1 of 20 Balloons as Part of NASA's BARREL (image) NASA/Goddard Space Flight Center Caption Scientists race through the Antarctic snow to launch one of 20 balloons as part of NASA's BARREL (Balloon Array for Radiation belt Relativistic Electron Losses) mission. Each balloon is equipped with instruments to help track how electrons from giant radiation belts surrounding Earth travel down magnetic field lines toward the poles. Credit NASA/S. Spain Usage Restrictions None Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.