BARREL

Balloon Array for Radiation-belt Relativistic Electron Losses (BARREL, sometimes called Balloon Array for RBSP Relativistic Electron Losses) was a NASA mission operated out of Dartmouth College that worked with the Van Allen Probes mission (formerly known as the Radiation Belt Storm Probes, or RBSP, mission). The BARREL project launched a series of high-altitude balloons during four science campaigns: January–February 2013 in Antarctica, December 2013–February 2014 in Antarctica, August 2015 in Sweden, and August 2016 in Sweden. Unlike the football-field-sized balloons typically launched at the Poles, these were each just 27 meters (90 ft) in diameter.

The last balloon was launched August 30, 2016. During the BARREL program, a total of 45 balloon payloads were built, and eight test flights and 55 science flights were carried out.