CS272 – Tech A

How we might go to Mars

Monday, November 29, 2010

Getting Home: Using Mars Resources for Fuel

A key question when proposing a mission to Mars is the notion of coming home to Earth. This notion would not be viable with the resources available on Earth, such that the amount of fuel required for a round trip to Mars would be very hard to handle for such a long distance. Thus, the only feasible option for such a return would be to find or manufacture the fuel for the home trip while on Mars. With articles discussing the technologies and resources for fuel on Mars, it seems like this will be the way to go when planning a Mars trip, and making it not just a one-way grave for astronauts.  There are two major possible options for the creation of fuel on Mars. One using the Martian atmosphere, and the other using nuclear elements found on the planet’s surface.

While the Martian atmosphere is quite different from our own (not to mention much thinner),  and is mostly comprised of carbon dioxide (CO2). There are two different methods that fuel can be produced by this. One is the electrolysis of the CO2 into carbon monoxide (CO) and oxygen (O2). The carbon monoxide is used as a fuel and the oxygen could be used elsewhere. This is a fairly simple method of making fuel with only the elements of the atmosphere. The other method would be to create a Sabatier reaction, “reaction of hydrogen with carbon dioxide at elevated temperatures and pressures in the presence of a nickel catalyst” (“Sabatier Reaction”, Wikipedia), which would output methane (CH4) and water (H2O). This method seems to be a little more involved but also produces water in the end, which is crucial for sustaining life on Mars. One rover, from a proposed NASA mission, was designed to used the first method to create a “self-refueling hopper” to sustain itself on the planet. I believe that this could be the method to get home from Mars.

The nuclear option for harnessing fuel on Mars would be through its rich Thorium (Th) deposits. “Any cubic meter of Earth, Moon or Mars has enough Th-232 to run a profligate American’s energy life for several years” (Alexander Cannara, IEEE Life Member). There are also detailed maps of the Martian surface noting the Thorium density in parts per million. Thus the quantity of the Thorium cannot be disputed, unlike the method required to create a nuclear reaction with it. Thorium is not inherently fissile, meaning it cannot start or sustain a nuclear reaction. It would require some “weapons-grade material” to start the reaction. This is something such as Plutonium-239 or Uranium-239, which we might have to bring with us from Earth. The unique part about this process is that Thorium will decay into Uranium-233 from the nuclear reaction which is a fissile material. Thus, once the Thorium decays to a certain point the external Plutonium and Uranium becomes unnecessary, and the process becomes self-sustaining. This would all be great in theory, and possibly even for fuel on Earth, but at the current time it seems that the technology is not there and much more complicated than methods using the Martian atmosphere.

In the end I feel that using the CO2 from the atmosphere will prove to be the ideal way to fuel both living on Mars and the trip home, and the notion of it being a one-way trip should seem out of the question even with today’s technology.


  • http://www.lpi.usra.edu/meetings/robomars/pdf/6098.pdf
  • http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=1559325
  • http://www.geoffreylandis.com/propellant.html
  • http://spectrum.ieee.org/tech-talk/energy/nuclear/is-thorium-the-nuclear-fuel-of-the-future
  • http://energyfromthorium.com/forum/viewtopic.php?f=6&t=759
  • http://www.ieer.org/fctsheet/thorium2009factsheet.pdf
posted by Chimpy at 3:07 AM  

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