Nasa sent 20 balloons over Antarctica in 2013 to track particles from space

High above the ice in Antarctica, a group of enormous balloons was quietly tracking a phenomenon that could not be seen from the ground. In January 2013, Nasa's BARREL mission sent 20 balloons drifting through the polar winds, carrying instruments designed to detect faint X-rays produced when energetic particles entered Earth's upper atmosphere. The experiment was part of a much larger effort to understand what happens inside the Van Allen radiation belts, where charged particles can become trapped by Earth's magnetic field and later escape towards the poles.As the balloons moved with the winds, their measurements were matched with observations from Nasa's Van Allen Probes, which were travelling through the radiation belts themselves. The unusual pairing gave scientists a chance to examine both ends of the same process: particles moving through near-Earth space and the traces they left behind when they reached the atmosphere.Nasa’s BARREL mission: How 20 giant balloons were used in 2013 to track X-rays over AntarcticaThe first Antarctic BARREL campaign involved 20 balloons. They were released at intervals of roughly a day or two, allowing the team to build up a spread of measuremen...