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History of Remote Sensing: In the Beginning

Remote sensing as a technology started with the first photographs in the early nineteenth century. Many significant events led to the launch of the Landsat satellites, which are the main focus of this tutorial. To learn about the milestones in remote sensing prior to the first Landsat, you can view a timeline of remote sensing in one of three areas - Photographic Methods, Non-Photographic Sensor Systems, Space Imaging Systems (taken from a table that appeared in the writer's (NMS) NASA Reference Publication 1078 (now out of print) on The Landsat Tutorial Workbook). That review ends with events in 1979. We present subsequent major highlights throughout the tutorial. A short summary of the events includes launching several other satellite/sensor systems similar to Landsat; inserting radar systems into space; proliferating of weather satellites; launching a series of specialized satellites to monitor the environment using, among other, thermal and passive microwave sensors; developing sophisticated hyperspectral sensors; and maturing a variety of sensors to gather imagery and other data on the planets and astronomical bodies.

The photographic camera has served as a prime remote sensor for more than 150 years. It captures an image of targets exterior to it by concentrating electromagnetic (EM) radiation (normally, visible light) through a lens onto a recording medium (typically silver-based film). The film displays the target objects in their relative positions by variations in their brightness of gray levels (black and white) or color tones. Although the first, rather primitive photographs were taken as "stills" on the ground, the idea photographing the Earth's surface from above, yielding the so-called aerial photo, emerged in the 1840s with pictures from balloons. By the first World War, cameras mounted on airplanes provided aerial views of fairly large surface areas that were invaluable for military reconnaissance. From then until the early 1960s, the aerial photograph remained the single standard tool for depicting the surface from a vertical or oblique perspective.

Satellite remote sensing originated early in the space age (both Russian and American programs). At first, by 1946, some V-2 rockets, acquired from Germany after World War II, were launched from White Sands, New Mexico, to high altitudes. These rockets, while not attaining orbit, contained automated still or movie cameras that took pictures as the vehicle ascended (see Section 12). Then, in the 1960s as man entered space, cosmonauts and astronauts in space capsules took photos out the window. In time, the space photographers had specific targets and a schedule, although they also have some freedom to snap pictures at targets of opportunity.


B/W photo of the Sinai Peninsula and the Red Sea.

  Sinai Peninsula and Red Sea

Color photo of the Gulf of California and southern California.

Gulf of California & Southern California

During the '60s, the first sophisticated imaging sensors were incorporated in orbiting satellites. At first, these sensors were basic TV cameras that imaged crude, low resolution (little detail) black and white pictures of clouds and Earth's surface, where clear. Resolution is the size of the smallest contrasting object pairs that can be sharply distinguished. Below, we show three examples from the Nimbus satellite's sensors to give an idea of how good the early photos were.

B/W image of Eastern India, Bangladesh and the Himalayas taken from the Nimbus satellite sensors.

Eastern India, Bangladesh, Himalayas

B/W image of Saudi Arabia taken from the Nimbus satellite sensors.

Saudi Arabia

B/W image of Eastern North America taken from the Nimbus satellite sensors
Eastern North America

Early on, other types of sensors were developed that " took images using the EM spectrum beyond the visible, into the near and thermal infrared regions . The field of view (FOV) was broad, usually 100s of kilometers on a side. Such synoptic areas of regional coverage were of great value to the meteorological community, so that many of these early satellites were metsats, dedicated to gathering information on clouds, air temperatures, wind patterns, etc.

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Primary Author: Nicholas M. Short, Sr. email:

Collaborators: Code 935 NASA GSFC, GST, USAF Academy
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