BARREL (Balloon Array for Radiation belt Relativistic Electron Losses) is a multiple-balloon investigation that will study Earth's Radiation Belts.
Atmospheric losses of relativistic electrons play an important role in radiation belt dynamics; precipitation into the atmosphere may even completely deplete the radiation belts in some cases.
BARREL is the first NASA Living With a Star Geospace Mission of Opportunity, and will support NASA's RBSP (Radiation Belt Storm Probes) mission.
1H was terminated today (Feb. 11th) at 16:16 UTC. It now has the longest record having flown for 22 days. 1I will beat it once it's cut down, and who knows, maybe 1A and 1T will also give it a run for it's money.