The research associated with this upcoming launch involves elucidating how highly charged electrons have been born while they generate and vanish repeatedly along with space storms caused by the disturbance of solar wind caused by space storms, and how space storms are developed.

The launch time of the second Epsilon Launch Vehicle with Exploration of energization and Radiation in Geospace (ERG) is set for 8:00:00 on Tuesday, December 20, Japan Standard Time. JAXA will broadcast a live launch report from the Uchinoura Space Center from 7:40 p.m. and can be viewed through the Internet.

JAXA, National Research and Development Agency Japan Aerospace Exploration Agency announces the time of launch of the second Epsilon Launch Vehicle with Exploration of energization and Radiation in Geospace aboard as follows:

• Launch Date: December 20, 2016 (JST)
• Time of Launch: 8:00:00 p.m. (Japan Standard Time, JST)
• Launch Window: 8:00 p.m. through 9:00 p.m. (JST)

 Geospace is the region of outer space near the Earth. The radiation belt called the "Van Allen radiation belt" lies within the geospace, and the belt captures a huge volume of highly charged energy particles that exceed mega electron volts.  

http://global.jaxa.jp/press/2016/12/20161218_epsilon2.html