New Mars Forums

Official discussion forum of The Mars Society and MarsNews.com

You are not logged in.

Announcement

Announcement: As a reader of NewMars forum, we have opportunities for you to assist with technical discussions in several initiatives underway. NewMars needs volunteers with appropriate education, skills, talent, motivation and generosity of spirit as a highly valued member. Write to newmarsmember * gmail.com to tell us about your ability's to help contribute to NewMars and become a registered member.

#176 2022-07-06 11:34:21

kbd512
Administrator
Registered: 2015-01-02
Posts: 7,362

Re: Nukemobiles on Mars

Mars_B4_Moon,

Gloucestershire Police "just" need to spend more money on gigantic batteries.  Maybe if the entire car was a gigantic rolling battery, with the officer sitting on the roof of the car, then it would be truly equal to a 10 gallon gasoline tank.

Since that bit of "derp" obviously didn't work, I have an even better idea that also won't work:

Let's force the public to use battery-powered Ambulances and Fire Engines.

After enough of these "batteries are the future" religious zealots die because they never make it to the hospital or their houses burn to the ground after the fire engine quits pumping, then perhaps the rest of them will have a "crisis of faith" in their new religion.

It's a pity that all the normal people will suffer as well, but the religion's dogma must be satisfied.

Offline

#177 2022-07-06 20:52:16

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 28,750

Re: Nukemobiles on Mars

Even emergency vehicle carries with them a power generator. So, buy one and put it in the trunk.

Offline

#178 2022-07-06 23:08:03

kbd512
Administrator
Registered: 2015-01-02
Posts: 7,362

Re: Nukemobiles on Mars

SpaceNut,

EVs don't carry a power generator with them.  Do what normal people do and put that generator under the hood of the vehicle where it belongs.  If you need to carry a backup power generator with you, then that means a pure battery powered vehicle doesn't work.  The reason it does not work is math.  Math is the foundation of all valid science.

1 gallon of gasoline weighs 6lbs / 2.7223kg and stores 33,700Wh of energy.  You can get half of that from a constant speed combustion engine.  The rest is lost as heat.  That means the energy density of a gallon of gasoline is 16,850Wh per gallon, or 6,189.6Wh/kg.  A 16,850Wh battery, at 160Wh/kg.  A Tesla Model 3 has a 75kWh battery pack that weighs 478kg, so 156.9Wh/kg.  That's a difference of 39.45 TIMES.  The energy densities figures for all the various other battery pack capacities all fall within about 5Wh of each other, provided they use the same cell type and chemistry.

No amount of wishful thinking can overcome that power-to-weight deficit on the part of batteries.  I know combustion engines have come quite a long way since their invention, but there has been no 40X improvement in power density per unit weight using a fuel 40X more energy dense than batteries.  A 2X to 5X on power-to-weight is about where you max out at, excluding rocket engines, since rockets will never power practical land motorized vehicles, much like batteries.  Modern engines are not 10X lighter than the engines of the early 1900s, let alone 40X lighter.  That's about where batteries would need to be to provide equivalent power-to-weight.  Something tells me that probably won't happen, because it hasn't happened in the past.

Modern 4-cylinder turbocharged engines generate about 825W/kg of weight.  A Ford flathead V8 generated about 330W/kg of weight.  That's a factor of 2X, maybe 3X improvement over time if you don't care about engine lifespan.  In other words, no night-and-day difference to be had.  If you skimp on engine materials, then your engine doesn't last very long.  Ford flatheads will outlive both of us.  That turbocharged 4-banger will be trash in 10 years or less.  The 3-banger in Nissan's e-POWER series hybrid system is 60mpg.  The Ford flathead V8 was 12mpg to 17mpg, possibly up to 25mpg with EFI since it's a 100hp motor.  That's a 2X to 4X improvement over existing engines.

At best, future batteries might see another 2X to 3X capacity improvement / weight reduction over existing models, hopefully within our lifetimes.  The electric motors are already 96% to 98% efficient.  The power conversion electronics are around 95% efficient.  The battery charge / discharge efficiency is already near 100%.  There's nowhere significant for battery or electric motor or power inverter efficiency to go.  It's already maxed out or nearly maxed out.  Those last few percentage points of improvement won't yield any dramatic results.

Some of the lab example Lithium-ion batteries of the early 1990s were achieving 100Wh/kg.  Now they're at 250Wh/kg and only completely different cell chemistries plus some packaging efficiencies can greatly improve upon that.  Tesla exploited the latter, and of course, "solving" the geometry problem worked.  Good for them, because that was very low-hanging fruit.  However, it's not possible to "solve" the gravimetric energy density problem that way more than once.  They can't improve much on energy density by making the individual cells larger, because then we have larger and larger void spaces between individual cells, which are not batteries, available space is not unlimited, and making the vehicle much larger also makes it heavier.

We saw a 2.5X cell capacity increase over 30+ years.  If we could sustain that rate of capacity improvement, which we can't, which is why Tesla used cell packaging geometry instead of cell chemistry changes to achieve their latest gravimetric and volumetric energy density improvement, then we might see 500Wh/kg by the time I'm in my 70s.  Total battery pack gravimetric energy density is about 64% of individual cell gravimetric energy density, so 320Wh/kg at the pack level vs 160Wh/kg, or a 2X improvement.  They can't do much more to improve aerodynamics or rolling resistance without drastically changing the car, but even if they did, it doesn't net much improvement because weight is what kills performance at city to highway speed ranges.

Lightyear Zero is the same weight of a normal 4-seat passenger car of its size class at 3,471lbs, whereas Telsa's Model 3 is a subcompact car with the weight of a Chevy Silverado light duty pickup truck from about 10 years ago, or about a 4,250lbs.  One uses 105-110Wh/km and the other is 250Wh/km.  Both vehicles can drive about the same distance.  Lightyear Zero ($265,000 USD; promise of $175,000 USD for production models) has a 60kWh (344 miles of driving range) battery and Tesla Model 3 ($58,000 USD) has a 82kWh (358 miles of driving range) battery.  So, 3X to 4.5X the cost for a 27% energy efficiency improvement.  Any bets on how breathtakingly expensive a 2X to 3X better battery will be?

Assuming we could even achieve a 2X to 3X gravimetric energy density improvement over existing batteries, what does that yield?

Unfortunately, not much.  Gasoline is still 20X more energy dense than batteries that don't exist.

Could you ever make a car 20X heavier to provide equivalent range and payload carrying capabilities, but still use less energy?

That's a hard "no", even if the car is riding on rails, but then it's not a car, it's a miniature train.

Why is that?

This universe has rules concerning weight and power.  I didn't invent them for sake of argument.  The universe did not consult with me before that decision was made, either.  If it had, then the rules would be considerably more flexible.

Did the universe conspire with "big oil" to crush your "green dreams"?

Not as far as I can tell.  If you want to blame something, then blame math and physics.

This will likely never work the way you want it to, because it requires battery tech that's decades and maybe centuries beyond what we know how to design and build.  Maybe AI can make magic happen, but I doubt it.  They've had AI and computational electro-chemistry software working on this specific problem for years on some of the world's most powerful supercomputers.  It's yielded a few interesting finds, but no real game changers.

What does this all mean?

As near as I can tell, there is no future without gasoline and diesel and kerosene.  We can use a lot less of it, but for society to continue to feed everyone and take them to work, it will never be zero or anything close to zero.  That is why recycling is required.  I don't make things up to argue or because I'm bored.  I'm telling you that you can't get to where you want to go from where you're at.  If you have the personal integrity to admit this to yourself, then share it with the people you tend to vote for and ask them what they know about this issue, because it's every bit as real as climate change and will accelerate climate change if pursued to its logical maxim.  Alternatively, a lot of people will starve to death.  If the way we "save the planet" is by killing half the people living on it, then that's not a good trade from my perspective.

Offline

#179 2022-08-12 13:00:54

Mars_B4_Moon
Member
Registered: 2006-03-23
Posts: 8,903

Re: Nukemobiles on Mars

NASA plans mini nuclear reactors for moon, could power lunar colony

https://www.businessinsider.com/nasa-pl … ony-2022-7

US Regulators to Certify First Small Modular Nuclear Reactor Design

https://www.extremetech.com/extreme/338 … tor-design

The Space Race is Going Nuclear

https://www.counterpunch.org/2022/08/11 … g-nuclear/

The American Nuclear Society describes itself as comprised of “10,000 members dedicated to advancing nuclear science and technology.”

Last edited by Mars_B4_Moon (2022-08-12 13:02:18)

Offline

#180 2022-09-06 04:30:01

Mars_B4_Moon
Member
Registered: 2006-03-23
Posts: 8,903

Re: Nukemobiles on Mars

Maybe there will be progress or maybe not and if some politically crazy were to send everyone back to steam power?

'It’s the end of the car as we know it'

https://www.vox.com/recode/23333356/ev- … on-driving

“Modern machines are in themselves useless,” Appleyard told Recode. “They have to be connected. There’s no point to a computer that’s not connected now. That connection is not yours — you don’t control it. Cars will be like that.”
As Appleyard sees it, the end of the car as we know it may be on the horizon.

Offline

#181 2022-10-09 16:43:11

Mars_B4_Moon
Member
Registered: 2006-03-23
Posts: 8,903

Re: Nukemobiles on Mars

Molten Salt Reactors: Maritime’s Nuclear Option
https://www.marinelink.com/news/molten- … ear-499681

old vid of Black n White photos uploaded to a social media channel in 2009

'Ford Nucleon Atomic Cars'

https://www.youtube.com/watch?v=bdL9rAti_fI

Our SpaceFlight Heritage: Project Orion, a nuclear bomb and rocket – all in one
https://www.spaceflightinsider.com/spac … mb-rocket/
The Ford Motor Company went so far as to come up with a car they called the Ford Nucleon

Last edited by Mars_B4_Moon (2022-10-09 17:30:35)

Offline

#182 2022-10-09 17:14:42

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 28,750

Re: Nukemobiles on Mars

That is one heavy old timer Ford car.

Offline

#183 2022-10-09 19:48:09

Calliban
Member
From: Northern England, UK
Registered: 2019-08-18
Posts: 3,352

Re: Nukemobiles on Mars

If NASA and the US Navy make progress with the lattice confinement fusion fast fission systems that they are developing, then something like the Ford Nucleon is at least technically possible.  The reactor would not need any plutonium or enriched uranium.  It would consist of a number of hollow slugs of depleted uranium, with titanium deuteride inserts.  These would sit within a cast iron block, which would contain cooling channels, shielding and would provide a heat sink.  Such a device would produce maybe 20 kilowatt of heat and a small brayton cycle engine would raise 5kWe (~8HP).  Units this small would be passively safe.  The engine block would have sufficient surface area to lose full power heat by radiation and convection.

I can see units like this being very useful on Mars for a huge range of applications.  They are small and compact enough to power vehicles without excessively bulky shielding solutions.  They are non-radioactive until activated.  So there should be no issues with launch.

On Earth, such units have applications as remote power sources.  The military applications are obvious.  They provide easy offgrid power in the kW range.  Could they be used to build an infinite range tank?  That is an interesting idea.  Such a vehicle would be slow, but would have no fuel limitations.  Starting from a base in Poland, you drive it all the way to Vladivostock!

For bulk energy applications, this discovery allows us to build pressure tube boiling water reactors, that run on natural uranium fuel and achieve high burnup.  That is a revolution in nuclear power, that will make it possible to build new reactors quickly and cheaply.

Last edited by Calliban (2022-10-09 19:53:15)


"Plan and prepare for every possibility, and you will never act. It is nobler to have courage as we stumble into half the things we fear than to analyse every possible obstacle and begin nothing. Great things are achieved by embracing great dangers."

Offline

#184 2023-03-14 16:57:42

Mars_B4_Moon
Member
Registered: 2006-03-23
Posts: 8,903

Re: Nukemobiles on Mars

Will the Moon or Mars have its humans drive the first Nuclear Space-Car?

New funding for space projects using Moon’s resources and nuclear power
https://www.independent.co.uk/news/uk/u … 95388.html
The projects could revolutionise the ability to journey deeper into space.

The UK Space Agency has announced new funding to support space exploration using the Moon’s resources and nuclear power.

China has made a breakthrough in  plans to acquire capability for nuclear power generation in space. The 801  institute under the 6th Academy of CASC has developed closed Brayton cycle thermoelectric generator technology. US & Russia have this tech already
https://twitter.com/AJ_FI/status/1634517124520484864

New Nuclear Fission Concept Could Power Future Rockets in Space
https://www.inverse.com/science/nuclear-fission-rocket
Besides the typical argument between solar sails and chemical propulsion lies a potential third way.

Offline

#185 2023-03-17 12:42:58

Mars_B4_Moon
Member
Registered: 2006-03-23
Posts: 8,903

Re: Nukemobiles on Mars

Rolls-Royce won a bid to put a nuclear reactor on the moon

they are involved in Car Manufacture, Aerospace,  Boats and controllable-pitch propellers

Rolls–Royce given £2.9m to explore nuclear power for future Moon bases
https://www.express.co.uk/news/science/ … moon-bases

Offline

#186 2023-05-27 06:15:26

Mars_B4_Moon
Member
Registered: 2006-03-23
Posts: 8,903

Re: Nukemobiles on Mars

With changes to a market of energy attitudes to 'Nuclear' are changing? China has previously said its lunar base would likely be powered by nuclear energy, Perseverance, nicknamed Percy with its helicopter, the Rover a similar design to its predecessor rover, Curiosiy uses a 110 watt radioisotope thermoelectric generator.

In news we see possible changes to attitudes with Nuclear power in space

Europe wants to build a nuclear rocket for deep space exploration
https://www.space.com/european-space-ag … propulsion

NASA has sights set on Mars with help from a nuclear rocket engine
https://www.nbcnews.com/science/space/n … -rcna84060
A conventional spacecraft powered by burning liquid fuel typically takes around seven or eight months to reach the red planet. Scientists have said nuclear rocket engines could shave off at least a third of that time.

On newmars topics users have discussed Betavoltaic Cell device, new Designs for liquid fluoride thorium reactor, Atomic Radioisotope battery or Atom Battery
The use of Curium-242, curium-244, Tritium, nickel-63, promethium-147, technetium-99

Calliban as an interesting link on Strontium-90 RTGs
https://newmars.com/forums/viewtopic.php?id=7025

older article on Vehicles for Titan and Europa

The autonomous submarines would roam above the ocean floor, taking high-resolution images that will be combined into a 3D map of the seafloor, looking for traces of life in the process.
https://www.space.com/orpheus-ocean-aut … technology
Robot Submarine on Jupiter Moon Europa is 'Holy Grail' Mission for Planetary Science
https://www.space.com/14997-jupiter-eur … robot.html
Titan Submarine: Exploring the Depths of Kraken
https://www.nasa.gov/content/titan-subm … of-kraken/

other discussions
US developing different versions of lunar nuclear power
https://newmars.com/forums/viewtopic.php?id=9772
Dust Blowers on Probes
https://newmars.com/forums/viewtopic.php?id=5698

Last edited by Mars_B4_Moon (2023-05-27 07:10:37)

Offline

#187 2023-11-25 17:47:00

Mars_B4_Moon
Member
Registered: 2006-03-23
Posts: 8,903

Re: Nukemobiles on Mars

Pentagon Awards Lockheed Martin $33.7 Million for Nuclear Spacecraft Project

https://gizmodo.com/lockheed-martin-air … 1851018036

Offline

#188 2023-12-10 10:23:53

Mars_B4_Moon
Member
Registered: 2006-03-23
Posts: 8,903

Re: Nukemobiles on Mars

Nuclear power on the moon: Rolls-Royce unveils reactor mockup

https://news.yahoo.com/nuclear-power-mo … 01170.html

Offline

Board footer

Powered by FluxBB