The Enhanced Thematic Mapper Plus (ETM+) aboard the Landsat 7 satellite was an improved version of the Thematic Mapper on Landsat 4 and Landsat 5. The ETM+ measured visible, near-infrared, and shortwave infrared light, along with thermal (heat) infrared radiation and included a panchromatic band with 15-meter spatial resolution. A hardware component failure in 2003 left wedge-shaped spaces of missing data in the imagery.