Landsat 1

Landsat 1, originally named the Earth Resources Technology Satellite (ERTS-1), was the first satellite in the Landsat program, a United States civilian satellite program for acquiring remote sensing imagery of the Earth. Launched on July 23, 1972, it was designed to collect data about the Earth's resources and environment, particularly land cover, agriculture, forestry, geology, and water resources.

The satellite orbited the Earth at an altitude of approximately 900 kilometers (560 miles) and had a near-polar, sun-synchronous orbit, allowing it to repeatedly image the same areas of the Earth at roughly the same local time. Landsat 1 carried two main instruments: the Return Beam Vidicon (RBV) camera system and the Multispectral Scanner System (MSS). The MSS proved to be the more valuable instrument, providing multispectral imagery in four spectral bands, allowing for the differentiation of various surface features based on their spectral reflectance.

Landsat 1 operated until January 6, 1978, significantly exceeding its design life of one year. The data collected by Landsat 1 revolutionized Earth observation and paved the way for subsequent Landsat missions, significantly advancing our understanding of the Earth's resources and environmental change. The data acquired during its mission remains a valuable historical archive for studying long-term environmental trends. The mission's success demonstrated the potential of space-based remote sensing for resource management and environmental monitoring, laying the foundation for numerous other Earth observation programs worldwide.