the point is that you can actually live inside the rockets when they first land, you don’t need to build extra housing immediately. this significantly simplifies the mission requirements, at least for the first few years.
tank volume is about 1000 m³, which stores about 5000 kg of oxygen assuming 5 bar of pressure, which lasts a crew of 10 for about half a (martian) year, or about as long as the winter sand storms threaten to reduce solar panel production, so you have enough oxygen to breathe through this time.
it is a myth and misleading to assume that energy supply has to be constant. it is good enough if you can intermittently replenish your live support resources.
I doubt you need to repurpose the fuel tank – any rocket that travels to Mars would need to spend at least a few months in space to get there, so it will already need adequate oxygen tanks in its life support system.
And after you land on Mars, what are you going to fill that oxygen tank with? In order to have any use for it, you’d have to be producing oxygen on-site. But if you can reliably produce oxygen on-site, then you probably don’t need storage for a huge extra supply for it. The existing life support tanks in the rocket’s habitation module should already be more than adequate for storing enough oxygen to keep the crew alive.
(And this whole thing is assuming you’d land the entire spacecraft on the surface, which may or may not be the most efficient way to do things.)
Honestly, if you’re serious about setting up a Martian colony, I think the best course is to first send robots to construct a base for you, so it’s ready when you get there.
And after you land on Mars, what are you going to fill that oxygen tank with?
electrolysis of water. needs two ingredients: electricity and water. you’d carry water tanks mid-flight to produce oxygen continuously, because it’s much easier to carry water than to carry oxygen, because oxygen tanks would need a lot of volume.
obviously the ship needs to harvest solar energy mid-flight to provide that electricity. on the surface of mars, you’d also harvest solar energy again (from the same solar panels) but because there’s day/night and summer/winter rhythm, you don’t have a steady source of electricity. so you need to produce oxygen when you have electricity and then store it for later time.
compare this to outer space, where there’s no night and also no winter. so you don’t need to store any oxygen there at all, as you can continuously produce it.
Assuming you’re completely dependent upon solar power, that might make sense. In that case, a large amount of oxygen storage is basically just a way of storing energy.
Honestly, though, if you want to build a real Martian base, I think nuclear power is the way to go. Then you can have plenty of electricity, without needing to worry about seasonal cycles, battery banks, dust storms, etc. Just imagine the maintenance nightmare of needing to send crews to the surface to clean off all the solar panels after every dust storm…
Nuclear power is going to require some heavier, more complex components to set up and maybe the occasional resupply of fissile material from Earth. (Even if Mars does have some good uranium deposits, setting up the production line to mine, refine, and enrich it would require an awful lot of infrastructure. You’d maybe eventually set all that up, but early on, you’ve probably got bigger, simpler objectives to complete.) But you can easily go years or decades between nuclear fuel supply runs, and in the meantime you get the benefit of abundant, reliable power.
sure, what could possibly go wrong by putting nuclear fissile material into a rocket and launching it into space… what makes you think that nuclear energy is any more attractive on mars than it is on earth? it’s being outcompeted by renewable energy.
what could possibly go wrong by putting nuclear fissile material into a rocket and launching it into space…
It’s nothing we haven’t done already. We already have nuclear-powered satellites, probes, and rovers.
what makes you think that nuclear energy is any more attractive on mars than it is on earth?
It’s not that nuclear energy is much more attractive – it’s that renewables on Mars are less attractive.
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Wind? Martian atmosphere is too thin to generate any meaningful power from wind – there just isn’t enough air to turn turbine blades with any significant force.
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Hydro? Complete non-starter: no flowing water available.
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Geothermal? Mars is much less geologically active than Earth – finding a good location for geothermal is going to be much more difficult, and it’s already kind of difficult on Earth.
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Solar? Your only real option, but even then, it’s much less efficient than on Earth because Mars is farther away from the sun and gets less sunlight.
Every type of renewable energy is either impossible or significantly less efficient on Mars. But Nuclear power would work just as well on Mars as it does on Earth.
There’s also the maintenance issue to consider. Nuclear power can be maintained by a small, well-trained crew that never needs to go outside of the power plant to do anything. But solar panels will need regular dust cleaning, which will be a labor-intensive process requiring lots of time on the surface.
Power storage is also an issue. Solar power will require huge amounts of battery banks to ensure you still have adequate power through night, winter, and dust storms. You’d have to size the solar arrays and batteries to account for the worst case scenario of a dust storm lasting all summer and going an entire Martian year with reduced energy production. But an adequately sized nuclear plant will remain adequately sized at all times, and you’d only want battery banks as an emergency backup in case something goes wrong and takes the nuclear plant temporarily offline.
Both are still viable, yes … but for a large, permanent base, I think nuclear power is the way to go. It’s easier to produce large amounts of power, easier to maintain, and the reliable steady production means you don’t need significant energy storage.
An inhabited Martian base will need lots of electrical power (mostly to heat occupied compartments). It seems a lot easier to me to have one modest-sized nuclear power plant, versus enormous fields full of solar panels and huge battery banks to try and meet the same needs.
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The Tyranny of the Rocket Equation
the rocket and payload have mass, so we need fuel to launch it. But the fuel itself has mass, so we need more fuel to launch the fuel, and more fuel to launch that fuel…
Basically, a chemical rocket requires way more fuel volume than what you have in mind here. Rockets average ~90% fuel by mass:
yeah i’m well aware of that, rockets are 90% fuel by mass, but not by volume. so there’s still a lot of volume around. also you need the live support system anyways for the travel there, why no still use it once you land?
Ok, well in the specific case of Mars, the planet lacks a magnetic field, plus the atmosphere is thin, which means there’s a lot of radiation exposure. Yes you’d definitely want to live inside the metal body of the ship in the short term, vs. say an inflatable habitat. But you’d want to make that very short term, like less than a week, and get yourself into an underground shelter for sleeping as soon as possible. Hopefully have some automated equipment dig it out for you before you arrive. You want several feet of rock between you and the radiation.
In order to get to Mars they’d have to survive the radiation of outer space, so I think we can assume the craft they arrived in can withstand the radiation from the planets surface.
this myth with the radiation seems to be very enduring. it comes up on literally every discussion about mars settlement, even though it’s not true. idk what to do about this, probably NASA will give out a statement in 5 years and declare that radiation is not actually that big an issue and then people will stop complaining about it.
What are you talking about?
The radiation exposure on the surface of Mars is much harsher than that on the surface of the Earth for two reasons: Mars lacks a global magnetic field to deflect energetic charged particles (1), and the Martian atmos- phere is much thinner (<1%) than that of Earth, providing little shielding against the high energy particles that are incident at the top of its atmos- phere. This environmental factor, for which there is no analog on Earth, poses a challenge for future human exploration of Mars
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Combining our measurements with those obtained during the cruise phase (22), we estimate a Total Mission dose equivalent of ~1.01 Sv for a round trip Mars surface mission with 180 days (each way) cruise, and 500 days on the Martian surface for this current solar cycle (Table 2).
https://www.science.org/cms/asset/b9057f23-375b-447a-ba62-65a4e7f691a4/pap.pdf
This is based on data collected by Curiosity. This value was confirmed by a more recently published study:
the accumulated dose equivalent is about 1.02 ± 0.13 Sv. This is quite consistent with the value obtained by Hassler et al. (2014), who estimated a value about 1.01 Sv based on RAD’s cruise measurement and the first 300 sols of surface measurement under similar solar modulation conditions.
1 Sievert (Sv) is 20x the DOE annual radiation limit for workers (5 rem), and 10x the average dose received on an ISS mission (10 rem). It’s also about 20% of a lethal dose (~500 rem).
https://www.scribd.com/document/100083925/DOE-Ionizing-Radiation-Dose-Ranges-Rem-Chart
This information was super easy to find. It’s not a myth, and the health risks are currently considered too high for human exploration of Mars.
