Satellite at this price, wow ! But even then. Far more logic would be 4G Wimax (towers have 3-4Km range in flat areas, and can service hundreds of active customers), a single satellite can't provide the same bandwidth that a dozen 4G towers (with 6 antennas each) can. 4G latency is 50-100ms, while satellites are typically 1 second plus. So you can think of VOIP / online games with 4G (even though it won't be a great experience, while satellite it's a non starter).
And there's the unlicensed 5GHz alternative (WISP), that need line of sight, but use very cheap equipment, the WISP can afford to have a small tower every Km (largest cost will be power, rent rather than the WISP tech), in areas where customers are desperate for better service, they might be able to put towers rent free in exchange for providing a viable alternative to wired monopolies.
You must be some 2Km away from the DSLAM (11k ft), or you're on some old, rusty cable. This is the kind of situation that would be a non event on fiber. 4G (Wimax) wireless or 5GHz wifi should outperform this easily. I support customers that use extremely cheap p2p unlicensed radios with 2,5Km links (with clear line of sight) delivering 45Mbps up+down performance with ease.
In most cases the bottleneck is the cost of laying a brand new network with as little as possible visual pollution / cost and regulatory hurdles. Designing a network with a limit of 250 meters cable run to each customer will require an insane numbers of G.fast DSLAMs, this alone makes this tech kinda dead on arrival. GPON allows for 10Km fiber runs, and share a fiber strand for up to 64 users, the fiber is then split as it gets further away from the wiring cabinet. 10Km fiber runs are a waste for dense areas, but leave the flexibility to service a few faraway customers in many cases. Comparing tech that requires 250 meters cabling range to tech that can do 10000 meters without trouble isn't even fun !
But the issue of monopoly first requires a new entrant interested in overlaying the network, in such a case, I see zero business case for G.fast.
G.fast is faster than VDSL2, but this 1 Gbps to the subscriber is very unrealistic. 1 Gbps speeds will only work for customers ultra close to the wiring closet. But let's face it, even 200-300 Mbps is ultra fast internet (copper or not).
35Mbps down, 3Mbps up from GVT in Brazil already here. In my case, I couldn't get a stable connection with one modem they supply, had to get the better modem, at about 400 meters external cable run plus another 100 meters internal cabling, in this distance, G.fast might pump my top theoretical speed (as detected by the modem from 50Mbps to maybe 200Mbps).
Prices up to 35mbps are very affordable, the next step (50/5) has a large price jump. So the issue isn't the technology here, it's cost (AND RANGE). In our case, telcos are already moving towards 100% fiber. While VDSL2 is (and G.fast will be) very range limited, GPON and P2P fiber can handle up 10 Km fiber runs with performance to spare, allowing for less wiring cabinets across town in a pure fiber network vs today's mixed fiber/copper networks, back to my telcos case, they were forced to design the network with a maximum cable run of 600 meters to every customer they service, requiring one wiring cabinet (in reality a tiny remote POP).
If the same network were designed from scratch using GPON only, they could have opted for up to 3Km to each customer, resulting in 1/10th in the number of cabinets, also GPON / GEPON fiber splitting allows ultra dense cabinets, with a 20 fiber strands handling two thousand customers (compared to 2000 copper pairs for the same two thousand customers). Copper cabinets for 1000 users is the size of a double door refrigerator, while GPON for 2000 users is less than the size of a mini bar.
So I'm not sure there will be too many business cases for maintaining copper networks, except in rare cases of extremely dense networks with top notch (recently laid) copper.
Finally, VDSL2 modems already use way more power than GPON subscriber units, I bet those G.fast modems will be small power hogs !
This tech is coming to the action way too late. Fiber will take over.
My bad... Beta decay doesn't add protons to the nucleus, it converts neutrons into protons+electron in this case happens twice:
U-238 + neutron = U-239
U-239 (beta decay) -> Np-239 (one more proton/electron, one less neutron)
Np-239 (beta decay) -> Pu-239 (one more proton/electron, one less neutron) That's what happens when you pretend you try use chemistry knowledge 20 yrs after studying it (and not using).
I'm also not a physicist, but this explanation must the right, because it's the same in multiple sources (Wikipedia, nuclear lectures from multiple sources).
For explanation of why the double beta decay adds a proton to the nucleus, see here:
The problem is fast reactors are un economical. We need breeder thermal reactors, that's really though to do ! The only known design that might do that trick is Thorium / U-233 based.
Specially since this is U-235 (the primary nuclear fuel currently in use on civilian nuclear power stations). Using U-235 for nuclear weapons is only common in first generation nuclear programs. You see, enriching uranium is a PITA (separating isotopes), while separating plutonium from anything else is soooo much easier (chemical separation). The trick is having a reactor that takes thatplentiful U-238 and hit it with a neutron to make Pu-239 (that nasty plutonium used in bombs). Plutonium isn't naturally occurring. If there are still US nuclear weapons that use U-235, those must be the oldest in the inventory. So, any association from that Russian nuclear fuel with nuclear bombs is only made by those without any nuclear physics knowledge.
U-238 is 99,3% of natural uranium. It's the stuff that enrichment removes from the base material (producing depleted uranium). A holy grail of peaceful nuclear is breeding Pu-239 from U-238 on the fly inside the reactor and the fission it, but having this happen mixed with all kinds of nasty beta emitters that make using that Pu-239 for nuclear weapons another PITA. Beta radiation is the stuff that really kills (used to kill cancer cells in radiotheraphy), but inside the reactor it's not an issue.
Not to mention that everybody that has significant stockpiles of Pu-239 want to destroy most of it ! Most nuclear reactors can't deal with nuclear fuel with lots of plutonium.
On the LFTR, ok, so it wasn't a full scale reactor, but if they made it work with 60s tech, it should be piece of cake to make a full scale one with today's advanced metalurgy, computer simulations,...
A startup has announced it's seeking regulatory aproval for a prototype reactor that combines the advantages of IFR with LFTR (they have a catchy name, WAMSR, Waste Annihilating Molten Salt Reactor), designed to use water reactor waste as fuel, but with salts as coolant instead of sodium. Very sharp girl gave the presentation. The presentation was more of a PR thing, but this would kill any interest in IFR reactors.
So all those people working on LFTR's, they all just sucking up investment money ?
What's the problem with LFTR (Liquid Fluoride Thorium Reactors) ? Don't tell me they are new tech, remember the nuclear powered bomber US Air Force project in the 60s, that was an LFTR project !
Humm, if this was 100% true, then why do the Ruskies keep those IFR "trouble makers" in operation ? If they're so bad, then why didn't we had a Chernobyl/Fukushima style nuclear accident with IFR reactors ?
You need to consult with the Nuclear History experts, that actually analyzed what was killed for technical reasons versus what was killed for political reasons !
The answer is North American and European countries don't want to invest in learning all there is safely operate IFR/LFTR reactors. The water reactor knowledge was acquired from nuclear weapons programs.
My contention is the light water reactor are conceptually the worse type of tech, they give a bad rep to everything else, and prevents heavy investments into alternatives due to Green Peace / Green Party brain dead everything nuclear is bad plus hidden forces I'll explain in a bit. They work, but create nasty toxic waste (even with uranium and plutonium reprocessing, the waste still has enormous nuclear energy left)
Another important tid bit of information. A Thorium molten salt reactors was operated in the 60's (under an experiment for the US Air Force, before ICBMs were reliable). Aka LFTR (Liquid Fluorine Thorium Reactors). LFTR use thermal neutrons (moderated by graphite), so have none of the neutron flux issues. And they use molten salts, so they don't have the sodium reactivity issues (LiF2 and BeF salts). And that project was executed with a tiny fraction of the fast breeder plutonium project. And killed for political reasons (Nixon's nuclear advisors were sold on Plutonium breeder reactors even though they knew those projects were likely to incur huge cost overruns). It's all recorded in the White House tapes from the 70s. And it's on youtube.
I believe that IFR reactors are the best solution to get rid of nuclear waste (produce energy and reduces nuclear waste down to low radioactivity elements). Perhaps 20-30 reactors (just enough to use up all the nuclear waste from water reactors). And for mass production LFTR might be the solution to the worlds energy problem.
All we need is transfer 100% of the nuclear fusion pipe dream programs into advanced nuclear fission projects, focused on funding only technologies that worked / are working now, IFR and LFTR reactors for instance.
Then there's the real problem. People in a position to actually influence those projects are in bed with the coal / oil lobby, and they know that LFTRs would kill Coal directly and Oil indirectly (with electric cars). That's the real reason many of those projects aren't being funded today !!!!!
So the real answer is: Solar and Wind are ultra expensive techs that give coal / natural gas another 10-20 yrs life, while LFTRs could kill coal and natural gas in 10 yrs if we went Manhattan Project on this. Plentiful base load energy instead of ultra expensive energy that don't work at night (solar) or only work 25% of the time (wind).
IFR reactors stand for INTEGRAL, FAST reactors (I'll explain why INTEGRAL and why FAST bellow)
IFR reactors promise (actually it has been done, economically by the former USSR, still in operation in Ukraine and a few other former USSR countries): 1 - Near total utilization of high energy elements (only low radioactivity elements removed as waste like Cs, Sr, Xe, removed elements are low radioactivity, decay in a century instead of 50000 yrs as in water reactor waste) Since the fuel is liquid and mixed with the coolant:
2 - Xenon bubbles to the top of the reactor and is removed (look up Xe-135 problems in conventional water/solid fuel reactors)
3 - adding new fuel and removing fission end products can be done without shutting down the reactor
4 - Low pressure operation (increase safety and reduces core reactor construction costs)
5 - High temperature operation results in 50% utilization of heat instead of 33% in water reactors 6 - IFR Nuclear final materials is far cheaper and safer to dispose (no Yuca mountain required), some materials actually have industrial usage (more revenue) 7 - IFR Nuclear can take nuclear waste from water reactors as fuel (free fuel, solve the nuclear waste problem from current nuclear reactors)
If you're interested, here comes the long explanation:
Exatly right, IFR reactors burn both U-235, U-238 (transmuted into Pu-239), and all transuranics, exactly what they call nuclear waste in water reactors. Large presence of transuranics kill the water reactor operation, but the IFR reactor burns it normally. Score 1 for IFR reactors.
Since the fuel is a liquid in IFR reactors, Xe-135 neutron poisoning (that is a serious issue in water reactors) is a non-issue, Xe-135 is a gas, with the fuel molten in the core, Xe-135 just bubbles up and gets captured in bottles, score 2 for IFR reactors
Fast reactors don't moderate neutrons, keeping them at high speed. Being fast, they're less likely to hit nucleus of fuel, but when they do, the chances are 99% of producing a nuclear fission (except for elements that require a neutron capture like U-238 and Th-232). That lower probability is compensated by:
1 - More nuclear fuel present
2 - Lack of large number of control rods (which are heavy neutron capturing elements), they're unnecessary
3 - Since the fuel is liquid, the quantities of fuel kept in the reactor can be tuned to an optimal level, in contrast with reactors that use solid fuel (that start with too much fuel, and end with just enough fuel, compensated by the control rods)
Since the fuel is liquid, it's easy to replace say 10% of old fuel with new fuel and take that 10% into a cheap on site reprocessing (hence INTEGRAL), then 10% number is likely wrong, just for argument's sake. This reprocessing is only meant to remove true nuclear waste (keeping Uranium, Plutonium, Thorium and all transuranics in), so it's far simpler and cheaper than Purex, Urex plants (remove only elements with nuclear weight much lighter than nuclear fuel and much heavier than the molten salt). Score 3 for IFR reactors.
Using a liquid sodium or salt to disolve the fuel and carry heat has another very interesting characteristic, those chemicals are liquid up to a very high temperature in low pressure (allowing for operation at 800 C, while water reactors operate at 350 C) this allows for gas turbines (using supercritical CO2 for instance) with conversion efficiency of 50% compared to 33% of water reactors. Score 4 for IFR reactors. As a matter of fact, sodium/salts require the reactor to reach 400 C before they become liquids (not a problem in any way).
This high temperature operation is achieved at very low pressure (no more than 2 or 3 atmospheres), compared to 150 atmospheres in light water reactors and 70 atmospheres in heavy water reactors greatly simplify the reactor design (95% of the main water reactor building size is due to the need to space in case there's
The Russians have a few Sodium cooled reactors operating for decades, if they can do it, why can't the US ?
I'm not talking about tiny experimental reactors babysat by experts 24x7, but large scale power plants that aren't even in Russia (Kazakhstan / Ukraine), that have been in production for 30+ years. There's no water inside the reactor, sodium doesn't corrode Steel, while water does. With all that said, LFTR sounds like a more interesting option, except that S-PRISM promises a solution to the nuclear waste from water reactors. LFTR uses Thorium, in a thermal reactor and is cooled by molten salts (chemically stable) quite the opposite of liquid sodium.
Is there an alternative that does what S-PRISM does, but with molten salt instead of molten metal ?
It's interesting the bait model employed today by GE and Westinghouse. They sell reactors at essentially cost price, then overcharge for the nuclear fuel. They have zero interest in reactors that use liquid fuel, since there's almost no money to be made in the fuel. Specially reactors that can run on cheap thorium (LFTR-Salt cooled), waste from water nuclear reactors, plutonium (IFR-Sodium cooled). If they have something interesting, they are waiting for a big govt handout to actually start it (GE-Hitachi S-PRISM).
And govt aren't helping either... S-PRISM promisses to extract 100x more energy from uranium than water cooled/moderated reactors, theoretically they're also a solution to the nuclear waste storage problem. But if it really were that great (with no hidden catch), then why shouldn't GE take one or two billion out of their huge cash reserves and make it happen quickly ?
That's the final point, those huge corporations always have some hidden poop hidden in the thing. Like the true cost of water nuclear plants considering there's no standardized nuclear fuel market (GE fuel can't be used in Westinghouse plants and vice-versa).
But the conversion to a dead lift vehicle would cost... Humm... Let me guess... Some 41 billion dollars ? That's called SLS ! This number is a realistic assessment by people that have no incentive to hide the real cost of things. http://en.wikipedia.org/wiki/Space_Launch_System#Program_costs With those 41 billion dollars, SpaceX can design replacements to everything the SLS program aims to do, build a nuclear thermal rocket second stage, and execute one demo mission to the moon, one demo mission to mars, and fund all launches to put a new ISS in orbit (launches only). And make a 50% profit on top of it. Again. it's a matter of economics... The reason the Shuttle was that big is it was suposed to be reuseable, as Elon explained, the wings/gliding concept is way too inefficient. I'm sure some people inside NASA knew the numbers were skittish, but again, govt workers don't care about billions that don't come from their pockets (taxpayers pay for that) and end up in the pockets of people that could employ them in the future. If it were up to me, NASA would be reduced to a 3 layer bureacracy (director, program manager, associate program manager), limited at 50 employees, everything would be outsourced, based on a model much like the CRS program. Oops, I just got another 1000's of enemies that would stand to loose their jobs. That's the problem with inefficient govt. My problem isn't with the scope of what the govt does, but the cost of what it does.
Much better than ULA that already holds the US government hostage to the tune of one billion US$ per year. It's not called ransom by the US government, but anyone looking at it with an open mind should reach the conclusion it is ransom ! The requirement should be that any launch services supplier must make no more than 50% of launch revenues from US govt launches, and keep at a minimum two completely independent suppliers (as in a CARTEL together like Boeing and Lockheed). PS: This criteria is taylor made to force ULA to crash and burn.
Let me add to this great comment, there's also a layer of aerospace high tech suppliers used to making a huge profit supplying to Boeing/Lockheed and the rest of the old school gang. SpaceX has pretty much gave that gang the boot, producing almost everything that is Space specific in house. That's a significant part of why their costs are so radically cheaper. ULA is just part (a large part nonetheless) of the whole inefficient space gang.
We need this kind of radical, crazy smart innovation elsewhere. I suspect Nuclear Fission suffers from the same thing (massive ultra conservative corporations that don't have the guts to do anything out of their own pockets, General Electric anybody). I suspect aircraft innovation is going far slower than it has to be due to lack of interest in any disruptive innovation (and massive certification costs).
It's interesting how SpaceX never nags about what others try to do with them, they just move on with maximum grace.
Just compare Falcon Heavy with the Space Shuttle. 53 tons to LEO ? STS could carry 25 tons. FH quoted @ US$ 135 million for over 6.4tons to GTO (about 20tons to LEO and over, probably threshold for cross feeding). Still 1/10th the cost. Much like F9 v1.1 vs Delta 4, 1/10th the cost.
Bottom line is STS was as much as ULA pork/jobs programs is today. Economically it was a Dinosaur. All the fuss about the project being suspended and resumed might have reduced the cost by 10 or 20%, but it would still have been uneconomical.
Govt workers don't care about govt money. Its not their pocket. Quite differently from Elon's decisions on SpaceX. ULA cares about its profits, with cost+ contracts, it ends up being just the same.
There's nothing to be gained from a DDoS. If you want to destroy the Koch brothers (I do), reduce your oil and coal consumption as much as possible, go green. Convince others to do the same. You can do a lot more damage to them by getting 10000 people to lay off oil and coal than any DDoS will do.
For the SES-8 and Thaicom-6 launches SpaceX commited 100% of the rocket's capabilities to boost the rocket into a super sync orbit. A GTO orbit is less than 36000Km x 185Km. SES-8 was inserted into a 80000Km x 295Km orbit. It reaches apogee when the moon is close by. This trick helps save fuel to allow SES-8 to live much longer. Typically satellites useful lives are limited by fuel used for station keeping maneuvers. In this sense, SES-8 and Thaicom-6 launches are even more valuable to their operators than a typical GTO launch. GEO satellites are responsible for circularizing the orbit, and this consumes a lot of their precious on board fuel.
The current Dragon could launch humans into space. NASA and SpaceX agreed it would be better to conduct a very thorough human certification process, if a human were a stowaway in any of the current Dragon launches, he/she would have made it into the ISS safely. With just the Falcon 9 margin of safety of being able to loose two engines and still reach a high enough altitude to engage the Dragon parachutes and do a normal ocean landing is already in theory safer than the Space Shuttle. Plus the simple fact they haven't lost a single primary load. But as usual, Govt bureaucracy never care about the costs, they're always chasing some perfect utopia. Dragon Rider is a good thing. My argument is just that even without Dragon Rider, once there are at least a half a dozen F9v1.1 without a hitch done plus the 5 F9v1.0 done prior, the system should be in practice safer than the Shuttle for human launches.
SpaceX already has a 4-5 year fully booked launch backlog. The company is safe. I argue that their lower launch prices will cause an substantial increase in launch demands. Cubesats + satellites in the 50-200 Kg weight should become commonplace. Multiple LEO communication satellite networks should emerge. A replacement to the ISS will become viable. And all of this is without any reusability. Elon already stated they have figured out all the major pieces to recover the first stage. My only question is in what shape the first stage will be recovered, what will be the refurbishing costs, how many times will they be able to reuse the first stage. Consider a few low risk usages for the recovered first stage:
launch a recycled Dragon with water, oxygen, food and other cheap items to the ISS.
launch prototype satellites / modules for the future space station / anything that's relatively cheap to build where it's cheaper to try again than to insure
That's the problem with the current status quo, launching is too expensive to launch something cheap, creating a vicious cycle of ultra expensive satellites to use ultra expensive launch services.
They already stated that Falcon 9 v1.1 is far more mass production friendly than the original recipe Falcon 9. All you need to do is to follow the pipeline. Between one F9 in the Cape, McGregor and finishing production, there are at least 3-4 rockets in various stages of production/testing/integration for launch. Right now it looks like the critical stage is a single facility in the cape and any delays during the static fire and launch delaying everything else. There are 15 launches scheduled to deliver rockets at the launch site by the end of 2014. Usually that would mean the last 2 would launch in 2015. Of those, 2 launches are for Vandenberg, so 13 launches for the Cape, perhaps 11 for actual launch in 2014 (Thaicom-6 possibly 2013 plus the last one for 2015). That's about one launch every 5 weeks. Very doable. If SpaceX gets the old shuttle launch pad, all of this becomes extremely feasible. They might even be able to launch earlier than scheduled if the payload is ready.
Because SpaceX is doing it without massive govt subsidies. ULA rockets were developed with pork barrel money. SpaceX designed and launched Falcon 1 with private money. Then NASA stepped in with the CRS contract and helped Falcon 9 development, they invested less than a single Space Shuttle launch would have costed, and that investment more than paid itself with the 4 CRS launches to the ISS executed. And BTW, SpaceX isn't NASA's sweetheart, they are COMPETING with Orbital Sciences, and Boeing is trying to get in too. The difference is there are no money guarantees, you must meet contract requirements (goals) to get some money. Moving forward, SpaceX is under contract to supply 5 or 6 Falcon 9 v1.1 + Dragon spacecraft for the cost of a single Space Shuttle launch ! And with the upgraded capabilities of Falcon 9 v1.1, they now will be able to cram a Dragon spacecraft with as much stuff as they can, the rocket can deliver it to the ISS while leaving fuel reserves to reuse the first stage. Now that's cost effectiveness.
Trying to compare the lack of media coverage of ULA launches with the great coverage of a revolutionary, economical rocket like the Falcon 9, is truly unfair !
Come talk to me after ULA launches 3 or 4 commercial satellites !
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Satellite at this price, wow ! But even then.
Far more logic would be 4G Wimax (towers have 3-4Km range in flat areas, and can service hundreds of active customers), a single satellite can't provide the same bandwidth that a dozen 4G towers (with 6 antennas each) can.
4G latency is 50-100ms, while satellites are typically 1 second plus.
So you can think of VOIP / online games with 4G (even though it won't be a great experience, while satellite it's a non starter).
And there's the unlicensed 5GHz alternative (WISP), that need line of sight, but use very cheap equipment, the WISP can afford to have a small tower every Km (largest cost will be power, rent rather than the WISP tech), in areas where customers are desperate for better service, they might be able to put towers rent free in exchange for providing a viable alternative to wired monopolies.
You must be some 2Km away from the DSLAM (11k ft), or you're on some old, rusty cable.
This is the kind of situation that would be a non event on fiber.
4G (Wimax) wireless or 5GHz wifi should outperform this easily.
I support customers that use extremely cheap p2p unlicensed radios with 2,5Km links (with clear line of sight) delivering 45Mbps up+down performance with ease.
In most cases the bottleneck is the cost of laying a brand new network with as little as possible visual pollution / cost and regulatory hurdles.
Designing a network with a limit of 250 meters cable run to each customer will require an insane numbers of G.fast DSLAMs, this alone makes this tech kinda dead on arrival.
GPON allows for 10Km fiber runs, and share a fiber strand for up to 64 users, the fiber is then split as it gets further away from the wiring cabinet. 10Km fiber runs are a waste for dense areas, but leave the flexibility to service a few faraway customers in many cases.
Comparing tech that requires 250 meters cabling range to tech that can do 10000 meters without trouble isn't even fun !
But the issue of monopoly first requires a new entrant interested in overlaying the network, in such a case, I see zero business case for G.fast.
Without doubt, G.fast will be a niche technology.
G.fast is faster than VDSL2, but this 1 Gbps to the subscriber is very unrealistic. 1 Gbps speeds will only work for customers ultra close to the wiring closet.
But let's face it, even 200-300 Mbps is ultra fast internet (copper or not).
35Mbps down, 3Mbps up from GVT in Brazil already here. In my case, I couldn't get a stable connection with one modem they supply, had to get the better modem, at about 400 meters external cable run plus another 100 meters internal cabling, in this distance, G.fast might pump my top theoretical speed (as detected by the modem from 50Mbps to maybe 200Mbps).
Prices up to 35mbps are very affordable, the next step (50/5) has a large price jump.
So the issue isn't the technology here, it's cost (AND RANGE).
In our case, telcos are already moving towards 100% fiber.
While VDSL2 is (and G.fast will be) very range limited, GPON and P2P fiber can handle up 10 Km fiber runs with performance to spare, allowing for less wiring cabinets across town in a pure fiber network vs today's mixed fiber/copper networks, back to my telcos case, they were forced to design the network with a maximum cable run of 600 meters to every customer they service, requiring one wiring cabinet (in reality a tiny remote POP).
If the same network were designed from scratch using GPON only, they could have opted for up to 3Km to each customer, resulting in 1/10th in the number of cabinets, also GPON / GEPON fiber splitting allows ultra dense cabinets, with a 20 fiber strands handling two thousand customers (compared to 2000 copper pairs for the same two thousand customers). Copper cabinets for 1000 users is the size of a double door refrigerator, while GPON for 2000 users is less than the size of a mini bar.
So I'm not sure there will be too many business cases for maintaining copper networks, except in rare cases of extremely dense networks with top notch (recently laid) copper.
Finally, VDSL2 modems already use way more power than GPON subscriber units, I bet those G.fast modems will be small power hogs !
This tech is coming to the action way too late. Fiber will take over.
My bad...
Beta decay doesn't add protons to the nucleus, it converts neutrons into protons+electron in this case happens twice:
U-238 + neutron = U-239
U-239 (beta decay) -> Np-239 (one more proton/electron, one less neutron)
Np-239 (beta decay) -> Pu-239 (one more proton/electron, one less neutron)
That's what happens when you pretend you try use chemistry knowledge 20 yrs after studying it (and not using).
Google is your friend, but for the lazy:
Right, the neutron capture makes U-239, then it undergoes two beta decays that add one proton to the nucleus:
http://en.wikipedia.org/wiki/Uranium-238
I'm also not a physicist, but this explanation must the right, because it's the same in multiple sources (Wikipedia, nuclear lectures from multiple sources).
For explanation of why the double beta decay adds a proton to the nucleus, see here:
http://en.wikipedia.org/wiki/Beta_decay
The problem is fast reactors are un economical.
We need breeder thermal reactors, that's really though to do !
The only known design that might do that trick is Thorium / U-233 based.
Specially since this is U-235 (the primary nuclear fuel currently in use on civilian nuclear power stations).
Using U-235 for nuclear weapons is only common in first generation nuclear programs. You see, enriching uranium is a PITA (separating isotopes), while separating plutonium from anything else is soooo much easier (chemical separation).
The trick is having a reactor that takes thatplentiful U-238 and hit it with a neutron to make Pu-239 (that nasty plutonium used in bombs). Plutonium isn't naturally occurring.
If there are still US nuclear weapons that use U-235, those must be the oldest in the inventory.
So, any association from that Russian nuclear fuel with nuclear bombs is only made by those without any nuclear physics knowledge.
U-238 is 99,3% of natural uranium. It's the stuff that enrichment removes from the base material (producing depleted uranium).
A holy grail of peaceful nuclear is breeding Pu-239 from U-238 on the fly inside the reactor and the fission it, but having this happen mixed with all kinds of nasty beta emitters that make using that Pu-239 for nuclear weapons another PITA. Beta radiation is the stuff that really kills (used to kill cancer cells in radiotheraphy), but inside the reactor it's not an issue.
Not to mention that everybody that has significant stockpiles of Pu-239 want to destroy most of it ! Most nuclear reactors can't deal with nuclear fuel with lots of plutonium.
On the LFTR, ok, so it wasn't a full scale reactor, but if they made it work with 60s tech, it should be piece of cake to make a full scale one with today's advanced metalurgy, computer simulations, ...
A startup has announced it's seeking regulatory aproval for a prototype reactor that combines the advantages of IFR with LFTR (they have a catchy name, WAMSR, Waste Annihilating Molten Salt Reactor), designed to use water reactor waste as fuel, but with salts as coolant instead of sodium. Very sharp girl gave the presentation. The presentation was more of a PR thing, but this would kill any interest in IFR reactors.
So all those people working on LFTR's, they all just sucking up investment money ?
What's the problem with LFTR (Liquid Fluoride Thorium Reactors) ?
Don't tell me they are new tech, remember the nuclear powered bomber US Air Force project in the 60s, that was an LFTR project !
Humm, if this was 100% true, then why do the Ruskies keep those IFR "trouble makers" in operation ? If they're so bad, then why didn't we had a Chernobyl/Fukushima style nuclear accident with IFR reactors ?
You need to consult with the Nuclear History experts, that actually analyzed what was killed for technical reasons versus what was killed for political reasons !
The answer is North American and European countries don't want to invest in learning all there is safely operate IFR/LFTR reactors. The water reactor knowledge was acquired from nuclear weapons programs.
My contention is the light water reactor are conceptually the worse type of tech, they give a bad rep to everything else, and prevents heavy investments into alternatives due to Green Peace / Green Party brain dead everything nuclear is bad plus hidden forces I'll explain in a bit. They work, but create nasty toxic waste (even with uranium and plutonium reprocessing, the waste still has enormous nuclear energy left)
Another important tid bit of information. A Thorium molten salt reactors was operated in the 60's (under an experiment for the US Air Force, before ICBMs were reliable). Aka LFTR (Liquid Fluorine Thorium Reactors). LFTR use thermal neutrons (moderated by graphite), so have none of the neutron flux issues. And they use molten salts, so they don't have the sodium reactivity issues (LiF2 and BeF salts). And that project was executed with a tiny fraction of the fast breeder plutonium project. And killed for political reasons (Nixon's nuclear advisors were sold on Plutonium breeder reactors even though they knew those projects were likely to incur huge cost overruns). It's all recorded in the White House tapes from the 70s. And it's on youtube.
I believe that IFR reactors are the best solution to get rid of nuclear waste (produce energy and reduces nuclear waste down to low radioactivity elements). Perhaps 20-30 reactors (just enough to use up all the nuclear waste from water reactors).
And for mass production LFTR might be the solution to the worlds energy problem.
All we need is transfer 100% of the nuclear fusion pipe dream programs into advanced nuclear fission projects, focused on funding only technologies that worked / are working now, IFR and LFTR reactors for instance.
Then there's the real problem. People in a position to actually influence those projects are in bed with the coal / oil lobby, and they know that LFTRs would kill Coal directly and Oil indirectly (with electric cars). That's the real reason many of those projects aren't being funded today !!!!!
So the real answer is: Solar and Wind are ultra expensive techs that give coal / natural gas another 10-20 yrs life, while LFTRs could kill coal and natural gas in 10 yrs if we went Manhattan Project on this. Plentiful base load energy instead of ultra expensive energy that don't work at night (solar) or only work 25% of the time (wind).
IFR reactors stand for INTEGRAL, FAST reactors (I'll explain why INTEGRAL and why FAST bellow)
IFR reactors promise (actually it has been done, economically by the former USSR, still in operation in Ukraine and a few other former USSR countries):
1 - Near total utilization of high energy elements (only low radioactivity elements removed as waste like Cs, Sr, Xe, removed elements are low radioactivity, decay in a century instead of 50000 yrs as in water reactor waste)
Since the fuel is liquid and mixed with the coolant:
2 - Xenon bubbles to the top of the reactor and is removed (look up Xe-135 problems in conventional water/solid fuel reactors)
3 - adding new fuel and removing fission end products can be done without shutting down the reactor
4 - Low pressure operation (increase safety and reduces core reactor construction costs)
5 - High temperature operation results in 50% utilization of heat instead of 33% in water reactors
6 - IFR Nuclear final materials is far cheaper and safer to dispose (no Yuca mountain required), some materials actually have industrial usage (more revenue)
7 - IFR Nuclear can take nuclear waste from water reactors as fuel (free fuel, solve the nuclear waste problem from current nuclear reactors)
If you're interested, here comes the long explanation:
Exatly right, IFR reactors burn both U-235, U-238 (transmuted into Pu-239), and all transuranics, exactly what they call nuclear waste in water reactors.
Large presence of transuranics kill the water reactor operation, but the IFR reactor burns it normally. Score 1 for IFR reactors.
Since the fuel is a liquid in IFR reactors, Xe-135 neutron poisoning (that is a serious issue in water reactors) is a non-issue, Xe-135 is a gas, with the fuel molten in the core, Xe-135 just bubbles up and gets captured in bottles, score 2 for IFR reactors
Fast reactors don't moderate neutrons, keeping them at high speed. Being fast, they're less likely to hit nucleus of fuel, but when they do, the chances are 99% of producing a nuclear fission (except for elements that require a neutron capture like U-238 and Th-232). That lower probability is compensated by:
1 - More nuclear fuel present
2 - Lack of large number of control rods (which are heavy neutron capturing elements), they're unnecessary
3 - Since the fuel is liquid, the quantities of fuel kept in the reactor can be tuned to an optimal level, in contrast with reactors that use solid fuel (that start with too much fuel, and end with just enough fuel, compensated by the control rods)
Since the fuel is liquid, it's easy to replace say 10% of old fuel with new fuel and take that 10% into a cheap on site reprocessing (hence INTEGRAL), then 10% number is likely wrong, just for argument's sake. This reprocessing is only meant to remove true nuclear waste (keeping Uranium, Plutonium, Thorium and all transuranics in), so it's far simpler and cheaper than Purex, Urex plants (remove only elements with nuclear weight much lighter than nuclear fuel and much heavier than the molten salt). Score 3 for IFR reactors.
Using a liquid sodium or salt to disolve the fuel and carry heat has another very interesting characteristic, those chemicals are liquid up to a very high temperature in low pressure (allowing for operation at 800 C, while water reactors operate at 350 C) this allows for gas turbines (using supercritical CO2 for instance) with conversion efficiency of 50% compared to 33% of water reactors. Score 4 for IFR reactors. As a matter of fact, sodium/salts require the reactor to reach 400 C before they become liquids (not a problem in any way).
This high temperature operation is achieved at very low pressure (no more than 2 or 3 atmospheres), compared to 150 atmospheres in light water reactors and 70 atmospheres in heavy water reactors greatly simplify the reactor design (95% of the main water reactor building size is due to the need to space in case there's
The Russians have a few Sodium cooled reactors operating for decades, if they can do it, why can't the US ?
I'm not talking about tiny experimental reactors babysat by experts 24x7, but large scale power plants that aren't even in Russia (Kazakhstan / Ukraine), that have been in production for 30+ years.
There's no water inside the reactor, sodium doesn't corrode Steel, while water does.
With all that said, LFTR sounds like a more interesting option, except that S-PRISM promises a solution to the nuclear waste from water reactors.
LFTR uses Thorium, in a thermal reactor and is cooled by molten salts (chemically stable) quite the opposite of liquid sodium.
Is there an alternative that does what S-PRISM does, but with molten salt instead of molten metal ?
It's interesting the bait model employed today by GE and Westinghouse.
They sell reactors at essentially cost price, then overcharge for the nuclear fuel.
They have zero interest in reactors that use liquid fuel, since there's almost no money to be made in the fuel.
Specially reactors that can run on cheap thorium (LFTR-Salt cooled), waste from water nuclear reactors, plutonium (IFR-Sodium cooled).
If they have something interesting, they are waiting for a big govt handout to actually start it (GE-Hitachi S-PRISM).
And govt aren't helping either... S-PRISM promisses to extract 100x more energy from uranium than water cooled/moderated reactors, theoretically they're also a solution to the nuclear waste storage problem. But if it really were that great (with no hidden catch), then why shouldn't GE take one or two billion out of their huge cash reserves and make it happen quickly ?
That's the final point, those huge corporations always have some hidden poop hidden in the thing. Like the true cost of water nuclear plants considering there's no standardized nuclear fuel market (GE fuel can't be used in Westinghouse plants and vice-versa).
But the conversion to a dead lift vehicle would cost ... Humm ... Let me guess... Some 41 billion dollars ?
That's called SLS ! This number is a realistic assessment by people that have no incentive to hide the real cost of things. http://en.wikipedia.org/wiki/Space_Launch_System#Program_costs
With those 41 billion dollars, SpaceX can design replacements to everything the SLS program aims to do, build a nuclear thermal rocket second stage, and execute one demo mission to the moon, one demo mission to mars, and fund all launches to put a new ISS in orbit (launches only). And make a 50% profit on top of it.
Again. it's a matter of economics... The reason the Shuttle was that big is it was suposed to be reuseable, as Elon explained, the wings/gliding concept is way too inefficient. I'm sure some people inside NASA knew the numbers were skittish, but again, govt workers don't care about billions that don't come from their pockets (taxpayers pay for that) and end up in the pockets of people that could employ them in the future.
If it were up to me, NASA would be reduced to a 3 layer bureacracy (director, program manager, associate program manager), limited at 50 employees, everything would be outsourced, based on a model much like the CRS program. Oops, I just got another 1000's of enemies that would stand to loose their jobs.
That's the problem with inefficient govt. My problem isn't with the scope of what the govt does, but the cost of what it does.
Much better than ULA that already holds the US government hostage to the tune of one billion US$ per year.
It's not called ransom by the US government, but anyone looking at it with an open mind should reach the conclusion it is ransom !
The requirement should be that any launch services supplier must make no more than 50% of launch revenues from US govt launches, and keep at a minimum two completely independent suppliers (as in a CARTEL together like Boeing and Lockheed).
PS: This criteria is taylor made to force ULA to crash and burn.
Let me add to this great comment, there's also a layer of aerospace high tech suppliers used to making a huge profit supplying to Boeing/Lockheed and the rest of the old school gang.
SpaceX has pretty much gave that gang the boot, producing almost everything that is Space specific in house.
That's a significant part of why their costs are so radically cheaper. ULA is just part (a large part nonetheless) of the whole inefficient space gang.
We need this kind of radical, crazy smart innovation elsewhere. I suspect Nuclear Fission suffers from the same thing (massive ultra conservative corporations that don't have the guts to do anything out of their own pockets, General Electric anybody). I suspect aircraft innovation is going far slower than it has to be due to lack of interest in any disruptive innovation (and massive certification costs).
It's interesting how SpaceX never nags about what others try to do with them, they just move on with maximum grace.
Just compare Falcon Heavy with the Space Shuttle.
53 tons to LEO ?
STS could carry 25 tons.
FH quoted @ US$ 135 million for over 6.4tons to GTO (about 20tons to LEO and over, probably threshold for cross feeding).
Still 1/10th the cost.
Much like F9 v1.1 vs Delta 4, 1/10th the cost.
Bottom line is STS was as much as ULA pork/jobs programs is today.
Economically it was a Dinosaur. All the fuss about the project being suspended and resumed might have reduced the cost by 10 or 20%, but it would still have been uneconomical.
Govt workers don't care about govt money. Its not their pocket. Quite differently from Elon's decisions on SpaceX. ULA cares about its profits, with cost+ contracts, it ends up being just the same.
There's nothing to be gained from a DDoS.
If you want to destroy the Koch brothers (I do), reduce your oil and coal consumption as much as possible, go green.
Convince others to do the same.
You can do a lot more damage to them by getting 10000 people to lay off oil and coal than any DDoS will do.
For the SES-8 and Thaicom-6 launches SpaceX commited 100% of the rocket's capabilities to boost the rocket into a super sync orbit.
A GTO orbit is less than 36000Km x 185Km.
SES-8 was inserted into a 80000Km x 295Km orbit.
It reaches apogee when the moon is close by.
This trick helps save fuel to allow SES-8 to live much longer. Typically satellites useful lives are limited by fuel used for station keeping maneuvers.
In this sense, SES-8 and Thaicom-6 launches are even more valuable to their operators than a typical GTO launch.
GEO satellites are responsible for circularizing the orbit, and this consumes a lot of their precious on board fuel.
Elon Musk is an inventor / engineer.
So far he hasn't made any science breakthroughs. Yet.
There's far more money / success / prestige in what he's doing than in science. He's in the right business.
The current Dragon could launch humans into space.
NASA and SpaceX agreed it would be better to conduct a very thorough human certification process, if a human were a stowaway in any of the current Dragon launches, he/she would have made it into the ISS safely.
With just the Falcon 9 margin of safety of being able to loose two engines and still reach a high enough altitude to engage the Dragon parachutes and do a normal ocean landing is already in theory safer than the Space Shuttle. Plus the simple fact they haven't lost a single primary load.
But as usual, Govt bureaucracy never care about the costs, they're always chasing some perfect utopia.
Dragon Rider is a good thing. My argument is just that even without Dragon Rider, once there are at least a half a dozen F9v1.1 without a hitch done plus the 5 F9v1.0 done prior, the system should be in practice safer than the Shuttle for human launches.
SpaceX already has a 4-5 year fully booked launch backlog.
The company is safe.
I argue that their lower launch prices will cause an substantial increase in launch demands.
Cubesats + satellites in the 50-200 Kg weight should become commonplace.
Multiple LEO communication satellite networks should emerge.
A replacement to the ISS will become viable.
And all of this is without any reusability. Elon already stated they have figured out all the major pieces to recover the first stage. My only question is in what shape the first stage will be recovered, what will be the refurbishing costs, how many times will they be able to reuse the first stage.
Consider a few low risk usages for the recovered first stage:
launch a recycled Dragon with water, oxygen, food and other cheap items to the ISS.
launch prototype satellites / modules for the future space station / anything that's relatively cheap to build where it's cheaper to try again than to insure
That's the problem with the current status quo, launching is too expensive to launch something cheap, creating a vicious cycle of ultra expensive satellites to use ultra expensive launch services.
They already stated that Falcon 9 v1.1 is far more mass production friendly than the original recipe Falcon 9.
All you need to do is to follow the pipeline. Between one F9 in the Cape, McGregor and finishing production, there are at least 3-4 rockets in various stages of production/testing/integration for launch.
Right now it looks like the critical stage is a single facility in the cape and any delays during the static fire and launch delaying everything else.
There are 15 launches scheduled to deliver rockets at the launch site by the end of 2014. Usually that would mean the last 2 would launch in 2015.
Of those, 2 launches are for Vandenberg, so 13 launches for the Cape, perhaps 11 for actual launch in 2014 (Thaicom-6 possibly 2013 plus the last one for 2015).
That's about one launch every 5 weeks.
Very doable.
If SpaceX gets the old shuttle launch pad, all of this becomes extremely feasible. They might even be able to launch earlier than scheduled if the payload is ready.
Because SpaceX is doing it without massive govt subsidies.
ULA rockets were developed with pork barrel money.
SpaceX designed and launched Falcon 1 with private money.
Then NASA stepped in with the CRS contract and helped Falcon 9 development, they invested less than a single Space Shuttle launch would have costed, and that investment more than paid itself with the 4 CRS launches to the ISS executed.
And BTW, SpaceX isn't NASA's sweetheart, they are COMPETING with Orbital Sciences, and Boeing is trying to get in too.
The difference is there are no money guarantees, you must meet contract requirements (goals) to get some money.
Moving forward, SpaceX is under contract to supply 5 or 6 Falcon 9 v1.1 + Dragon spacecraft for the cost of a single Space Shuttle launch !
And with the upgraded capabilities of Falcon 9 v1.1, they now will be able to cram a Dragon spacecraft with as much stuff as they can, the rocket can deliver it to the ISS while leaving fuel reserves to reuse the first stage.
Now that's cost effectiveness.
Trying to compare the lack of media coverage of ULA launches with the great coverage of a revolutionary, economical rocket like the Falcon 9, is truly unfair !
Come talk to me after ULA launches 3 or 4 commercial satellites !