This balloon is nearing the end of the fill process. The balloon is filled with about 25,000 cubic
feet of helium, and when released will ascend to 35 km altitude. At ground level we only fill about
10% of the total balloon because the helium expands into the remaining volume as the balloon rises..
Most of the balloon is visible as a thin strip lying on top of the red plastic sheet in the middle of
the picture. The plastic sheets are there to protect the thin balloon material (six ten-thousandths of an
inch thick, about the same as a medium duty garbage bag) from abrasion by the Antarctic ice.

In the foreground is the balloon payload. It is about 40kg of science instruments and batteries. Inside
the center box is a NaI X-ray detector, magnetometer, flight computer, satellite modem and batteries.
The large booms on the top of the payload are used to make a vector measurement of the electric field.

The MINIS Antarctic balloon campaign was conducted by UC Berkeley graduate student, John Sample,
and by U. Washingon graduate student Michael Kokorowski (A Berkeley Physics undergraduate '02).
The campaign took place at the South African National Antarctic Expedition base. Several South
African colleagues are visible in this photo.