Welcome Guest [Log In] [Register]
Speculative biology is simultaneously a science and form of art in which one speculates on the possibilities of life and evolution. What could the world look like if dinosaurs had never gone extinct? What could alien lifeforms look like? What kinds of plants and animals might exist in the far future? These questions and more are tackled by speculative biologists, and the Speculative Evolution welcomes all relevant ideas, inquiries, and world-building projects alike. With a member base comprising users from across the world, our community is the largest and longest-running place of gathering for speculative biologists on the web.

While unregistered users are able to browse the forum on a basic level, registering an account provides additional forum access not visible to guests as well as the ability to join in discussions and contribute yourself! Registration is free and instantaneous.

Join our community today!

Username:   Password:
Add Reply
[Rant] Why I dislike Space Enthusiasts; Even though I arguably am one?
Topic Started: Jan 15 2012, 11:14 AM (3,277 Views)
lamna
Member Avatar


The middle east isn't all that well developed. There are some very rich people here, but there are a lot of very poor ones too, even in the Gulf states, and they get an awful lot of immigration from Asia too.
Living Fossils

Fósseis Vibos: Reserva Natural


34 MYH, 4 tonne dinosaur.
T.Neo
 
Are nipples or genitals necessary, lamna?
[flash=500,450] Video Magic! [/flash]
Online Profile Quote Post Goto Top
 
Zerraspace
Member Avatar
UD Needs You!
 *  *  *  *  *
I suppose the US and the UK don't have their share of homeless, vagabonds living off welfare, and dependents on food stamps? I actually live here and I've spent years in the US, so I think I'm qualified to judge the differences between them. You have a valid point regarding immigration (but it's a point I did bring up earlier), and the general Middle East is far from wonderful, but in the richer Gulf States such as those I listed life is sweet for native-born citizens (I've relatives who worked there and in the US) - they practically get paid for living in those countries! If neither experience nor UN-rated HDI is fit as an indicator then I'd like to know what is.

(Awaiting next denunciation despite attempts at research... <_< )
Have you got what it takes to beat back hostile alien forces and vicious Space Mafia agents to defend liberty and justice for citizens across the galaxy? Join Universal Defense NOW (for more information, please enlist)!

Quote:
 
That is how we first set foot on the planet we have come to know as Zainter, the world that would change our lives forever.
- Remake of Zainter
Offline Profile Quote Post Goto Top
 
T.Neo
Member Avatar
Translunar injection: TLI
 *  *  *  *  *  *  *  *  *  *
Quote:
 
Right now that seems to describe more people than not. According to the 2006 UN Report, population growth was positive in 204 countries, 130 of those with growth rates above 1%, while only in 25 nations were these negative. In general less developed countries have higher population growth rates but there were several important exceptions to the contrary - in particular many of the well off Arabic Gulf States (Kuwait, Saudi Arabia, Qatar, the United Arab Emirates) count amongst the top 50, all with rates above 2%, putting them on par with several African nations, and they all similarly have HDI over 0.75, again, putting them in the top 50. Of these, the Emirates has the highest growth rate (2.85%) and the highest HDI (0.846, putting it almost on par with the UK). This may be attributable to high populations of immigrant workers, but there could be a cultural impetus, and these are projected to change: all I'm saying is that it is not a simple correlation between living standards and population growth. There are also a number of major political and economic factors keeping these standards from visibly increasing reasons in regions that most need it, and you'll need greater production of resources and sounder distribution of them for any of this to happen. Most of what gains we will make will end up going to the most developed nations anyway...


Measuring by population growth rate may be fair, but measuring by birth rate is far better.

Also, I am talking about nations over 0.8... or even over 0.9. I haven't actually bothered to put birth rates and HDI (or other indicators of how well-off a nation is) in a graph together, but maps that show HDI and birth rate are pretty indicative:

Spoiler: click to toggle


Spoiler: click to toggle


It isn't that much of a far-out concept, the societal and economic pressures in developed nations, along with better education, promote lower birth rates.

Of course there are more underdeveloped and developing nations on the planet than their are developed ones. But there's nothing stopping developing nations from, well, developing. They'll get there, the question is a matter of when.

Quote:
 
I believe you answered your own question there. We only discussed fuel prices but even at an acceleration of only 1 milligee and mass ratio 1.08 the MCV can hardly pay for its own propellant (at least, not with its current cargo), and there is the matter of paying employees even while they’re idling. Like I asked, how do you intend to deal with the prices?


You can either argue with physics or you can argue with economics... I sure know which one I'd least want to argue with. :P

My overwhelming feeling is that this huge super-accelerating megamacho spacecraft will not result in a profitable operation.

The amortisation of overheads thing is most important when you're running a service or making a product. The thing is, your quantity here is measured in kilograms of whatever metal you return from the asteroid. It doesn't matter if you return that quantity in one or two or ten flights a year. Your cost comes from your overheads, recurring costs, etc, and your revenue comes from kilograms of material returned.

The key is to return enough material to cover your costs and turn a profit.

Quote:
 
I've seen figures Project Daedalus - 50000 tons of fuel to power a 54000 ton spaceship, for a mass ratio of 13.5, and that's only for a one-way journey. Past a mass ratio of 1.588 the mass of fuel required to propel the MCV will outweigh both ship and cargo combined (it does because this is a two way journey, and the cargo is only loaded for the return home), and any increase in propellant will mostly be to contend with pushing the propellant itself. Unless the cargo is extremely valuable, it’s simply a waste of mass and money.


Daedalus is an interstellar probe though, not an asteroid mining tug (it's also two stage, etc, there are a lot of differences in it).

Quote:
 
As for the VASIMIR scheme, I considered the dV to be the same as for the MCV when moving at an acceleration of 1 milligee and heading to the same asteroid – 200843 m/s one way – with 60% engine efficiency and effective exhaust velocity of 294000 m/s, in hopes of minimizing mass ratio. At $13.95 billion to fill, you’re going to need more than 8000 tons of nickel and cobalt to pay up (for 95% nickel and 5% cobalt, that translates into $282.7 million of nickel and $18.9 million of cobalt, aka $301.6 million of metal). Refining various rare and precious metals should cover the costs quite handily, but given their low concentrations even in asteroids it’ll take quite a while to find sufficient quantities of those.


Simple solution: go slower.

Also, engine efficiency with VASIMR does not affect propellant consumption. Propellant is just what you pump into the engine. Efficiency determines how large a powerplant you need- that would either be a nuclear reactor or solar panels. Those provide the energy, the propellant is just working mass.

Quote:
 
I'm only quoting figures here - I was pretty skeptical of only $200 billion (note the figure I did choose). What I’m trying to say is that yes, the numbers are mind-boggling, but the returns would be more than worth if we were willing to put up the commitment. I don’t see anybody giving such commitment, however…


Fair enough, but my point is that how mind boggling the project is, is proportional to how unwilling or unable people would be to commit to it.

Already just introducing a microbar of gas into the atmosphere to sublime large amounts of CO2 would likely be unfeasible.

And the economic return must be explained. For example, you won't have ten trillion dollars of GDP right off the bat. The economy there would have to grow into that. And that could take decades or even centuries. And then what is that GDP even worth? How does it pay back to the nations that funded the project in the first place? Shipping goods from Mars isn't really practical, IP and information services surely can't generate a revenue in the trillions back to Earth every year.

Money is only really worth what it is, well... worth.
Edited by T.Neo, Jan 21 2012, 11:04 AM.
A hard mathematical figure provides a sort of enlightenment to one's understanding of an idea that is never matched by mere guesswork.
Offline Profile Quote Post Goto Top
 
Zerraspace
Member Avatar
UD Needs You!
 *  *  *  *  *
T.Neo
 
I am talking about nations over 0.8... or even over 0.9.


With the exception of Japan, all nations with HDI exceeding 0.9 can be found in America, Europe or Australia, as can most of those with HDI over 0.8, and of the remainder the greater part were either colonies of or historically influenced by said nations. Those that were not and without exception have population growth rates exceeding %1, leading me to believe that it is cultural rather than economic and societal factors that ultimately control birthrate (by the way, could you have provided a legend for the former graph).

T.Neo
 
But there's nothing stopping developing nations from, well, developing. They'll get there, the question is a matter of when.


So technology cannot improve even though all past trends suggest this should be, yet we can expect improved living standards in third world countries simply because trends suggest it? Even if you say conditions are steadily improving, so is technology. I am not going to argue global affairs, lest this become a messy debacle in itself, but suffice to say there are enormous barriers to improved living standards in most of these countries, political, economical and cultural, quite a few of those caused by nations which are already developed and none of which will readily give way. Most apparent signs of “progress” are merely grabs for public approval and local manipulation, and if any of those nations did make it out of the gutter we’d probably regret it. If you do not believe that even one of these factors is in any way relevant, then at least do the research or bring up proper arguments to counter, rather than treating them as if they weren’t there.

T.Neo
 
You can either argue with physics or you can argue with economics... I sure know which one I'd least want to argue with. :P

My overwhelming feeling is that this huge super-accelerating megamacho spacecraft will not result in a profitable operation.

The amortisation of overheads thing is most important when you're running a service or making a product. The thing is, your quantity here is measured in kilograms of whatever metal you return from the asteroid. It doesn't matter if you return that quantity in one or two or ten flights a year. Your cost comes from your overheads, recurring costs, etc, and your revenue comes from kilograms of material returned.

The key is to return enough material to cover your costs and turn a profit.



If physics were the only constraint facing us then we need never have begun this discussion, T. Neo, since there seem to be plausible spacecraft concepts in circulation - perhaps including one of your own, if you were willing to divulge the details… Economics is the more pressing challenge here, and it’s that even more than the functioning of the ship that has me worried. Even if you take loans or somehow absorb the costs into the company, the fact is that you have employees with set salaries, and they can only realistically wait for their pay check for some time (schoolteachers in Lebanon usually take part-time jobs to cover the summer vacation, so it may be possible for them to wait out the time with other occupations, but there are limits to how long such contracts would last). So long as the MCV can only deliver a set mass, more and more of the vessel’s returns will have to be spent simply on paying those salaries, and your annual income is (obviously) decreased; if given a choice between two vessels with the same fuel requirements corporations will choose the faster, and if the difference in speed is significant enough it may even outweigh cost concerns. I don’t see how you can feasibly sustain operations longer than two years – people simply wouldn’t be able to hold to a contract or company (if companies could even operate on those timescales) nor could the required infrastructure and equipment be set up quickly enough to warrant further initiative, and unless the cargo were almost pricelessly valuable customers would simply turn to more immediately provided Earthly items. If mission time exceeds three years (however you go about that) we might as well forget about Brachistochrone orbits entirely and stick with Hohmann transfers, probably saving us quite a bit of fuel in the process.

T.Neo
 
Simple solution: go slower.


In short, you cannot simply ignore the timeframe of the operation and slow your spaceship down to a near standstill to run it cheaply. You might be able to wait that long, but your banker and CEO can’t, and ultimately they’re responsible for giving you the green light: if the proposed craft is to actually stand a chance of seeing use in a corporate-driven world, you’ll need to find a balance between fuel costs and delivery time, and that’s what I’ve been struggling with.

Lowering the mass of the MCV will not lower the ship’s mass ratio – delta-v will remain unchanged, as will the exhaust velocity (seeing as neither is reliant on mass), hence the quantity of fuel and deliverables will decrease at exactly the same rate (provided the proportion of cargo to ship remains the same – cargo capacity of necessity would want to remain maximized), as will the margin between them. Power loss will also decrease by this factor (seeing as it is proportional to F=ma) as will the radiator area (seeing as it is proportional to P). The only thing that does not decrease at the same rate is the size of the engine, which only decreases to the square of the mass (since it is proportional to the square of power) – in short, it’s effectively larger. The only reasons I could see for shrinking the MCV would be the (somewhat) great ease of constructing it and handling the power loss, and it’s effectively more expensive for its mass too…

T.Neo
 
Also, engine efficiency with VASIMR does not affect propellant consumption. Propellant is just what you pump into the engine. Efficiency determines how large a powerplant you need- that would either be a nuclear reactor or solar panels. Those provide the energy, the propellant is just working mass.


Again you mention VASIMIR, and this time you have me confused. If it’s not fuel, then what does the mass ratio indicate for VASIMIR? Are you saying that it achieves differing thrusts from the same mass of propellant simply by imparting different energies, in short that propellant mass is wholly independent of the desired velocity or distance? If that’s indeed the case, I can see why you’re partial to it, but wouldn’t you then simply have to deal with the titanic size of the powerplants required to run the drive? The solar cells would dwarf my radiators by several multiples (particularly at that distance from the sun), and nuclear reactors would have the same (if not higher) fuel requirements that mine do.
Have you got what it takes to beat back hostile alien forces and vicious Space Mafia agents to defend liberty and justice for citizens across the galaxy? Join Universal Defense NOW (for more information, please enlist)!

Quote:
 
That is how we first set foot on the planet we have come to know as Zainter, the world that would change our lives forever.
- Remake of Zainter
Offline Profile Quote Post Goto Top
 
T.Neo
Member Avatar
Translunar injection: TLI
 *  *  *  *  *  *  *  *  *  *
Quote:
 
With the exception of Japan, all nations with HDI exceeding 0.9 can be found in America, Europe or Australia, as can most of those with HDI over 0.8, and of the remainder the greater part were either colonies of or historically influenced by said nations. Those that were not and without exception have population growth rates exceeding %1, leading me to believe that it is cultural rather than economic and societal factors that ultimately control birthrate (by the way, could you have provided a legend for the former graph).


Population growth rate doesn't provide a clear example of where overall global population is climbing or declining or by how much. Immigration plays a role too, and that shows where people are moving on the planet, but not what growth is happening where.

It is a better idea to look at birth rates.

Also, many of the nations you say were colonies or had been culturally influenced, were influenced before current population trends (most of them, pre 1960s).

The former graph has black as highest population growth and dark green as lowest population growth, going from black, to red, to yellow, to green.

I am not sure, and I have not researched any data to back this up, but my feeling is that the high growth rates of countries such as the UAE are due to high immigration rates.

Quote:
 
So technology cannot improve even though all past trends suggest this should be, yet we can expect improved living standards in third world countries simply because trends suggest it? Even if you say conditions are steadily improving, so is technology. I am not going to argue global affairs, lest this become a messy debacle in itself, but suffice to say there are enormous barriers to improved living standards in most of these countries, political, economical and cultural, quite a few of those caused by nations which are already developed and none of which will readily give way. Most apparent signs of “progress” are merely grabs for public approval and local manipulation, and if any of those nations did make it out of the gutter we’d probably regret it. If you do not believe that even one of these factors is in any way relevant, then at least do the research or bring up proper arguments to counter, rather than treating them as if they weren’t there.


Ahem? Who would regret it? Not all of us live in the developed world, here... :|

Firstly, I won't deny the grabs for public approval and mnipulation. They certainly exist. But real statistics, economic growth, HDI, etc, are not a sham. If you insist that they are, without any concrete proof, then... we have a conspiracy theory.

I may be wrong, but you also seem to be fairly antagonistic towards the underdeveloped and/or developing world.

Secondly, it depends on what trends you are talking about. Saying "all historical trends show that technology will improve" is untrue, because technology development, for example, reaches an asymptote and stagnates, or because a certain technology is not practical or useful in the way writers of past times forsaw it as.

And you can't equate technology development with human development. Economics/human society is a single system, and while there are historical or cultural variables, it makes just as much sense to equate the same knowledge of human society to the DRC as to a hypothetical civilisation on Mars.

Thirdly, there are arguably trends in specific places in the world that show 'un-development', due to unrest, economic failure, or other reasons (I can't give an example as it isn't something I've thrown much research at).

Quote:
 
If physics were the only constraint facing us then we need never have begun this discussion, T. Neo, since there seem to be plausible spacecraft concepts in circulation - perhaps including one of your own, if you were willing to divulge the details… Economics is the more pressing challenge here, and it’s that even more than the functioning of the ship that has me worried. Even if you take loans or somehow absorb the costs into the company, the fact is that you have employees with set salaries, and they can only realistically wait for their pay check for some time (schoolteachers in Lebanon usually take part-time jobs to cover the summer vacation, so it may be possible for them to wait out the time with other occupations, but there are limits to how long such contracts would last). So long as the MCV can only deliver a set mass, more and more of the vessel’s returns will have to be spent simply on paying those salaries, and your annual income is (obviously) decreased; if given a choice between two vessels with the same fuel requirements corporations will choose the faster, and if the difference in speed is significant enough it may even outweigh cost concerns. I don’t see how you can feasibly sustain operations longer than two years – people simply wouldn’t be able to hold to a contract or company (if companies could even operate on those timescales) nor could the required infrastructure and equipment be set up quickly enough to warrant further initiative, and unless the cargo were almost pricelessly valuable customers would simply turn to more immediately provided Earthly items. If mission time exceeds three years (however you go about that) we might as well forget about Brachistochrone orbits entirely and stick with Hohmann transfers, probably saving us quite a bit of fuel in the process.


Physics defines the economics though. Usually, more physically demanding setups are more costly.

I really don't see what the problem is. For me it is simple. You have expenditure and you have revenue. Let's say (just for example) your yearly expenditure is $500 million. Your transit ship arrives every year and delivers $550 million of material, that you stockpile. You now have $550 million of worth that you can sell to generate revenue. All you need to do is ensure that your expenditure does not exceed your revenue.

Ordering time isn't really an issue, because you'll have that material stockpiled. Or you could simply sell the whole batch off in one go- just as long as you have enough money to cover your expenditure. That is the key.

Quote:
 
In short, you cannot simply ignore the timeframe of the operation and slow your spaceship down to a near standstill to run it cheaply. You might be able to wait that long, but your banker and CEO can’t, and ultimately they’re responsible for giving you the green light: if the proposed craft is to actually stand a chance of seeing use in a corporate-driven world, you’ll need to find a balance between fuel costs and delivery time, and that’s what I’ve been struggling with.


And if the ship costs so much that I cannot truthfully say to my banker and CEO that the enterprise will be viable?

Maybe I'm not seeing the problem here, but as far as I can understand, as long as you have the money to cover your expenditures and run at a profit. It doesn't matter at which rate you aquire that money, as long as there's enough of it.

In the space launch business, contracts are often made over multi-year timescales, with the first money being paid years before the launch (and final payment).

Quote:
 
Lowering the mass of the MCV will not lower the ship’s mass ratio – delta-v will remain unchanged, as will the exhaust velocity (seeing as neither is reliant on mass), hence the quantity of fuel and deliverables will decrease at exactly the same rate (provided the proportion of cargo to ship remains the same – cargo capacity of necessity would want to remain maximized), as will the margin between them. Power loss will also decrease by this factor (seeing as it is proportional to F=ma) as will the radiator area (seeing as it is proportional to P). The only thing that does not decrease at the same rate is the size of the engine, which only decreases to the square of the mass (since it is proportional to the square of power) – in short, it’s effectively larger. The only reasons I could see for shrinking the MCV would be the (somewhat) great ease of constructing it and handling the power loss, and it’s effectively more expensive for its mass too…


When did I suggest lowering the mass of the ship?

I mostly agree though. The only advantage to a smaller MCV is that it would be cheaper to develop and construct (most likely). It'd also be cheaper to operate, but then it'd also bring in less valuable material. It'd have to fly more often to make up for that, and at a set flight rate, that means it'd have to operate for a longer period of time.

Going slower however, means you need less propellant... less massive propellant tanks, a less massive engine to accelerate the propellant, etc...

Quote:
 
Again you mention VASIMIR, and this time you have me confused. If it’s not fuel, then what does the mass ratio indicate for VASIMIR? Are you saying that it achieves differing thrusts from the same mass of propellant simply by imparting different energies, in short that propellant mass is wholly independent of the desired velocity or distance? If that’s indeed the case, I can see why you’re partial to it, but wouldn’t you then simply have to deal with the titanic size of the powerplants required to run the drive? The solar cells would dwarf my radiators by several multiples (particularly at that distance from the sun), and nuclear reactors would have the same (if not higher) fuel requi
rements that mine do.


For rocket propulsion, fuel and propellant can either be seperate or one thing. For chemical rockets, the propellant is the fuel, since the propellant contains the chemical energy to blast itself out the back.

For a nuclear thermal rocket, for example, the fuel (energy source) is located in the nuclear fuel rods in the engine. The propellant contains no energy; the energy is merely imparted to it by the fuel.

For an electric thruster (such as VASIMR) electricity is used to impart energy to the propellant. The propellant again does not contain the energy; this energy is provided by another power source (such as a nuclear reactor or solar array).

For some fusion thrusters (like the ones we've been talking about), propellant and fuel are one and the same. The propellant contains the energy to shoot itself out of the engine. In other fusion concepts, the fusion debris is used to impart energy to a propellant (such as liquid hydrogen).

Secondly, the sizes and masses required of such a system can only be determined by math, estimates and real figures. I'm not willing to believe your statements on this matter without futher research. Most of them don't sound right to me- like solar arrays weighing more than radiators. Solar arrays are a totally different ballgame to thousand-kelvin radiators for a science fiction fusion engine.

In addition, pick a Near Earth Asteroid as your destination. It makes everything far easier, in terms of distance to the sun, dV, transit time, etc. It's probably a more realistic destination, as well.
A hard mathematical figure provides a sort of enlightenment to one's understanding of an idea that is never matched by mere guesswork.
Offline Profile Quote Post Goto Top
 
Zerraspace
Member Avatar
UD Needs You!
 *  *  *  *  *
You know, I did give you a source containing the birthrates of all the world's countries over the past 25 years and projected rates for the next 50 that you could easily have used against me (speaking of which, the birthrates in all Gulf States with HDI exceeding 0.8 is greater than 2 - 2.29 for Bahrain, 2.31 for the United Arab Emirates and 2.66 for Qatar).

T.Neo
 
Also, many of the nations you say were colonies or had been culturally influenced, were influenced before current population trends (most of them, pre 1960s).


That is the significance of their mention; these nations have had the time for local culture to integrate foreign values and are more likely to act like them than those recently taken under wing, which tend to rebel against their new leaders.

T.Neo
 
Thirdly, there are arguably trends in specific places in the world that show 'un-development', due to unrest, economic failure, or other reasons (I can't give an example as it isn't something I've thrown much research at).


Russia and the former states of the Soviet Union shortly after their collapse are good examples, even if their HDI remains fairly high as far as the global average goes.

T.Neo
 
I may be wrong, but you also seem to be fairly antagonistic towards the underdeveloped and/or developing world.


To be honest I thought I was being more antagonistic towards the developed world. My reasons I will keep to myself, thank you.

T.Neo
 
Ahem? Who would regret it? Not all of us live in the developed world, here... :|


A change in the tip of the worldwide pyramid of power is always troubling, especially for the developing nations which cannot adequately defend against it, particularly in this age of globalization. I don't live in the developed world either, in case my near constant mention of a small country somewhere on the shores of the Mediterranean doesn't strike a bell... although to be honest, I thought you were British. Where do you live?

Zerraspace
 
I am not going to argue global affairs, lest this become a messy debacle in itself.


May we please respect the desire to avoid starting a dogfight and lay this to the ground? There is too much potential for heated clashes of opinion and given our locations I'm not sure our teachers could even look each other in the eye. Physics we can resolve, politics we can't.

T.Neo
 
Secondly, it depends on what trends you are talking about. Saying "all historical trends show that technology will improve" is untrue, because technology development, for example, reaches an asymptote and stagnates, or because a certain technology is not practical or useful in the way writers of past times forsaw it as.

And you can't equate technology development with human development. Economics/human society is a single system, and while there are historical or cultural variables, it makes just as much sense to equate the same knowledge of human society to the DRC as to a hypothetical civilisation on Mars.


The general progress of technology has been positive, and conquerors of recessing empires often redeveloped or re-archived much of their lost knowledge, arts and culture (take pretty much any Mesopotamian civilization after Sumeria and the early Arabic empires such as the Abbasids). To the extent of our knowledge we are more advanced than in any other point in human history, and our unequaled capabilities of data storage coupled with globalization to spread and ingrain it should provide some protection against total withdrawal (unlike those earlier empires, our technological theory would be available to practically anybody in the world, giving an opportunity for any advancing power to build upon it).

T.Neo
 
I really don't see what the problem is. For me it is simple. You have expenditure and you have revenue. Let's say (just for example) your yearly expenditure is $500 million. Your transit ship arrives every year and delivers $550 million of material, that you stockpile. You now have $550 million of worth that you can sell to generate revenue. All you need to do is ensure that your expenditure does not exceed your revenue.

T.Neo
 
Other things aside, the other expenses are the issue. In space launch, only a tiny fraction of the total cost is propellant. Most has to do with the manufacture of the vehicle and the operation of the facility that launches it.

Development cost is divided over the number of flights in a program, and unit cost divided over the number of flights of a unit.


Consider first that a ship must proceed the MCV to the asteroid in order to place the mining equipment, and even more time must be given for the equipment to actually collect enough metals to fill the MCV. Even if the equipment delivery ship is never meant to return that adds at least another year in our current scenario before the business can bring in its first income, which further delays the chances of its perusal. Companies have amazingly short attention spans and will not pursue projects without almost immediate returns, particularly if they have enormous expenses attached to them, which implies that they have a reliable means of generating profit beforehand anyway.

I see the point you're trying to make - so long as revenue covers expenditure, the mission is viable. What I'm trying to get at is that there are costs related to how long it takes for this mission to occur. Employees are not machines that can be stuffed in the closet or deactivated for the length of the mission, they need to be paid for the time it takes the MCV to get there, and the money owed increases with every extra day the ship is in orbit; nor can the company simply go to sleep without dissolving itself for the resulting two years, it takes even more cash to maintain itself and whatever equipment is on Earth to receive the MCV when it returns. The amount of metals you're bringing back is not changing; your revenue is not changing, yet it has to cover these increasing costs. Your example illustrates it well - say your yearly expenditures (without fuel) are $500 million, and the ship can only hold $550 million dollars worth of metal. There is a possibility of positive retinue for yearly trips (depending on how quickly those $50 million disappear) - two-year trips, wherein $550 million must pay for over one billion dollars, not so.

Besides which, if you can't convince the space enthusiast (namely me), how will you convince them?!


T.Neo
 
This ship is really fancy- it gives me an overwhelming "Star Trek" feeling. Even if you had the technology to make a ship like that work, you wouldn't build a ship like that- at least not for a task like this.

T.Neo
 
My overwhelming feeling is that this huge super-accelerating megamacho spacecraft will not result in a profitable operation.

T.Neo
 
When did I suggest lowering the mass of the ship?


Technically, you never openly suggested it, but that was the implied feeling.

T.Neo
 
Secondly, the sizes and masses required of such a system can only be determined by math, estimates and real figures. I'm not willing to believe your statements on this matter without further research. Most of them don't sound right to me- like solar arrays weighing more than radiators. Solar arrays are a totally different ballgame to thousand-kelvin radiators for a science fiction fusion engine.


Assuming wet mass of 9000 tons (corresponding to the MCV dry mass with cargo) and maximum exhaust velocity (294000 m/s) with acceleration of 1 milligee and 60% efficiency, the power requirements of a VASIMIR driven spacecraft are roughly 22.05 GW; even at one tenth the exhaust velocity that's still on the order of gigawatts. As of the end of 2010 global solar power production was 40 GW, and that's receiving several times the insolation available at the distance of the asteroid. The world's largest photovoltaic plant, the Sarnia Photovoltaic Power Plant, contains about 966,000 square meters of photovoltaic cells, and only provides power of 80 MW. What does that tell you?

Nevertheless, I will listen to figures if you can provide them. I would also like to know exactly how much propellant such a vehicle needs, seeing as it seems to be independent of mass ratio (seeing as there must surely be a limit to how much energy can be imparted to any set mass of it).

T.Neo (Who else?)
 
In addition, pick a Near Earth Asteroid as your destination. It makes everything far easier, in terms of distance to the sun, dV, transit time, etc. It's probably a more realistic destination, as well.


I chose a ridiculous target so as to prove a point. If we could make mining the farthest meaningful asteroid a profitable operation, then any closer ones would be easy pickings. Do you have a particular target in mind?

As if I weren't long-winded before... :r
Edited by Zerraspace, Jan 22 2012, 05:30 PM.
Have you got what it takes to beat back hostile alien forces and vicious Space Mafia agents to defend liberty and justice for citizens across the galaxy? Join Universal Defense NOW (for more information, please enlist)!

Quote:
 
That is how we first set foot on the planet we have come to know as Zainter, the world that would change our lives forever.
- Remake of Zainter
Offline Profile Quote Post Goto Top
 
lamna
Member Avatar


He's a South African, an Anglo-African if I'm not mistaken, or at least one of the civilized Dutch.

Small country on the shores of the Mediterranean? Good god man, could you be more vague? That could be anywhere from Monaco to Lebanon!

Though most of it is quite well developed. The Balkans are a bit behind, as is Mashriq and various parts of North Africa. But I don't think there is anywhere that isn't fairly well developed. Well things are rather dire in the Gaza Strip, but I doubt you're from there.
Living Fossils

Fósseis Vibos: Reserva Natural


34 MYH, 4 tonne dinosaur.
T.Neo
 
Are nipples or genitals necessary, lamna?
[flash=500,450] Video Magic! [/flash]
Online Profile Quote Post Goto Top
 
T.Neo
Member Avatar
Translunar injection: TLI
 *  *  *  *  *  *  *  *  *  *
Quote:
 
You know, I did give you a source containing the birthrates of all the world's countries over the past 25 years and projected rates for the next 50 that you could easily have used against me (speaking of which, the birthrates in all Gulf States with HDI exceeding 0.8 is greater than 2 - 2.29 for Bahrain, 2.31 for the United Arab Emirates and 2.66 for Qatar).


Yeah... about that, I seem to be having a little bit of trouble noticing hyperlinks, it seems. :|

The Gulf States seem to be outliers. Just because they're an exception to the rule doesn't mean the rule itself is an exception.

Quote:
 
That is the significance of their mention; these nations have had the time for local culture to integrate foreign values and are more likely to act like them than those recently taken under wing, which tend to rebel against their new leaders.


I'm not sure if we're on the same page here, what I was trying to say is that these nations were only (or predominantly) influenced pre 1960 or so.

The time passed since colonisation or influence has ended will mean the local culture will be more diverged from that of the previous regime. Precepts of the coloniser's culture will be discarded for or augmented by more traditional values or even new occurances within the culture post-colonisation.

Quote:
 
A change in the tip of the worldwide pyramid of power is always troubling, especially for the developing nations which cannot adequately defend against it, particularly in this age of globalization.


Which is why the free world* must wield its power so that its scope encompasses more, not fewer nations.

*And actually live up to its name at the same time, which is a tall order.

Quote:
 
I don't live in the developed world either, in case my near constant mention of a small country somewhere on the shores of the Mediterranean doesn't strike a bell... although to be honest, I thought you were British. Where do you live?


I seem to be missing the mention of this country as well. Obviously I am not paying enough attention (as lamna said, it is pretty vague though).

I am predominantly Anglo-African, with varied European ancestry. I live in South Africa.

Quote:
 
given our locations I'm not sure our teachers could even look each other in the eye.


That's fine, I couldn't look my teachers in the eye myself. I couldn't care what they would have to say. ;)

Quote:
 
The general progress of technology has been positive, and conquerors of recessing empires often redeveloped or re-archived much of their lost knowledge, arts and culture (take pretty much any Mesopotamian civilization after Sumeria and the early Arabic empires such as the Abbasids). To the extent of our knowledge we are more advanced than in any other point in human history, and our unequaled capabilities of data storage coupled with globalization to spread and ingrain it should provide some protection against total withdrawal (unlike those earlier empires, our technological theory would be available to practically anybody in the world, giving an opportunity for any advancing power to build upon it).


All fair points, but I don't what direct relation this has to the development of specific technologies/technological fields.

Quote:
 
Consider first that a ship must proceed the MCV to the asteroid in order to place the mining equipment, and even more time must be given for the equipment to actually collect enough metals to fill the MCV. Even if the equipment delivery ship is never meant to return that adds at least another year in our current scenario before the business can bring in its first income, which further delays the chances of its perusal. Companies have amazingly short attention spans and will not pursue projects without almost immediate returns, particularly if they have enormous expenses attached to them, which implies that they have a reliable means of generating profit beforehand anyway.


I don't see it as fair to say that companies are notoriously shortsighted. Companies often take on projects that only pay off after several years.

Quote:
 
I see the point you're trying to make - so long as revenue covers expenditure, the mission is viable. What I'm trying to get at is that there are costs related to how long it takes for this mission to occur. Employees are not machines that can be stuffed in the closet or deactivated for the length of the mission, they need to be paid for the time it takes the MCV to get there, and the money owed increases with every extra day the ship is in orbit; nor can the company simply go to sleep without dissolving itself for the resulting two years, it takes even more cash to maintain itself and whatever equipment is on Earth to receive the MCV when it returns. The amount of metals you're bringing back is not changing; your revenue is not changing, yet it has to cover these increasing costs. Your example illustrates it well - say your yearly expenditures (without fuel) are $500 million, and the ship can only hold $550 million dollars worth of metal. There is a possibility of positive retinue for yearly trips (depending on how quickly those $50 million disappear) - two-year trips, wherein $550 million must pay for over one billion dollars, not so.


The numbers I presented aren't representative of anything, they were only intended to illustrate my point.

I really, really do not see what the problem is here. I don't get it. It's simple maths.

Maybe you just want a more powerful spacecraft? :ermm:

Quote:
 
Besides which, if you can't convince the space enthusiast (namely me), how will you convince them?!


I'm having a much harder time convincing myself of the supermacho fusion drive than I am of the low event-rate, that's my concern.

Quote:
 
Technically, you never openly suggested it, but that was the implied feeling.


Fair enough, that is true. But I only imagined it coupled with essentially a total redesign of the vehicle concept.

Quote:
 
Assuming wet mass of 9000 tons (corresponding to the MCV dry mass with cargo) and maximum exhaust velocity (294000 m/s) with acceleration of 1 milligee and 60% efficiency, the power requirements of a VASIMIR driven spacecraft are roughly 22.05 GW; even at one tenth the exhaust velocity that's still on the order of gigawatts. As of the end of 2010 global solar power production was 40 GW, and that's receiving several times the insolation available at the distance of the asteroid. The world's largest photovoltaic plant, the Sarnia Photovoltaic Power Plant, contains about 966,000 square meters of photovoltaic cells, and only provides power of 80 MW. What does that tell you?


The first thing it tells me is that the available power per square meter is lower on the Earth's surface than in space. We have an atmosphere in the way.

The second thing it tells me is that area may mean total plot area on which the power plant is located, rather than solar cell area alone. I'm probably wrong here though.

If we take a wattage per square meter of 1300w/m^2, and assume an efficiency of 0.24 (apparently currently achievable) and that the solar arrays are pretty well aligned with the Sun (like those on the ISS, for example), I get a panel that, if expressed as a square, would be 8.4 kilometers on a side.

...which is quite a big number, and there are also other constraints, etc, but it may be possible if the support structure and panels are light enough. It is probably far less challenging than a fusion drive.

There is also still nuclear power. There are a lot of issues that come with that (it also needs radiators!) but the effort may be worth it. Depends on how the systems trade against eachother.

Quote:
 
Nevertheless, I will listen to figures if you can provide them. I would also like to know exactly how much propellant such a vehicle needs, seeing as it seems to be independent of mass ratio (seeing as there must surely be a limit to how much energy can be imparted to any set mass of it).


You're misunderstanding me here: the amount of propellant the vehicle needs is the mass ratio. And I never said anything about how much energy is imparted to the propellant, just that it is imparted to the propellant by an outside source and does not come from the propellant itself.

The mass of the power generator is part of the mass of the vehicle, not the propellant.

Quote:
 
Do you have a particular target in mind?


Any well accessible NEO would probably do. Perhaps 4660 Nereus would do, dV to rendezvous with it is apparently ~5km/s, it is M-type, though fairly small (on the order of hundreds of meters in dimention). Plus, considering the forum, it would make a nice in-joke... :ermm:
A hard mathematical figure provides a sort of enlightenment to one's understanding of an idea that is never matched by mere guesswork.
Offline Profile Quote Post Goto Top
 
Spugpow
Member Avatar
Prime Specimen
 *  *  *  *  *  *  *
Quote:
 
Of course there are more underdeveloped and developing nations on the planet than their are developed ones. But there's nothing stopping developing nations from, well, developing. They'll get there, the question is a matter of when.


Quote:
 
Which is why the free world* must wield its power so that its scope encompasses more, not fewer nations.


Unfortunately, the world can't even support the number of first worlders it has _now_ . Can you imagine what things would be like if even the population of China consumed the same amount of energy and resources per person that the U.S. does today?
Edited by Spugpow, Jan 23 2012, 03:52 AM.
My deviantart page: http://amnioticoef.deviantart.com/
Offline Profile Quote Post Goto Top
 
lamna
Member Avatar


I've got something that pisses me off about Space Enthusiasts! I just remembered, I wish they'd stop whining about how much better funded militaries are.

The fact of the matter is, if we don't send probes to Jupiter, we don't learn about Jupiter which is a shame, but that's all it is. A shame. If we don't have the very best military equipment, people get killed.

They bitch and complain about governments using space agencies as places to scrape funding from when things get rough, then get misty-eyed at the thought of doing the same to their military.
Edited by lamna, Jan 23 2012, 04:55 AM.
Living Fossils

Fósseis Vibos: Reserva Natural


34 MYH, 4 tonne dinosaur.
T.Neo
 
Are nipples or genitals necessary, lamna?
[flash=500,450] Video Magic! [/flash]
Online Profile Quote Post Goto Top
 
T.Neo
Member Avatar
Translunar injection: TLI
 *  *  *  *  *  *  *  *  *  *
What do you mean "world can't support"? It depends on how resources are utilised.

And first world does not mean US, there are plenty first world countries that are far more ecologically conservative than the US.

The alternative of stunting development, leaving people in undesirable conditions with large amounts of inequality, is undesirable. You pick.
A hard mathematical figure provides a sort of enlightenment to one's understanding of an idea that is never matched by mere guesswork.
Offline Profile Quote Post Goto Top
 
Zerraspace
Member Avatar
UD Needs You!
 *  *  *  *  *
Spugpow
 
Unfortunately, the world can't even support the number of first worlders it has _now_ . Can you imagine what things would be like if even the population of China consumed the same amount of energy and resources per person that the U.S. does today?


My feeling is that consumption of resources is increasing more quickly than our ability to extract them. The resources necessary to sustain modern civilization and its standards do exist, we simply cannot implement or use them well enough, which for all intent and purposes, might as well be a deficit.

T.Neo
 
It depends on how resources are utilised.


If you expect even or even mildly considerate distribution of resources, then you're a better man than I.

T.Neo
 
Stunting development, leaving people in undesirable conditions with large amounts of inequality, is undesirable. You pick.


I don't see that the common citizen will be given a choice in the matter.

Zerraspace
 
Lebanese seem to think they found America first (back when the world knew them as the Phoenicians)

lamna
 
The middle east isn't all that well developed.

Zerraspace
 
I actually live here and I've spent years in the US, so I think I'm qualified to judge the differences between them. You have a valid point regarding immigration (but it's a point I did bring up earlier), and the general Middle East is far from wonderful...

Zerraspace
 
Schoolteachers in Lebanon usually take part-time jobs to cover the summer vacation...

Zerraspace
 
I don't live in the developed world either, in case my near constant mention of a small country somewhere on the shores of the Mediterranean doesn't strike a bell...


I had made further mention of my current residence beforehand, but in retrospect most of this was in Member Introductions. I live in Lebanon, and don't be fooled by the apparently high HDI: this only applies to the capital and coastal cities, home to perhaps 75% of the population where living conditions almost equal those in first world countries (aside from the occasional bombing every decade). For the rest of the nation power and running water aren't even guarantees, and suffice to say I am not one of the more blessed "majority". Lebanon is also infamous for having the worst internet quality in the world (we had known this for years, and the BBC actually posted an article on the matter), hence my response times and research may be a little less than satisfying.

T.Neo
 
That's fine, I couldn't look my teachers in the eye myself. I couldn't care what they would have to say. ;)


Whether or not you are more intelligent than your teachers does not mean that they don't have a point. If nothing else they provide you a starting point from which to complete or correct their information.

T.Neo
 
If we take a wattage per square meter of 1300w/m^2, and assume an efficiency of 0.24 (apparently currently achievable) and that the solar arrays are pretty well aligned with the Sun (like those on the ISS, for example), I get a panel that, if expressed as a square, would be 8.4 kilometers on a side.

...which is quite a big number, and there are also other constraints, etc, but it may be possible if the support structure and panels are light enough. It is probably far less challenging than a fusion drive.

There is also still nuclear power. There are a lot of issues that come with that (it also needs radiators!) but the effort may be worth it. Depends on how the systems trade against eachother.


T.Neo
 
You're misunderstanding me here: the amount of propellant the vehicle needs is the mass ratio. And I never said anything about how much energy is imparted to the propellant, just that it is imparted to the propellant by an outside source and does not come from the propellant itself.

The mass of the power generator is part of the mass of the vehicle, not the propellant.


I notice that you did not attempt calculating the weight of said panel. Assuming it is composed of 0.1 mm thin sheets of monocrystalline silicon with approximate density of 2329 kg/m3, the weight of the entire structure would be roughly 16,433 tons, and this is before adding supporting structures. My radiators weigh merely 40 tons before any such addition, and while more supporting structure will be required per area even you did not express the belief that this would range into the mass of tens of thousands of tons. I should also note that the calculated power ratings were for a wet mass of 9000 tons, which suffice to say we have well exceeded.

Nuclear power is no solution, seeing how you must now bring fuel equal if not greater than that required by a fusion drive as well as the additional weight of propellant (which, if mass ratio is any indicator, is roughly 61760 tons for the described journey at maximum exhaust velocity of 294000 m/s, compared to combined ship and cargo weight of 9000 tons). Would it not simply be easier to use the nuclear power to propel the ship directly?

You will have to provide me numbers similar to those I've given you if you intend to convince me, because your explanations are not making matters any clearer. VASIMIR might provide a suitable predecessor to the fusion drive, but energy, weight and fuel comparisons lead me to believe that the fusion drive is ultimately superior.

T.Neo
 
I really, really do not see what the problem is here. I don't get it. It's simple maths.


That seems fair, seeing as I cannot understand what reason you have to favor the VASIMIR. Perhaps some other interested member should attempt to explain, or for the purposes of this discussion we should consider ourselves both right, seeing as we cannot prove each other wrong?

T.Neo
 
Any well accessible NEO would probably do. Perhaps 4660 Nereus would do, dV to rendezvous with it is apparently ~5km/s, it is M-type, though fairly small (on the order of hundreds of meters in dimention). Plus, considering the forum, it would make a nice in-joke... :ermm:


Yes, perhaps we should name the first MCV Riparia. Do you think Empyreon would mind? :angel:

Given the length of our journey and the relatively short orbital period of 4660 Nereus (roughly 1.82 years), we probably have some choice in flight time. Let us assume that the MCV is only launched towards the asteroid during the four months when Earth is closest to its projected position. Therefore the Earth at maximum forms a 45 degree angle with the future position of the asteroid, and the asteroid achieves its maximum distance from the Earth when at aphelion - 2.025 AU. Through some basic trigonometry, we can determine that the greatest distance between the Earth and asteroid for said launches is 1.496 AU.

The MCV remains the same as before - dry mass of 1000 tons, with 8000 tons of cargo capacity and accelerating at 1 milligee towards its destination with 20% engine efficiency. As determined, delta-v equals 94729 m/s, and time till arrival is nearly 110 days. Mass ratio equals 1.0358, hence 322.7 tons of fuel will be required for the return journey and 47.35 tons will be required for the approach, with an extra 30 in reserve making for a grand total of 400 tons. However, this makes the assumption that the Earth's ending position is relatively unchanged near the end of the journey, when in fact during the near four months of approach the Earth will have moved significantly across its orbit, and its actual position upon arrival will be far removed from that of its origin. To avoid adding extra fuel, the MCV will remain at the asteroid for 4 or 5 months, giving it plenty of time to be loaded and for the Earth to move back towards its starting distance. This way, fuel costs of $0.74 million (with lifting costs of $88 million) and operation times only slightly over one year are made possible.
Have you got what it takes to beat back hostile alien forces and vicious Space Mafia agents to defend liberty and justice for citizens across the galaxy? Join Universal Defense NOW (for more information, please enlist)!

Quote:
 
That is how we first set foot on the planet we have come to know as Zainter, the world that would change our lives forever.
- Remake of Zainter
Offline Profile Quote Post Goto Top
 
lamna
Member Avatar


Well you could always change your nationality if you didn't want us to be so confused.
Living Fossils

Fósseis Vibos: Reserva Natural


34 MYH, 4 tonne dinosaur.
T.Neo
 
Are nipples or genitals necessary, lamna?
[flash=500,450] Video Magic! [/flash]
Online Profile Quote Post Goto Top
 
Zerraspace
Member Avatar
UD Needs You!
 *  *  *  *  *
Point taken, lamna. I am also an American citizen, and when I first joined the forum I was in the US, so when I moved I never really saw the need to change it.
Edited by Zerraspace, Jan 23 2012, 07:17 AM.
Have you got what it takes to beat back hostile alien forces and vicious Space Mafia agents to defend liberty and justice for citizens across the galaxy? Join Universal Defense NOW (for more information, please enlist)!

Quote:
 
That is how we first set foot on the planet we have come to know as Zainter, the world that would change our lives forever.
- Remake of Zainter
Offline Profile Quote Post Goto Top
 
lamna
Member Avatar


Whereabouts in Lebanon are you then, if not the capital? Hopefully not to far South or in the mountains, they were bad enough before Assad started his foolishness.
Living Fossils

Fósseis Vibos: Reserva Natural


34 MYH, 4 tonne dinosaur.
T.Neo
 
Are nipples or genitals necessary, lamna?
[flash=500,450] Video Magic! [/flash]
Online Profile Quote Post Goto Top
 
1 user reading this topic (1 Guest and 0 Anonymous)
Go to Next Page
« Previous Topic · General Discussion · Next Topic »
Add Reply