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I agree that systems will have to have built in protection against terrorist attack. We are already living with these sorts of realities in relation to nuclear power stations, nuclear weapons, oil refineries, dam operations and rail systems. So it wouldn't be that new. I'm pretty sure you could design triggers that would bring traffic to a safe halt wherever any unusual pattern emerged.
Louis,
louis wrote:Make mistakes? Including killing someone on a road? Hmmm... I agree with the video guy that there comes a point where you have to say "Is that ethical if you can avoid it?" We didn't say "let engine drivers make mistakes on the railway", we brought in automatic signalling and automatic braking.
Would it be ethical to murder a single child if you could cure all cancers by doing so?
As some who has spent the past 20 years programming computers, admittedly mostly business systems for major corporations, I can tell you unequivocally that there is a major difference between a discrete computer control systems and one that has full authority over an entire motor vehicle or network of motor vehicles. If my sales history loading code has an issue, then the worst that can happen is that the sales history doesn't get loaded for last month. Every networked vehicle could become unusable at the exact same moment if the control network crashes or the cell towers fail.
In the quadrillions of miles that human drivers have driven motor vehicles, there has never been a single instance of an event wherein every driver suddenly decided to turn left or right at the exact same instant in time across multiple continents. That kind of incident can and does happen when networked control systems have full authority over traffic like network traffic (IP routing, for example), and it happens with boring regularity. Every computer on the network will suddenly decide to start routing its traffic to a single system that it overloads / overwhelms, a disaster that happens at the speed of light. Since the data being transmitted is simple business data, most of the time nobody dies as a result.
I don't get the sense that you have any slight clue about how dangerous this has the potential to be. Elon Musk sure does, and he's not so gung-ho on the idea.
My car has operated without any problem with its various automated systems for the last 7 years. Pretty remarkable really. I managed to split a tyre on knife-sharp kerb and also smash a wing mirror - total driver error!
I accept your point about the way computers "talk" to us. That is partly I think a function of IT specialists who, in my experience, are completely incapable of setting out their thoughts in English - invariably their poor grasp of grammar and semantics means they end up producing ambiguous sentences, but they are of course quite unaware of the ambiguities themselves! I remember being blithely told by one IT guy in the early days of computing that you had to click the start button to switch off your computer as though that were obvious and why would I have been confused by that!...
So, not really a problem of the systems themselves I would say.
I've had a similar problem re Virgin media. You are dealing with people who are working from a script, won't tell you if they have any engineering experience and are clearly on a bonus for NOT sending round an expensive engineer to your home!
I have all sorts of trouble with automated systems. Most of the time, I do not understand what the questions (or the instructions) mean. I see English words, but in context, there is no common meaning. That is what I mean when I say "we share a vocabulary, but not a common dictionary". There is absolutely NOTHING about computer anything that is obvious or intuitive to me. This technology DID NOT EXIST until I was well into middle age, and my mind has since rigidified. There is no help for that.
I just went through that problem trying to get AT&T to fix a 60-Hz loud buzz on my landline phone line. This is the second repair request I have submitted; the first repair lasted less than 30 minutes. There is NO WAY to talk to a human being at AT&T. The automated voicemail system you drop through trying to create a repair ticket is more brainless, utterly brain-dead, than a squashed June bug. Right down to simulated clicking noises as if a real human being were typing something in.
I can tell this is utter BS, and I really resent these automated voicemail systems! It is so patently obvious that they care more about money than customer service, even on what is ostensibly a customer service line! That lie is why I resent it so. AT&T is not the only one I really resent for this reason, but it is one of the very worst.
GW
I accept the point about scale but it does show that at such a vast distance, we can keep such vehicles alive and functioning despite the challenges of temperature shifts, dust storms and rough terrain. No reason to think it would be any different for big rovers on Mars.
Louis,
louis wrote:We've had rovers on Mars that have kept going for 12 or more years.
We have a team of engineers sitting in a room at NASA, carefully planning out where the rover will drive to, 24 hours to 1 week in advance of them sending the commands to actually drive there. I can moonwalk backwards through sand faster than those rovers actually drive.
How practical is it to have a semi-autonomous / remotely operated vehicle that drives slower than a human can walk, assuming it's not for a science mission where the tax payers can afford to keep an entire team of specialists in a computer room for 10+ years?
We've had rovers on Mars that have kept going for 12 or more years.
The idea we can't produce reliable driverless vehicles for Mars is nonsense. But of course, I accept anything can "go wrong".
However, I am sure on any road trail on Mars there will be multiple ways of attracting help. If you break down and are unable to communicate, your absence of progress will be noted. There will be in-vehicle radio communications and emergency supply points for oxygen, food and water etc. at walkable intervals. There may well be a cable laid roadside for communications (though I am not sure that will be necessary). Any rover on the road will have emergency supplies to last at least three days. Journey plans will be automatically filed (similar principle to when mountaineers go climbing or pilots go flying, filing their route beforehand), so a rescue party will come find you if you don't complete your journey within say three hours after you were supposed to complete it. On most road trails there will be other traffic (human and robot) that will stop for vehicles that are immobile and are showing a visual distress signal.
When it comes to exploring on Mars expeditions will have mutiple rovers so that people can be rescued if one breaks down.
Did you actually watch the video through? There's a lot of safety info at the end. These driveless vehicles are incredibly safe compared with human drivers.
My experience with computer controls is very mixed. Things that are hard-wired to do a job have turned out reliable, after half a century or so. Things that are programmable with alterable software are still too unreliable, as all of our experiences with desktops and laptops has proven since about 1980, and still today.
Even the decades-of-experience experts at JPL still have trouble with it, doing those probes in space and on other worlds. And look at Hubble: almost lost due to an unreliable computer they could not fix. It works again ONLY because there were some back-up units that had not also failed! And take one guess as to why the F-35 is years late and tens of billions of $ over budget. I double-dog dare you! Guess! (Answer: bad software code.)
If you have some computer-controlled self-driving car or remote-operated car squiring you around on Mars, and you have a Hubble-type computer failure because dust and extreme cold got into the works, a failure that strands you miles away from water and oxygen, just what are you going to do when you cannot get it going again? Get out and walk many miles back in one of those bulky immobilizing "space suits" they have been designing?
You're gonna die out there!
Now, if it's "just a car" with a hard-wired power supply and power controls, and all-mechanical manual driving controls (steering, brakes,
throttle, lights), the stranding is unlikely to happen in the first place! Why? Because it has way-to-hell-and-gone fewer possible failure modes! Every single line of code in a computer software controlled system is another failure mode. (So is parts count, but that ranges from a few to about a thousand or so. A LOT less!)I repeat: EVERY SINGLE LINE OF CODE IN A COMPUTER SOFTWARE CONTROLLED SYSTEM IS ANOTHER FAILURE MODE!
Typically, computer software-controlled systems like that have hundreds of thousands to millions of lines of code. That is one whopping lot of failure modes! We already have troubles at home with items that are only thousands to at most tens of thousands of lines. Stuff like Windows 8 and 10, for example. What pieces of crap they have proven to be!
You DO NOT want that on the moon, on Mars, or even on any of the public highways right here on Earth! They push this for trucks and cars on the highways here because of the money to be made. IT IS NOT SAFE! It will NOT be safe for over half a century yet (if then)!
A car driving around sightseeing (for exploration purposes) is not the only off-world application here. There is also construction equipment: stuff like front-end loaders, backhoes, cranes, bulldozers, etc. You are simply NOT EVER going to automate the manual art (yes, I said ART, and art it is) of operating stuff like that! Unless you have operated such equipment (and I have), you will NOT understand the truth of that statement! So, all I can say is trust those of us who have, and thus know. You WILL need human drivers for all of those things, and more!
Now you might rig systems to remotely operate construction equipment like that, on the moon and on Mars. IF AND ONLY IF you have sufficient sensory information for the remote operator to see AND FEEL what has been going on! You might be successful, if you do this as a hard-wired system with as low a parts count as possible. You WILL NOT be successful if try to do this with software code, precisely because EVERY LINE OF CODE IS ANOTHER FAILURE MODE!
Obviously, I am no fan of AI stuff. I have half a century's workplace experience to back that assessment up.
GW
Make mistakes? Including killing someone on a road? Hmmm... I agree with the video guy that there comes a point where you have to say "Is that ethical if you can avoid it?" We didn't say "let engine drivers make mistakes on the railway", we brought in automatic signalling and automatic braking.
I realise millions enjoy driving. I quite enjoy it myself. It gives you at least an illusion of powerful autonomy, if only till the next set of traffic lights brings you to a halt. But I don't think it's really an essential part of being human.
I am a gradualist though. I think most people will adopt driverless driving because in the end the ability to rest, sleep, work, entertain yourself or properly engage with family will prove more alluring than the illusion of powerful autonomy. In somewhere like the UK where nearly the whole country is being turned into a 20 MPH zone, there isn't much fun in driving now anyway.
Humans will be required at every stage of building a city on Mars and yes I agree it would be fantastic to be part of such a process. People will need to plan, perform some of the trickier manouevres in the construction process e.g. perhaps plumbing and cabling, electrics and so on.
Louis,
The only way to truly learn and grow is to do things for yourself and to be permitted to make mistakes or even fail, however painful or costly they may be. If we're effectively putting people inside a very technologically sophisticated rubber room, how do you propose we accomplish that? We need people to boldly go where no one has gone before, you know? It's that kind of mission. There are times when it's not fun or seems like drudge work, but there are also times when it is incredibly rewarding. I can think of few other tasks as rewarding as building a city from scratch on another planet and exploring places that no human ever has. If we take that away from people, then what do we have left?
They might drive for leisure. Maybe for exploration where it's rough terrain. But generally they won't need to drive. For much of the 19th and 20th century most people got around on foot or by train. They didn't own a horse and they didn't own a car. It didn't make them less human.
Robots still need oversight. If you had a mining outpost, I think you'd need a small team there to oversee robotic operations.
It's interesting to speculate where all the labour will go in a colony of say 10,000 (permanent and temporary residents)...I'd say something like this:
1. Administration, planning and design (e.g. urban planning).
2. Spaceport operations/communications
3. Agriculture, food processing and food preparation.
4. Energy sector
5. Recycling operations
5. Life support (including water and sanitation and waste disposal)
6. Scientific research/university staff/exploration missions
7. Health care and monitoring
8. Leisure, culture and sports/maintaining Earth-like-environments
9. Retail and warehousing
10. Tourism and hotels.
11. Advertising and marketing (primarily on behalf of Earth-based companies)
12. Interior maintenance.
13. Industrial processes and manufacture.
14. Transport maintenance.
15. Media work (both within the colony and in broadcasting to Earth).
16. Construction.
17. Mining operations.
It doesn't take long before you realise you've got 10,000 people being very busy.
Louis,
Based upon everything I've read about what you envision people doing on Mars:
1. They're not going to drive anywhere
2. They're not going to explore anything
3. They're not going to be involved any construction tasks
4. They're not going to be involved in growing and caring for their food crops
5. They're not going to be involved any mining or prospecting tasks
6. They're not going to use any energy to accomplish those tasksThat sounds like a luxury resort for the obscenely rich, not a frontier colony environment. If we're not gainfully employing people, then why bother sending people to Mars at all? You can do all of those things right here on Earth if that's what you really want to do. The rich still use humans rather than robots, but that's pretty much what they already do. I'm not personally interested in moving to another planet tens of millions of miles from Earth so that I can have my own personal army of mechanical slaves waiting on me hand-and-foot. I want the personal freedom to live dangerously without constantly requiring permission from anyone else, to use my ingenuity and hard work to build a life for my family while expanding humanity's presence in space, and to use my free time to better understand Earth within the much greater context of our solar system and the universe by exploring another planet that was once remarkably similar to Earth.
I think UV light is useful to a number of species, most notably pollinating insects. Flowers have lots of bold markings visible in the UV spectrum but not in the rest of the spectrum. So if you were assuming natural pollination, you'd probably want to maintain the UV part of the spectrum, or pollination would probably become far less efficient.
This new topic is a spinoff from the original Artificial Suns topic by Tom Kalbus ...
This topic is offered to collect facts and practical advice for those who will be designing lighting systems for habitats for human beings away from Earth, as well as on Earth in underground shelters, or underwater shelters, as they become more popular.
tahanson43206 wrote:For SpaceNut .... it is time for this older topic to return to view...
While the topic itself appears (my first impression) to be about solar objects (like our Sun) I am hoping to restart the topic with something a bit more practical.
Years ago, after World War II, there were a number of war surplus search lights available, and I remember then painting the sky for festivals to the South and North where small cities were located in the rural region where our family lived. That was when I attended a one room school, to put it into context.
Those search lights were designed to produce light from a hefty electric arc. Some movie projectors ran on the same technology, but I've only read about that. I never saw one in operation.
With Calliban's initiative to design a hefty 1 Mw fission reactor that can be deployed for 10 years at a time, we can see possibilities for Mars habitation opening that might not have been possible with less robust power sources.
It is in this context that I invite (hopefully learned) discussion of the specific requirements for an "artificial sun" lighting system for large cavernous spaces on Mars. The spectrum of the Sun is the one we (humans and animals and plants) have "grown up" with, so I would expect an artificial sun to reproduce the beneficial spectra, while eliminating (if possible) the frequencies that serve no useful purpose, such as Ultra Violet ones.
This subtopic is introduced within the larger topic of Terraformation.
This is ** not ** Terraformation ... this would be Terrasimulation, accomplished on the scale of habitats, and not an entire planet.
(th)
Presumably Mr Heisler accepts Dr Fauci and the NY Times as august authorities...
https://dailysceptic.org/todays-update/
Even Fauci is now having to admit that the Israeli data shows the vaccine is a failure.
American data is lagging behind Israel's as the USA is well behind Israel on proportion vaccinated.
And let me pick up Mr Heisler on his use of "unvaccinated". The people who are "unvaccinated" according to him will include probably a majority who have had the vaccine but only one shot. They are not "fully vaccinated".
My take is that the virus was naturally abating this summer, as it did last summer, but the weakened immune systems of so many vaccinated people has given it new life.
I can just hear Pelosi's trademark little snort-snigger after she says "I'm a good little Catholic girl"...I'm sure her Mafiosi father was a good little Catholic boy as well.
EdwardHeisler,
EdwardHeisler wrote:David Frum is not a leftist or liberal opponent of the Republican Party. He is a long-time conservative Republican leader and former speech writer for President George W. Bush. There clearly isn't much left of the Republican Party. It's dead, buried and gone forever.
MSNBC and The Atlantic don't publish conservative opinions, at all or ever. David Frum sure as hell isn't a conservative or a Republican, either. He believes in abortion, gun control, perpetual victimhood, blaming white people for every problem that has ever happened since the dawn of time, and the list goes on. There's nothing conservative about him. He detests former President Trump and that's why CNN / MSNBC / The Atlantic, publishes his opinion pieces. If David Frum praised one thing that he thought former President Trump did right, he'd be looking for work the very next day.
Remember when Pelosi said she was a "good little Catholic girl"... who apparently believes in abortion?
Calling yourself a Catholic doesn't make you what you choose to label yourself as.
Going to Church on Sunday doesn't make you a conservative / Republican or a liberal / Democrat.
I'm sure the Republicans will be thrilled to know their party is gone. I guess that's why they picked up so many more seats in the House. Every election cycle as who holds power flip-flops back and forth between meaningless choices, I see the side that won declare that the other side is dead, buried, and gone forever. Then they lose the House / Senate / Presidency the very next election cycle. It's getting rather silly at this point.
I think there's a maths error in your post in the following section.
404,500,000MWh * 8.99300528MWh/m^2 = 3,637,670,635.76m^2 = 3,637.67km^2
But nuclear power only provides 20% of our power so that figure represents 10% of the requirement if you make 50% and store 50% of what you need when wind and solar produce nothing.
So... 36,376.7km^2
Surely you should be multiplying the 3,637.67 figure by 2.5 (20% x 2.5 = 50%) not 10 to get the storage requirement (as defined by you - not me, see below). That would give you a figure of 9094 sq kms as the total land area under your analysis
However, that's still to misread the situation.
No way would you be storing 50% of the energy requirement. You would be storing whatever percentage in a year's total green energy output (solar + wind + hydro + geothermal + energy from waste + wave + tidal + sea current + biofuel) fell short of the required total. Remember the non-intermittent elements like hydro and energy from waste can probably be ramped up to 15% of total during periods of low wind and solar. So it's really a question of how do you ensure the remaining 85% is non-intermittent using the storage system.
For that, you have to look at days when wind and solar fails to meet 85% of the energy requirement and days when it exceeds that requirement (possibly above 100% on some days). When I've looked at the UK there are maybe on average 3-4 days per month when there is very low wind and solar. But there are also days when there is an abundance of wind and solar energy. The shortfall periods maybe amount to 10% of the total produced. That would amount to roughly 36 days of needing to be supplied from stored energy but of course you aren't just draining batteries all the time, you are also replenishing them in times of surplus. I suspect the 150 hours target storage time (just over 6 days) was chosen carefully and equates to this sort of scenario where you are having to provide about 10% of the total energy output from storage (let's say beyond diurnal storage which won't be an issue). 6 days would cover both a freakish low period and also a period when Period A of low wind and solar is followed quickly - say within a week by a second Period B of low wind and solar.
At 150 hours, the overall storage capacity would be less than 2% of 85% of annual energy output.
So on your figures I make that a total area requirement for the Form Energy system of 309.2 sq. kms. Somewhat less that your figure! If all the units were housed in 10 storey equivalents of concrete car parks that would be a land requirement of 30.9 sq kms or 5.5 kms x 5.5 kms. If that were split into 1000 facilities dotted around the country each unit would be 4000 sq. metres or 63 metres x 63 metres.
Louis,
Is it easier to stack washing machines that weigh as much as SUVs when they're sitting on the ground or when they're 100 feet up?
I think we both know the answer to that question.
You need 8,993m^2 to store 1GWh worth of electricity.
1/3 acre = 1348.950792
1348.950792 / 150MWh = 8.99300528m^2 per MWh
8.993m^/2 * 1,000MWh = 8,993m^2
Net generation for US nuclear plants was 809TWh in 2019.
809 * 0.5 = 404.5TWh (assumes wind and solar combined provide a 50% capacity factor to provide half of the total power requirement)
404.5TWh = 404,500,000MWh
404,500,000MWh * 8.99300528MWh/m^2 = 3,637,670,635.76m^2 = 3,637.67km^2
But nuclear power only provides 20% of our power so that figure represents 10% of the requirement if you make 50% and store 50% of what you need when wind and solar produce nothing.
So... 36,376.7km^2
That's equivalent to the total land area of Maryland and Rhode Island combined. Granted, those are two of our smallest states, but you should drive through both of them to get a sense for how big they truly are, then imagine a battery sitting atop every square inch of both states.
When these things are filled with electrolyte, they will weigh about as much as 1/4m^3 of Iron plus 3/4m^3 of H2O (at least 2,725kg/m^3, and possibly double that based upon the prototype design I saw- tough for me to judge mass, but it looks like a giant steel cheese grater). That means you'll need a foundation more solid than any skyscraper in existence to hold up the crushing weight of a 10 story battery made that way, and then that structure will cover the entire land area of Rhode Island. A 50 story skyscraper with 3,000m^2 of floor space per floor only weighs approximately 250,000t (steel reinforced concrete, excluding the foundation, obviously). Each square meter of "battery space" weighs as much as 1/9th of that entire 250,000t building, excluding the foundation. If the actual battery weight is closer to 5,000kg, then that's delving deep into the realm of absurdity.
Maybe for offshore use in floating platforms so we don't have to construct the world most solid and therefore expensive foundation across a land are twice the size of Wales?
Or maybe this is pure fantasy?
Re land usage, that can of course (I assume) be addressed by building "up". I can't see any particular reason why you couldn't have a ten level warehouse if you wanted. It would be a lot more expensive of course, but could last for hundred years. However in the USA, there is still abundant land available in most States so it's probably not much of an issue there.
I think as well, that in terms of solar and wind such a system would allow you to operate with fewer wind turbines and solar panels, thus taking up less acreage for the energy generation (I am assuming that would be the case because currently a lot of energy is earthed ie wasted when there is an oversupply but with this system, in perods of over supply all the excess energy could be stored, so at other times the "oversupply" can be fed back into baseload. I am not sure how much smaller the wind and solar capacity could be but I'm thinking maybe something like 10%.
Exciting times!
tahanson43206,
While very interesting from a cost and simplicity perspective, and I do like technology that is both simple and cheap because it means John Q. Public understands how to use and maintain it and can actually afford to do so (it looks stupidly simple to me, which is why it just might work), Form Energy says they can achieve a power storage density of around 3 MW / 450MWh PER ACRE of land surface area, and that each individual battery cell is approximately the size of a washing machine. Their pilot project battery would then cover about 1/3rd of an acre of land, provide 1MWe of continuous power and store 150MWh of energy (1MWe for 150 hours). For comparison purposes, a fossil fuel energy storage mechanism providing 150MWh of energy, at 50% thermodynamic efficiency, requires roughly 7,412 gallons of crude oil. Current combined cycle gas turbines achieve 65% thermal efficiency and solid oxide fuel cells can achieve 80% thermal-to-electrical efficiency, so Form Energy's solution faces stiff competition wherever land area is at a premium. Apart from that issue, which is significant in many places, I like every other aspect of what they did. It's cheap, abundant, easily recyclable, and completely non-toxic (Iron / Oxygen / Salt / Water). If we can obtain enough energy to mine the raw materials without falling into an energy trap, then it makes good sense to me. They're claiming that their battery can also last for 20+ years, which is highly desirable and perhaps more important than all other considerations. We need to start thinking about energy generating and storage technologies in terms of human lifetimes, and start building infrastructure that withstands the test of time, because renewable energy doesn't provide the same amount of surplus energy as coal / gas / oil or nuclear energy.
Large Scale, Long Duration Energy Storage, and the Future of Renewables Generation
As the above link indicates, Form Energy is demonstrating a 1MW / 150MWh capacity battery for Great River Energy.
Form Energy's battery (referred to by TA) does sound like it could be the Holy Grail of green energy - and who would bet against a Bezos-backed company?
https://www.dailymail.co.uk/sciencetech … -days.html
I particularly like the idea it can store energy for 150 hours potentially. That's over 6 days - and I think that would mean in a country like the UK, a green energy system could be entirely reliable, with no intermittency in output. When I've looked at charts of very low wind/solar in the UK the maximum period seems about 3-4 days.
I am not sure how the $20 per KwH of storage figure translates into cost of power ouput per KwH.
Yes I recall the article.
The company behind the technology described in the article at the link below would appear to be solidly in Louis' corner:
https://www.fool.com/investing/2021/07/ … renewable/
But Somerville, MA's Form Energy has built a battery powered by pellets of iron, one of the world's most common elements, which costs a mere $6 per kilowatt-hour of storage on individual cells. Packaged in a battery system, the cost comes squarely in line with experts' $20 per kilowatt-hour target.
Form Energy's battery functions by intaking and expelling oxygen, and using an electrical current to charge and discharge iron to rust and back again, charging the battery in the process.I wonder what efficiency is possible with this curious mechanism.
The article reminds me of a discussion started by (I think Louis) when I first joined the forum. It was about a company (or more likely a college) investigating combustion of iron power as a way to create steam. The output of the process would have been clinkers of rust.
A battery based upon the principle of oxidation of iron would (presumably) not require high temperatures.
If someone with posting privileges is inspired to investigate this report, I'd be interested to learn more about the concept.
If the process has reached the press, it would (presumably) have patent applications on file, so there might be something available in US government files.
(th)
Well obviously I think any PV panel system is going to be space-rated and tested for the temperature swing on Mars. I can't see anything that suggests PV panels can't operate on Mars.
No one's going to be using your ordinary domestic panels on Mars, I think we can agree on that but I think there are several companies producing PV system that can work on Mars.
Louis,
There are no commercial solar panels that will work on Mars, either. The kinds of photovoltaics that NASA uses there cost a million dollars per kilowatt of output. That's fine for a tiny rover with a few hundred watts of installed capacity at most. That's not going to work for a colony that requires gigawatts of power. Look at the operating temperature range on any commercial panels. None of those are going to survive when the night temperatures on Mars are mildly cryogenic in nature.
Seeing how far driverless cars have come, I don't think there will be much call for drivers on Mars...
https://www.youtube.com/watch?v=yjztvddhZmI
Apart from some possible requirement for human driving in an exploration setting (not certain but possible) we can be assured driverless vehicles will have no problem dealing with cleared road trails on Mars. This will be very helpful when it comes to bringing in raw materials such as ores from mining operations at a great distance from the industral processing centres. A steady stream of driverless rover trucks will bring in the material, possibly in convoy. Will be a great sight watching a convoy travelling through the night.
The article certainly underlines there are many issues to be addressed in dealing with nuclear reactors on Mars.
There are certainly no nuclear reactors ready to begin work on Mars. The Kilowatt reactors are the closest we have and they are only scheduled for an experimental lunar outpost towards the end of the 2020s. If you want to get to Mars by 2027, you have think solar plus storage.
I personally see nuclear power as a later potential addition to the energy economy of Mars. I can see the case for nuclear reactors in that (a) they could definitely add net "active" energy to the regolith and atmosphere, and so might have a useful role in terraformation, and (b) Mars will have vast tracts of uninhabited land where reactors could be located and if they became dangerous, it wouldn't be a particularly big deal (in contrast to Earth). However, they will be a big draw on labour time, which will be one of the scarcest factors on Mars, so if we can find other ways of terraforming and powering Mars then we should probably pursue those paths.
https://www.yahoo.com/news/us-army-trie … 04173.html
For Calliban (primarily) and all welcome to comment (Louis... have a field day!)
The article at the link above is by an author who ( I ** think ** ) did scientific work at a base supported by a nuclear reactor developed by the US Army.
A better representation of what I remember from the article is that the author has worked on ice cores collected at the time.
The US Navy has been working successfully with small, powerful reactors throughout the time period of the Army experiments.
It is possible the conditions faced by engineers working for the Army were more difficult.
In any case, the article is difficult to read for anyone wanting to be able to support nuclear fission for home power production.
The US Army is (according to the article) once again studying the potential of small portable reactors, with (hopefully) 50 years of additional experience and (hopefully) wisdom.
The U.S. military’s first attempts at land-based portable nuclear reactors didn’t work out well in terms of environmental contamination, cost, human health and international relations. That history is worth remembering as the military considers new mobile reactors.
[Get our best science, health and technology stories. Sign up for The Conversation’s science newsletter.]
This article is republished from The Conversation, a nonprofit news site dedicated to sharing ideas from academic experts. It was written by: Paul Bierman, University of Vermont.
Wrapping this up for Calliban ... while there may be others in the membership who could comment in this field, you are the ** only ** member who has been willing to invest time in detailed support of fission power plants for Earth, Mars and anywhere in the Solar Systems that humans will venture in years to come.
The challenges faced by the US Army (and probably the Russians and Chinese) in developing tactical fission reactors are not ** too ** different from the challenges to be faced by designers for off-Earth sites.
(th)
Latest from Felix, informative as ever...
Thanks Calliban.
Hardness of ice increases as temperature declines.
http://www.minsocam.org/ammin/AM43/AM43_48.pdfAt -50°C it is as hard and strong as ordinary grade concrete. You would need explosives to mine it. Or lots of low grade heat.
Yep, these are reasonable concerns. Space X never goes there in their public statements but it is in my view perfectly valid for the FAA to be concerned about such an event.
If you want to know what an explosion on the pad of Super Heavy would be like, the closest equivalent is explosion of N1. Super Heavy has 3,400 metric tonnes of LCH4/LOX. N1 had 2,300 tonnes of RP1/LOX. That's including all 3 stages: Block A, B, and V. Actually the 1964 version had 2,383 tonnes, but the video says 2,300. Earth departure stage was Block G with 55.8 tonnes more. But then subtract however much the engines consumed before the explosion. You get the idea.
Click image for YouTube video. It will auto-start at 5:10, so right at the explosion.
https://i.ytimg.com/vi/gklVhRzkVqA/maxresdefault.jpgSources: Astronautix index, click on N1 1964 - A, N1 1964 - B, N1 1964 - V, and N1 Block G.
Wikipedia: SpaceX Starship and N1 (rocket) Comparison to Saturn V.
The age of the rover on Mars is drawing to a close.
Space X's Starship make them redundant. Why invest in a small rover when you can have a human-pasenger rover weighing maybe 2 tons under Space X's approach plus several helicopters and a rocket hopper....or just refueld your Starship and it can go visit any numbers of places on Mars.
A number of interesting points in your post.
I did know NW Europe had some of the best wind resources in the world, but thought the South China Sea wasn't so bad...looking at the map I don't think it is that bad but not as good as NW Europe, I will accept.
I can see that they might follow a "French" policy of Big Nuclear. It is obviosuly a solution and a big country like China can afford a nuclear accident or two, especially given their totalitarian system of politics.
But educated people in China don't trust their government to even do the basics on public health checks re food products like milk. They know their government lie. Their government will lie about nuclear power as well.
So. well it's the choice of the Chinese people, but I don't accept it's the best policy. China has plenty of renewable resources and longer term I think they are a safer bet.
Yes, if we had sane politics across the world, now would definitely be a good time to pursue international co-operation. Aiming to make every country energy independent seems to me like a really good first step. But there will be big losers from such a policy!
louis wrote:The EU does have a plan to convert the North Sea into a green energy hub. Denmark has already announced plans to create an energy island some 80 miles off the coast. Making hydrogen obviates the need to lay cables from wind farms to the coast and, it seems, they think they can use existing natural methane pipelines to pipe hydrogen back to the mainland for use in power generation. Perhaps they are thinking in terms of upgrading the seals?
Chinese energy demands are so huge and so heavily dependent upon coal, that they cannot afford to neglect any option at present. China cannot import more than a fraction of its coal requirements, for the simple reason that it consumes more coal than the entire rest of the world produces together, at present. Likewise, it is now the world's largest natural gas importer, in spite of natural gas providing just 3% of generated power. It is an energy consuming monster.
But I doubt they would attempt to emulate Denmark. Below is a link to a global wind resource map.
https://windenergy.dtu.dk/english/news/ … 787f84503aThe North Sea and North Atlantic area, have the best wind energy resources in the world, by a long shot. With access to these resources, Denmark is planning to build an offshore 3GW hydrogen production facility, for the less than bargain price of £20bn. Chinese wind resources are nowhere near as good. For as long as the Chinese have some coal production, it will be much cheaper to burn it in thermal powerplants for backup, when solar and wind are not meeting demands.
I would point out that Chinese nuclear generating capacity is expanding rapidly. Starting from a low base in the early 2000s, they now have over 50GW of generating capacity and plan to have available 300GW by 2030 and 1400GW of fast neutron reactors by 2100. This is probably the only way that the Chinese will be capable of supplying first world levels of energy to a population of 1.5bn beyond 2050, absent the development of nuclear fusion. Reactor build times are much more rapid than Western world standards, with reactors completed within 5-6 years of start of construction and in some cases as little as 4 years. For this reason, project costs are much lower and nuclear power is a cheap means of generating electricity in China.
I would agree with Kbd512's sentiment that now is a good time to pursue international cooperation on energy and resource issues. But history is less than encouraging on this point. It was energy supply shortages that led to the Japanese attack on Pearl Harbour. They needed the US Navy out of the way before they annexed Indonesia, with its abundant energy reserves. Likewise, the Japanese invasion of Machuria was prompted by shortages of coal and minerals.
As an aside: The Japanese economy was the first casualty of rising energy cost of energy. As an importer of virtually all of its fossil energy, Japan was more vulnerable to declining EROI than any other industrial nation. Before Fukushima, they had plans to roll out fast neutron reactors to meet the majority of their energy needs by mid century.
"throw the switch and walk away"
Don't forget to first alert your local branch of AQ or any otherterrorist group interested in such matters.
tahanson43206 wrote:This post is not intended to detract from the impact of #162 about a Tesla with (what must have been) a manufacturing defect catching itself on fire, but it ** is ** offered in hopes of encouraging Calliban to continue (?) working on a plan for a 1 Megawatt reactor that could be built in the hundreds if not thousands, and deployed all around the world in secure locations for 10 year trouble free, totally reliable delivery of power to customer groups, from communities through factories all the way to (latest news) bitcoin server farms!
I asked Google for help, and it came up with a "Count of Electric Power Industry Power Plants, 2009 through 2019.
The list is (apparently) showing 1 Megawatt or greater systems.
https://www.eia.gov/electricity/annual/ … 04_01.html
There appear to be on the order of 3,000+ fossil fueled systems that might be candidates for replacement by well designed, modular fission reactors.
The global opportunity would presumably be considerably greater.
The dearth of energy that Calliban sees coming could most definitely be alleviated by robust deployment of modular nuclear plants, independently of whatever the renewable enthusiasts come up with.
(th)
No need. There are already dozens of small modular reactor concepts, in various stages of development.
https://en.m.wikipedia.org/wiki/Small_modular_reactorIn the western world, these will cost so much to develop that most of them will never get off the drawing board. The Russians and Chinese are already building them.
If I were to pick a favourite from existing concepts, for sustainability and scalability, it would be the lead cooled fast reactor, using metallic tube-in-duct fuel. Excellent neutron economy, high operating temperature and an inert coolant with good compatability with steam, CO2 and stainless steel. The coolant is also non-pressurised, reducing the potential for loss of coolant accidents. The high operating temperature allows a reactor plant to lose lots of decay heat by thermal radiation from the primary circuit. That makes it very suitable for a 'throw the switch and walk away' mode of operation. A compact S-CO2 generating plant would be suitable for a portable modular power source, that is mass produced in a factory environment and then shipped by road or rail as a whole unit or as modular components that can be assembled rapidly.
For a 1MWe unit, we want a powerplant that can fit into one of these.
https://en.m.wikipedia.org/wiki/ISO_668The core would be in the form of a metallic cartridge, with stainless steel lined cooling tubes running through it. The central core would be uranium-plutonium-zirconium alloy. The outer core would be 238U-Zr alloy. As the reactor operates, neutron leakage from the inner core would breed plutonium in the outer core. This would maintain the reactivity of the core, as inner core plutonium burned up, allowing long core life. Control rods would be stainless steel clad boron steel. Shielding and reflection would be provided by molten lead, both coolant and shield tank.
I remember as a child collecting bubble gum cards with the X-15 series being one of the featured craft and my favourite. They looked sooo cool.
Looking back, I'm not sure what the point of the development programme was, except to keep the Air Force in the space race! It didn't lead anywhere did it?
Re TH 1322:
There are a lot of stories about the rocket plane testing. Folks who saw "The Right Stuff" would be aware of the competition between Chuck Yeager in the various versions of the X-1 and Scotty Crossfield in the D-558-2 to be the "fastest man alive". That was less a competition than most would think from the movie.
Douglas Aircraft built the D-558-2. Their company test pilot for it was Bill Bridgeman, who went directly from testing propeller-driven A-1 Skyraiders to rocket plane flight, via a few hours with Tony Levier in a subsonic two-seat F-80 jet (now known as a T-33). Bridgeman flew the D-558-2 to Mach 1.98 before Douglas ever turned it over to NACA and Crossfield, who trained himself to fly it, eventually breaking Mach 2.
It was Bridgeman who identified the necessity of controlling pitch with the trim control that moved the horizontal stabilizer, because the elevator was "washed out" in the wake created by the shock waves at its hinge line. That's how both he and Crossfield were forced to fly the craft on its missions.
Yeager's near-death experience in the X-1 was not in the original X-1, but in the larger X-1A with the bubble canopy. He tumbled out of the sky at almost Mach 2.5 in it. Later versions addressed the problems, with Mach 2.5 safely reached in the X-1E.
The original X-1 had both elevators and a large-motion pitch trim that moved the stabilizer. It did not break the sound barrier using elevators for pitch control, it used the trim. The later versions had the "all moving tail" horizontal stabilizer design typical of all supersonic jets today.
In 1947, the all-moving tail concept was a military secret that went into the design of the F-86, which gave it supersonic dive capability that its opponent in Korea, the Mig-15, did not have. Yeager nearly got himself killed flight-testing a captured Mig-15 over Okinawa about 1951 or 1952, reaching Mach 0.94 in the dive. About 1960, he was part of a tour of aviation types in Russia. The Russians were astonished he survived a near-sonic dive in the Mig-15. None of their test pilots had survived it.
It was the X-2 that finally reached above 70,000 feet and above Mach 3. The original version had too small a vertical fin for adequate supersonic stability in the thin air. Mel Apt died because of that, attempting a Mach 3 turn at about 70,000 feet. I've seen the cockpit camera footage of that. Later versions had a larger fin, and could do the missions without losing control.
That's the rocket plane work that fed into the X-15 program. It rolled out in 1958, I remember the Walter Cronkite news story on the TV about that roll-out. They got started with 4 little engines, then the big XLR-99 engine became available about 1960 or 1961. That's when it busted past Mach 4 and past 50 miles altitude. With the drop tanks, it busted past Mach 6. There were 199 flights of the 3 birds, with one fatal crash. Several X-15 pilots took the bird above 50 miles, earning astronaut wings in it. Neil Armstrong was one of them.
GW
Not sure I am following your train of thought there.
As far as I understand it, the choice is between a launch from Boca Chica (ie from the tower) and a launch from a sea platform. The FAA has not yet approved a launch from Boca Chica.
That's my understanding as of now.
What do you mean by "stacking".
I may well have this wrong but I understand there is a test platform for static fire tests.
We're in Starship is Go... topic, so I'll toss out a request for anyone who might come across a report on how the "great tower" controversy is playing out.
If Elon could be trusted not to launch from the tower, I'd be in favor of letting him try stacking. However, I would NOT be surprised if no one trusts Elon to restrain himself if he gets the tower built. Besides, his engineers can use computer modeling to test stacking, so the need for physical testing is less than it might have been in the early days of rocket development.
(th)
Presumably the first orbital test would have only a very light "payload"?
The raptor engine for stage 1 will need to run for more than 10 minutes as it pushes starship on the path towards orbit. These engines after many attempts may need longer test stand testing before selecting the units to go into the stage assembly.
There is not going to be much room for error or for a bad engine since the mass being moved to orbit is so great.