The High Resolution Gamma-ray and Hard X-ray Spectrometer (HIREGS) is flown on a 29 million cubic-foot helium balloon measuring almost 400 feet in diameter when fully inflated at float altitude.
The 3000+ lb. instrument is lifted to an altitude of 130,000 feet, and circumnavigates the Antarctic continent in 10-20 days as it follows the high-altitude wind pattern.
At the end of its flight, the instrument descends by parachute and is recovered by plane or helicopter.
