Quote from: Impaler on 07/10/2016 08:48 amFailure to even consider atmospheric water collection is a major over-site in the paper. It is clearly the source which is most widely distributed and most easily processed, the technical challenge is basically just a sufficient power supply which is something that needs to be cracked anyway.Atmospheric extraction was considered and ruled out. See p26 of presentation.Quote1 kg water is contained in 250,000m3 of atmosphereQuoteThe air handling system implied by these calculations would be on the same order of magnitude as the largest air compressors known on Earth: ~600,000 CFM, requiring 65 megawatts to run, and roughly 5x5x10m in size.CONCLUSION: The mass, power, volume, and mechanical complexity of the system needed for this approach are far outside of what is practical for deployment to Mars.And here they didn't even include the power required to get water back out of the zeolite... which is far from trivial.
Failure to even consider atmospheric water collection is a major over-site in the paper. It is clearly the source which is most widely distributed and most easily processed, the technical challenge is basically just a sufficient power supply which is something that needs to be cracked anyway.
1 kg water is contained in 250,000m3 of atmosphere
The air handling system implied by these calculations would be on the same order of magnitude as the largest air compressors known on Earth: ~600,000 CFM, requiring 65 megawatts to run, and roughly 5x5x10m in size.CONCLUSION: The mass, power, volume, and mechanical complexity of the system needed for this approach are far outside of what is practical for deployment to Mars.
I believe the compression is needed to get sufficient flow rate through the zeolite beds to achieve the water extraction rate needed. Cannot just open a canister of desiccant and expect a significant capture rate by diffusion alone -- gotta pump 250,000cubic meters of Martian atmosphere through the beds to get one liter of captured water.
Quote from: AncientU on 10/17/2016 12:59 amI believe the compression is needed to get sufficient flow rate through the zeolite beds to achieve the water extraction rate needed. Cannot just open a canister of desiccant and expect a significant capture rate by diffusion alone -- gotta pump 250,000cubic meters of Martian atmosphere through the beds to get one liter of captured water.There may be ways to use natural flow to extract water from the atmosphere.In fact, you could mine gypsum, extract water from the gypsum, and dump the anhydrite back onto the surface where it will slowly reabsorb water from the atmosphere and become gypsum again. In fact, you could have sheets of something like gypsum or other hydrated minerals that you harvest periodically, dehydrate, then place back onto the Martian surface to reabsorb water. Perhaps arranged vertically along with the direction of the wind to maximize flow rates and areal density of plates.I bet that'd be more energy efficient.
It's really more like farming, isn't it? If you just had fields of these hydrating minerals, it'd be more efficient than raw regolith, since you have to heat up all the regolith, but only part of it yields water.
Of course somebody making maps is going to have to label the area Tatooine. It's practically mandatory.
Quote from: Chris_Pi on 10/18/2016 04:15 amOf course somebody making maps is going to have to label the area Tatooine. It's practically mandatory. Or Arrakis, Vulcan, Geonosis, Korhal...Desert planets are a surprisingly overdone theme in sci-fi I realize.
Propellants MR dp (kg/L) ve (m/s) Id (Ns/L)O2/CH4 3.6 0.8376 3656 3062O2/C2H4 2.7 0.9007 3678 3313
When liquid fuels such as ethanol and n-propanol were included, the total solar-to-fuel efficiency was 2.9%.