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November 1972 Popular Electronics
 Table of Contents
Wax nostalgic about and learn from the history of early electronics. See articles
from
Popular Electronics,
published October 1954 - April 1985. All copyrights are hereby acknowledged.
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Ever since the advent
of Google Earth in 2001
(hard to believe, non?), high resolution photos from orbiting satellites has become
routine, expected technology rather than awe-inspiring technology. In 1970 when
this article appeared, however, satellite imagery was still in its infancy. The
TIROS 1 weather
satellite, with a mere 78-day lifespan, had been launched just a decade earlier.
Nations' militaries had the biggest and best platforms, and pictures like those
now routinely seen on Google Earth were highly classified. If you recall, governments
had conniption fits over Google's photos taken of secret installations. Civilians
eventually got space-based images of Earthly weather systems on the evening news
forecast segment, and some commercial users could purchase high resolution photos
from specially licensed private companies. Nowadays, satellites carry not only optical
sensors, but sensors covering a broad span in the electromagnetic spectrum, gravity
sensors, particle detectors and other types of sensors.
Satellite Pictures Show Earth's Resources
 One of the important sources of information
obtained from the Earth Resources Technology Satellite (ERTS), launched last July
by NASA, is the multitude of photo-graphs of the earth that are transmitted back
daily. There are more than 300 prime subscribers for the data and they represent
35 countries. The data is available through negative and positive prints processed
with Eastman Kodak Company equipment.
The ERTS photographic system has the capability of churning out as many as 300,000
photos weekly. Since it photographs only a section of the earth each day, it takes
the satellite 18 days to cover the entire world. There are seven sensors on the
satellite-each relaying separate data back to NASA ground stations located at Goddard
Air Force Base; Fairbanks, Alaska; and Goldstone, California. Data from the satellite
are fed to computers at Goddard and then to a photo laboratory; and a complete set
of 61 prints is sent each day to Sioux Falls, S.D., where scientists, geologists,
etc., can view areas of interest.
Posted March 11, 2024
(updated from original post
on 10/2/2017)
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