As always there is a trade to be considered. Plants naturally provide an oxygen source and CO2 scrubbing. Allowing the plants to die during a dust storm means we need to replace this capability. While it is eminently feasible to supply a reserve of lithium hydroxide canisters and O2 candles this does require a mass and power budget. Perhaps these budgets would be better spent on an oversized solar farm that provides benefits during non-storm times. 344 kW is a pretty hefty power budget, especially when a dust storm has reduced solar power output to as little as 1%, but we don't necessarily need all of that power to keep the plants alive and my working assumption is we can shut down non-critical operations like ice mining and propellant production. Perhaps we don't actually need to kill off all the plants in the manner that was depicted in National Geographic's Mars series.
3.2 Comprehensive power generation conceptAs an example, the following concept is basedon the power consumption estimates fromAntarctic research stations. Similar to proposedstations on Mars, for Antarctic stations electricityis required for light, pumps, and scientificexperiments. Based on Neumayer-Station III data,which can host up to 40 people, this amounts to70 kW – 300 kW. For heating, i.e. thermal energy,another 70 – 150 kW are required for Antarctica.For Mars, an even better building insulationconcept is required, reducing the required thermalenergy further.
There are certainly some interesting trades. I would imagine that sufficient CO2 removal and O2 production capacity could be arranged via a fairly modest ECLSS like an over sized version of what is currently used on the ISS. I'm not sure of the exact power requirements but suspect it might be manageable on perhaps 2-4 kilopower units. This reference states 14.2kw required to keep a crew of 6 alive.http://www.marsjournal.org/contents/2006/0005/files/rapp_mars_2006_0005.pdfpossibly supplemented by other storage and back up power options such as fuel cells, batteries and residual solar (even at very low levels). It would be interesting to identify the likely scenarios for solar power loss on Mars in terms of likelihood, duration and intensity.I had not realised that killing off the plants had been suggested in National Geographic's Mars series, is this available anywhere? If used this would make the types of plant grown and especially the time to harvest a key factor.Ultimately they will have to have multiple contingency plans for different scenarios no doubt shorter or lesser storms could be managed a lot more easily, but the worse case also needs to be considered and I suspect is manageable. Plants can be regrown within weeks and months.
Baseline Mars One Habitat Architecture: A firstsimulation of the baseline Mars One habitat indicatedthat with no ISRU-derived resources, the first crewfatality would occur approximately 68 days into themission. This would be a result of suffocation from toolow an oxygen partial pressure within the environment,as depicted in Figure 8.At the same time, the habitat would be put into astate of high fire risk due to the oxygen molar fractionexceeding the 30% safety threshold, as indicated inFigure 9.Further investigation revealed that this non-intuitiveresult is primarily caused by the plants producingexcessive oxygen, increasing oxygen partial pressure tooutside their partial pressure control box, and causingthe pressure control assemblies to vent air. Because thePCAs are not able to selectively vent a gas species, theoxygen molar fraction remains the same after venting,while the total atmospheric pressure reduces. Nitrogenis then selectively introduced into the environment tobring down the oxygen molar fraction. Over manycycles of air venting and nitrogen being introduced foroxygen molar fraction control, the nitrogen tank emptieson day 66 of the mission (see Figure 10).When this occurs, the continually increasing oxygenproduction by the plants increases the oxygen molarfraction within the habitat beyond the fire safety threshold. At the same time, because nitrogen is nolonger available to make up for module leakage, thehabitat total pressure drops. The result is thesimultaneous decreasing of oxygen partial pressure andincreasing oxygen molar fraction.Further analysis indicated that the oxygenproduction of the plants in fact increases as crops reachmaturity. In this simulation case, all crops were grownin batch mode, with lettuce being the first to reachmaturity at 30 days into the mission, followed by wheat,which reaches maturity at day 62. Figure 9 depicts theincrease in oxygen molar fraction that occurs shortlyafter these mission days.
Thanks for the post re the NG I will have to watch the whole thing. You raise some interesting points. I assume that the human v plant oxygen balance does not work because excess organic matter is produced. This might be rectified by composting waste which consumes a lot of oxygen under normal circumstances or adding herbivores as you suggest or even insects. However it would then make it very difficult to allow the plants to die as I suggested, because it would effectively also kill or at least seriously dislocate the entire ecosystem including microorganisms.It might therefore be better to avoid any "reboot the entire ecosystem" option if it was in any way avoidable. I think this might only be avoidable by providing the power needed to maintain business as usual. Having said that it might be possible to manage on somewhat less power by lowering the temperature and or the light levels a bit to slow down growth. It's hard to say how effective this might be.
No such thing as a 100 sol dust storm. I mean, do we have 100 day thunderstorms on Earth? Our plants wouldn't survive, either.
This paper by Michael Smith:https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2019JE006107shows large global dust storms lasting on the order of 100 sols - peak obscuration by dust might be shorter but it can be fairly bad for 100 sols. I wouldn't count out the possibility.
First off, at what speed do most Martian dust storms blow?Next, since the atmosphere is thinner, what does that translate into Earth equivalent?Can the solar panels be mounted higher off the ground to avoid a lot of dust? Can they either have a small nuclear reactor or a battery bank to store excess electricity during the daylight hours to last for say several days or a week or more? Which would have less mass being transported from earth, a self contained nuclear reactor or equal power battery bank? Something to consider, a two year supply of dry or canned goods could be brought from earth for emergencies, along with medicines and vitamins for 2 years. A greenhouse should provide all the plant based food for an outpost like this. Rabbits is not a bad idea, but also chickens to provide not only meat, but eggs. Birds might have fewer problems adjusting than mammals. Worth at least a study.
My idea of how a Mars settlement would function:1) most calories would be from vat-grown foods, not likely in greenhouses. Greenhouses primary would produce nice-to-haves that improve health and wellbeing of astronauts, not critical for survival.
2) Mars' cold climate and dessicating atmosphere mean that food can easily be stored essentially indefinitely just frozen in a cave somewhere. Or just bury a barrel of food. (Keep it from the sun so you don't have freeze/thaw cycles.)
3) The vast majority of power for Mars would be for making propellant for vehicles and perhaps secondarily for making structural materials like plastics and steel and maybe various chemicals. Something like 90-95% of power would be for those things. Some of this would be shared with vat food production.
4) There will be large amounts of propellant at the settlement at any one time. Propellant is methane and oxygen. Possibly CO or hydrogen for fuel, but most likely methane. Either way, ridiculous amounts of oxygen.
5) Any large buildings would need zero extra energy for heating. the near-vacuum makes really good insulation almost trivial, and the need to enclose everything (instead of having a billion out-buildings and houses you walk in between) means you're likely to have fewer, larger buildings than a similar sized settlement on Earth. Maybe just one or two main large enclosures. That helps reducing the surface area and would improve heat retention.
6) CO2 scrubbing can be done regeneratively fairly easily and with almost no energy input, especially if higher CO2 levels are tolerated for extenuating circumstances.
So you don't need 90-95% of energy during a dust storm. That alone would reduce the power required. You don't need heating, you don't need greenhouses (if the storm is going to last an extremely long time, you'll just have to replant almost everything). You can subsist on stored food and oxygen, for months. A small amount of power can be supplied by generators running on ISRU propellant normally used for rockets (you'd pause the vast majority of rocket launches) if in the depths of the dust storm (this being an extremely rare occurrence, like getting a hurricane in New York). You'd STILL get SOME power from the solar arrays, no matter how bad the storm (and the worst parts wouldn't and can't physically last more than a few days).
Unlike on Earth, you wouldn't get major damage to equipment from a storm. No major tornados, no hurricanes, no hail, no flooding, no forest fires, etc.
Oh. Okay, biospheres are not a reasonable thing IMHO. I wouldn’t attempt it.
Industrial life support from the beginning.
I was just establishing how *I* would do it.
A small research lab in a large settlement would be fine and could just use the backup generators.
Martian dust is more like smog than anything else. Images can took impressive, but in reality visibility is still substantial. For example Viking 1 colour images taken on sols 282 and 324 showed the effects of a large dust storm (Tau between 5 and 6) in a colour composite by Olivier de Goursac (https://www.planetary.org/space-images/20131231_sol282_324dust_storm197) look impressive but the horizon ~3 km distant is still visible. Under Visual Flight Rules (VFR) helicopters are able to fly in visibility down to 3 km (CASA 2021) without reliance on external navigation aids or instruments.Smith et al. (2018), in a study of visibility in Gale crater during the 2019 dust storm, concluded that visibility was reduced to less than three km. Guzewich et al. (2019) refined this to 2.7 km. Ground operations are even less constrained. Activities around the station should not be impeded with visibility down to a few hundred m, and some field work would also be possible provided it was at previously visited sites with a marked trail (vehicle tracks would be adequate).The Martian, great movie that it was, isn't a a documentary!
