The atmosphere of Mars, composed of a thin layer of carbon dioxide, provides a significant challenge in colonizing the Red Planet. Without breathable oxygen in the atmosphere, Mars colonists will forever be trapped indoors, or within the confines of spacesuits. A new process developed at Caltech, inspired by comets, may hold the secret to transforming carbon dioxide in the Martian atmosphere into breathable oxygen.
A ready supply of oxygen is vital to human spaceflight, and the gaseous, molecular oxygen we breath in the atmosphere is composed of pairs of atoms of oxygen, called O2. Carbon dioxide, CO2, is made up from two atoms of oxygen on opposite sides of a carbon atom.
“[W]e thought it would be impossible to combine the two oxygen atoms of a CO2 molecule together because CO2 is a linear molecule, and you would have to bend the molecule severely for it to work. You’re doing something really drastic to the molecule,” Konstantinos Giapis, a professor of chemical engineering at Caltech, stated.
Astronomers knew that molecular oxygen may be found in the tails of comets, although the exact mechanism which formed the gas remained a matter of debate. Giapis and his team examined the question, proposing an unknown chemical process might be at work.
It’s a Gas, Gas, Gas
Most chemical reactions require heat to be applied, fueling the reaction. Giapis showed that some reactions can convert kinetic energy of molecules in motion into energy useful to initiate a reaction. When molecules of water strike oxygen-containing materials like sand or rust, the water molecules can rip apart, forming molecular oxygen and hydrogen. This process takes place near comets, as water driven off from a comet as it approaches the Sun is accelerated backward by the solar wind, until it crashes back on the frozen surface.
Giapis and his team accelerated molecules of CO2 onto a gold plate, finding the process converted a fraction of the carbon dioxide into breathable oxygen.
The device they developed energizes the gas, ionizing the molecules, before accelerating them through an electric field toward a collision with their target. This process, which could represent a new branch of chemistry, does not require extreme speeds to convert the molecules, their research reveals.
“You could throw a stone with enough velocity at some CO2 and achieve the same thing. It would need to be traveling about as fast as a comet or asteroid travels through space,” Giapis stated.
Computer simulations were developed to model the experiment. This task proved challenging, due to the chaotic nature of movements within the moving molecules.
A similar effect may already be taking place in the upper atmosphere of Mars, as high-velocity dust particles strike molecules of carbon dioxide. This could account for a layer of oxygen seen in the upper atmosphere of Mars, researchers believe.
Mars is where the action is for the next thousand years. The characteristic of human nature, and perhaps our simian branch of the family, is curiosity and exploration. When we stop doing that, we won’t be humans anymore. I’ve seen far more in my lifetime than I ever dreamed. Many of our problems on Earth can only be solved by space technology. The next step is in space. It’s inevitable.
— Arthur C. Clarke
Is Everyone Packed for Mars? Don’t Forget Your Oxygen!
Science fiction stories are replete with tales of human civilization terraforming Mars, developing that planet from a frozen desert into a world were people can live comfortably.
Carrying oxygen along on a human mission to Mars greatly increases the weight (and therefore, the financial and fuel costs) of such a mission. This new device from Caltech converts just one to two percent of the molecules that strike it into breathable oxygen, making it ineffective for use aboard a spacecraft. However, the technology discovered here may pave the way to a future mechanism capable to converting large quantities of carbon dioxide into life-giving oxygen.
“Enabling sustained human life on another planet will require a great deal of resources and we cannot possibly bring everything we will need. We have to get creative. If we can transform an existing and plentiful resource like carbon dioxide into a variety of useful products, the space — and terrestrial — applications are endless,” said Monsi Roman, program manager of NASA’s Centennial Challenges program.
In addition to providing air for astronauts and space colonists, knowledge of the process could also lead to direct benefits here at home, in the development of devices capable of scrubbing carbon dioxide from the atmosphere.