Carbon Dioxide in Spaaaaaaaaaaaace!!!!

by Chris McMahon

OK, this post is slightly silly.

I’ve always been fascinated by the fact that CO – carbon monoxide – can be used as a rocket fuel. Oxidised with Oxygen, it makes CO2. It’s not a very good rocket fuel – its specific impulse is around 259 seconds, which compares to the all-time-favourite of Hydrogen/Oxygen at 459s and the dreamy-eyed SF fan’s dream of a Nuclear Thermal Rocket using a hydrogen monopropellant at 847s.

The lower the impulse, the less percentage of your original rocket mass will be lifted into orbit.

To get from the Earth’s surface to LEO (low Earth orbit), you need a DeltaV of between 9-10,000 m/s.

Using Hydrogen/Oxygen that might mean you can deliver 10-13% of the original rocket mass into orbit (staging helps as you drop away unwanted ‘tankage’ mass).

For the dreamy NTR, this is over 30% of the original rocket mass!

Now for my concept CO rocket (reacting with O2). Only 2% of the original mass makes it into orbit. That probably means a messy and expensive craft with multiple staging. A lot of dough for no-show.

Still . . . it does mean you get to use CO.

Now if you could just put nuclear reactors close to the sources of large amounts of CO2 – then you could use high temperature processes to split the CO2 to CO and O2 and makes tonnes and tonnes of crappy CO/O2 rocket fuel.

Of course, if you had that sort of power, why not make Hydrogen and Oxygen from water. And of course – if people let you just put nuclear reactors everywhere, then why not let us use NTRs to get into orbit!

Most of the CO2 produced from recombining the CO and O2 would end up back in the atmosphere, so it’s probably not going to help the greenhouse effect much. However – if you could manage to take large quantities of CO and O2 into space, it would probably make a serviceable rocket fuel for orbit to orbit transfers and Moon visits. And then you get the CO2 in spaaaaaaace:)

Practical? Not in the least.

But then again, I did say this post was slightly silly 🙂

PS: If you want to play with the Delta-V calculator check here.


  1. Interesting to think such commonplace chemicals can work as rocket fuel (for some definitions of work).

    My favorite way to get off Earth is a sky hook. All you have to do is build it in the first place, and then figure out how to keep it in orbit until it starts catching returning loads. And do you really want those asteroid miners firing off partially refined ores from the belt, at Earth, in excess of the escape velocity? 😉

    Thanks for the link. I’ve squirreled it away, as one never knows when something just like that will come in handy.

    1. Hi, Pam. The space elevator would be a great way to go – but the materials required just seem as likely as an anti-gravity drive right now unfortunately. I love the idea though – you could power your ascent with any sort of crummy internal combustion engine. I love the image – ‘On the third try the rusty outboard motor spluttered to life. Tosco checked his breather, and the tiny lift car limped its way to the stars. . ..’

      It was a fun little calculator!

  2. I’ve always wondered why no one’s tried ACTUAL ROCKET FUEL!

    By that I mean of course Tequila, Vodka, Wild Turkey and a yeager bomb mixed together in a silver cask wine bladder.

      1. The Makeshift Rocket? Something like that. Powered by beer, if I remember correctly. I think I had the Ace Double edition, with a funky cobbled together rocket on the cover somewhere for a long time…

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