The biggest question with the capsules was structural damage done by reentry. Since they weren't designed with aerodynamics in mind, the areas affected by the plasma stream were difficult to gage.
The "Big Gemini" capsule I linked to was created with the idea of reusability in mind, and actually solved the "splash-down" problem by use of a parawing and landing gear. It was the only capsule that would have had an outer-shell designed to withstand reentry in a reusable fashion.
Re:Want some Tritium? It's already started...
on
Nuclear Batteries
·
· Score: 1
Try the watches section here. They've got a wide selection of Tritium watches.
I'm well aware of this method. The idea here is to create an electrostatic charge that causes attraction of the piezoelectric cantilever, producing power. Such a design would only produce enough power for a MEMS type device. If they want to power cell phones, they're going to need to do it in the thermal range. I'm still trying to figure out how feasible it is to produce a tiny SRG for a cell phone.:-) At the very least, pelters are very small and could easily fit in a phone.
BTW, there's a very interesting video about NASA and Parawings here.
Re:These are already in use for some applications
on
Nuclear Batteries
·
· Score: 1
While it's ten years old, the prices haven't changed much at all. Americanium, for example, has not dropped in price *at all* despite its heavy use in smoke alarms.
What's wrong with parawings? It's not like the parawing was to blame for the Genesis probe. The probe failed to deploy ALL of its chutes. Because of that, NASA suspects that there may have been an error in the control software.
Yeah, my four year old son gets a real kick out of watching launch videos, so I've seen that one quite a few times.:-)
In all fairness to Wikipedia, they simply pointed out that when the landing was televised without the launch being televised, it started a conspiracy theory about whether the Buran actually flew. Someone should probably add that the launch video has since been released to the public, and that the poor conditions described by the Russian media can be easily seen.
You might want to check that. There are a couple different videos of the launch out there.
The Buran launched. It was no conspiracy theory. The only conspiracy was the Russian decision to follow the US's designs instead of paving their own way in space. Guess Reagan really did lead them around by the nose, eh?;-)
No, I mean this one. The one you pointed to was just a test model. You can see one of them in Gorky Park in Moscow. (Just like the Mir space station in Robot World in Wisconsin Dells, Wisconsin.)
There were two orbiters completed, but only one flew. Its flight was unmanned, and went without serious difficulties. After that the Russian government ran out of money and pawned the program to Ukraine in exchange for a loan. The first orbiter (the one that flew) was sadly lost in hanger collapse a few months ago.:-(
Re:Well I'll be damned
on
Nuclear Batteries
·
· Score: 1, Insightful
When your [dog|kid] eats a gram of plutonium, it is far more toxic than eating an equivalent gram of lead, cadmium, or other non-radioactive heavy metal.
Have you been listening to Nader again? You might want to read this.
Ingestion is rarely a problem with Plutonium. The vector of most concern is inhalation. Thankfully, this isn't much of a problem as it takes SEVERE force to powderize plutonium. Basically, someone would have to intend to powderize it. And if they did powderize it, they're most likely to kill themselves rather than anyone else. Once dispersed, there wouldn't be sufficient quantities in the air for someone to get cancer from.
Read the first link on dirty bombs in my original post for more info.
Agreed. But the idea I've been presenting to people is to actually lease the batteries. At least initially, they'd be VERY expensive. If they were leased to people who could afford it, the costs could be spread over time, and severe penalties could be written into the contract for non-return of the device. Even if the device is broken, it needs to be returned.
The actual mechanics would be the cheap part. The radioisotopes would cost thousands of dollars per device. As time goes on, the devices would be remanufactured with inert materials replaced, and the price would slowly drop.
I wouldn't worry about that too much. Manufacturers would tend to be smart enough to choose materials that are not water soluble. In addition, they'd probably melt the materials inside a block of non-reactive metal to make sure the materials stay in a solid form.
As long as the materials are treated with respect by the manufacturer, consumers shouldn't have too much to worry about. Even if the manufacturer DOES screw up, it's doubtful that so little material could cause much of a problem. You might be interested in this link.:-)
Re:Unknown Error In The Submission
on
Nuclear Batteries
·
· Score: 4, Insightful
Is it better than any other energy source out there (with the possible exception of wind)? Yes.
The part that I think people have a hard time understanding is this: large amounts of energy is dangerous.
There's no ifs, ands, or buts about it. If you're generating megawatts of power, you're using something that could kill a lot of people. The only difference between nuclear materials and convential chemicals is that nuclear allows us to get more power for less materials. We could achieve explosions of similar magnitudes with TNT, but who wants to be hauling around hundreds of tons of TNT when a bomb only a few tons in size will do the same thing?
Re:These are already in use for some applications
on
Nuclear Batteries
·
· Score: 3, Interesting
Re:New addition to the Patriot Act?
on
Nuclear Batteries
·
· Score: 1
Don't forget about Uranium-laced false teeth!
Re:Someone who knows their physics please tell me
on
Nuclear Batteries
·
· Score: 1
They're trying to power MEMS devices at the moment. Cell phones and laptops are still a ways away.
Honestly, I think the military should begin developing portable SRGs. One of the biggest problems with their current "future-soldier" concepts (read: A guy with a monocle and a computer) is battery life and weight. An SRG would be smaller, and would probably outlast just about any mission the Generals can think up.
Can anyone else think of a misssion that would exhaust 5-10 years worth of power?;-)
Re:Well I'll be damned
on
Nuclear Batteries
·
· Score: 5, Informative
In all seriousness, there are larger RTGs. The Cassini probe started off with a few kilowatts of power at its disposal. Over time that has dropped, but the probe still has a significant amount of power to pull from. According to Wikipedia, the craft will still be producing ~628 watts at the end of its 11 year mission.
Re:Well I'll be damned
on
Nuclear Batteries
·
· Score: 2, Insightful
Ummm... considering that their useful lifetime is about 5-10 years, I wouldn't worry about it.
Re:Someone who knows their physics please tell me
on
Nuclear Batteries
·
· Score: 4, Informative
Some kind of reverse Peltier gizmo can't be used to create a solid-state nuclear battery?
You know, they used to use these things in pacemakers before Chernobyl happened. After Chernobyl, everyone got scared about "nuclear" anything. Now dead batteries in a pacemaker are a very real concern, whereas they used to be good until you were dead from other causes.
They're not explosive. Most nuclear batteries use a radioisotope that's already "burned". i.e. Pu-238 oxide is used in RTGs so that there's no chance of it burning. It still emits plenty of radiation once it's chemically stable, so the only thing you have to worry about are rednecks who think it's funny to melt down the batteries and mix them with paint for glow-in-the-dark wallpaper. Even then, I rather doubt it will have much effect on them.
I've been harping on the idea of using nuclear batteries in cell phones and laptops for the past year or so. To date I've been called a variety of names for it, the least of which is "crazy". Yet here we are. Researchers are SERIOUSLY talking about using radioisotopes as power sources!
In case anyone is wondering how these work, the idea is that the radiation from a small amount of radioactive material (NOT fissable material!) is captured and converted into electricity or other forms of energy. There is very little radiation emitted by these devices, because the radiation IS the power! Letting it escape would be poor economy.
NASA has used these sorts of devices in spacecraft for 40+ years, starting with the Apollo missions. NASA's earlier designs produced about 75 watts utilizing a few pounds of Plutonium-238. Pu-238 was an excellent choice because it is useless for bombs, and has a short half-life (~80 years). With the public finally calming down about nuclear technology, NASA is now developing a more efficient device called an SRG. These devices get about 55 Watts per 600 grams of PU-238. This is way more efficient than current RTGs, like the ones used on Apollo.
The primary downsides to Nuclear Batteries is that they are expensive and they don't scale. They are expensive because the nuclear materials are very rare and expensive to process. If we started using these materials in massive quantities, it's a certainty that the prices would drop. They are not scalable, because the amount of materials required means that a few hundred watts is the largest device one could construct with a reasonable size, weight, and expense.
As for anyone who's worried about dirty bombs, I suggest you read this and this. The threat has been greatly overstated, and is actually less effective than a regular bomb. The real problem is the issue of keeping the materials out of landfills. Even today, there's a big problem with Lead, Cadium, and other dangerous materials ending up in landfills. Radioisotopes wouldn't be much worse, but there is an upper limit on how much you want to add to the sub-soil.
Re:Seems possible to me
on
After the X Prize
·
· Score: 2, Informative
Now, I normally don't exhalt the Russians but one thing they have definately done right was in sticking with capsules.
I forgot to address this point. The Russians DID build a winged craft: The Buran. Their one design mistake was the choice to make it cargo capable like the US shuttle. If they'd built something just large enough for people, and left the cargo to the Protons and Energias, they might still be flying them today.
The only reason why I'm partial to lifting bodies is that they tend to make the craft a bit more reusable. As far as I'm aware, there hasn't ever been a reusable capsule produced. The only reusable capsule design I'm aware of is the Big G, which I linked to in my post.
Of course, the advantage to a parafoil, is that it's like having wings without actually having wings. The big question is: is it cheaper to refurbish a non-cargo lifting body or is it cheaper to refurbish a non-cargo, parafoil return capsule? The biggest concern is that surfaces other than the heat shield often get scorched during reentry of capsules. With lifting bodies, the affected areas tend to be easy to cover in their entirety.
Hmm... I think the only way to know with some degree of certainty is to crunch some number and run a few simulations.
Re:Seems possible to me
on
After the X Prize
·
· Score: 4, Informative
Looks like we need a new moderation category - "Understatment".
(grin)
Honestly, reentry isn't THAT bad. The shuttle has it particularly difficult because it's designed for a very shallow reentry angle. As I understand it, the military demanded a large cross-range ability so that the shuttle could go up, perform spy stuff over the USSR, and hit the ground again after one orbit.
A steeper angle requires less shielding. The idea (as I understand it) is to accept a faster increase in heat buildup in exchange for a faster rate of deceleration. Once the craft is deep enough in the atmosphere and has shed enough speed, the atmosphere will actually begin to cool the surface.
The Apollo missions used a simple and inexpensive shield that consisted of an ablative epoxy/silicon material. Such a shield could easily be made replaceable after every flight. The shuttle's tiles OTOH, are supposed to be non-ablative and reusable. However, the number of tiles that they ended up needing resulted in very expensive post-flight inspections.
Honestly, the tech isn't that hard. The early space-modules were nothing more than some sheet metal, a space suit, a few maneuvering jets, and a heat shield. The early Mercury capsules even used a simple, non-ablative shock plate that pushed the atmospheric plasma around the edges of the capsule, preventing heating of the craft itself.
But your destination is actually outer space. In the case of an aircraft, your destination is a country with laws. Methinks that maritime law is more applicable because you will probably land in the same country you took off in (or close).
Slashdot Mirror
The biggest question with the capsules was structural damage done by reentry. Since they weren't designed with aerodynamics in mind, the areas affected by the plasma stream were difficult to gage.
The "Big Gemini" capsule I linked to was created with the idea of reusability in mind, and actually solved the "splash-down" problem by use of a parawing and landing gear. It was the only capsule that would have had an outer-shell designed to withstand reentry in a reusable fashion.
Try the watches section here. They've got a wide selection of Tritium watches.
I'm well aware of this method. The idea here is to create an electrostatic charge that causes attraction of the piezoelectric cantilever, producing power. Such a design would only produce enough power for a MEMS type device. If they want to power cell phones, they're going to need to do it in the thermal range. I'm still trying to figure out how feasible it is to produce a tiny SRG for a cell phone. :-) At the very least, pelters are very small and could easily fit in a phone.
BTW, there's a very interesting video about NASA and Parawings here.
While it's ten years old, the prices haven't changed much at all. Americanium, for example, has not dropped in price *at all* despite its heavy use in smoke alarms.
What's wrong with parawings? It's not like the parawing was to blame for the Genesis probe. The probe failed to deploy ALL of its chutes. Because of that, NASA suspects that there may have been an error in the control software.
Yeah, my four year old son gets a real kick out of watching launch videos, so I've seen that one quite a few times. :-)
In all fairness to Wikipedia, they simply pointed out that when the landing was televised without the launch being televised, it started a conspiracy theory about whether the Buran actually flew. Someone should probably add that the launch video has since been released to the public, and that the poor conditions described by the Russian media can be easily seen.
You might want to check that. There are a couple different videos of the launch out there.
;-)
The Buran launched. It was no conspiracy theory. The only conspiracy was the Russian decision to follow the US's designs instead of paving their own way in space. Guess Reagan really did lead them around by the nose, eh?
No, I mean this one. The one you pointed to was just a test model. You can see one of them in Gorky Park in Moscow. (Just like the Mir space station in Robot World in Wisconsin Dells, Wisconsin.)
:-(
There were two orbiters completed, but only one flew. Its flight was unmanned, and went without serious difficulties. After that the Russian government ran out of money and pawned the program to Ukraine in exchange for a loan. The first orbiter (the one that flew) was sadly lost in hanger collapse a few months ago.
When your [dog|kid] eats a gram of plutonium, it is far more toxic than eating an equivalent gram of lead, cadmium, or other non-radioactive heavy metal.
Have you been listening to Nader again? You might want to read this.
Ingestion is rarely a problem with Plutonium. The vector of most concern is inhalation. Thankfully, this isn't much of a problem as it takes SEVERE force to powderize plutonium. Basically, someone would have to intend to powderize it. And if they did powderize it, they're most likely to kill themselves rather than anyone else. Once dispersed, there wouldn't be sufficient quantities in the air for someone to get cancer from.
Read the first link on dirty bombs in my original post for more info.
Agreed. But the idea I've been presenting to people is to actually lease the batteries. At least initially, they'd be VERY expensive. If they were leased to people who could afford it, the costs could be spread over time, and severe penalties could be written into the contract for non-return of the device. Even if the device is broken, it needs to be returned.
The actual mechanics would be the cheap part. The radioisotopes would cost thousands of dollars per device. As time goes on, the devices would be remanufactured with inert materials replaced, and the price would slowly drop.
I wouldn't worry about that too much. Manufacturers would tend to be smart enough to choose materials that are not water soluble. In addition, they'd probably melt the materials inside a block of non-reactive metal to make sure the materials stay in a solid form.
:-)
As long as the materials are treated with respect by the manufacturer, consumers shouldn't have too much to worry about. Even if the manufacturer DOES screw up, it's doubtful that so little material could cause much of a problem. You might be interested in this link.
Is it better than any other energy source out there (with the possible exception of wind)? Yes.
The part that I think people have a hard time understanding is this: large amounts of energy is dangerous.
There's no ifs, ands, or buts about it. If you're generating megawatts of power, you're using something that could kill a lot of people. The only difference between nuclear materials and convential chemicals is that nuclear allows us to get more power for less materials. We could achieve explosions of similar magnitudes with TNT, but who wants to be hauling around hundreds of tons of TNT when a bomb only a few tons in size will do the same thing?
Have you seen the cost for a gram of Tritium?! That's why it's not used more.
Don't forget about Uranium-laced false teeth!
They're trying to power MEMS devices at the moment. Cell phones and laptops are still a ways away.
;-)
Honestly, I think the military should begin developing portable SRGs. One of the biggest problems with their current "future-soldier" concepts (read: A guy with a monocle and a computer) is battery life and weight. An SRG would be smaller, and would probably outlast just about any mission the Generals can think up.
Can anyone else think of a misssion that would exhaust 5-10 years worth of power?
In all seriousness, there are larger RTGs. The Cassini probe started off with a few kilowatts of power at its disposal. Over time that has dropped, but the probe still has a significant amount of power to pull from. According to Wikipedia, the craft will still be producing ~628 watts at the end of its 11 year mission.
Ummm... considering that their useful lifetime is about 5-10 years, I wouldn't worry about it.
Some kind of reverse Peltier gizmo can't be used to create a solid-state nuclear battery?
Congratulations, you've just described an RTG.
You know, they used to use these things in pacemakers before Chernobyl happened. After Chernobyl, everyone got scared about "nuclear" anything. Now dead batteries in a pacemaker are a very real concern, whereas they used to be good until you were dead from other causes.
What happens when they blow up?
They're not explosive. Most nuclear batteries use a radioisotope that's already "burned". i.e. Pu-238 oxide is used in RTGs so that there's no chance of it burning. It still emits plenty of radiation once it's chemically stable, so the only thing you have to worry about are rednecks who think it's funny to melt down the batteries and mix them with paint for glow-in-the-dark wallpaper. Even then, I rather doubt it will have much effect on them.
I've been harping on the idea of using nuclear batteries in cell phones and laptops for the past year or so. To date I've been called a variety of names for it, the least of which is "crazy". Yet here we are. Researchers are SERIOUSLY talking about using radioisotopes as power sources!
In case anyone is wondering how these work, the idea is that the radiation from a small amount of radioactive material (NOT fissable material!) is captured and converted into electricity or other forms of energy. There is very little radiation emitted by these devices, because the radiation IS the power! Letting it escape would be poor economy.
NASA has used these sorts of devices in spacecraft for 40+ years, starting with the Apollo missions. NASA's earlier designs produced about 75 watts utilizing a few pounds of Plutonium-238. Pu-238 was an excellent choice because it is useless for bombs, and has a short half-life (~80 years). With the public finally calming down about nuclear technology, NASA is now developing a more efficient device called an SRG. These devices get about 55 Watts per 600 grams of PU-238. This is way more efficient than current RTGs, like the ones used on Apollo.
The primary downsides to Nuclear Batteries is that they are expensive and they don't scale. They are expensive because the nuclear materials are very rare and expensive to process. If we started using these materials in massive quantities, it's a certainty that the prices would drop. They are not scalable, because the amount of materials required means that a few hundred watts is the largest device one could construct with a reasonable size, weight, and expense.
As for anyone who's worried about dirty bombs, I suggest you read this and this. The threat has been greatly overstated, and is actually less effective than a regular bomb. The real problem is the issue of keeping the materials out of landfills. Even today, there's a big problem with Lead, Cadium, and other dangerous materials ending up in landfills. Radioisotopes wouldn't be much worse, but there is an upper limit on how much you want to add to the sub-soil.
Now, I normally don't exhalt the Russians but one thing they have definately done right was in sticking with capsules.
I forgot to address this point. The Russians DID build a winged craft: The Buran. Their one design mistake was the choice to make it cargo capable like the US shuttle. If they'd built something just large enough for people, and left the cargo to the Protons and Energias, they might still be flying them today.
The only reason why I'm partial to lifting bodies is that they tend to make the craft a bit more reusable. As far as I'm aware, there hasn't ever been a reusable capsule produced. The only reusable capsule design I'm aware of is the Big G, which I linked to in my post.
Of course, the advantage to a parafoil, is that it's like having wings without actually having wings. The big question is: is it cheaper to refurbish a non-cargo lifting body or is it cheaper to refurbish a non-cargo, parafoil return capsule? The biggest concern is that surfaces other than the heat shield often get scorched during reentry of capsules. With lifting bodies, the affected areas tend to be easy to cover in their entirety.
Hmm... I think the only way to know with some degree of certainty is to crunch some number and run a few simulations.
Looks like we need a new moderation category - "Understatment".
(grin)
Honestly, reentry isn't THAT bad. The shuttle has it particularly difficult because it's designed for a very shallow reentry angle. As I understand it, the military demanded a large cross-range ability so that the shuttle could go up, perform spy stuff over the USSR, and hit the ground again after one orbit.
A steeper angle requires less shielding. The idea (as I understand it) is to accept a faster increase in heat buildup in exchange for a faster rate of deceleration. Once the craft is deep enough in the atmosphere and has shed enough speed, the atmosphere will actually begin to cool the surface.
The Apollo missions used a simple and inexpensive shield that consisted of an ablative epoxy/silicon material. Such a shield could easily be made replaceable after every flight. The shuttle's tiles OTOH, are supposed to be non-ablative and reusable. However, the number of tiles that they ended up needing resulted in very expensive post-flight inspections.
Honestly, the tech isn't that hard. The early space-modules were nothing more than some sheet metal, a space suit, a few maneuvering jets, and a heat shield. The early Mercury capsules even used a simple, non-ablative shock plate that pushed the atmospheric plasma around the edges of the capsule, preventing heating of the craft itself.
But your destination is actually outer space. In the case of an aircraft, your destination is a country with laws. Methinks that maritime law is more applicable because you will probably land in the same country you took off in (or close).