Extraterrestrial Resource Utilization

One of the major problems that we face as we explore the Solar System is the need to carry all of our propellants, food, water, oxygen, and other supplies with us.  If we had had to explore America the same way that we explore space, The United States not extend more than about 100 miles from the Atlantic coast, as shown in this illustration.

In order to explore the Solar System effectively, we need to be able to utilize local resources to replenish our consumables.  American pioneers could refill their water barrels at a river, allow their animals to graze on the prairie, and hunt for the food that they ate while exploring.  Once they decided to stay in one area, they planted farms to feed them, and built shelters to protect them.  We need to be able to do the same thing as we explore the Solar System.

In terms of energy, the most costly portion of any space mission is getting from the Earth's surface to low earth orbit (LEO).  Fully one-half of an interplanetary mission energy budget is spent getting into LEO.  Robert Heinlein one said, "Once you're in LEO, you are half way to anywhere."  If we didn't have to lift all of the oxygen, water, food and fuel for a complete round trip, we wouldn't need such large spacecraft, which means they would be much "cheaper" to launch. 

Let's take a look at two places where we could conceivably re-supply our interplanetary missions.

The Moon

In 1998, the data returned by Lunar Prospector spacecraft indicated that water ice is present at both the north and south lunar poles, in agreement with Clementine results for the south lunar pole reported in November 1996. Although the data is not conclusive, the total amount of water ice is estimated to be approximately 6 trillion kg (6.6 billion tons). (Williams, 1999)

This water ice could be electrolyzed to produce hydrogen and oxygen.  As we have discussed, these two elements are the most efficient chemical fuels known.  If we were to design, build and deploy an ice mining/electrolysis unit to an appropriate area of the Moon's surface, we could travel to the moon with just enough fuel and water to get there, then refuel our vessel for the return trip.

The ice could also be, which would provide us with the water needed for drinking and hygiene, as well as farming.  Hydroponic gardens could be used to grow the food we would consume while exploring the Moon.

Mars

Mars has soil that could be processed to produce oxygen, as well as water (in the polar ice caps or in subsurface permafrost) that could be electrolyzed to produce oxygen and hydrogen propellants. However, Mars is unique in possessing an atmosphere of carbon dioxide (CO₂) that represents a potential extraterrestrial resource. (Frisbee, 2000h)

If we bring a supply of hydrogen with us, we can set up a Sabatier / Water Electrolysis process to produce oxygen and methane.  The Sabatier process uses hydrogen gas as a catalyst to produce methane and water from the carbon dioxide found in the Martian atmosphere:

CO₂ + 4H₂ --> CH₄ + 2H₂O

Some of the water is then electrolyzed to produce hydrogen and oxygen:

2H₂O + electricity --> 2H₂ + O₂

This results in supplies of methane, water, hydrogen, and oxygen.  The methane and oxygen could be used to power vehicles needed to explore the Martian surface, while hydrogen and oxygen could be used to refuel the spacecraft for the return trip.  The water and carbon dioxide would also allow us to set up farms, as we discussed for the Moon.  Of course, the oxygen would also be used to keep us alive. (Zubrin & Wagner, 1997)

These are but two ways that extraterrestrial resources could be used to facilitate the human exploration of the Solar System.  There are other plans being made for the possible use of resources from other planets.  All of these plans are summarized in the chart below. 

This site was created in fulfillment of SAO course requirements 
for HET602a, Semester 1, 2000 by Dennis Ward.

©2000 by Dennis Ward, All rights reserved.