40 Years of Earth Observation: From the Beginning

Landsat 1 ready to launch

July 23, 2012 • The first Landsat satellite was launched forty years ago on July 23, 1972. At the time, the satellite had an awkward and rather hard-to-say original name: The Earth Resources Technology Satellite, or ERTS. The primary instrument on Landsat 1, was slated to be the the Return Beam Vidicon, but the sensor had to be shut down 15 days after launch due to a massive power surge. Fortunately, another experimental instrument on board, the Multispectral Scanner, produced spectacular data.

Data from the MSS could be downlinked to the ground in real-time when over a ground receiving station, or recorded to an onboard Wide-Band Video Tape Recorder. The Wide-Band Video Tape Recorder flown on Landsat 1 was the largest tape recorder ever flown in space in 1972; it weighted-in at 76 pounds, contained 1800 feet of 2" tape, and could record 3.75 GB of data (the highest storage capacity of all orbiting recorders at the time!)

A USGS cartographer who had been cynical about the MSS producing cartographically accurate data with “a little mirror in space,” turned to his colleagues after seeing the first MSS image and said “Gentlemen, that's a map.” He later wrote a letter to the MSS engineer Virginia Norwood stating “...the MSS is a real mapping instrument.”

Today, 40 years after the first Landsat launch, six Landsat satellites have successfully orbited the Earth supplying a continuous record of Earth's changing landscape, and the next Landsat satellite is scheduled to launch in Feb. 2013. A poster presentation chronicling some of the Landsat history and imagery is available here (PDF file size = 185 MB).

Further information:
+ NASA's Earth Observatory: First Landsat image in U.S. archive
+ Looking back at the Landsat 1 launch (video, YouTube)
+ Landsat Looks and Sees
+ Landsat multimedia

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