Welcome to the Dartmouth Balloon Group homepage.
BARREL is preparing for the Sweden 2015 campaign.
We conduct scientific balloon experiments to study the Earth's radiation belts.
Specifically, we are studying the loss of relativistic electrons from the outer
radiation belts. Understanding and quantifying electron losses is a vital component of
understanding radiation belt dynamics. Recent results, including those from the 2000
MAXIS balloon campaign, have shown that losses could empty the radiation belts of
relativistic electrons in days if no acceleration was taking place! Thus, losses must be
included in any successful physics-based models of the radiation belts. (Right: Launch of MAXIS 2000 balloon at McMurdo Station,
The main way for radiation belt electrons to be lost inside geosynchronous orbit is to
the Earth's atmosphere. This is called relativistic electron precipitation or REP for
short. We observe the bremsstrahlung X-rays produced as the electrons are scattered into
the atmosphere. Since the X-rays don't penetrate to the ground, we use high altitude
balloons to carry our X-ray detectors to an altitude of more than 120,000 feet (~35km).
Unlike spacecraft which move quickly through a precipitation region, balloons offer a
nearly-stationary platform from which the temporal and spatial structure of the
precipitation can be studied.