Rockets!

If polywell fusion is developed, in what ways will the world change for better or worse? Discuss.

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saddogmobile
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Re: Shielding

Postby saddogmobile » Thu Aug 30, 2007 5:49 am

ANTIcarrot wrote:And yet you still believe nuclear power aircraft would ever get built?


ANTIcarrot, I've got more than a few ideas on what to do with an IEF core if it ever becomes commercially available, I'm sure you'll like none of them. Your numerous objections and negative feelings on everything are duly noted, and ignored. In the 50's and 60's the US government did more than a little research on nuclear powered Aircraft/spacecraft, they stoped due to two factors "Nuclear Pansies" and the nuclear "trident" if they had not been a factor Project Pluto would have been the lasting deterrent.

the basic limit to any "way out there" idea is power supply, with a low weight high energy power source and the right electrical and mechanical systems the posibility exists for us to do several things in the field of SSTO

first thing to develop would be a suborbital spaceplane the marine's SUSTAIN would be a good candidate project, I wonder what carrier launch and recovery and a range of anywhere In the Hemisphere and back would do for force projection.

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Postby Roger » Thu Aug 30, 2007 11:59 pm

ANTIcarrot wrote:
Yes, and concord was faster than a 747. Speed is not the most important thing in the world. It didn't make concord competitive.

No but to continue flying 30 year old, very thirsty jet engines on a 30 year old airplane, with no replacement on the horizon, is a pretty good way to be not competitive.
I like the p-B11 resonance peak at 50 KV acceleration. In2 years we'll know.

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Postby ANTIcarrot » Sun Sep 02, 2007 1:16 pm

MSimon wrote:Were we discussing nuclear powered aircraft in the thread?


This is why I kept telling you to check MR BUSSARD's OWN PROPOSALS before defending them. He has really proposed (seriously) using giant super sonic nuclear powered SSTO aircraft to get things into orbit. Even if you missed that, the whole 'getting into orbit' requires that you fly through the atmosphere first, and then come back down again to land. What part of this escaped your attention?

You are personally insulted by a request to stay on topic?


"Have you ever heard of the KSC? I guess you've never heard of the KSC! Hah! You're stupid! LOL!" I've forgotten more than you know about rocket science. You have absolutely no business repeatedly implying that I lack the education to know about the KSC. Especially after the complete drivel you type next...

My point about the Kennedy Space Center is that it is a place on land that allows you to launch over water so that you can keep humans out of the maximum danger zone.


This is like 'failing to know what thermal neutrons are'. Rockets today (including the shuttle) are designed to operate at their maximum possible performance. It would be child's play to design a rocket for maximum reliability instead, and still be able to carry a useful payload into orbit. You don't need a 'maximum danger zone' for reliable vehicles. Now a reliable chemical rocket with a sensible payload doesn't need a coastline, just a 200m wide chain circle, surrounded by a chain link fence and countryside, and some Admin buildings in the next field. This fact is about as popular with NASA white-collar welfare programme as polywell is with the ITER white-collar welfare programme.

The only difference is this concept has been looked at and confirmed by many groups, which is a level of pier review that polywell still lacks.
Some light reading material: Half Way To Anywhere, The Rocket Company, Space Technology, The High Fronter, Of Wolves And Men, Light On Shattered Water, The Ultimate Weapon, any Janes Guide, GURPS Bio-Tech, ALIENS Technical Manual, The God Delusion.

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Re: Shielding

Postby ANTIcarrot » Sun Sep 02, 2007 2:40 pm

saddogmobile wrote:ANTIcarrot, <snip> Your numerous objections and negative feelings on everything are duly noted, and ignored.


This sounds more and more like pseudoscience every time people like you express such sentiments. Polywell is a really neat idea, but really neat ideas (from Mr Bussard and/or nuclear energy in general) tend to come with hidden problems that the advocates dislike to acknowledge. What I've said to others I'll now say to you: Pretending that a problem you do not like does not exist does not help anyone; least of all yourself.

In the 50's and 60's the US government did more than a little research on nuclear powered Aircraft/spacecraft, they stoped due to two factors "Nuclear Pansies" and the nuclear "trident"


And also predictable factor C: Nuclear powered jet engines didn't work as well as people thought they would.

Trident won out against nuclear bombers because, in the given application of putting nukes on target half a world away (which is damned close to getting into orbit) nuclear technology could not compete with chemical technology. Isn't that an interesting lesson? Nukes aren't always best. Well gee golly gosh, what an amazing surprise that is.

Project Pluto would have been the lasting deterrent.


Pluto was a neat idea, but it would never have been a lasting deterrent. Reasonably simple early ground and air based early warning radar would spot them. As would russian destroyers. Then they could have been shot down by reasonably conventional russian SAMs and AAMs.

the basic limit to any "way out there" idea is power supply,


Plus, you know, little things like material science, safety, reliability, scalability, cost, etc.

first thing to develop would be a suborbital spaceplane the marine's SUSTAIN would be a good candidate project, I wonder what carrier launch and recovery and a range of anywhere In the Hemisphere and back would do for force projection.


It's hardly a new concept. Back in the 60s Icarus was the same thing on a much larger scale, and with slightly better engineering. But the concept is still one of a large slow unmanouverable blind target sitting way up in the sky shouting KILL ME in infrared for minutes at a time. It could be done, but it's still skirting close to being a solution in need of a problem; given that US troops are already stationed five minutes from most major world trouble spots already.

Nuclear power also seems a poor choice for this application. Again the whole pesky radiation thing. Most marines want to have healthy kids at some point; good luck calling them pansies.
Some light reading material: Half Way To Anywhere, The Rocket Company, Space Technology, The High Fronter, Of Wolves And Men, Light On Shattered Water, The Ultimate Weapon, any Janes Guide, GURPS Bio-Tech, ALIENS Technical Manual, The God Delusion.

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IEC Fusion Rocket Poster

Postby MSimon » Thu Sep 13, 2007 3:01 pm


rexxam62
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Re: Rockets!

Postby rexxam62 » Fri Sep 14, 2007 7:38 pm

Zixinus wrote:What are the possibilities of using Polywell as a rocket? What can be done? Relativistic electron beams are mentioned. What of this?


I have not read this whole thread and I dont intend to do it either. Just have one comment. Tom Ligon on the Space Show said that IEC Fusion rocket cocept is the hardest of all applications IEC Fusion will have.

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Postby MSimon » Tue Oct 30, 2007 6:09 am

David,

No special tax is best.

What can be done to help humanity will depend on the price of energy.

Simon

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Postby cuddihy » Wed Oct 31, 2007 2:29 am

DavidWillard wrote:The QED rocket would change the environment of who holds the balance of power. It really sucks to be the enemy when you can have a 100 MW Laser strike on your motorcade or a shower of 25 Km/sec steel rods rain down on your offensive troops. Read "Footfall" By Larry Niven and Jerry Pournell.

You really don't think the US Navy and Air Force isn't chomping at the bit to get upstairs and stay there? Some country will cross that line and I hope it's not a despotic one. Even if there are treaties to ban the military from space that stick, there is still the issue of fractional orbital bombarding.

We can get the radioactive waste to a nice exit trajectory 90 degrees from our solar ecliptic. That takes ludicrous amounts of delta-V, but it would only be the sure way to satisfy Greenpeace.

We can be mining the Moon, or asteroid belts and get the miners back in some respectable time frame instead of strip mining tar sands of Canada.

How about a covenant with the investors to establish that certain products to benefit humanity are completed? A tax of sorts on licensing the reactor and the power usage? Establish some decent goals to help humanity in general.


ANTIcarrot repeated a meme I've seen repeated on several forums that REB thrusters or other types of high-power, high-thrust electric thrusters have never been considered. Baloney. they've just never been practical, with the tiny power rates available from solar. A standard arc-jet is scalable to a large degree, without a loss of ISP, although reusability woul dbe an issue on a mega-arcjet.
Tom.Cuddihy

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Postby kunkmiester » Tue Jun 09, 2009 5:22 am

Just how radioactive does water get? Last I knew, it wasn't a whole lot. You have to convince the ignorant of that, of course, but that's another story. I'm seeing three memes in this thread:

You have technical challenges related directly to the polywell. We can really only speculate on these, since the base technology isn't here yet.

You have other technical challenges, ship design, shielding, etc. These are mostly just crunching numbers, engineering rather than science, so to speak. On many of them, we have reliable past data to work from, such as aerodynamics.

You have political challenges, convincing people this isn't the end of the world, and it's actually best to site a spaceport geographically, rather than politically.
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Postby D Tibbets » Sat Jun 13, 2009 7:27 am

I thought about various comments untill I realized all but the last was 1.5 yrs old... But, I think I recall R. Nebel mentioning that 1/10,000 fusions would result in a neutron (with P-B11), not the 1000 mentioned. Also, high GW output for boosting into LEO would be the only time the onboard Bussard reactor would be runing anywhere near capacity. You might need to wait a few days befor docking with a space station, but by the time you were ready to land, the cool down time for induced radioactivity would have mostly passed. And, even the shuttle has to be handled with kit gloves for the first few hrs after landing due to concerns about toxic chemicals like hydrazine.
As far as costal launches- as there has never been a SSTO there are always boosters that fall to Earth. It is very convient to have these fall into the ocen, unless you are limited like the Russians, where low population savanas/ deserts are the next best thing.

As far as water becoming radioactive, a hydrogen picking up a neutron would not be a problem. The more rare native or new formed deuterium picking up a neutron to form tritium would be of some concern. What the oxygen in water does with neutrons I have no idea. I suspect the largest concern would be contaminants- even with double distilled and deionized water there would be contaminates from any container, pipes, etc. Water is not called the universal solvant for nothing (especially hot water).


Dan Tibbets
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93143
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Postby 93143 » Sat Jun 13, 2009 6:30 pm

D Tibbets wrote:But, I think I recall R. Nebel mentioning that 1/10,000 fusions would result in a neutron (with P-B11), not the 1000 mentioned.


Actually, his figure was 1/100,000,000, mostly due to poor ash confinement. The primary neutronic side reaction is alpha+11B.

And it's 'kid gloves', not 'kit gloves'.

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Postby D Tibbets » Sat Jun 13, 2009 7:02 pm

93143 wrote:
D Tibbets wrote:But, I think I recall R. Nebel mentioning that 1/10,000 fusions would result in a neutron (with P-B11), not the 1000 mentioned.


Actually, his figure was 1/100,000,000, mostly due to poor ash confinement. The primary neutronic side reaction is alpha+11B.

And it's 'kid gloves', not 'kit gloves'.


Sorry, I've been looking at too many DSLR camera/ lens kits recently.

And, what about the deuterium contamination in your hydrogen supply? Even with isotopic seperation I doubt you could get below a few parts per million (actually I have no idea how pure you could make the hydrogen with herculean efforts).


Dan Tibbets
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93143
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Postby 93143 » Sun Jun 14, 2009 6:01 am

D Tibbets wrote:And, what about the deuterium contamination in your hydrogen supply?


I don't know - it's his figure, not mine.

Also, the deuterium fraction in seawater is already around 1/6000, resulting in a D-D fusion rate down seven and a half orders of magnitude from pure deuterium even if you do nothing at all to get rid of it. Doesn't sound like much of an issue even with moderate isotopic separation...

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Postby MSimon » Sun Jun 14, 2009 7:40 am

93143 wrote:
D Tibbets wrote:And, what about the deuterium contamination in your hydrogen supply?


I don't know - it's his figure, not mine.

Also, the deuterium fraction in seawater is already around 1/6000, resulting in a D-D fusion rate down seven and a half orders of magnitude from pure deuterium even if you do nothing at all to get rid of it. Doesn't sound like much of an issue even with moderate isotopic separation...


That is barely worth worrying about. A reduction from 1 part in 6000 to 1 part in 20,000 should be enough (if needed) to get the D-D neutron fraction below 10% of all other reactions combined.

In fact if the D-D neutrons are below 10% (better 1%) of all other neutrons produced by side reactions they can be (for practical purposes) ignored.

Does reverse osmosis reduce the D fraction? By how much?
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