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China prepares to grow vegetables on Mars

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Re: China prepares to grow vegetables on Mars

#121

Post by iwwr »

apr wrote: post #83
iwwr wrote: post #66

Earlier quoted context omitted.

If you have a nuclear reactor or extensive solar panels, you may just as well use it to split CO2 into O2 and CO (monoxide gas can also burned as fuel). Plant photosynthesis is rather inefficient if your goal is a breathable atmosphere. If the goal is biomass for food, then just call up Monsanto for a few space-dense crops. It would probably easier to oversize the powerplant (to generate oxygen, growlights, melt wate…

If you burn CO as fuel you are producing CO2 back.

It may be useful as fuel for a mars vehicle or for rockets (electric vehicles will take you not very far and it's hard to strap the nuclear reactor to it). CO is easier to store than hydrogen. Of course, if you have a steady supply of ice you can make methane/methanol which is better for that purpose. But to extract ice you will need heavy mining machinery, earth-moving etc...

CO + O2 fuel would make more sense on Venus, where water would be more scarce (water is present in thin clouds of sulphuric acid in about 25% concentration). The surface, however, is another business.

More on Venus (a surprisingly appealing place to go): http://www.space.com/5653-cloud-cities-venus.html

And a story by Geoffrey Landis http://www.asimovs.com/2010_09/exc_story1.shtml

Re: China prepares to grow vegetables on Mars

#122

Post by robryan »

danielweber wrote: post #110
robryan wrote: post #99

Earlier quoted context omitted.

I wonder if on a mission to mars you can place a resupply module in the right orbit to allow it to be docked with on the way to mars.

It's just ("just") a six-month trip. If you want to break things into smaller shipments, launch them directly to the Mars surface. Even better, this means you can get a significant portion of your mission hardware (including your return vehicle) ready and waiting on the Martian surface, having survived what is probably the most dangerous part of the mission (landing) before your humans launch. (Two year launch window…

What I was thinking of was sending something out on a slower path, maybe back past Earth or something and then sending the main craft at a faster speed to meet somewhere along the way.

You are right it probably isn't needed, was more just wondering if it were possible or would the speed differences make docking too hard. I guess the slower moving craft would run through a lot of fuel to bring its speed up enough when close to docking.

Re: China prepares to grow vegetables on Mars

#123

Post by anigbrowl »

tptacek wrote: post #119
anigbrowl wrote: post #108

Earlier quoted context omitted.

China doesn't have political freedoms, but our incarceration rate is about 7 times higher than theirs; indeed, the USA has the highest incarceration rate in the world: http://en.wikipedia.org/wiki/List_of_countries_by_incarcerat... I don't want to go way off-topic with this, but it's a pet issue of mine because I think it's a human-rights disaster.

I probably agree with the principle behind your comment, but: * Those incarceration numbers come from the Chinese government and haven't been audited by any third party (a perennial complaint about Chinese prison statistics) * They don't necessarily capture every form of detention present in China, including forced labor camps, administrative detention, house arrest, and pre-trial holding. * Speaking of which, Chines…

We won't settle this here, although I'd like to offer lots of coutnerexamples. As I said earlier, it's not that I think China is so great as that I'm deeply disturbed by the flaws in the US criminal justice system. Maybe we should pick this up via email?

Re: China prepares to grow vegetables on Mars

#124

Post by tptacek »

anigbrowl wrote: post #123
tptacek wrote: post #119

Earlier quoted context omitted.

I probably agree with the principle behind your comment, but: * Those incarceration numbers come from the Chinese government and haven't been audited by any third party (a perennial complaint about Chinese prison statistics) * They don't necessarily capture every form of detention present in China, including forced labor camps, administrative detention, house arrest, and pre-trial holding. * Speaking of which, Chines…

We won't settle this here, although I'd like to offer lots of coutnerexamples. As I said earlier, it's not that I think China is so great as that I'm deeply disturbed by the flaws in the US criminal justice system. Maybe we should pick this up via email?

Done!

Re: China prepares to grow vegetables on Mars

#125

Post by danielweber »

robryan wrote: post #122
danielweber wrote: post #110

Earlier quoted context omitted.

It's just ("just") a six-month trip. If you want to break things into smaller shipments, launch them directly to the Mars surface. Even better, this means you can get a significant portion of your mission hardware (including your return vehicle) ready and waiting on the Martian surface, having survived what is probably the most dangerous part of the mission (landing) before your humans launch. (Two year launch window…

What I was thinking of was sending something out on a slower path, maybe back past Earth or something and then sending the main craft at a faster speed to meet somewhere along the way. You are right it probably isn't needed, was more just wondering if it were possible or would the speed differences make docking too hard. I guess the slower moving craft would run through a lot of fuel to bring its speed up enough when…

If order to meet, they would need to match both position and velocity. Meaning whatever history they had gone through, they both had to get to that position-and-vector.

There are some faster and slower paths. More missions to Mars have taken an 8-month-or-so journey because it's easiest and lowest power, and all unmanned cargo are probably going to take that route.

But by using just a bit more energy, you can cut the travel time down to about 6 months.

Most Mars missions involve launching stuff to land on the Mars surface (or maybe in orbit) that would take the slower path while the humans take the faster path.

(If you really want a bigger craft than you can launch from Earth at one time, just link up in LEO.)

Re: China prepares to grow vegetables on Mars

#127

Post by mogrim »

takluyver wrote: post #54
mogrim wrote: post #49

Earlier quoted context omitted.

Although if you've got water (and there is water on the moon) and a nuclear powerplant generating loads of electricity, getting oxygen's not a problem.

It appears that you don't have much carbon, though (see 'Lunar regolith' on Wikipedia). So once you've got your oxygen generator set up, you may have to fly coal up there to burn for CO2. Once you're set up, though, you should be able to keep the carbon in a closed loop between humans, the encapsulated air and the plants.

Didn't realise that, although beyond reading pulp SF, I've not done any kind of investigation into the subject!

How much carbon/coal would you need to support a colony of say, 5 people (+plants)?

Re: China prepares to grow vegetables on Mars

#128

Post by takluyver »

mogrim wrote: post #127
takluyver wrote: post #54

Earlier quoted context omitted.

It appears that you don't have much carbon, though (see 'Lunar regolith' on Wikipedia). So once you've got your oxygen generator set up, you may have to fly coal up there to burn for CO2. Once you're set up, though, you should be able to keep the carbon in a closed loop between humans, the encapsulated air and the plants.

Didn't realise that, although beyond reading pulp SF, I've not done any kind of investigation into the subject! How much carbon/coal would you need to support a colony of say, 5 people (+plants)?

If the plant material to support each person is drawing down 2 moles CO2 per hour (doubled from earlier calculations, because not all the carbon ends up in edible parts), then a tonne of carbon should supply the plants needed for 5 people for a year. By the end of the year, you've probably closed the loop, so the fixed carbon is returning to the air.

Re: China prepares to grow vegetables on Mars

#129

Post by flyinRyan »

TazeTSchnitzel wrote: post #62
Aardwolf wrote: post #55

I'm all for this, the current policy of "don't contaminate Mars with organic materials" brings us nowhere, let's put some life on there and see what happens!

I'd be a big fan of sending loads of bacteria with the potential to survive, and some water and stuff, to Mars. Just to see what happens. Hey, the Martian environment would be a "gross evolutionary pressure", right? :)

Fantastic. We can check back in a few million years to see how it's working.
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