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Guide Index

Out of Thin Air

NASA's Way to Mars

Why Go to Mars?

We're on Our Way

Houston, We've Had a Problem!

Getting There

Viewer Challenge
in the classroom
TEACHING GUIDES


Journey to Mars: Out of Thin Air


Some early explorers on Earth ran into trouble when they did not follow the practice of living off the land. As you see on this episode of Frontiers, aerospace engineer Robert Zubrin believes interplanetary pioneers should follow the same principle and use the Martian atmosphere to make fuel and other products. Zubrin elaborates his vision and his plans for a Mars mission he calls "Mars Direct."

Curriculum Links
National Science Education Standards
Related Frontiers Shows and Activities
Chemistry on Mars: A Simple Electrolysis Experiment
Discussion: What Do We Know About Mars?




CURRICULUM LINKS


CHEMISTRY


reactions

EARTH
SCIENCE


astronomy, solar system

HISTORY


exploration, moon landing, U.S.

TECHNOLOGY


engineering, inventions




NATIONAL SCIENCE EDUCATION STANDARDS

SCIENCE AS INQUIRY / PHYSICAL SCIENCE
5-8: Properties and Changes of Properties in Matter
9-12: Chemical Reactions
EARTH AND SPACE SCIENCE
5-8: Earth in the Solar System
9-12: Origin and Evolution of the Universe
SCIENCE AND TECHNOLOGY
5-8,
9-12:
Understandings about Science and Technology
SCIENCE IN PERSONAL AND SOCIAL PERSPECTIVES
5-8: Science and Technology in Society
9-12: Natural Resources
HISTORY AND NATURE OF SCIENCE
5-8: Science as a Human Endeavor
9-12: Historical Perspectives




RELATED FRONTIERS SHOWS AND ACTIVITIES



ACTIVITY: CHEMISTRY ON MARS: A SIMPLE ELECTROLYSIS EXPERIMENT

Engineer Robert Zubrin has worked out step-by-step plans for a Mars mission at a relatively low cost. One of his basic principles is living off the land and using local resources. On Frontiers, Zubrin shows how rocket fuel could be made out of raw materials in the Martian atmosphere.

In the Mars chemical plant, the Sabatier reaction combines carbon dioxide with hydrogen to produce methane (which forms the basis for methanol rocket fuel) and water (CO2 + 4H2 = CH4 + 2H2O). After water (H2O) is obtained, it can be separated into its two components, hydrogen and oxygen. Similarly, scientists have proposed that oxygen can be obtained from ice on the moon. The oxygen would be stored as rocket propellant, and the hydrogen recycled back into the chemical plant to make more methane and water. The methanol would also be used by Mars rovers as fuel. Zubrin also has a plan for making ethylene (C2H4) - another fuel and the basis of plastics - out of carbon dioxide and hydrogen.

In this activity, you will perform a simplified method of aqueous electrolysis to split water into its two chemical elements using electric current from a battery.



MATERIALS
  • 2 pencils sharpened at both ends
  • 1 9-volt battery
  • 15# amp coated fuse wire
  • water in a beaker about 6 cm deep
  • scissors
  • heavy paper
  • waterproof tape
PROCEDURE

  1. Cut two pieces of fuse wire about 20 cm each. Remove about one inch of coating from each end of each wire. Make a loop at one end of each wire that fits around the point of a pencil.

  2. Place a square of paper on top of the beaker of water. Push the pencils through it so they rest with their points in the water. Place the wire loops around the pencil points sticking out of the water.

    beaker and battery setup
  3. Wind the free end of one wire around the positive terminal of the battery and tape to secure; wind the free end of the other wire around the negative terminal and secure.

    SAFETY PRECAUTION: When the wires are attached to the battery terminals, they are electrically "live." Be careful not to allow exposed wires to touch each other while live -- the battery could overheat or explode.


  4. Watch the pencil points in the water. What happens? Bubbles of oxygen and hydrogen should form around the pencil points.

  5. How do you know which bubbles are oxygen and hydrogen? Observe the battery terminals. Oxygen collects around the pencil attached to the positive terminal (+). Hydrogen collects around the pencil attached to the negative terminal (-). Explore why this happens. Which pencil do you think will have the most bubbles around it and why?


DISCUSSION: WHAT DO WE KNOW ABOUT MARS?

  • Pathfinder and other Mars missions have given us much information about the red planet. The planet appears red because a fine, iron-rich dust covers most of the surface.

  • The Martian day is very similar to ours: 24 hours and 7 minutes. The planet rotates on an axis with a 24-degree tilt. Compare to Earth's day and orbit.

  • The carbon-rich atmosphere on Mars is about 1% as thick as Earth's atmosphere. The "thin air" of Mars consists of 95% carbon dioxide and 3% nitrogen, with traces of oxygen, argon, carbon monoxide and water. Compare this chemical composition with the Earth's atmosphere.

  • Mars is believed to have been much warmer and wetter in its distant past, with a much thicker layer of CO2, or a "greenhouse effect." Water today is frozen as permafrost in the soil and in the southern polar cap as dry ice. What scientists learn about how Mars's climate changed could help us understand Earth's climate.





 

Scientific American Frontiers
Fall 1990 to Spring 2000
Sponsored by GTE Corporation,
now a part of Verizon Communications Inc.