Friday, we dropped 270lbs (~120kg) of ballast from the payload. If we'd had a balloon that leaked and progressively lost significant altitude (like the 2001 TIGER flight), this ballast would have been very useful in maintaining our normal altitude. Luckily, our balloon this flight is performing great, so dropping the ballast just gives us a little extra boost, and a little bit more data. Since the Galactic Cosmic Rays we're looking for can interact with the atmosphere before reaching our instrument, it makes sense to have as little atmosphere above us as possible, so a boost in altitude is very welcome.
It's pretty clear when we actually dropped the ballast:
Sean and Thomas are on their way down to the Ice for the second time this season. They're coming back to do the recovery of the instrument, whenever our flight gets terminated. Right now they should be on the plane from L.A. to Sydney, and are scheduled to arrive here in McMurdo sometime next Tuesday.