trip to mars

Originally published in The Technology Teacher, December 2001, by the International Technology Education Association
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It’s been over 25 years since humans set foot
on “unearthly” ground—the moon, that is. It took
only a few days to get to the moon, so the Apollo
astronauts didn’t have time to get bored. Our next
destination in the human exploration of space will
probably be Mars. Although we don’t yet have any
definite plans for getting there, many people are
busy working on the many problems that will have
to be solved to accomplish this very difficult goal.
The main challenge is that Mars is much
farther away than the moon. Mars is the fourth
planet from the Sun, and Earth is the third planet
from the Sun. It takes Earth about 365 days to
make one orbit around the Sun (one Earth year). It
takes Mars 687 Earth days to make its journey
around the Sun. So to get to Mars, we blast off
from Earth going in the same direction as Earth
and Mars are both traveling around the Sun, and by
adding a little speed using the spacecraft’s engines,
we eventually match up with Mars’orbit and catch
up to Mars itself. If we don’t care about gas
mileage, we can really step on it and get there in
six months! A more fuel-efficient trip takes about
11 months.
So, after a six-month journey, you land on
Mars and have to stay at least 19 months, until
Mars and Earth approach their closest positions
again before you take off for the six-month journey
home. You will be gone a total of about 2-1/2
years!
This is a long time to be cooped up in a
spaceship or in a Mars habitat with a few other
crewmates! How would you pass the time? And
how would you plan for all the crewmates to get
along together?
Plan Ahead!
Imagine you and your two, three, or four
crewmates are planning for a trip to Mars. Assume
that all your basic needs for air, food, water, and
warmth will be met by the basic design of the
spaceship and the supplies that have already been
stowed aboard. All you and your mates must do is
decide what personal items to take to pass the time
and keep yourselves entertained and happy.
Packing for a L-o-o-o-ng
Trip to Mars
Originally published in The Technology Teacher, December 2001, by the International Technology Education Association
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All the items your crew takes along must fit
into a box 1 meter wide by 1 meter high by 1 meter
deep—in other words, having a volume of 1 cubic
meter (1 m3). (One meter is about 39-1/2 inches).
Remember, scientists and engineers almost
always use the metric system of measurements,
rather than the imperial system (using feet and
inches). The metric system is based on tens and is
much easier to work with. In the imperial
system,you must remember odd numbers, like 12
inches to a foot, 3 feet to a yard, 5,280 feet to a
mile, and so on. In the metric system, there are
1000 millimeters in a meter, 100 centimeters to a
meter, 10 millimeters to a centimeter, and 1000
meters to a kilometer. Piece of cake!
Materials You Will Need for
Planning:
· For the class, you will need a meter stick,
poster board or cardboard, and tape (any
kind).
· For each person, you will need a metric ruler
or tape measure, graph paper, and pencil.
· For each team, you will need a collection of
thin markers or colored pencils.
How Big is This Box Again?
To get a good idea of how big a 1-m3 box
really is, you might actually construct one for
whole class to see. Use the poster board or cardboard
to tape together a cube 1 m on each side.
Strategies for Planning
Get into teams of 3 to 5 people. Decide
together what you would like to take to Mars. All
the items selected by your team must fit into the 1-
m3 box. You might start out by brainstorming
ideas, writing everyone’s suggestions on a board or
paper. Then, as a group, discuss and decide on the
best selection of items to take. Keep in mind . . .
· For maximum variety, you might want to pool
your interests and take items you can all share
and enjoy.
· For electronics that require batteries, you must
take along enough batteries to last 2-1/2
years.
· There are no electronics repair shops or
computer experts (unless you are one!) in
space.
Conversion factors:
Inches to millimeters: in x 25.4 = mm
Inches to centimeters: in x 2.54 = cm
Feet to centimeters: ft x 30.48 = cm
Feet to meters: ft x 0.3048 = m
Yards to meters: yd x 0.9144 = m
Miles to kilometers mi x 1.6 = km
Metric Units:
1 meter = 1000 millimeters
1 meter = 100 centimeters
1 meter3 = 1,000,000,000 millimeters3
1 meter3 = 1,000,000 centimeters3
Originally published in The Technology Teacher, December 2001, by the International Technology Education Association
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· There is no cell phone service in space.
· There is no internet in space.
· There is no cable and satellite TV in space.
· To save space, you might want to consider
items that can be disassembled and reassembled
when needed.
· For one year of this period you will be in zero
gravity in the spaceship, and for the rest of the
time you will be in gravity only one-third as
strong as Earth’s in your Mars habitat.
· The weight of your items doesn’t matter.
Assume your Mars-bound spacecraft will be
assembled in space, so the entire weight of it
does not have to be launched from Earth all at
one time.
Making Sure It Will All Fit
Once you have your group’s list, you need to
find out whether everything will fit before you go
to the trouble of obtaining all the items and trying
to stuff them into the 1-m3 box. You need to find
out the volume of each of the items, then add them
all up to see whether their combined volumes is
equal to or less than 1 m3.
Divide up the list so that each person in the
group is responsible for obtaining the measurements
of some of the items. Members of the group
may actually own the items or may have to go to a
store to find them. Once the item is in hand, just
use a metric ruler or tape measure to get its height,
width, and depth in centimeters or millimeters.
Then, multiply these three numbers together to get
its volume. If the object is an odd shape, consider
how large a box it would take to hold it, and just
measure its largest dimensions.
If no one knows where to get hold of the item,
try looking on the internet for a site that sells the
item and see if you can find out its dimensions.
The dimensions will no doubt be given in inches,
so you will need to convert to centimeters or
millimeters before calculating the volume.
Packing Your “Virtual” Box
Now, without actually bringing in all the
items and shoe-horning them into the box, we are
going to pack the box on paper! This is called
“planning.” This is the way engineers design
complicated things. They put all the parts together
on paper (or using a computer), before going to all
the bother and expense of making and then trying
to fit together the actual parts.
Using graph paper, first decide the scale you
will use. For example, you might have one square
equal 5 centimeters.
Do the drawings as a group. Each person
should have the opportunity to do at least one
drawing.
Draw one side of the 1-m3 box on the graph
paper. Now, using colored pencils or thin markers,
draw the items that would fit into the box, as they
would appear from one side. Label the items, and
include their measurements.
Now, using another piece of graph paper,
draw another side of the box. Now, make a drawing
that shows how the packed box would look
from that side.
Using still other pieces of graph paper, draw
the packed box from the top, bottom, and the other
two sides. You should end up with six drawings,
plus a list of the items in the box..
Hint: For odd-shaped items, if you know the
measurements of the individual parts, you can nest
the items together to take up the least space.
Explaining Your Rationale
Present your list and six drawings to the rest
of the class, and explain . . .
· What was the process your team used to
decide what to put into the box?
· What compromises were necessary in choosing
the items?
· Why were the items picked?
· What items had to be left out?
· Do all the items represent the agreement of
the team, or were some individuals given
their chosen item for some reason?
Originally published in The Technology Teacher, December 2001, by the International Technology Education Association
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What is NASA Doing About
Mars Right Now?
No human expedition to Mars is being
planned yet by the National Aeronautics and Space
Administration (NASA). However, NASA is
working on technologies that will enable future
robotic (unmanned) missions to help solve some of
the many mysteries about the red planet.
Missions being considered include orbiters,
landers, rovers, robotic airplanes, balloons, subsurface
explorers, life detectors, sample return missions,
and advanced communications systems to
get all this data back to Earth.
Using these technologies, NASA hopes to . . .
· Find out whether life ever existed on Mars.
· Learn about the climate on Mars.
· Learn about the geology on Mars.
· Prepare for humans to go to Mars!
Learn more about NASA’s Mars Exploration
Program at http://mars.jpl.nasa.gov, and play the
Mars Adventure game at http://
spaceplace.jpl.nasa.gov/mars_rocket.htm .
This article was written by Diane Fisher, science and technology writer and developer of The Space
Place website, and Rose Ryland, middle school math teacher in Pasadena, California. It is provided
through the courtesy of the Jet Propulsion Laboratory, California Institute of Technology, under a
contract with the National Aeronautics and Space Administration. Illustrations are by Alex Novati.
Facts to Know for Your Trip to Mars
Average distance of Mars from Sun: 1-1/2 times farther than Earth
Length of Mars year: 687 Earth days
Length of Mars day: 24 hours, 37 minutes
Mass (amount of matter it contains): About 1/10th of Earth’s
Diameter (distance across): About ½ of Earth’s
Number of moons: 2 (Phobos and Deimos)
Surface gravity compared with Earth: 0.38 (If you weigh 100 pounds on Earth, you will
weigh only 38 pounds on Mars)
Atmospheric pressure at Mars surface: Only about 1/100th (or less) of Earth’s
Main gases in atmosphere: Carbon dioxide, with a bit of nitrogen, oxygen, and
argon.
Time for a spacecraft to travel At least six months, depending on the positions of
to Mars from Earth: the two planets in their orbits around the Sun.
Artist’s concept of a sample return
mission blasting off from Mars.