They went to investigate solar wind-stirred storms in our planet's magnetic field, but, after working for three years, two NASA solar-powered probes faced a dark demise, trapped in the Earth's shadow. NASA researchers now think they can give the twin satellites another shot by altering their courses and sending them instead to study the moon. NASA launched the probes in 2007 as a set of five identical satellites in the THEMIS Mission (Time History of Events and Macroscale Interactions during Substorms), meant to orbit Earth and send information during brief (2-3 hour) "substorms" when the magnetic field surrounding the Earth releases stored energy from solar winds. To understand the start of these "space tornadoes" responsible for the northern and southern lights, NASA placed the probes in very precise orbits, but for two craft that meant, one day, they would face prolonged battery-draining time in the Earth's shadow.
"When we realized ...
