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There's been talk of shipping a nuclear reactor to power a base on Mars. The Antarctic experience indicates pretty clearly that from a reliability point of vie

There's been talk of shipping a nuclear reactor to power a base on Mars. The Antarctic experience indicates pretty clearly that from a reliability point of view, we're almost certainly better off with solar panels, wind turbines and batteries.

enkid 5y ago
Are wind turbines really viable with Mars's atmosphere?
- ceejayoz 5y ago
  Not very. https://www.nasa.gov/centers/ames/news/releases/2001/01_72AR.html https://www.nasa.gov/centers/ames/news/releases/2001/01_72AR... > "Only during dust storms on Mars is there enough wind energy to operate a wind turbine," said Michael Flynn, another NASA Ames scientist. On Earth about 10 meters (33 feet) per second wind speed is needed to make electricity with wind turbines; on Mars about 30 meters (98 feet) is needed because of the extremely thin air, according to Bubenheim.
  - qayxc 5y ago
    Incidentally, though, during storms is when power is needed most, as solar won't work very well during that time.
    - ceejayoz 5y ago
      Sure, but a nuclear plant solves that issue without sitting around being useless 90% of the time.
      - qayxc 5y ago
        But do you have the necessary infrastructure to maintain a nuclear reactor on Mars? As the article points out, the device required significant manpower, had reliability issues and wasn't cost effective. While it'd be relatively simple to build wind power locally once infrastructure is in place, the same cannot be said for nuclear power on Mars. Autonomy and self-reliance are critical factors for outposts on Mars - a point that cannot be overstated.
        fastball 5y ago
        We've made a lot of improvements to nuclear reactor design since the 60s, and potentially we'll have working fusion by the time we have a colony on Mars, which would probably be the best solution (can easily get H from water and then would have He which is useful). I can't imagine a viable self-sufficient Mars colony that doesn't involve a lot of manpower anyway (I'm talking thousands of people).
        qayxc 5y ago
        Well a working fusion reactor would render any current power source obsolete anyway. I wasn't necessarily thinking about complete self-sufficiency, just the fact that it might take up to 2½ years to get replacement parts.
        fastball 5y ago
        Right but without complete self-sufficiency that applies to any power generation method. The only viable solution is to have enough raw material and redundancy on Mars that you can recycle things if something fails. e.g. have multiple redundant reactors, if one breaks you fix it, if it can't be fixed you dismantle it and start using the parts to build a new one, taking parts from other things when necessary and using parts you can't use for other things. Basically there needs to be enough "stuff" on Mars that you can use stuff to make other stuff in perpetuity. To my mind that would require enough diversity of equipment that you'd want on the order of 1000 / 10k people. And of course Mars is not a totally barren world – another big part of the solution is to build things with materials that can be gathered on Mars.
        ClumsyPilot 5y ago
        We have since deployed many nuclear reactors in space, with totally different reliability, so those should be used as reference. They can be packed on a rocket, launched, turned on and work for years unattended ( they powered societ radar satellites) Cost is dominated by weight in space, and a large wind turbine needs hundreds to thousands of tons of concrete for foundations - are those going to be brought from Earth? Can you make concrete on Mars?
- deleted 5y ago
  [deleted]
- qayxc 5y ago
  Let's do a simple calculation, shall we? Wind power is calculated by A * v³ * ρ * η A is the area, e.g. π/2 * r² for horizontal axis designs, ρ is the air density and η is the total system efficiency (limited to <59% and safe to assume to be >0.4 for modern systems) and v is the wind speed. Mars' atmosphere is about 1% of Earth's atmosphere in density. Given a wind speed of 7 m/s² (the optimal wind speed for most modern wind turbines), on Mars we'd get only 1% of the power we'd get on Earth. A 100m installation (~2.6MW on Earth) would deliver only 21kW on Mars. The average wind speed during a year is slightly higher on Mars, though, at 10 m/s² [0]. The average power output thus would be about 61kW. The most important time, however, would be dust storms, which render solar useless. Wind speeds have been recorded to exceed 30 m/s² during dust storms. Assuming we can efficiently shield the generator from the dust, the power output would peak at 1.7MW. A more conservative 17 m/s² for dust storms still yields about 308kW. 100m class wind turbines, while rare on Earth (e.g. GE Haliade-X [1]) would be easier to build on Mars given the significantly lower gravity. Wind turbines would work on Mars and have great synergy with solar - when solar doesn't work (e.g. during dust storms), wind turbines would be most efficient. Wind power wouldn't be the first choice for powering a Mars station, though. As can be seen above, installations would have to be pretty significant in size to deliver noteworthy amounts of power. [0] https://nssdc.gsfc.nasa.gov/planetary/factsheet/marsfact.html https://nssdc.gsfc.nasa.gov/planetary/factsheet/marsfact.htm... [1] https://www.ge.com/renewableenergy/wind-energy/offshore-wind/haliade-x-offshore-turbine https://www.ge.com/renewableenergy/wind-energy/offshore-wind...
  - HPsquared 5y ago
    A 100m wind turbine would require a lot of material and/or energy to construct, though - some of the materials would have to be processed locally, I wonder what the embodied energy of such a structure would be, and how long it would take to be net energy positive.
  - Denvercoder9 5y ago
    I don't think 100m wind turbines on Mars are feasible anytime soon. Even Starship has only a 18m high cargo area, so even if we assume that blades are assembled out of two parts in-place, you get only a 40m radius. That reduces the average power to just 10 kW. Furthermore, I think your average 10 m/s is an overestimation -- the source gives it as the high limit outside of dust storms.
nipponese 5y ago
I feel like nuclear power is the only tech that people perceive to be static in development. Isn’t it like saying we should have stopped using computers in the 40s because they were big, expensive, slow, and we’re only frequently used to kill people?
- Gravityloss 5y ago
  Nuclear power was great until 1986. Then it was bad. Then it was getting a bit better until 2011. Then it was bad again. Now it's a getting bit better again.
  - Accujack 5y ago
    ...and up until today, we're still using reactor technology from 70 years ago.
    - fastball 5y ago
      Which to me indicates that it is a fantastic technology if they're still around after 70 years. Nobody is building new reactors with 70 year old designs though.
  - andredz 5y ago
    Why? Could you source your statement? Not that I'm doubting you, but I would like to learn more. :)
    - imagine99 5y ago
      1986: https://en.wikipedia.org/wiki/Chernobyl_disaster#Nuclear_debate https://en.wikipedia.org/wiki/Chernobyl_disaster#Nuclear_deb... 2011: https://en.wikipedia.org/wiki/Fukushima_Daiichi_nuclear_disaster https://en.wikipedia.org/wiki/Fukushima_Daiichi_nuclear_disa... and in the aftermath for example https://en.wikipedia.org/wiki/Nuclear_power_phase-out#Germany https://en.wikipedia.org/wiki/Nuclear_power_phase-out#German...
robbiep 5y ago
No, it indicates exactly nothing. You’re talking about 1970e technology (ie when the computing power on Apollo was roughly a pocket calculator) vs how we will actually get there, a period during which nuclear reactor designs have also evolved, and the navy in particular has learned a huge amount. How does one article on the third portable reactor built tell us clearly anything at all about how we should power a hypothetical Mars base more than 60 years later
- Clewza313 5y ago
  We've made great leaps in safety measures since then. I'm not convinced we've made much in the way of progress in terms of miniaturization, simplicity or cost of operation though, as you can see from the ludicrous cost overruns seen for basically all recent reactors.
  - Manuel_D 5y ago
    Miniaturization is not desirable for nuclear power because of regulation. Each nuclear power plant is required to pay 375 million dollars in insurance, regardless of size. So this incentivizes building plants as large as possible. Even without regulation, things like surface area to volume ratio still make larger reactors more efficient.
merpnderp 5y ago
Wind turbines? We're going to ship 30 meter blades to Mars so we can barely power a microwave and a few lightbulbs? A 1MW installation in a good location on Earth will average ~300kW. On Mars that will likely be 1% because of the air density difference, or 3kW.
- deleted 5y ago
  [deleted]
- xyzzyz 5y ago
  Solar power on Mars would also give you around half the energy you get on Earth, per unit area. It’s basically like running solar panels on earth well beyond Arctic circle.
- godelski 5y ago
  30m sounds small. Also, not only is the atmosphere thinner, but sand particles are 4x smaller. Have fun repairing those moving parts with that erosion.
- nicoburns 5y ago
  And this is one if many, many reasons why Mars is and always will be orders of magnitude harder to habitate than earth.
- ncmncm 5y ago
  Given the different conditions, you would use a different design on Mars: probably a no-moving-parts ion-release system.
  - slipframe 5y ago
    There simply isn't much energy in that wind, no matter how you plan to harvest it. It's like trying to get water from a stone (possible, but you won't get much.)
    - ncmncm 5y ago
      You just need to process a great deal more of it. But there is no upper limit to the size of an ionizing grid, and the mass is negligible.
andyxor 5y ago
Are you talking about the Kilopower project https://en.wikipedia.org/wiki/Kilopower https://en.wikipedia.org/wiki/Kilopower it’s completely different design from conventional “pressurized water” reactors with drastically reduced complexity, using heat pipes and solid core, it’s more like a battery really, and we’ve been sending nuclear batteries to space for many decades
tyingq 5y ago
Is an experience with a reactor designed and built in the very early 1960's really relevant? Would you also use experiences with early solar cells to vet out their viability today?
londons_explore 5y ago
Nuclear power requires serious amounts of cooling... Without easy-access to water and evaporative cooling on Mars, I can imagine you'd be needing super big radiators pointing at the sky to make even modest amounts of electrical power. Solar might work out better...
elsonrodriguez 5y ago
From a reliability point of view, you're better off with constant power to keep humans alive, instead of fluctuating power that can cause humans to die.

enkid 5y ago

Are wind turbines really viable with Mars's atmosphere?

ceejayoz 5y ago
Not very. https://www.nasa.gov/centers/ames/news/releases/2001/01_72AR.html https://www.nasa.gov/centers/ames/news/releases/2001/01_72AR... > "Only during dust storms on Mars is there enough wind energy to operate a wind turbine," said Michael Flynn, another NASA Ames scientist. On Earth about 10 meters (33 feet) per second wind speed is needed to make electricity with wind turbines; on Mars about 30 meters (98 feet) is needed because of the extremely thin air, according to Bubenheim.
- qayxc 5y ago
  Incidentally, though, during storms is when power is needed most, as solar won't work very well during that time.
  - ceejayoz 5y ago
    Sure, but a nuclear plant solves that issue without sitting around being useless 90% of the time.
    - qayxc 5y ago
      But do you have the necessary infrastructure to maintain a nuclear reactor on Mars? As the article points out, the device required significant manpower, had reliability issues and wasn't cost effective. While it'd be relatively simple to build wind power locally once infrastructure is in place, the same cannot be said for nuclear power on Mars. Autonomy and self-reliance are critical factors for outposts on Mars - a point that cannot be overstated.
      - fastball 5y ago
        We've made a lot of improvements to nuclear reactor design since the 60s, and potentially we'll have working fusion by the time we have a colony on Mars, which would probably be the best solution (can easily get H from water and then would have He which is useful). I can't imagine a viable self-sufficient Mars colony that doesn't involve a lot of manpower anyway (I'm talking thousands of people).
        qayxc 5y ago
        Well a working fusion reactor would render any current power source obsolete anyway. I wasn't necessarily thinking about complete self-sufficiency, just the fact that it might take up to 2½ years to get replacement parts.
        fastball 5y ago
        Right but without complete self-sufficiency that applies to any power generation method. The only viable solution is to have enough raw material and redundancy on Mars that you can recycle things if something fails. e.g. have multiple redundant reactors, if one breaks you fix it, if it can't be fixed you dismantle it and start using the parts to build a new one, taking parts from other things when necessary and using parts you can't use for other things. Basically there needs to be enough "stuff" on Mars that you can use stuff to make other stuff in perpetuity. To my mind that would require enough diversity of equipment that you'd want on the order of 1000 / 10k people. And of course Mars is not a totally barren world – another big part of the solution is to build things with materials that can be gathered on Mars.
      - ClumsyPilot 5y ago
        We have since deployed many nuclear reactors in space, with totally different reliability, so those should be used as reference. They can be packed on a rocket, launched, turned on and work for years unattended ( they powered societ radar satellites) Cost is dominated by weight in space, and a large wind turbine needs hundreds to thousands of tons of concrete for foundations - are those going to be brought from Earth? Can you make concrete on Mars?
deleted 5y ago
[deleted]
qayxc 5y ago
Let's do a simple calculation, shall we? Wind power is calculated by A * v³ * ρ * η A is the area, e.g. π/2 * r² for horizontal axis designs, ρ is the air density and η is the total system efficiency (limited to <59% and safe to assume to be >0.4 for modern systems) and v is the wind speed. Mars' atmosphere is about 1% of Earth's atmosphere in density. Given a wind speed of 7 m/s² (the optimal wind speed for most modern wind turbines), on Mars we'd get only 1% of the power we'd get on Earth. A 100m installation (~2.6MW on Earth) would deliver only 21kW on Mars. The average wind speed during a year is slightly higher on Mars, though, at 10 m/s² [0]. The average power output thus would be about 61kW. The most important time, however, would be dust storms, which render solar useless. Wind speeds have been recorded to exceed 30 m/s² during dust storms. Assuming we can efficiently shield the generator from the dust, the power output would peak at 1.7MW. A more conservative 17 m/s² for dust storms still yields about 308kW. 100m class wind turbines, while rare on Earth (e.g. GE Haliade-X [1]) would be easier to build on Mars given the significantly lower gravity. Wind turbines would work on Mars and have great synergy with solar - when solar doesn't work (e.g. during dust storms), wind turbines would be most efficient. Wind power wouldn't be the first choice for powering a Mars station, though. As can be seen above, installations would have to be pretty significant in size to deliver noteworthy amounts of power. [0] https://nssdc.gsfc.nasa.gov/planetary/factsheet/marsfact.html https://nssdc.gsfc.nasa.gov/planetary/factsheet/marsfact.htm... [1] https://www.ge.com/renewableenergy/wind-energy/offshore-wind/haliade-x-offshore-turbine https://www.ge.com/renewableenergy/wind-energy/offshore-wind...
- HPsquared 5y ago
  A 100m wind turbine would require a lot of material and/or energy to construct, though - some of the materials would have to be processed locally, I wonder what the embodied energy of such a structure would be, and how long it would take to be net energy positive.
- Denvercoder9 5y ago
  I don't think 100m wind turbines on Mars are feasible anytime soon. Even Starship has only a 18m high cargo area, so even if we assume that blades are assembled out of two parts in-place, you get only a 40m radius. That reduces the average power to just 10 kW. Furthermore, I think your average 10 m/s is an overestimation -- the source gives it as the high limit outside of dust storms.

nipponese 5y ago

I feel like nuclear power is the only tech that people perceive to be static in development. Isn’t it like saying we should have stopped using computers in the 40s because they were big, expensive, slow, and we’re only frequently used to kill people?

Gravityloss 5y ago
Nuclear power was great until 1986. Then it was bad. Then it was getting a bit better until 2011. Then it was bad again. Now it's a getting bit better again.
- Accujack 5y ago
  ...and up until today, we're still using reactor technology from 70 years ago.
  - fastball 5y ago
    Which to me indicates that it is a fantastic technology if they're still around after 70 years. Nobody is building new reactors with 70 year old designs though.
- andredz 5y ago
  Why? Could you source your statement? Not that I'm doubting you, but I would like to learn more. :)
  - imagine99 5y ago
    1986: https://en.wikipedia.org/wiki/Chernobyl_disaster#Nuclear_debate https://en.wikipedia.org/wiki/Chernobyl_disaster#Nuclear_deb... 2011: https://en.wikipedia.org/wiki/Fukushima_Daiichi_nuclear_disaster https://en.wikipedia.org/wiki/Fukushima_Daiichi_nuclear_disa... and in the aftermath for example https://en.wikipedia.org/wiki/Nuclear_power_phase-out#Germany https://en.wikipedia.org/wiki/Nuclear_power_phase-out#German...

robbiep 5y ago

No, it indicates exactly nothing. You’re talking about 1970e technology (ie when the computing power on Apollo was roughly a pocket calculator) vs how we will actually get there, a period during which nuclear reactor designs have also evolved, and the navy in particular has learned a huge amount. How does one article on the third portable reactor built tell us clearly anything at all about how we should power a hypothetical Mars base more than 60 years later

Clewza313 5y ago
We've made great leaps in safety measures since then. I'm not convinced we've made much in the way of progress in terms of miniaturization, simplicity or cost of operation though, as you can see from the ludicrous cost overruns seen for basically all recent reactors.
- Manuel_D 5y ago
  Miniaturization is not desirable for nuclear power because of regulation. Each nuclear power plant is required to pay 375 million dollars in insurance, regardless of size. So this incentivizes building plants as large as possible. Even without regulation, things like surface area to volume ratio still make larger reactors more efficient.

merpnderp 5y ago

Wind turbines? We're going to ship 30 meter blades to Mars so we can barely power a microwave and a few lightbulbs? A 1MW installation in a good location on Earth will average ~300kW. On Mars that will likely be 1% because of the air density difference, or 3kW.

deleted 5y ago
[deleted]
xyzzyz 5y ago
Solar power on Mars would also give you around half the energy you get on Earth, per unit area. It’s basically like running solar panels on earth well beyond Arctic circle.
godelski 5y ago
30m sounds small. Also, not only is the atmosphere thinner, but sand particles are 4x smaller. Have fun repairing those moving parts with that erosion.
nicoburns 5y ago
And this is one if many, many reasons why Mars is and always will be orders of magnitude harder to habitate than earth.
ncmncm 5y ago
Given the different conditions, you would use a different design on Mars: probably a no-moving-parts ion-release system.
- slipframe 5y ago
  There simply isn't much energy in that wind, no matter how you plan to harvest it. It's like trying to get water from a stone (possible, but you won't get much.)
  - ncmncm 5y ago
    You just need to process a great deal more of it. But there is no upper limit to the size of an ionizing grid, and the mass is negligible.

andyxor 5y ago

Are you talking about the Kilopower project https://en.wikipedia.org/wiki/Kilopower https://en.wikipedia.org/wiki/Kilopower it’s completely different design from conventional “pressurized water” reactors with drastically reduced complexity, using heat pipes and solid core, it’s more like a battery really, and we’ve been sending nuclear batteries to space for many decades

tyingq 5y ago

Is an experience with a reactor designed and built in the very early 1960's really relevant? Would you also use experiences with early solar cells to vet out their viability today?

londons_explore 5y ago

Nuclear power requires serious amounts of cooling... Without easy-access to water and evaporative cooling on Mars, I can imagine you'd be needing super big radiators pointing at the sky to make even modest amounts of electrical power. Solar might work out better...

elsonrodriguez 5y ago

From a reliability point of view, you're better off with constant power to keep humans alive, instead of fluctuating power that can cause humans to die.