No, You Don’t Have To Worry About Emissions From SpaceX’s Mars Rocket

October 30th, 2019 by Harry Stoltz

No, you don’t have to worry about emissions from SpaceX’s Mars rocket. It’s actually a green machine.

In my last article, in which I reported on SpaceX’s update to its Mars rocket, Starship, I read many concerned comments regarding the environmental effects that such a system might cause.

Currently, we are unsure as to exactly how much spaceflight accounts for total greenhouse gas emissions per year, but there is consensus that it would be a very small number several orders of magnitude less than 1%. While not zero, this is an extremely negligible amount, especially when compared to emissions due to agriculture (~24%) and energy production (~25%). However, the concern is that this number will rise “astronomically” as rocket reusability drives prices down and launches become increasingly more common.

Additionally, SpaceX plans to take on the airline industry and use Starship for point-to-point transportation here on earth. At face value, this seems like it could be catastrophic for the environment, but don’t fret! When I attended SpaceX’s event late last month, they unveiled their plan for clean fuel production.

The idea is that Starship will unconventionally run on methane and oxidizer. One of the reasons why SpaceX chose methane (CH4) as the fuel is because it can be readily produced on Mars, as well as Earth. (It is worth noting, however, that methane is incredibly abundant on earth, so SpaceX will likely not need to produce it here.) During the presentation, SpaceX CEO Elon Musk gave a brief synopsis of the process they will be using, but left out a few details.

In order to create both the oxygen and methane fuel on Mars, SpaceX will need to collect water and carbon dioxide. Mars’ atmosphere is 95% carbon dioxide, and frozen water is plentiful on the poles, making them both relatively easy to collect. Then, they will split the water into hydrogen and oxygen gas through a process known as electrolysis. Electrolysis is naturally energy intensive, which is where their plan to use solar energy comes into play. After that, they will add the hydrogen gas to carbon dioxide that they’ve collected from either Mars or Earth and run them both through something called the Sebatier Process, which will produce methane, and water as a side product. All that’s left is to liquify the methane and oxygen gas through a cryogenic system, and the rocket has all the fuel it needs!

Since SpaceX will use solar power to provide energy to pull carbon dioxide out of the atmosphere on both Earth and Mars, this would have the effect of mitigating emissions here on our planet, as well as altering the atmosphere of Mars. Furthermore, when the fuel burns, it releases water and carbon dioxide back into the atmosphere, leaving both open to recollection. SpaceX can theoretically recycle the same materials over and over again, without creating any net emissions! With this approach, SpaceX has essentially developed a carbon-neutral propulsion system, which is something that will become a vital asset in the future.









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