BARREL research balloon release. BARREL (Balloon Array for Radiation belt Relativistic Electron Losses) was a NASA research mission carried out in Antarctica for three months until March 2014. The launch crew (right) are holding the instrument payload as the top of the balloon rises overhead where they can release it. The mission released 20 balloons to study the Van Allen belts, two large belts of radiation that surround the Earth and interact with the solar wind. Each balloon was airborne for up to three weeks, with instruments detecting charged particles spiralling down the magnetic fields near the South Pole. Photographed on 2 February 2014.