2 new NASA satellites to track space weather for solar storms

Washington: A new mission set to blast off for low-Earth orbit will study magnetic storms around the Earth and learn more about how they affect our atmosphere and satellites.

NASA's Tandem Reconnection and Cusp Electrodynamics Reconnaissance Satellites, or TRACERS for short, mission represents a pair of satellites that will fly in a sun-synchronous orbit — meaning they are always over the dayside of the Earth — and pass through the polar cusps. The cusps are, in essence, two holes in Earth's magnetosphere, where the field lines dip down onto the magnetic poles.

When an influx of solar wind particles slam into Earth's magnetosphere, they can overload the magnetic-field lines, causing them to snap, disconnect and then reconnect. Magnetic reconnection, as the process is called, can release energy that accelerates charged particles down the funnel-shaped cusps and into our atmosphere, where they collide with molecules and, if a solar storm is intense enough, generate auroral lights. When TRACERS launches — expected to be no earlier than late July — it will seek to learn more about the magnetic-reconnection process and how space weather affects our planet. "What we'll learn from TRACERS is critical for understanding, and eventually predicting, how energy from our sun impacts not only the Earth, but also our space- and ground-based assets, whether it be GPS or communications signals, power grids, space assets or our astronauts working in space," said Joe Westlake, Director of NASA's Heliophysics Division, in a NASA teleconference.

Historically, the problem in studying magnetic reconnection has been that when a satellite flies through the region of reconnection and captures data, all it sees is a snapshot. Then, 90 minutes or so later on its next orbit, it takes another snapshot. In that elapsed time, the region may have changed, but it's impossible to tell from those snapshots why it's different.

It could be because the system itself is changing, or the magnetic-reconnection coupling process between the solar wind and Earth's magnetosphere is moving about — or maybe it is switching on and off.

"These are fundamental things that we need to understand," said TRACERS' principal investigator, David Miles of the University of Iowa, in the same teleconference. That's why TRACERS is important, because it is two satellites working in tandem rather than being a lone magnetic explorer. "They're going to follow each other at a very close separation," said Miles. "So, one spacecraft goes through, and within two minutes the second spacecraft comes through, and that gives us two closely spaced measurements."

Together, the twin spacecraft will measure the magnetic- and electric-field strengths where magnetic reconnection is taking place, as well as what the local ions and electrons trapped in the magnetosphere are doing. "What TRACERS is going to study is how the output of the sun couples to near-Earth space," said Miles. "What we're looking to understand is how the coupling between those systems changes in space and in time."