BARREL stands for "Balloon Array for Radiation-Belt Relativistic Electron Losses." It is a NASA funded Mission of Opportunity for the Radiation Belt Storm Probe (RBSP) NASA Satellite mission, set to launch on May 18, 2012. The Principal Investigator (PI) of BARREL is Robyn Millan, a professor in the Physics and Astronomy Department at Dartmouth College.
For more information on BARREL, see the first entry in blog from the 2009 BARREL Antarctic Campaign:
In addition, a new BARREL website is currently under construction. Check it out now, and then come back soon to see new additions!