Between the blue sky above us and the infinite blackness of space lies a frontier that scientists have only just begun to investigate. In "At the Edge of Space," NOVA takes viewers on aN exploration of the earth-space boundary zone that's home to some of nature's most puzzling and alluring phenomena: the shimmering aurora, streaking meteors, and fleeting flashes that shoot upwards from thunderclouds, known as sprites. Only discovered in 1989, sprites have eluded capture because they flicker into existence for a mere split-second -- 40 times faster than an eye blink. In a high-flying weather observation plane, we ride with scientists as they hunt for sprites and finally succeed in snaring them in 3D video, gaining vital clues to unraveling their mystery. Combining advanced video technology with sequences shot from the International Space Station, this film probes the enigmas of the boundary zone and brings viewers an intriguing new viewpoint on their planet.