[SIR-CED LOGO]

Module 1 - Mission to Planet Earth

B) Viewing the Earth from Space

Objectives

  1. Students will be introduced to how spacecraft and space shuttles can be used for remote sensing.
  2. Students will be able to display earth images on the computer using the program Sigma0. Students will learn how to open images and do basic image analysis.
  3. Students will use the Galileo earth image to identify three major characteristics of the earth.
  4. Students will be introduced to optical technology as used in remote sensing.

Image data for Module 1 contained in the /MODS1TO5/MODULE01/IMAGES directory should be copied over to your computer before beginning this module. The files you will need are in this directory are GalOptic.gif and GalInfra.gif.

Galileo

Galileo is a NASA spacecraft mission to Jupiter. The spacecraft, consisting of an orbiter and an atmospheric entry probe, was launched aboard the Space Shuttle Atlantis on October 18th, 1989. Galileo is flying a complex path that requires three planetary fly-bys for gravitational boosts (like a kind of sling-shot). This gives NASA scientists three opportunities to look at the Earth through Galileo's instruments, which include a color camera.

After its launch in 1989, Galileo entered a gravity-assist path which is needed to attain the energy necessary to reach Jupiter. It passed Venus on February 10, 1990, and Earth on December 8, 1990. A final pass by Earth on December 10, 1992 put Galileo on a direct trajectory leg to Jupiter. This Venus-Earth-Earth gravity-assist (VEEGA) trajectory will take more than six years from launch to arrival at Jupiter. When Galileo arrives in December 1995, an atmospheric probe will descend through Jupiter's clouds and send its scientific measurements to Earth via the orbiter. Then the orbiter will begin an orbital tour of Jupiter to study and map the major satellites from as close as a few hundred miles and to monitor the behavior of Jupiter's atmosphere and magnetosphere for about two years.

Images

The first image the students will display [GalOptic.gif] is a color picture taken by Galileo at a distance of roughly 2.1 million kilometers while on its first pass in 1990. It shows the whole earth, with South America prominent near the center. At the top, the east coast of the United States, including Florida, is visible. Picturesque weather fronts are visible in the South Atlantic at the lower right. The west coast of Africa is visible on the horizon at right. This is an optical image, taken using red, green, and violet filters. You will notice that a sizable amount of area is covered by clouds. When areas are cloud-covered, a camera using visible light can not see through the clouds to the land below.

The second image displayed by the students [GalInfra.gif] is another Galileo image of the same area. This image was taken three minutes earlier, using light in the near infrared, with a wavelength of 1 micron. This wavelength easily penetrates atmospheric hazes and enhances the brightness of land surfaces. You can see that less land has been obscured by clouds than in the optical image.

Teacher's Guide - Table of Contents

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

Jet Propulsion Laboratory
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