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Module 1 - Mission to Planet Earth
Activities
A) Mission to Planet Earth
In response to concerns about the earth's environment, the National
Aeronautics and Space Administration (NASA) is initiating a program to study
the earth as a system. This program is called Mission to Planet Earth.
Discussion Points:
1) You have been appointed as a member of the science team for Mission to Planet Earth. What aspects of the earth do you want to study?
2) You are on a spaceship entering the solar system. The third planet from
the sun looks as if it might support life. What signs would you look for in
order to determine if life exists?
Module 1 - Mission to Planet Earth
Activities
B) Earth from Space
1) You are a scientist working on the Galileo Mission. What is the main
mission of your spacecraft?
2) Why does the Galileo spacecraft need to do three planetary fly-bys as part
of its mission to Jupiter?
3) Galileo passed over the Earth at a distance of 2.0 million kilometers.
The spacecraft has the ability to make images using many different types of
instruments, such as optical and infrared "CAMERAS".
What would you expect the
spacecraft to "SEE" as it passes over:
5) What sort of instrument do you think took this image?
6) What aspects of this image would lead you to guess that
there might be life
on this planet?
7) Where on earth do you guess this is? Look at a map to check your guess.
Now, look at the image called
GalInfra.gif (164K GIF)
Does the image fit
completely onto the screen?
If not, adjust your window size
so you can see the entire image.
8) What is the most notable difference between the two images (GalOptic and GalInfra)?
9) Now look for more subtle differences. In which image can you see more
land?
The GalOptic image was taken by a normal, optical camera.
GalInfra is an image taken by a special instrument
which can take images in
the infrared. This records "HEAT WAVES" and is able
to penetrate clouds and
haze much more easily. Only one infrared wavelength was used in this image.
Thus, it is only possible to show the image as shades of gray ranging from
black to white.
10) Identify at least five things that you can see on the earth from these images.
Module 1 - Mission to Planet Earth
Activities
C) Remote Sensing
1) What do we mean by the words remote sensing?
Remote sensing instruments actually record only the amount of light that
comes in to them. On the satellites we use today,
the amount of light coming
in is counted by a digital sensor. Whatever it counts
is then turned into a
set of digital numbers (DNs) that represent the quantity of light. In
the SIR-CED program, the DN's range from 0 to 255.
That is, it is possible to
represent the amount of light returned as some amount
from smallest (DN = 255) to largest (DN = 0).
In the computer exercise below we'll see
how this works.
Consider the following sorts of situations:
2) You are an environmental research scientist, studying rain forests. You would like to know what is happening in the area around the Amazon river. Would these views of the earth be helpful to you?
3) You are a weather forecaster who needs to follow a rapidly building
hurricane off the coast of Brazil.
Would this view of the earth be useful to
you?
4) What do you think you would see if you could obtain a more detailed view of
the area? Make a list of a few things that you have heard about South
America. How much closer up do you think you would need to get to see those
things?
5) Now open
GalAndes.gif (151K GIF).
What features can be identified in both the
image of the whole earth and the image of the Andes Mountains? Look at the
images and at a map. Can you tell where in South America you might be?
This is a false color image of the Andes, made by using a combination
of visible light and infrared light.
The image is also a mosaic or combination of a
lot of different images joined together to make one image (a bit like a
crossword puzzle).
You might like to have a map with you as you look at this image. The mosaic shows the area where Chile, Peru, and Bolivia meet. Lakes Titicaca and Poopo can be seen as nearly black patches from top to bottom; a large light blue area below and left of Lake Poopo is Salar de Uyuni, a dry salt lake some 120 kilometers across. These lakes lie in the Altiplano, a region between the western and eastern Andes, which is covered by clouds. The water/ice content of the clouds is indicated by their shade of pink. The vegetated Gran Chaco plains east of the Andes are pale green (right of image). The light blue patches in the mountains to the north are glaciers.
6) Think about the two situations described above (rain forest and weather forecasting). In what ways would the GalAndes image match your needs better than the Galileo images you have already studied? In what ways would it be worse?
7) Scientists use remote sensing to study three
broad categories of interest:
Land Studies, Ocean Studies, and Atmospheric Studies. Look at the Earth
features below, and place each under the correct category.
Earth Features: ocean currents, rainfall, cloud cover, vegetation cover, presence of plankton, hydrology, disaster monitoring, wave height and direction, wind speed and direction, meteorology, oil or mineral deposits, geologic mapping, flooding extent, deforestation.
| Land Studies | Ocean Studies | Atmospheric Studies |
|---|
Module 1 - Mission to Planet Earth
Activities
D) Zoom-In on Los Angeles
1) The GalAndes image and the GalInfra images both make use of
infrared rays to image portions of the earth.
Now we'll take a look at a radar
image of a closer view of the earth.
Look at
LASEASAT.gif (424K GIF).
This is an image of Los Angeles and the surrounding area as
taken from the SEASAT SAR satellite in 1978. The image was
taken from the West. This is a very large image.
2) This radar image is similar to the Infrared image taken by the Galileo spacecraft in one way since it is shown in gray scale. Locate the city of Burbank. Later we will see what sorts of characteristics would make something particularly "BRIGHT" to radar. Notice the darker area just underneath. These are the Hollywood Hills which reach towards the left (West) into the Santa Monica Mountains. The famous HOLLYWOOD sign is located here.
3) List five features of the city that you can readily make out, such as streets and mountains.
4) Now look at
LAZoomIn.gif (467K GIF).
This image is a close up of downtown Los Angeles, with
Dodger stadium featured at the top center.
What features can
be identified in both the
LASEASAT and LAZoomIn images?
5) Next look at the
LASIRC.gif (258 GIF)
image.
This is a radar image of Los Angeles
collected by the SIR-C radar in October 1994,
16 years after the SEASAT image.
6) In the two images of Los Angeles (LASEASAT.gif and
LASIRC.gif), what are some features visible in one image but not in the
other? What differences can you see? What might have changed in Los Angeles
between 1978 and 1994?
7) Why do you suppose scientists like to use grayscale images instead of
color images?
8) Consider using remote sensing for military and weather forecasting purposes.
Make a list of advantages and disadvantages for all four different distance
views of parts of the earth that you have seen.
Military Weather forecasting
Advantage Disadvantage Advantage Disadvantage
GalOptic
GalAndes
LASEASAT
LAZOOMIN
Module 1 - Mission to Planet Earth
Activities
Key Terms
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Converted to the IBM-PC by Al Wong, sirced03@southport.jpl.nasa.gov
Jet Propulsion Laboratory
4800 Oak Grove Drive
Pasadena, CA 91109