understanding of the fundamental high-energy processes at the core of the solar flare problem." ... more

RHESSI
What is a solar flare? - How does RHESSI work? - What are the scientific objectives? - How does RHESSI make images? - RHESSI Spectroscopy

Solar TErrestrial RElations Observatory (STEREO)
STEREO (Solar TErrestrial RElations Observatory) is the third mission in NASA's Solar Terrestrial Probes program (STP). The mission, launched in October 2006, has provided a unique and revolutionary view of the Sun-Earth System. The two nearly identical observatories - one ahead of Earth in its orbit, the other trailing behind - have traced the flow of energy and matter from the Sun to Earth. STEREO has revealed the 3D structure of coronal mass ejections; violent eruptions of matter from the sun that can disrupt satellites and power grids, and help us understand why they happen. STEREO is a key addition to the fleet of space weather detection satellites by providing more accurate alerts for the arrival time of Earth-directed solar ejections with its unique side-viewing perspective.

Why the need for STEREO?
Coronal mass ejections (CMEs), are powerful eruptions that can blow up to 10 billion tons of the Sun's atmosphere into interplanetary space. Traveling away from the Sun at speeds of approximately one million mph (1.6 million kph), CMEs can create major disturbances in the interplanetary medium and trigger severe magnetic storms when they collide with Earth's magnetosphere.

Large geomagnetic storms directed towards Earth can damage and even destroy satellites, are extremely hazardous to Astronauts when outside of the protection of the Space Shuttle or the International Space Station performing Extra Vehicular Activities (EVAs), and they have been known to cause electrical power outages.

CMEs: a Fundamental Science Challenge
Solar ejections are the most powerful drivers of the Sun-Earth connection. Yet despite their importance, scientists don't fully understand the origin and evolution of CMEs, nor their structure or extent in interplanetary space. STEREO's unique stereoscopic images of the structure of CMEs will enable scientists to determine their fundamental nature and origin." ... more

Hinode: Mission to the Sun
Hinode is an international mission to study our nearest star, the sun. To accomplish this, the Hinode mission includes a suite of three science instruments -- the Solar Optical Telescope, X-ray Telescope and Extreme Ultraviolet Imaging Spectrometer.

Together, these instruments will study the generation, transport, and dissipation of magnetic energy from the photosphere to the corona and will record how energy stored in the sun's magnetic field is released, either gradually or violently, as the field rises into the sun's outer atmosphere.

By studying the sun's magnetic field, scientists hope to shed new light on explosive solar activity that can interfere with satellite communications and electric power transmission grids on Earth and threaten astronauts on the way to or working on the surface of the moon. In particular they want to learn if they can identify the magnetic field configurations that lead to these explosive energy releases and use this information to predict when these events may occur.

Led by the Japan Aerospace Exploration Agency (JAXA), the Hinode mission is a collaboration between the space agencies of Japan, the United States, the United Kingdom and Europe. NASA helped in the development, funding and assembly of the spacecraft's three science instruments. Hinode is part of the Solar Terrestrial Probes (STP) Program within the Heliophysics Division of NASA's Science Mission Directorate in Washington. The Solar Terrestrial Probes Program is managed at NASA's Goddard Space Flight Center in Greenbelt, Md. NASA's Marshall Space Flight Center in Huntsville, Ala., managed the development of instrument components provided by NASA, with additional support by academia and industry." ... more

Solar Dynamics Observatory (SDO)
"The Solar Dynamics Observatory (SDO) will be taking a closer look at the Sun, the source of all Space Weather. Space Weather affects not only our lives here on Earth, but the Earth itself, and everything outside its atmosphere (astronauts and satellites out in space and even the other planets).

The Sun, our closest star, is still a great mystery to scientists. SDO will help us understand where the Sun's energy comes from, how the inside of the Sun works, and how energy is stored and released in the Sun's atmosphere... yes, the Sun has an atmosphere! By better understanding the Sun and how it works, we will be able to better predict and better forecast the "weather out in space" providing earlier warnings to protect our astronauts and satellites floating around out there.

SDO is the first satellite under the Living with a Star (LWS) program at NASA. The spacecraft is being designed to fly for five years. However, since satellites go through a lot of testing and retesting, they often keep working long past their initial mission life. SOHO for example, which was built to fly for five years, in 2005 celebrated its 10 year anniversary in 2005!

SDO is unlike any other satellite. It will be collecting huge amounts of data everyday. In fact SDO will produce enough data to fill a single CD every 36 seconds..." more

Living With a Star Program (LWS)
Heliophysics is the study of the Sun and its interactions with Earth and the solar system. The Heliophysics science program consists of two strategic programs/mission lines: the Solar Terrestrial Probes and Living with a Star; one Principal Investigator- led competed line (the Explorers); and a set of Research programs including a fleet of operating missions known as the Heliophysics System Observatory. All play a part in the development of scientific understanding of the heliophysics system.

Living With a Star emphasizes the science necessary to understand those aspects of the Sun and space environment that most directly affect life and society. LWS missions target the linkages across the interconnected system with an ultimate goal of enabling a predictive understanding. The first LWS mission is the Solar Dynamics Observatory (SDO), which was launched early in 2010. This mission observes how the Sun’s magnetic field is generated and structured and stored magnetic energy is converted and released into the heliosphere in the form of solar wind, energetic particles, and variations in the solar irradiance. The second LWS mission will be the Radiation Belt Storm Probes (RBSP). The twin RBSP spacecraft will determine how charged particles in space near the Earth are accelerated to hazardous energies that affect satellites, astronaut safety, and high-altitude aircraft. Concurrently with RBSP, the Balloon Array for Radiation-belt Relativistic Electron Losses (BARREL) will measure the high-energy particle precipitation from the radiation belts into our Earth's atmosphere. RBSP will launch in 2012." ... more

Advanced Composition Explorer (ACE) Mission Overview
The Advanced Composition Explorer (ACE) is an Explorer mission that was managed by the Office of Space Science Mission and Payload Development Division of the National Aeronautics and Space Administration (NASA).

ACE launched on a McDonnell-Douglas Delta II 7920 launch vehicle on August 25, 1997 from the Kennedy Space Center in Florida.

The Earth is constantly bombarded with a stream of accelerated particles arriving not only from the Sun, but also from interstellar and galactic sources. Study of these energetic particles contributes to our understanding of the formation and evolution of the solar system as well as the astrophysical processes involved. The Advanced Composition Explorer (ACE) spacecraft carrying six high-resolution sensors and three monitoring instruments samples low-energy particles of solar origin and high-energy galactic particles with a collecting power 10 to 1000 times greater than past experiments.

ACE orbits the L1 libration point which is a point of Earth-Sun gravitational equilibrium about 1.5 million km from Earth and 148.5 million km from the Sun. From its location at L1 ACE has a prime view of the solar wind, interplanetary magnetic field and higher energy particles accelerated by the Sun, as well as particles accelerated in the heliosphere and the galactic regions beyond.

ACE also provides near-real-time 24/7 continuous coverage of solar wind parameters and solar energetic particle intensities (space weather). When reporting space weather ACE provides an advance warning (about one hour) of geomagnetic storms that can overload power grids, disrupt communications on Earth, and present a hazard to astronauts.

The spacecraft has enough propellant on board to maintain an orbit at L1 until 2024." ... more

Space Observatories
Virtual Space Physics Observatory - Virtual Heliospheric Observatory - ACE RTSW - SPASE - VWO - VEPO

CINDI: Coupled Ion Neutral Dynamic Investigation
"The CINDI investigation is a key component of the science objectives of the Communication/Navigation Outage Forecast System (C/NOFS) undertaken by the Air Force Research Laboratory and the Space and Missile Command Test and Evaluation Directorate. CINDI will study the elements that influence space weather near Earth's equator."... more

CINDI: at The Center for Space Sciences in the University of Texas at Dallas
The Coupled Ion Neutral Dynamics Investigation (CINDI) is a joint NASA/US Air Force funded ionospheric (upper atmosphere) plasma sensors built by the Center for Space Sciences at the University of Texas at Dallas. This instrument package is now flying on the Air Force's Communication/Navigation Outage Forecast Satellite (C/NOFS) launched in spring 2008.

CINDI will discover the role of ion-neutral interactions in the generation of small and large-scale electric fields in the Earth's upper atmosphere. Ion-neutral interactions are a key process in controlling the dynamics of all planetary atmospheres and their understanding is important to describing the electrodynamic connections between the Sun and the Upper Atmosphere.

The CINDI investigation is carried out as an enhancement to the science objectives of the Communication/Navigation Outage Forecast System (C/NOFS) undertaken by the Air Force Research Laboratory (AFRL) and the Space and Missile Command Test and Evaluation Directorate (SMC/TEL). This program will utilize satellite and ground-based data to develop and evaluate a real-time system for forecasting the presence of radio scintillation caused by equatorial ionospheric plasma structure. The C/NOFS satellite will provide measurements of ionospheric electric fields and particle drifts, the total plasma density, and radio diagnostics. In addition the CINDI instruments will provide measurements of the 3-D neutral winds and ion drifts. The C/NOFS satellite will be operated continuously for at least 1 year. During that time the CINDI science investigations will be undertaken and will provide essential input to real-time specification and prediction models being developed by C/NOFS. This synergistic relationship optimizes the productivity and resources for the CINDI mission."... more

The Cluster mission
"The aim of the Cluster mission is to study small-scale structures of the magnetosphere and its environment in three dimensions. To achieve this, Cluster is constituted of four identical spacecraft that will flight in a tetrahedral configuration. The separation distances between the spacecraft will be varied between 600 km and 20 000 km, according to the key scientific regions.

A Study of Small-Scale Plasma Structures and Processes
Cluster is currently investigating the Earth's magnetic environment and its interaction with the solar wind in three dimensions. Science output from Cluster greatly advances our knowledge of space plasma physics, space weather and the Sun-Earth connection and has been key in improving the modeling of the magnetosphere and understanding its various physical processes.

Cluster II is part of an international collaboration to investigate the physical connection between the Sun and Earth. Flying in a tetrahedral (triangular pyramid) formation, the four spacecraft collect the most detailed data yet on small-scale changes in near-Earth space and the interaction between the charged particles of the solar wind and Earth's atmosphere. This enables scientists to build a three-dimensional model of the magnetosphere and to better understand the processes taking place inside it.

Instruments
Each of the four spacecraft carries an identical set of 11 instruments to investigate charged particles, electrical and magnetic fields. These were built by European and American instrument teams led by Principal Investigators." ... more

Cluster At NASA
Cluster II - ISTP

The Geotail mission
"The GEOTAIL mission is a collaborative project undertaken by the Institute of Space and Astronautical Science (ISAS) and the National Aeronautics and Space Administration (NASA). Its primary objective is to study the dynamics of the Earth's magnetotail over a wide range of distance, extending from the near-Earth region (8 Earth radii (Re) from the Earth) to the distant tail (about 200 Re). The GEOTAIL spacecraft was designed and built by ISAS and was launched on July 24, 1992.

The Geotail mission measures global energy flow and transformation in the magnetotail to increase understanding of fundamental magnetospheric processes. This will include the physics of the magnetopause, the plasma sheet, and reconnection and neutral line formation (i.e., the mechanisms of input, transport, storage, release and conversion of energy in the magnetotail). Geotail, together with Wind, Polar, SOHO, and Cluster projects, constitute a cooperative scientific satellite project designated the International Solar-Terrestrial Physics (ISTP) program which aims at gaining improved understanding of the physics of solar terrestrial relations.

Geotail is a spin-stabilized spacecraft utilizing mechanically despun antennas with a design lifetime of about four years. The nominal spin rate of the spacecraft is about 20 rpm around a spin axis maintained between 85 and 89 deg to the ecliptic plane. Geotail is cylindrical, approximately 2.2 m in diameter and 1.6 m high with body-mounted solar cells. Geotail also has a two-hour back-up battery subsystem which operates when the spacecraft is in the Earth's shadow."... more

Geotail Links
NASA's Polar, Wind and Geotail - Geotail Mission at NASA - UMD Space Physics Group

The Wind mission
"The Wind spacecraft is the first of two U.S. missions of the Global Geospace Science (GGS) initiative, which is part of a worldwide collaboration called the International Solar-Terrestrial Physics (ISTP) program. The aim of ISTP is to understand the physical behavior of the solar-terrestrial system in order to predict how the Earth's magnetosphere and atmosphere will respond to changes in solar wind.

WIND was launched on November 1, 1994 and was positioned in a sunward, multiple double-lunar swingby orbit with a maximum apogee of 250Re during the first two years of operation. This will be followed by a halo orbit at the Earth-Sun L1 point. The science objectives of the WIND mission are:
          . Provide conplete plasma, energetic particle, and magnetic field input for magnetospheric and ionospheric studies.
          . Determine the magnetospheric output to interplanetary space in the up-stream region
          . Investigate basic plasma processes occuring in the near-Earth solar wind
          . Provide baseline ecliptic plane observations to be used in heliospheric latitudes from ULYSSES.

Wind plays a crucial role -- essentially that of a scout and sentry -- in the fleet of ISTP satellites. The task of Wind is to measure crucial properties of the solar wind before it impacts the Earth's magnetic field and alters the Earth's space environment (which contains charged particles, electric and magnetic fields, electric currents and radiation) and upper atmosphere in a direct manner."... more

Wind Links
NASA's Polar, Wind and Geotail - NASA Science Wind

The Polar mission
"The region over the poles of the Earth is one of the most important regions of space that is studied by the ISTP Project. The Polar spacecraft was launched on February 24, 1996 to obtain data from both high- and low-altitude perspectives of this active region of geospace.

High above the poles the particles of the solar wind and the energy of the wind can find their way into the magnetosphere. At lesser altitudes energy is transferred from electric fields and electromagnetic waves to electrons that then plunge into the atmosphere to create the aurora. At mid-altitudes nearer the equator the satellite passes through the Earth's trapped radiation, the Van Allen belts. Out of the polar ionosphere flows plasma to populate the magnetosphere. Through this region particles and energy flow from the geomagnetic tail to the atmosphere. Thus the instruments on the Polar satellites see a lot of action in the various plasma parameters that they measure.

Three of the twelve scientific instruments aboard the Polar satellite are used to image the aurora in various wavelengths when the satellite is near apogee, high over the northern polar region. The other nine instruments make measurements in-situ, at the location of the satellite, around the entire orbit. They measure the fluxes of charged particles, electrons and protons, as well as heavier ions, from thermal energies into MeV energies. They measure magnetic and electric fields, plus electromagnetic waves. They must make these measurements in great detail in order for scientists to be able to learn new things about the environment in the region over the poles of the Earth.

Data for scientific studies are obtained not only from instruments on Polar but also from the fleet of other ISTP satellites and collaborating missions, supported by a large array of ground-based instruments."... more

Polar Links
NASA's Polar, Wind and Geotail - UMD Space Physics Group

The TIMED mission
"Thermosphere, Ionosphere, Mesosphere Energetics and Dynamics (TIMED) explores the Earth's Mesosphere and Lower Thermosphere (60-180 kilometers up), the least explored and understood region of our atmosphere. It is known that the global structure of this region can be perturbed during stratospheric warmings and solar-terrestrial events, but the overall structure and dynamics responses of these effects are not understood. Advances in remote sensing technology employed by TIMED will enable us to explore this region on a global basis from space.

An ultraviolet view of the aurora is superimposed on a city lights image from a weather satellite. The TIMED spacecraft made three passes over the U.S., but after the peak of the storm.

Credit: NASA/APL/Meteorological Satellite Applications Branch, Air Force Weather Agency.

Located between approximately 40-110 miles (60-180 kilometers) above the Earth's surface, the MLTI region is sensitive to external influences from the Sun above and atmospheric layers below it. Its chemical and thermal balance can change rapidly due to naturally-occurring and/or human-induced changes to the energy contained within this region.

The primary science objective of the TIMED mission is to understand the energy transfer into and out of the Mesosphere and Lower Thermosphere/Ionosphere (MLTI) region of the Earth's atmosphere (energetics), as well as the basic structure (i.e., pressure, temperature, and winds) that results from the energy transfer into the region (dynamics)."... more

TIMED Links
TIMED - Solar EUV Experiment (SEE)

The TWINS-A and TWINS-B observatories mission
"The Two Wide-angle Imaging Neutral-atom Spectrometers missions, TWINS-A and TWINS-B, provide a new capability for stereoscopically imaging the magnetosphere. By imaging the charge exchange neutral atoms over a broad energy range (~1-100 keV) using two identical instruments on two widely spaced high-altitude, high-inclination spacecraft, TWINS will enable the 3-dimensional visualization and the resolution of large scale structures and dynamics within the magnetosphere for the first time. In contrast to traditional space experiments, which make measurements at only one point in space, imaging experiments provide simultaneous viewing of different regions of the magnetosphere. Stereo imaging, as done by TWINS, takes the next step of producing 3-D images, and will provide a leap ahead in our understanding of the global aspects of the terrestrial magnetosphere.

The TWINS instrumentation is essentially the same as the MENA instrument on the IMAGE mission. This instrumentation consists of a neutral atom imager covering the ~1-100 keV energy range with 4ºx4º angular resolution and 1-minute time resolution, and a simple Lyman-alpha imager to monitor the geocorona.

TWINS will provide stereo imaging of the Earth's magnetosphere, the region surrounding the planet controlled by its magnetic field and containing the Van Allen radiation belts and other energetic charged particles. TWINS will enable three-dimensional global visualization of this region, which will lead to greatly enhanced understanding of the connections between different regions of the magnetosphere and their relation to the solar wind."... more

TWINS-A and TWINS-B Links
TWINS at SRI - LAD/TWINS instrument

ARTEMIS mission
"ARTEMIS stands for "Acceleration, Reconnection, Turbulence and Electrodynamics of the Moon's Interaction with the Sun". The ARTEMIS mission uses two of the five in-orbit spacecraft from another NASA Heliophysics constellation of satellites (THEMIS) that were launched in 2007 and successfully completed their mission earlier in 2010. The ARTEMIS mission allowed NASA to repurpose two in-orbit spacecraft to extend their useful science mission, saving tens of millions of taxpayer dollars instead of building and launching new spacecraft.

THEMIS mission
THEMIS is a mission to investigate what causes auroras in the Earth's atmosphere to dramatically change from slowly shimmering waves of light to wildly shifting streaks of color. Discovering what causes auroras to change will provide scientists with important details on how the planet's magnetosphere works and the important Sun-Earth connection.

THEMIS Will Judge What Causes Highly Dynamic Aurora
On a clear night over the far northern areas of the world, you may witness a hauntingly beautiful light display in the sky that can disrupt your satellite TV and leave you in the dark. The eerie glow of the northern lights seems exquisite and quite harmless. Most times, it is harmless. The display, resembling a slow-moving ribbon silently undulating in the sky, is called the aurora. It is also visible in far southern regions around the South Pole.

Occasionally, however, the aurora becomes much more dynamic. The single auroral ribbon may split into several ribbons or even break into clusters that race north and south. This dynamic light show in the polar skies is associated with what scientists call a magnetospheric substorm. Substorms are very closely related to full-blown space storms that can disable spacecraft, radio communication, GPS navigation, and power systems while supplying killer electrons to the radiation belts surrounding Earth."... more

The Interstellar Boundary EXplorer (IBEX)
"IBEX is a small explorer NASA mission to map the boundary of the solar system.

The IBEX spacecraft is a small satellite the size of a bus tire. IBEX will observe the solar system Boundary while in orbit around Earth. It has "telescopes" on the spacecraft that will look out towards the edge of the solar system. However, these telescopes are different than most telescopes. They collect particles instead of light. These particles are called energetic neutral atoms (ENAs). The ENAs will provide information about the solar system's boundary by traveling toward Earth from beyond the orbit of Pluto. The particles travel for as little as a month to up to 11 years to complete the journey. By collecting these particles, scientists can make the first map of the boundary of our solar system. This boundary is created by the interaction between the solar wind and the interstellar medium. The solar wind streams out into space and carves out a protective bubble around the solar system called the heliosphere.

How Does IBEX study the boundary of the solar system?
Unlike many satellites in space that collect light, IBEX collects particles. These particles come from the boundary of the solar system and beyond - from the interstellar medium. IBEX has two sensors that collect particles as the satellite orbits the Earth. The satellite spins as it orbits so that over the course of six months, each sensor has the opportunity to collect particles from every part of the sky. As they collect the particles, the sensors and spacecraft keep track of the area the particles came from, the time they entered the sensor, the mass of the particles, and the amount of energy each particle has. This allows the science team to build a map of how many particles of each energy came from each direction in the sky.

By analyzing the map, the team of scientists can determine what the interaction of the solar wind and interstellar medium is like in all of the areas of the protective bubble around the solar system. For example, scientists are trying to find out if there are some areas where the interstellar medium stops the solar wind from flowing outward more quickly (like slamming on the brakes) than other places (where a slow gradual stop may occur.) Also, scientists are trying to determine the overall shape of the bubble which may be affected by differences in density, and magnetic fields in the interstellar medium."... more