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JOURNEY TO MARS -- IT'S A LONG SHOT!
MASTER TEACHER Kathrine Price
GRADES 10-12
OVERVIEW
This two- or three-day lesson plan introduces some of the
concepts which explain how humans manage to navigate a spaceship to Mars, and
why that task is so difficult. The first day activity allows students to
physically model the orbits of Earth and Mars, then to derive a definition of
retrograde motion of a planet from their observations. On the second day,
students learn about the voyage of the Mars Pathfinder, and compare features on
global maps of Earth and Mars.
ITV SERIES
Passport to Knowledge: Live from Mars: Program 4 - Destination
Mars
LEARNING OBJECTIVES
Students will be able to:
* Explain retrograde motion
* Describe the teamwork involved in navigating a vehicle
to and on Mars
* Compare geographic elements of Earth and Mars
VOCABULARY
retrograde motion - the apparent "backward"
motion of a planet; night-to-night observations show the planet moving
across the sky in a direction opposite to the general motion of other planets.
Pathfinder - NASA mission to Mars which landed on July 4,
1997.
Sojourner - Pathfinder's rover.
trajectory -the curved path that a projectile or orbiting body
takes in space.
petals -After landing on Mars, Pathfinder opened as a
flower blooms, with three petals flat on the ground.
high-gain antenna -radio communications link used for
very high data rates such as pictures
low-gain antenna -radio communications link used for low
data rates (telemetry such as temperature or wind speed)
MATERIALS
One sign or other marker each for Sun, Earth, Mars
chalk - enough to draw large arcs on sidewalk or floor
meter stick
For each pair of students:
global map of Earth - a map that shows spot elevations and
bathymetry (sea floor depth)
global map of Mars:
An Explorer's Guide to Mars.
40" x 26" poster #505. $6.00 each.
vendor:
The Planetary Society - Sales Dept.
65 North Catalina Avenue
Pasadena, CA 91106-2301
phone: (626) 793-1675
fax: (800) 966-7827
e-mail: http://planetary.org
For each student:
paper and pencil for notes
3 Activity Sheets:
Earth and Mars orbit diagram
Focus for Viewing
Earth/Mars Comparisons
PRE-VIEWING ACTIVITY
Day One: Retrograde motion activity. Tell the
students that when Mars is viewed from Earth every night for months, its
position in the night sky appears to change relative to the
"background" of much more distant stars. (The word
"planet" means "wanderer".) Usually the planet
advances across the sky from one week to the next, but sometimes the relative
orbits of Earth and Mars cause Mars to appear to move backwards across the sky.
This apparent backwards progression is called "retrograde motion".
Demonstration:
Take students to a very large room or outdoors. Tell
students that they will model the motion of Earth and Mars relative to the Sun
and to very distant stars. Choose a location for the sun. Draw a chalk
circle around the Sun location about six meters in diameter to represent Earth's
orbit around the sun. (Note that the planet orbits are elliptical, so you
could modify this to show and elliptical path, with the sun at one focus.)
Then draw a second circle around the Sun about nine meters in diameter to
represent the orbit of Mars.
Fact and calculation: It takes 365 Earth days for Earth to
orbit the sun, and it takes 687 Earth days for Mars to complete one orbit around
the sun. Our model will represent one-half of an Earth year, so the Earth
will progress half-way through its orbit in that time. How far will Mars
move in the same time? (About 26% or about one-quarter of its orbit around
the Sun.) As you view the solar system from the North Star, planets rotate
on their axes and revolve around the Sun counterclockwise. Mark the
beginning and ending positions for a 6-month path for Earth on its orbit circle.
(If the orbit were a clock face, marking hours 9 through 3 will work.)
Number these positions 1-7, beginning with the 3:00 position -- remember that
Earth will move counterclockwise around the circle! Mark corresponding
positions 1-7 for Mars, beginning at about the 1:30 position and continuing
counterclockwise to about the 10:30 position (about one-quarter of the circle).
Ask one student to represent the Sun, and give that student the
Sun sign. Give two other students the Earth and Mars signs so that they
can represent the two planets. All other students will represent distant
stars, so should stand in "fixed" positions far (but within hearing
distance) from the "solar system". Begin with Earth and Mars at
position 1. Ask Earth to describe the location of Mars relative to the
fixed background of stars. (All students should take careful notes
throughout the demonstration.) Earth and Mars move to position 2, and
Earth again describes the apparent position of Mars relative to the stars.
Continue through position 7.
Back in class, give students time to work in pairs to
conceptualize their observations.
Distribute Earth-Mars diagram handout, and ask students to
compare and contrast the diagram with their observations from the demonstration.
List facts that can be derived from this exercise. Facts derived might
include:
- Earth travels in an orbit closer to the sun than Mars.
- Earth completes its orbit in about half the time taken by
Mars.
- Apparent retrograde motion is due to the planets being
relatively close to each other, and our viewing them against a distant
background of stars.
Day Two:
Introduce the video, saying that segments of the video have been
chosen to illustrate the team work involved in sending a spaceship to Mars, and
to show some of the exciting preliminary results from the Mars Pathfinder
mission.
FOCUS FOR VIEWING
Distribute Focus For Viewing Activity Sheets, one to each
student. Tell students that questions about each video segment are grouped
as Segments, so they will focus on the first set of questions during the first
video Segment A. To give students a specific responsibility while viewing,
before viewing each segment, ask a student to volunteer to read aloud the
questions for that segment so that students will know what they are to watch
for. At each indicated pause point, allow students to work in pairs to
complete the questions for that segment. If necessary, rewind and replay
the segment before continuing.
Say, "During the first segment of the tape you will be
looking for ways in which Mars resembles Earth and some reasons for studying
Mars". Ask for a volunteer to read questions 1-3 on the Focus for
Viewing sheet. Begin tape at the December 4, 1996 delta rocket
launch in the dark, following the Matt Golombek Nov. 19, 1996 classroom
interview. Audio is of the countdown to launch. Pause tape
after narrator says, "... and in those answers, may lie a better
understanding of our home planet, Earth". Video shows a hemisphere
view of Mars. This concludes Segment A. Ask students to work in
pairs to answers to questions 1-3 on their Activity Sheet.
While students are working, fast forward just past the image
of a time clock showing "Time to Pathfinder Landing" to a man sitting
on the ground with a model of Pathfinder and Sojourner. Tell students that
Segment B shows how teamwork was used to solve the problem when one of
Pathfinder's petals was stuck on one of the landing airbags shortly after
landing. To give students a specific responsibility while viewing, ask a
volunteer to read questions 4-6. Resume Segment B through Brian
Cooper's explanation of how rover is controlled on Mars. Pause at
the end of the computer animation of the rover. Narrator finishes with,
"Now we know Pathfinder and Sojourner would survive for many months on
Mars, returning amazing and instructive data". Ask students to
complete questions 4-6.
Fast forward to "Marvelous Mars" logo.
Say, "Segment C is about Marvelous Mars. Listen and look for the
highest and lowest temperatures on Mars, and the length of a day and a year on
Mars". To give students a specific responsibility while viewing, ask
a volunteer to read questions 7-9. Resume tape to show Marvelous
Mars Segment C. Pause tape after narrator says, "24 hours and
37 minutes". Image is of the rotating planet Mars. Ask students
to work in pairs to answer questions 7-9.
Tell students, "The next segment explains the
difficulties in navagating a spacecraft to Mars. Pay special attention to
how the Navigator team does its job". To give students a specific
responsibility while viewing, ask a volunteer to read questions 10-13. Resume
tape. Pause at the end of Global Surveyor Mission Planner, Wayne
Lee's statement, "... this is a small change, but it makes a big difference
at the end." Ask students to work in pairs to answer questions 10-13.
While students are answering questions, fast forward to
Camille Moody (blonde narrator), just after the picture of a Dad and baby, when
she begins with, "July 4, 1997, after a 7 month journey, the day and hour
of truth ...". Tell students, "Segment E is a fairly rapid
sequence showing the stages just before the Pathfinder landing. Try to
keep track of all of the events in the landing sequence. Also look for
information on how we knew the landing had been successful". To give
students a specific responsibility while viewing, ask a volunteer to read
questions 14-16. Resume tape to show Segment E. Pause after
narrator says, "after 21 years, an American spaceship was safely back on
Mars". Ask students to work in pairs to answer questions 14-16.
Say, "Every science endeavor has elements of success and
elements that the scientists would like to do over again. Focus your
attention in this last segment on the successes and problems of the first days
of the Pathfinder mission". Ask a volunteer to read questions 17-18.
Resume tape to show Segment F. Stop after, "this has
been a weekend we will never forget the rest of our lives". Ask
students to work in pairs to answer questions 17-18.
POST-VIEWING ACTIVITIES
Distribute Earth/Mars Comparisons activity sheet. Use
global maps of Earth and Mars and other available resources to find answers for
as many items as possible. Compare answers - information will vary
somewhat, depending on resources used. This activity will probably
continue into Day 3.
ACTION PLAN
1. Visit some of these websites to discover more about the
successful Mars Pathfinder mission:
http://mpfwww.jpl.nasa.gov
http://bang.lanl.gov/solarsyss
http://seds.1pl.arizona.edu/billa/tnpl
2. Implement other lessons from the Teacher's Guide for
Live From Mars. This Guide may be obtained by contacting:
Passport to Knowledge - Live From Mars
phone: 1-800-626-LIVE
http://quest.arc.nasa.gov/mars
EXTENSIONS
Language Arts
* Download images of Mars from websites listed above.
Write accompanying descriptions to create an illustrated journal of Pathfinder
events and discoveries.
* Read, then compare and contrast these two science
fiction works, written nearly 40 years apart.
- Ray Bradbury, The Martian Chronicles. Garden City, NY:
Doubleday and Company, 1958. ISBN 0-385-03862-3.
- Arthur C. Clarke, The Snows of Olympus: A Garden on Mars
óthe illustrated story of human colonization of Mars. New Your: W.W.
Norton & Company, 1995. ISBN 0-393-03911-0.
History
Research the early ideas about Mars, beginning with Percival
Lowell's description of canals and civilizations on Mars.
Mathematics
1. Calculate conversions (for example, metric to English,
or degrees C to degrees F) for all quantitative measures in this lesson.
2. Create scale drawing of the orbits of Earth (and
Earth's moon) and Mars around the Sun. Pay attention to the elliptical
shape of the orbit, and to the aphelion (farthest from Sun) and perihelion
(closest to Sun) positions of the planets.
Journey to Mars -- It's a Long Shot!
Activity Sheet: Focus for Viewing
Segment A
1. Mars resembles Earth in these ways:
a.
b.
c.
d.
e.
f.
2. Compare Mars and Earth in terms of:
a. diameter
b. land surface area
c. temperature
d. atmospheric density
e. volcanoes
3. Why study Mars?
Segment B
4. How do scientists use models to help solve problem?
5 a. How is the problem of the rover camera's poor
depth perception dealt with by rover driver, Brian Cooper?
5 b. How does Brian Cooper tell the rover where to go
on Mars?
6. What is Sojourner designed to do?
a. cameras
b. wheels
c. APX ("sniffer")
Segment C
7. Highest recorded temperature on Mars is
8. Lowest temperature on Mars is
9. compare length of a year and a day on Earth and Mars
Segment D
10. How do you hit a moving target?
11. What is the job of the Navigator team?
12. What two changes are made in a trajectory
correction maneuver?
13. What % change is that? (do the calculation)
Segment E
14. List the Pathfinder landing sequence in the correct
order:
drawn in by
Mars gravity; accelerated up to 16,600 mph
separated from
cruise stage
about 60 feet
from impact, airbags inflate, and rockets on backshell fire
3 minutes
later, parachute deploys as spacecraft separates from aeroshell
tether lowers
lander toward surface
lander cut
loose from tether
bounces on
surface for 2.5 minutes before coming to rest
enters
atmosphere; heat shield glowing
15. How long did it take the radio transmission to be
returned to Earth from Pathfinder?
16 a. All electromagnetic energy travels at the speed
of light, and this includes radio waves. Given the time lag in question
15, how far was Mars from Earth at the time of Pathfinder landing?
16 b. Is this a constant distance? Explain.
Segment F
17. What went well with the Pathfinder landing?
18. What went wrong with the Pathfinder landing?
How was the problem fixed?
Journey to Mars -- It's a Long Shot!
Earth/Mars Comparisons
Be sure to specify correct units where appropriate.
Earth
Mars
Land area
Sea surface area
equatorial diameter
Maximum distance from Sun
Minimum distance from Sun
Day length (one Mars day is a "sol")
Number of Earth days in a year
Degree of rotational axis tilt
Maximum surface temperature
Minimum surface temperature
Surface materials
Percent of atmospheric gasses:
nitrogen
oxygen
carbon dioxide
water vapor
Atmospheric density
Composition of polar caps
Highest elevation
Lowest elevation
Largest canyon:
length
depth
width
Largest volcano:
height
diameter
Largest impact crater:
diameter
Journey to Mars -- It's a Long Shot!
Activity Sheet: Focus for Viewing
TEACHER'S VERSION
Segment A
1. Mars resembles Earth in these ways:
a. deserts
b. sand dunes
c. polar caps
d. canyons
e. extinct volcanoes
f. ancient river channels, lakes
2. Compare Mars and Earth in terms of:
a. diameter
Mars is about 1/2 the diameter of Earth
b. land surface area about the same
c. temperature
much colder
d. atmospheric density thin(<1% of Earth's
atmospheric density at
SL)
e. volcanoes
gigantic - largest in solar system
3. Why study Mars?
to understand climate changes on Mars
to better understand Earth's environment
to search for evidence of pre-existing life on Mars
Segment B
4. How do scientists use models to help solve problems?
Generally, to manipulate and solve a problem
remotely.
Specifically, trouble-shooting problem with petals
not opening correctly.
5 a. How is the problem of the rover camera's poor
depth perception dealt with by rover driver, Brian Cooper?
3-D viewing goggles
5 b. How does Brian Cooper tell the rover where to go
on Mars?
He places "lawn dart" icons on
the monitor; system calculates locations on Mars; command sent to
rover to move to those locations
6. What is Sojourner designed to do?
a. cameras small camera for close-up
images
b. wheels dig into soil to
determine texture and composition
c. APX ("sniffer") (Alpha
Proton X-ray Spectrometer) determines mineral ID
Segment C
7. Highest recorded temperature on Mars is 17°
C or 63°F
8. Lowest recorded temperature on Mars is -143°
C or -255°F
9. Compare length of a year and a day on Earth and Mars
687 Earth days/Mars year
24 hrs 37 mins/Mars day
Segment D
10. How do you hit a moving target?
aim for where target will be when you arrive;
not where it is when you launch.
11. What is the job of the Navigator team?
4 trajectory correction maneuvers accomplished by
firing main rocket engine
12. What two changes are made in a trajectory
correction maneuver?
change direction and speed
velocity = 55,000 mph; change velocity by 25
mph
13. What % change is that? (do the calculation)
25 mph
* 100 = 0.045 % change in velocity
55,000 mph
Segment E
14. List the Pathfinder landing sequence in the correct
order:
1
drawn in by Mars gravity; accelerated up to 16,600 mph
2
separated from cruise stage
6 or 7 about 60 feet from impact, airbags
inflate, and rockets on backshell fire
4 3
minutes later, parachute deploys as spacecraft separates from aeroshell
5 tether
lowers lander toward surface
6 or 7 lander cut loose from tether
8 bounces
on surface for 2.5 minutes before coming to rest
3 enters
atmosphere; heat shield glowing
15. How long did it take the radio transmission to be
returned to Earth from Pathfinder?
11 minutes
16 a. All electromagnetic energy travels at the speed
of light, and this includes radio waves. Given the time lag in question
15, how far was Mars from Earth at the time of Pathfinder landing?
(speed of light is about 186,000
miles/second)
186,000 mi/sec * 60 sec/min * 11 min =
122,760,000 miles
16 b. Is this a constant distance? Explain.
No, because distance between the 2 planets
depends on the relative position of each in their orbit around the Sun.
Segment F
17. What went well with the Pathfinder landing?
landing phase
picturers from high-gain antenna
18. What went wrong with the Pathfinder landing?
How was the problem fixed?
It took several hours to get petals open -
airbags were interfering with operation of rover ramp.
Teamwork and use of models solved the problem.
Journey to Mars -- It's a Long Shot!
Earth/Mars Comparisons
TEACHER'S VERSION **
Be sure to specify correct units where appropriate.
Earth
Mars
Land area 148,000,000
km2 or 57,000,000 mi2 144,000,000
km2 or 56,000,000 mi2
Sea surface area 363,000,000 km2
or 139,000,000 mi2
0
Equatorial diameter
12,756 km or 7,928 mi
6,768 km or 4,218 mi
Maximum distance from Sun
152,100,000 km
249,200,000 km
Minimum distance from Sun
147,100,000 km
206,600,000 km
Day length (one Mars day is a "sol") 24
hours
24 hours 37 minutes
Number of Earth days in a year
365.25
687
Degree of rotational axis tilt
23.5
25
Maximum surface temperature
136° F
310 K
Minimum surface temperature
-130° F
150 K
Surface materials
granite and basalt
silicon and iron
Percent of atmospheric gasses:
nitrogen
78 %
2.7 %
oxygen
21 %
0.13%
carbon dioxide
0.03%
95 %
water vapor
up to 4 %
0.03 %
Atmospheric density
1013 mb at sea level
6 mb at datum
Composition of polar caps
water ice
carbon dioxide ice
Highest elevation
Mt. Everest (8,848 meters)
Olympus Mons (27 km)
Lowest elevation Mariana
Trench (~11 km below SL) Hellas
basin (4 km below datum)
Largest canyon:
length
Grand Canyon (446 km)
Vallis Marineris (4,000 km)
depth
Grand Canyon (1.6 km)
Vallis Marineris (~10 km)
width
Grand Canyon (30 km)
Vallis Marineris (~600 km)
Largest volcano:
height
Mt. Guallatiri , Chile (6,063 meters)
Olympus Mons (27 km)
diameter
Guallatiri (6.1 km)
Olympus Mons (600 km)
Largest impact crater:
diameter
Sudbury, Canada (140 km)
Hellas (~2,000 km)
Updated: April 01, 2008
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