The MSS sent back 300,000 images over its six-year lifespan and changed scientists’ approach to remote sensing, adding the dimension of time to analyses of Earth’s resources and surface covers. After launch, the engineers at NASA and the scientists at the US Geological Survey (USGS)-who would manage the project once the satellite was in orbit-were shocked at the high fidelity of the data the chattering imager sent back, and it almost immediately became the vehicle’s primary imager. Expectations for the scanner, whose scan mirror buzzed distressingly during testing as it whirred back and forth at 13 times per second, were low.Īmong the concerns voiced before launch were fears that its moving parts would not work properly in space, but it was also unknown whether a scanner could produce high-quality digital imagery while careening around the planet at a speed of 14 orbits per day. When NASA launched the Earth Resources Technology Satellite, later known as Landsat, in July 1972, the first spacecraft dedicated to monitoring Earth’s surface carried two imaging instruments-a camera and an experimental multispectral scanner (MSS) that recorded data in green and red spectral bands and two infrared bands.
