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Mission Guide Magnetospheric Multiscale Mission National Aeronautics and Space Administration Mission Guide Magnetospheric Multiscale Mission Table of Contents 1. MMS Quick Facts 2. Introduction to MMS 3. Scientific Focus 4. The Magnetosphere 5. Current State of Knowledge 6. What's Important To Science 7. What's Important To the World At Large 8. Spacecraft and Instruments 9. MMS Feature Stories 10. Background Material a. NASA's Solar Terrestrial Probes b. MMS Glossary c. Acronyms and Abbreviations d. MMS Key Messages MMS Quick Facts Mission focus: The Magnetospheric Multiscale, or MMS, mission provides the first three-dimensional view of gigantic explosions in space that release energy and fast-moving particles, a process called magnetic reconnection. MMS uses four identical spacecraft to observe reconnection directly in the magnetic space environment, or magnetosphere, surrounding Earth. By studying reconnection in this nearby, natural laboratory, MMS helps us understand reconnection elsewhere as well, such as in the atmosphere of the sun and other stars, in the vicinity of black holes and neutron stars, and at the boundary between our solar system's heliosphere and interstellar space. Launch Vehicle: ATLAS V 421 Launch Vehicle Launch Site: Cape Canaveral Air Force Station, Florida Scheduled Launch Date: March 12, 2015 Dimensions: At launch, with a full load of propellant, each observatory weighs approximately 2,998 pounds (1360 kg). This is about the weight of a compact car. Each MMS observatory is in the shape of an octagon, roughly 11 feet across and 4 feet high. When stacked together in the launch vehicle, the four MMS observatories are over 16 feet tall. In space, with axial booms and wire booms extended, each observatory grows to be about 94 feet tall and 369 feet wide; a span that would stretch across most of Fenway Park. Orbit: Over its two-year prime mission, MMS will travel in two different highly elliptical, Earth orbits. Each orbit is designed to pass through two separate areas of magnetic reconnection in near- Earth space. During the first 1.5 years MMS will fly through the dayside boundary where Earth's magnetic fields meet up with those from the sun. During the last six months, MMS will focus on the night side of Earth, flying through reconnection sites in Earth’s magnetic tail. The first phase of the mission has an orbit that reaches 1,600 miles (2,550 km) altitude at its closest approach to Earth and extends out to 43,500 miles (70,080 km) at its farthest. For the second mission phase, the closest approach remains the same, but the orbit will extend out to 95,000 miles (152,900 km) at its farthest point from Earth – this is about 41 percent of the distance to the moon. Organization: MMS involves a number of institutions in the United States, as well as partners in Europe and Japan. MMS is the fourth NASA Solar Terrestrial Probes Program mission. Goddard built, integrated, and tested the four MMS spacecraft and is responsible for overall mission management and mission operations. The Southwest Research Institute in San Antonio, Texas, leads the Instrument Suite Science Team, with the University of New Hampshire leading the FIELDS instrument suite. Science operations planning and instrument command sequence development will be performed at the MMS Science Operations Center at the University of Colorado’s Laboratory for Atmospheric and Space Physics in Boulder. Introduction to MMS In March 2015, NASA plans to launch the Magnetospheric Multiscale, or MMS, mission. MMS consists of four identical spacecraft that will orbit around Earth, traveling through the dynamic magnetic system surrounding our planet to study a little-understood phenomenon called magnetic reconnection. Reconnection occurs when magnetic field lines explosively realign and release a gigantic burst of energy. It is a fundamental process throughout the universe that taps energy stored in magnetic fields and coverts it into heat and the energy to cause particles to speed up to nearly the speed of light. Magnetic reconnection is a phenomenon unique to plasma -- that is, the mix of positively and negatively charged particles that make up the stars, fill space, and account for an estimated 99 percent of the observable universe. Magnetic reconnection occurs naturally in near-Earth space where MMS can access it, offering the first chance to study this phenomenon directly instead of observing it from afar. MMS will travel directly through areas near Earth known to be magnetic reconnection sites. On the sun-side of Earth, reconnection can link the sun's magnetic field lines to Earth's magnetic field lines, allowing material and energy from the sun to funnel into Earth's magnetic environment. On the night side of Earth, reconnection helps trigger auroras, also known as the Northern or Southern lights. The four MMS observatories will travel in an adjustable pyramid formation to gather a three- dimensional snapshot of their environment. This will help scientists determine if any given event occurs in an isolated spot, across a wide area simultaneously, or moves through space. Several spacecraft, such as NASA's Time History of Events and Macroscale Interactions during Substorms, or THEMIS, mission and the European Space Agency and NASA's Cluster, have previously gathered tantalizing data when they happened to witness a magnetic reconnection event in Earth's magnetosphere. MMS, however, is the only mission dedicated to the study of this phenomenon. The Magnetosphere and Magnetic Reconnection Because Earth has a magnetic core, it behaves much like a giant magnet in space. A small bar magnet, the kind you could hold in your hand, for example, produces a set of magnetic field lines around itself. These point from the north magnetic pole of the bar to the south one and guide the movement of any electrically conducting or magnetized material nearby. A pile of iron filings for example would align themselves along these otherwise invisible lines, corralled into place by the magnetic structure. The iron filings also become a powerful way to see that magnetic structure. The magnetic lines around Earth are much more extensive and more complicated – but the basic laws of physics are the same. Known as the magnetosphere, the magnetic structures around Earth point from the south pole to the north pole and keep magnetized material, such as the electrically charged plasma particles that fill space, constrained to move along those field lines. Just as with the iron filings, by tracking those particles, scientists can "see" the field lines of the magnetosphere. Earth's magnetic fields are also greatly affected by other magnetized structures in space. The sun, for example, sends out a constant stream of what's called the solar wind, which travels with an embedded magnetic field. The solar wind helps mold the shape of the magnetosphere, so that it looks somewhat like a comet: snub and rounded at the front with a long tail trailing behind. Giant eruptions of solar material called coronal mass ejections, or CMEs, can also travel toward Earth, compressing the front of the magnetosphere. When the magnetic field of the solar wind is aligned just right, this onrush of solar material can link up with Earth's magnetosphere – the hallmark of a magnetic reconnection event. The magnetic field lines within plasmas are choosy about breaking or merging with other field lines and only do so under certain conditions: If the field lines in the solar wind are pointed in the opposite direction of those in the magnetosphere, then the entire pattern changes. Everything realigns into a new configuration. The amount of energy released by magnetic reconnection can be formidable. It taps into the stored energy of the magnetic field, converting it into heat and kinetic energy that sends particles zooming off, penetrating further into near-Earth space than usual. Even more powerful and explosive realignments can occur on the night side of Earth in the magnetotail, the long tail of the magnetosphere that points away from the sun. During reconnection, the particles continue to follow the rules of electromagnetism. They are still constrained to travel along the magnetic field lines, but have been heated and accelerated by what amounts to a huge pump in the sky. Reconnection can channel this movement into new directions, especially downward toward Earth. Particles and electromagnetic energy flow down toward the polar regions and cause a flash of light when they collide with atoms and molecules in the atmosphere. This is an aurora. This inrush of particles and energy can also cause other changes in the magnetosphere, such as causing the radiation belts – two giant donuts of radiation surrounding Earth – to intensify and swell. What's Important to Science While humans rarely witness magnetic reconnection on Earth, it is a fundamental process that occurs throughout the universe. Being able to peer directly into the heart of this phenomenon, as it occurs, will improve our understanding of how it affects our solar system, our sun, the stars in our galaxy, and even black holes. Scientists want to know exactly what conditions -- what tipping points -- set off magnetic reconnection. Much of what we currently know about the small-scale physics of magnetic reconnection comes from theoretical studies and computer models. True understanding requires observing magnetic reconnection up close, as MMS will be able to do in Earth's magnetosphere. Reconnection occurs wherever conducting gases, called plasma, are magnetized. Plasma fuels stars and fills the near vacuum of space. Plasma behaves unlike the gases we normally experience on Earth because they are tightly linked to their own set of magnetic fields entrapped in the material. Changing magnetic fields affect the way charged particles move and vice versa, so the net effect is a complex, constantly adjusting system that is sensitive to minute variations.
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