Recently named Time’s Person of the Year, Elon Musk announced that SpaceX is launching a program to extract carbon dioxide from the atmosphere into rocket fuel. Few details have been released, but we know that such a process could allow return trips from the planet Mars.
SpaceX would like to produce fuel on Mars
SpaceX aims to send humans to Mars as early as 2026, before offering regular freights. Then the question of take-off weight arises. To allow such a trip, you can not afford to fill the tanks for the round trip. The idea would then be to make the most of the raw materials available at the place of destination. On Mars, you have a little water in the form of ice, of course, but above all a lot of carbon dioxide. It even makes up 96% of the Martian atmosphere.
On Mars, the ideal would therefore be to be able to make rocket fuel from CO2. NASA is also trying it out with its Mars Oxygen In-Situ Resource Utilization Experiment (or MOXIE), deployed on the red planet by Perseverance.
Its goal is to turn part of the planet’s carbon dioxide-rich atmosphere into oxygen. At the moment, this is just a technology demonstration. However, this could eventually make it possible to fill the oxygen tanks that astronauts will need to return to Earth.
Elon Musk, meanwhile, is said to be aiming for the same goal, but how he plans to go about it is not entirely clear.
“SpaceX is launching a program to extract CO2 from the atmosphere and turn it into rocket fuel,” Musk tweeted on Monday. “Please contact us if you are interested”. One imagines that SpaceX is appealing to all the thinkers who may be able to make this process a reality.
Using Sabatier’s reaction?
The only intervention likely to direct us is a “Yup” answered by Musk in response to an engineer referring to Sabatier’s reaction. This chemical reaction discovered in 1897 by the French chemists Paul Sabatier and Jean-Baptiste Senderens makes it possible to produce methane (a potential fuel for rockets) and water from carbon dioxide CO2 and hydrogen at high pressure and temperatures.
If the plan is indeed to rely on the Sabatier reaction, the downside would be that all the unburned methane released would have a warming effect several times greater than the carbon dioxide used to make it. In an interstellar medium, it wouldn’t matter much. On the other hand, this could be a problem during the take-off phases. Alternatively, carbon dioxide could be converted into liquid fuel.
So there is nothing concrete at the moment. Case to follow. In the meantime, those who have ideas on how to produce such a fuel are invited to join SpaceX.