University of Delaware researchers in Sweden have launched a giant balloon taller than a football field that is now flying at the edge of space to collect data on cosmic rays -- the most super-charged particles in the universe. The balloon, which is 396 feet tall and 459 feet in diameter when fully inflated, was set aloft at 4:34 a.m. on May 17 from Esrange Space Centre near Kiruna, Sweden, in the Arctic Circle. It is flying at a speed of more than 40 knots and an altitude of nearly 27 miles. Its payload of cosmic ray detectors, housed in a pressurised shell, will be cut free in northwestern Canada and float back down to Earth on a parachute, and then secured and recovered, likely by helicopter. Cosmic rays are extraterrestrial high-energy electrons, protons, and heavier nuclei that enter our atmosphere.