BLAST (for Balloon-borne Large Aperture Submillimeter Telescope) is a 1.8-meter far infrared telescope that is flown in a high-altitude balloon. It has made several flights from different locations, including Antarctica, its first operational flight in 2005. Its second operational flight damaged the original 2-meter operational mirror, which was replaced by a 1.8 meter mirror.
Its instrument is an imaging Fourier transform spectroscope, modeled after the Herschel Space Observatory SPIRE design, and the project served as a pilot for that instrument.
A follow-on balloon-borne project, BLASTPol, including polarimetry was carried in the 2010-2012 time frame. A third version, BLAST-TNG is in development for 2019-2020.