The Elfen mission has two science goals:

1. To understand the heavy ion composition of the solar wind and its influence on the dayside of the Earth’s magnetosphere;
2. To understand the origin of and processing involving ions in the plasma sheet. 

To achieve these goals, the Elfen mission will carry two instruments: a spectrometer to determine the in-situ heavy ion composition, and a magnetometer to determine the contemporaneous plasma regime of the Earth’s magnetosphere traversed by the Elfen spacecraft.