Why SpaceX isn’t YET synthesizing methane in Boca Chica but IS using solar

[su27k]

https://twitter.com/elonmusk/status/1470519292651352070

SpaceX is starting a program to take CO2 out of atmosphere & turn it into rocket fuel. Please join if interested.


Will also be important for Mars

[Vultur]

Well, they will need the technology for Starship's Mars ISRU anyway since the Martian atmosphere is CO2, so why not get ecological/PR points for developing it?

Seriously doubt it will be a significant source for "Earthside" operations though, due to cost.

And Earths atmosphere actually has less CO2 than Mars's... 410-420 ppm out of ~100kPa is about 41-42 Pa, vs 95% of Mars's atmosphere... nominal datum 610 Pa, but probably more at likely landing sites, so 600-800 Pa maybe?

Partial pressure of CO2 maybe 15-20 times greater on Mars?

And Mars is a lot colder than South Texas, so if you are using cooling to separate it, it's lower energy too.

[meekGee]

Well, they will need the technology for Starship's Mars ISRU anyway since the Martian atmosphere is CO2, so why not get ecological/PR points for developing it?

Seriously doubt it will be a significant source for "Earthside" operations though, due to cost.

And Earths atmosphere actually has less CO2 than Mars's... 410-420 ppm out of ~100kPa is about 41-42 Pa, vs 95% of Mars's atmosphere... nominal datum 610 Pa, but probably more at likely landing sites, so 600-800 Pa maybe?

Partial pressure of CO2 maybe 15-20 times greater on Mars?

And Mars is a lot colder than South Texas, so if you are using cooling to separate it, it's lower energy too.

Unless they find a convenient industrial source of CO2 exhaust.

[john57sharp]

  What ever happened to Pons and Fleischmann?

There is a glimmer of hope still, UK entrepreneur Richard Dinan is hoping to produce small fusion reactors once the world wakes up to the possibility, all hopes pinned on the giant ITER working in the next 5 or so years (NB not 30!) He’s also looking at HETs and recycled plastic fuel motors, all very relevant. More here https://ukspacebulletin.wordpress.com/2021/12/08/richard-dinan-making-nuclear-fusion-reality/


Cheers
John

[CS88]

Well, they will need the technology for Starship's Mars ISRU anyway since the Martian atmosphere is CO2, so why not get ecological/PR points for developing it?

Seriously doubt it will be a significant source for "Earthside" operations though, due to cost.

And Earths atmosphere actually has less CO2 than Mars's... 410-420 ppm out of ~100kPa is about 41-42 Pa, vs 95% of Mars's atmosphere... nominal datum 610 Pa, but probably more at likely landing sites, so 600-800 Pa maybe?

Partial pressure of CO2 maybe 15-20 times greater on Mars?

And Mars is a lot colder than South Texas, so if you are using cooling to separate it, it's lower energy too.

Unless they find a convenient industrial source of CO2 exhaust.

Put it on the back end of any ethanol plant. They spew out CO2 (to the atmosphere) from fermenting the corn into ethanol, which is then used as an additive for gasoline.

[Twark_Main]

Well, they will need the technology for Starship's Mars ISRU anyway since the Martian atmosphere is CO2, so why not get ecological/PR points for developing it?

Based on the prior discussion here....   shouldn't the answer be obvious?

Because that would be dishonest and greenwashing.

R&D is good. Dishonesty is bad.

[Vultur]

I don't think it is really dishonest though.

It wouldn't make environmental sense to use as an on-Earth fuel source *today*. But if one expects the electric grid to be very low carbon & have lots of excess capacity at some times of the year, then it will make sense.

Musk is very optimistic on solar as the primary energy source for civilization, and so I think he expects that situation to arrive sooner than most would expect.

EDIT: Also, there may be a secondary goal here: as a demonstration of how you can have things that require liquid fuel, and can't work off batteries, still work in an "all-electric" future. This is arguably a "PR" goal (as I don't think anyone really believes that synthetic fuels are impossible) but not, I think, a dishonest one. It's arguable that demonstrating that might actually speed up the transition.

[Twark_Main]

I don't think it is really dishonest though.

It wouldn't make environmental sense to use as an on-Earth fuel source *today*. But if one expects the electric grid to be very low carbon & have lots of excess capacity at some times of the year, then it will make sense.

As long as that is made clear, then yes I agree it's not dishonest.

If we're giving a simplistic taking carbon out of the air = good narrative (which I've already seen examples of "in the wild"), then it's dishonest.

[DistantTemple]

Well, they will need the technology for Starship's Mars ISRU anyway since the Martian atmosphere is CO2, so why not get ecological/PR points for developing it?

Seriously doubt it will be a significant source for "Earthside" operations though, due to cost.

And Earths atmosphere actually has less CO2 than Mars's... 410-420 ppm out of ~100kPa is about 41-42 Pa, vs 95% of Mars's atmosphere... nominal datum 610 Pa, but probably more at likely landing sites, so 600-800 Pa maybe?

Partial pressure of CO2 maybe 15-20 times greater on Mars?

And Mars is a lot colder than South Texas, so if you are using cooling to separate it, it's lower energy too.

Unless they find a convenient industrial source of CO2 exhaust.

Put it on the back end of any ethanol plant. They spew out CO2 (to the atmosphere) from fermenting the corn into ethanol, which is then used as an additive for gasoline.

And/or from cement kilns. Since its from the chemical process, maybe a high % of CO2. Co2 from Cement is a difficult nut to crack, Musk making use of this would be interesting.

[Robotbeat]

True, hooking it up to a cement factory would be kind of low hanging fruit.

[DistantTemple]

True, hooking it up to a cement factory would be kind of low hanging fruit.

That's exactly the point.
Also CO2 from cement production is a big issue, as there is little that can be done to reduce it. Therefore capture and storage or reuse is an "common good". 7% of global CO2 emissions (phys.org https://phys.org/news/2021-10-concrete-world-3rd-largest-co2.html) is from cement production.
If you can get it fairly concentrated, it appears easier than scavenging it at 410ppm!

[Robotbeat]

Hey that’s 418ppm now! Gets easier every year!
*nervous laughter*

[AndyH]

Since Elon's in Texas, he can skip all the intermediate steps and go straight to methane capture.

https://www2.tceq.texas.gov/oce/eer/index.cfm?fuseaction=main.getDetails&target=373798

EMISSIONS EVENT

Venting of field gas is occurring at Ratliff Booster Station due to the shut down of compression units from the below freezing weather conditions. The shut down resulted in rising pipeline pressures that caused the safety vent valve to open.

25 tons of methane free for the taking.

[MP99]

For the folks fussy enough to insist on pure methane because they like to use their engines more than once (eg. SpX), it's not a huge ask to separate out the liquid CO2 fraction (for sale to the nearest soft drink manufacturer) and the rest of the nasties (like H2S and the occasional acid) once you've compressed your natural gas stream enough to fill your fuel tank.

If that CO2 is pure enough to go for food use, then it would be an ideal feedstock to a Sabatier plant.

Cheers, Martin