Name Active Description and purpose Stratoscope I 1957–59 12-inch telescope attached to a polyethylene balloon.[3] This was the first balloon-borne astronomical telescope.[4] It took photographic images of the sun, showing granulation features. In 1959 it was flown again, this time with a television transmitter.[3] Stratoscope II 1963–71 36-inch telescope with a tandem balloon system.[3] THISBE 1973–76 Infrared telescope used for observations of extended sources, including OH airglow, the zodiacal light, and the central galaxy region.[5] HIREGS 1991–98 High-resolution spectrometer for examining gamma ray and hard X-ray emissions from solar flares and galactic sources. It used an array of liquid nitrogen-cooled germanium detectors.[6] BOOMERanG experiment 1997–2003 Microwave telescope with cryogenic detectors that was carried on long-duration flights over the antarctic.