Module 1 - Mission to Planet Earth
B) Viewing the Earth from Space
- Students will be introduced to how spacecraft and space shuttles
can be used for remote sensing.
- 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.
- Students will use the Galileo earth image to identify three
major characteristics of the earth.
- Students will be introduced to optical technology as used in remote
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 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.
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.
Converted to the IBM-PC by Al Wong, firstname.lastname@example.org
Jet Propulsion Laboratory
4800 Oak Grove Drive
Pasadena, CA 91109