Imaging Radar
Seeing the Earth in a New Way
A First Lesson

The Spaceborne Imaging Radar-C (SIR-C) flew twice on the Space Shuttle Endeavour in 1994. The mission of SIR-C was to gather data about our planet's environment that could be used by scientists to help us learn more about how Earth works and how it's changing.

How We See Our Planet

We're used to seeing images of Earth taken with ordinary cameras that see things the same way our eyes do: with visible light provided by the Sun, or by a flash. To take images of Earth from space, radar does not need sunlight or flash. Radar provides its own version of light in the form of microwaves, which illuminate the surface being imaged.

Because radar provides its own illumination, it can do things that ordinary cameras can't. Radar can see through the clouds, take images at night, look throught the dense trees that cover a forest, and see through desert sands. We can see the Earth in ways we never have before.

Educational Objectives

To look at radar images of Earth and understand how they are different from visible light images.
To learn how radar images help us understand Earth
To name environmental issues that radar images can help us understand, and suggest how that understanding can be used to help solve the issues.

Seeing Through Desert Sands

This image is a composite of a radar image into a visible light image. It shows the sands of the Sahara Desert. The orange parts of the image shows the sands as seen from a visible light camera. The strip through the middle shows the same area as seen through the eyes of radar. Very little detail is shown in the visible light image, whereas the radar image can see through the desert sand to the layers underneath to reveal ancient drainage patterns.

The Mountain Gorilla Habitats of Rwanda

[RWANDA IMAGE]

How Radar Unmasks a Surface

The color variations in the image (at left) show how radar responds to the surface being imaged. In general, rough spots appear bright, smooth spots appear dark. The black at the top of the image is a lake, the green area shows the gorillas bamboo forest, the purple areas are lava flows, the rough areas are mountainous terrain.

Exercises

Discuss with the class the value of the radar image of Rwanda. How can we use what we learn from the image to help the animals and the people that inhabit the area?
Have class members name three environmental issues. List ways that radar images from space can give us information needed to help manage and solve the issues.

Student/Teacher Lessons Guided Tour

Converted to the IBM-PC by Al Wong, sirced03@southport.jpl.nasa.gov

Jet Propulsion Laboratory
4800 Oak Grove Drive
Pasadena, CA 91109