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VENUS TOPOGRAPHY BOX
One of the biggest problems NASA encounters when trying to explore other planets and
moons is finding a landing site. Many times orbiting spacecraft can't see boulders
or small cliffs on the planet's surface. These unknown features can destroy the
delicate equipment of the lander. One problem found especially on Venus is cloud cover.
Venus's clouds cover the entire surface of the planet, so the Magellan spacecraft
had to use radar when it began mapping the surface of Venus. In this experiment
you will come up with a landing site in each of your topography boxes by combiningmany techniques
used by that NASA.
Key Question:
Where on the surface of Venus can I land my multi-million dollar spacecraft?
Objectives:
1. To measure the topography of a given area and make a contour map from that data.
2. To learn about remote sensing and measuring; surface features and contour maps;
and research techniques.
3. To become familiar with recent discoveries and missions, especially the Magellan
mission.
Materials:
(per group of 3-5):
- Venus topography box
- Bamboo skewer
- Paper lander
INSTRUCTIONS:
Important:
DO NOT OPEN THE BOX UNTIL INSTRUCTED TO DO SO!
After you take your data, you will have to show your map and be able to explain it
to the NASA representative (your teacher). Once you have done this, you will be
allowed to remove the box top and really land the spacecraft.
PART I: CALIBRATE THE INSTRUMENTS
Step 1: Take the skewer and with a marker or dark pencil, place a tic mark one centimeter
away from the pointed end. Continue to place tic marks at one centimeter intervals
until you reach the end of the skewer.
Step 2: Color with a pink marker or crayon the space between the pointed end and the
first centimeter tic mark.
Step 3: Color the spaces between the remaining marks in these colors, in order,
: pink (already done), red, orange, yellow, light green, dark green, blue, purple,
brown, and black. Appendix 1 has a chart to help you. You may not need all these
colors, so some may be left out.
Step 4: Color the boxes on the key to the graph paper on page 6 according to Appendix
1.
Note
: when reading the instrument, a high number
will represent low elevation
. This is because you have measured the distance between the clouds and the surface,
so high numbers are further away from the clouds.
PART II: DATA COLLECTION
Make sure the skewer is standing straight when you take a measurement.
Step 1: Choose a hole and gently
stick the skewer into it, pink end first, (as you were shown). Forcing the skewer
can damage the box.
Step 2: Make a point on the graph paper (page 6) where you inserted the skewer.
Step 3: Next to the point, write the number of centimeters below the box top that
point is. Then make a little dot of color next to the number that represents the
color of the centimeter showing on the skewer.
Step 4: Repeat the process for each hole on your box.
PART III: SURFACE MAPPING
Step 1: Look at the grid you made of the data points. Make a loop around all the
pink points; don't connect the dots. This should be a small closed loop. You may
have two loops of the same color on the paper; that's fine. You don't have to close
the loop, if it goes outside your grid (data region). If you have no pink loop, go down
the list of colors until you find one.
Step 2: Now make a loop around all the red points; the loop of pink points should
be inside the red loop.
Step 3: Continue this for the other colors, each time the previous loops should be
inside the new loop. No new lines should cross the old lines.
Again, it's okay to have two closed loops of the same color.
Step 4: Now that you have closed loops, color in the rings. Start with the innermost
loop (pink), and work your way out to avoid confusing the colors.
QUESTIONS
1. What geologic features do you see? List them below:
2. Does this look like a good area to land? Why or why not?
3. Where shall we land the spacecraft (assuming your region is the only choice on
the planet)? Describe by grid coordinates.
Make a box on your map showing where you want to land the spacecraft, then show the
contour map to your teacher and get approval to land. How does your map compare
to the surface?
Contour Maps
Contour maps are a way of showing different heights (elevations) on a flat surface.
Most often these maps look like a group of loops and lines (contours) that describe
the land in a particular area. Many times these contours are drawn on road maps
or on other types of maps. Each contour connects points at the same height. Since for
our purposes the high ground rests on top of the lower ground, the lines never cross.
These maps are useful to many people besides NASA landing teams. Hikers, forest
rangers, oil companies, deep sea divers and ship navigators all use contour maps daily
to find out where they are, and what the land or sea bottom near them looks like.
Remote Sensing
When you felt around on the surface of Venus with your bamboo skewer, you were doing
what NASA does with radar, you were "remote sensing". What that means is that NASA
doesn't have to be able to see the planet to get an idea of its surface. They send
up an orbiter probe and it sends radar down to the surface of the planet where it hits
the ground and bounces back. The farther away the ground is, the longer it takes
the signal to return to the ship. This tells you the height and depth of the surface
features of the planets. When the orbiter receives the radar signal that bounced back,
the computers record how long it took to come back and they know how far the radar
traveled before it hit the planet. Now you can have an idea of the planet's surface
without ever having to land on it!
Magellan
Venus is often called Earth's twin because it is about the same size as the Earth
and it has an atmosphere over its rocky surface. It is this atmosphere that prevents
us from seeing the planet's surface because it contains dense clouds. These clouds
cover the entire planet's surface.
As we found out, radar signals can penetrate the cloud cover, and are used to map
the surface. This method of mapping is called radar altimetry and was used on the
Magellan mission to Venus. Magellan was placed in orbit around Venus in 1990. Thanks
to this way of mapping, the Magellan orbiter was able to map almost all of the surface
of Venus.
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