By looking close to home, NASA’s newest mission with provide a window to the universe.
- The Magnetospheric Multiscale, or MMS, mission was created to study how magnetic fields around Earth interact with activity from the sun.
- The Earth has a magnetic field like a bar magnetic that is generated by its spinning liquid metal core.
- The magnetic field forms an invisible bubble around the Earth.
- Explosive activity on the sun hurls its own magnetic field and plasma into space. When that stuff is thrown our way it interacts with
Earth’s magnetic fields releasing energy. This is what leads to aurora.
What Is Magnetic Reconnection?
Like stretched rubber bands, magnetic fields store energy that is released when the fields lines realign – explosively accelerating particles to nearly the speed of light.
This process of energy release from magnetic fields is called magnetic reconnection. Studying and understanding this fundamental process is the main purpose of MMS. This process creates interesting phenomena both near and far on objects with magnetic fields. It causes eruptions on the sun, it releases energy from matter disks around black holes and neutron stars into space, it even happens at the boundaries of the giant bubble surrounding the solar system, letting in charged particles from the rest of the galaxy.
How would you like to understand a fundamental process happening throughout the universe? You can – MMS will unlock the answers on a small-scale using Earth as a laboratory. Scientists will share these discovers with us then we too will understand the process that happens on small and big scales, happening from close to home to the farthest reaches of the universe.
MMS LAUNCHES March 12, 2015
The MMS mission uses four identical spacecraft to provide the first ever three-dimensional view of gigantic explosions in space that release energy and fast-moving particles, the process called magnetic reconnection.
MMS in 30 Seconds
The Amazing and Beautiful Results of Magnetic Reconnection
Magnetic Reconnection and Space Weather
Magnetic reconnection is also one of the most important drivers of space weather events, which can affect:
• communications networks
• GPS navigation
• electrical power grids
• satellite computers in space
• astronaut health
Magnetic reconnection is fundamentally the source of all space weather near Earth. It initiates solar flares and coronal mass ejections on the sun and is the process that allows energy from those explosions to cross the boundaries of the protective bubble around Earth – the magnetosphere — into near Earth space. Space weather can disrupt electronics on board spacecraft, affect GPS signals and lead to communications blackouts on Earth. Understanding space weather and what initiates it will also be crucial for protecting the health of astronauts journeying to Mars.
Magnetic Reconnection Near Earth
MMS will travel through two known areas of reconnection near Earth: on the dayside where magnetic fields from the sun connect to Earth’s fields and on the night side where Earth’s own fields can reconnect with each other.
Why Four Spacecraft?
There are four spacecraft in order to get three-dimensional science information. Four spacecraft also give MMS the necessary observational perspectives to determine whether reconnection events occur in an isolated locale, everywhere within a larger region at once, or traveling across space.
Each spacecraft can be thought of as the point of a triangular pyramid, or tetrahedron. As the tetrahedron flies through space, it can measure the three-dimensional properties of magnetic reconnection regions. The separation distances will vary depending on the orbit and can be changed as the mission progresses. The inter-spacecraft distance can be made to be as large as 250 miles (400 km) to as small as 6 miles (10 km).
Building Four Spacecraft Isn’t Easy
Major Engineering Feat
The four MMS spacecraft were built simultaneously at NASA’s Goddard Space Flight Center over the course of five years – a feat that required extraordinary coordination.
Over 1000 people have worked on it. The MMS spacecraft will fly through reconnection regions in well under a second, so key sensors were built to take measurements 100 times faster than any previous mission.
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11 Scientific Experiments
The instruments measure energies of charged particles, the movement of plasma, and electric and magnetic fields. Each MMS observatory carries 11 scientific experiments, made up of 25 separate sensors. The instruments will measure energies of charged particles, the movement of plasma, and electric and magnetic fields, with unprecedentedly high – on the order of milliseconds — time resolution and accuracy. An early engineering feat was simply determining how to place all 25 sensors so they wouldn’t interfere with each other or block each other’s view.
The numerous MMS instruments are divided into three investigations or groups:
- Hot Plasma Suite: to observe the nature of the charged gas, or plasma, present during reconnection
- Energetic Particles Detector Suite: to observe the fast-moving, energetic particles
- Fields Suite: to observe electric and magnetic fields and waves
Details can be found at http://www.nasa.gov/mission_pages/mms/spacecraft/instruments.html.
Imagine flying by the Grand Canyon in 0.03 seconds – less time than it takes to blink an eye – and having to record what you see.
That’s what MMS must do. It flies through reconnection regions just a mile across at speeds of 30-60 miles a second. Many of the instruments aboard MMS have unprecedentedly high – on the order of milliseconds — time resolution and accuracy.
Getting to Space
• Launch scheduled for March 12, 2015
• Cape Canaveral Air Force Station, Florida
• Launch vehicle: ATLAS V 421
Launch and Deploy
MMS in Space
The spacecraft orbits will be controlled with an onboard propulsion system that uses 12 thrusters to adjust the orbit of each spacecraft. The spacecraft are tracked and commanded from a control center at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.
One way that NASA will track the MMS fleet is through highly accurate and sensitive GPS receivers. They must be incredibly sensitive because the MMS orbit places it above the GPS constellation at times, so the MMS GPS receiver must lock onto GPS signals that arrive from the other side of Earth.
STAY TUNED: More to come after MMS launch on March 12, 2015
For in-depth prelaunch, countdown and launch day coverage of the liftoff of MMS, visit:
For NASA TV schedules and video streaming information, visit:
For more information about the MMS mission, visit: