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PostPosted: Fri Sep 18, 2009 6:30 pm 
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If one of the legs breaks, well... spheres roll.


If there are sufficient legs, it wont. I would have telescopic legs that can be adjusted to the terrain. Also I would have them be tilted outward for greater stability.
I would put the engines into an equatorial ring. So you can modulate them for turns, etc.


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PostPosted: Fri Sep 18, 2009 7:11 pm 
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kurt9 wrote:
paulmarch wrote:
kurt9 wrote:
I have a question about the dielectric material necessary for the Mach experiments. Is this the major engineering hurtle right now? Is the material cited in the powerpoints, BaTiO3, sufficient for realizing a demonstration device? Or do you need a better material? What about grain size?


The current M-E experiments use COTS Vishay/Cera-Mite Y5U barium titanate alloy ceramics as the dielectric in their 500pF at 15kV cap size. It's good enough for proof of principle tests, but for a working M-E thruster, much better materials are needed with their optimized parameters dependent on the type of M-E thruster built. If it’s a rotor based UFG, then we need to extend the lifetime of the material and decrease its internal losses while keeping the e-r=5,000 or greater. For MLT's we would also need to add higher magnetic permeability to the dielectric mix as well. Smaller grain size or just going to single crystal versions like quartz crystals needs to be investigated. That's a luxury we've not been able to afford to date due to the very small resources available for this M-E research.


Please let me know the specification for the desired dielectric for both examples of M-E thrusters. Presumably these would either have to be single crystal or, if multi-crystaline, nanosized grains. If multi-crystaline, internal stress is going to be a problem. Presumably these have to be fabricated in large sizes for a working thruster.


Kurt9:

First off, is there any way to append jpg, doc, and/or pdf files to this Polywell forum? It’s a real pain in the posterior not being able to point to documents or slides that I’ve already authored for other folks who have asked similar questions, like I can at the “Next Big Future” or “NASASpaceflight.com” forums.

Now, in any M-E device, per Andrew Palfreyman’s STAIF-2006 M-E math model and a later unpublished “constrained input power” math model we created together in 2008, which are both based on Jim Woodward’s M-E derivation, the magnitude of the generated M-E derived mass/energy fluctuation signal in the energy storing dielectric is proportional to the available active dielectric mass, but inversely proportional to the density and volume of this active dielectric mass. What these three requirements translates out to is that the magnitude of the M-E delta mass/energy signal is proportional to the peak electrical and mechanical stresses applied to a given volume of the dielectric until it breaks at least. This high dielectric stress requirement limits the maximum lifetime of the dielectric so in any M-E device, a tradeoff between performance verses lifetime will have to be made. Also of note is that since the M-E signal is expressed in a cyclic manner that is in counter-(180 deg)-phase to the cap’s self-generated electrostrictive signal, using a dielectric material with a small electrostrictive constant is a big plus. Otherwise the M-E signal is cancelled out by the electrostrictive signal (E-S) until the M-E signal is driven large enough to overwhelm the E-S signal. This can happen because the M-E signal’s expression is much more nonlinear with input power than the E-S signal.

Operationally, the controlling M-E parameters of interest are the following. The dielectric’s M-E signal is proportional to the summation of the applied ac & dc bulk (relative to the distant stars) accelerations and the square of the da/dt “Jerk” accelerations. Desired peak bulk accelerations should be measured in thousands of gees or higher. Next, the M-E signal is proportional to the capacitance of the accelerated M-E cap dielectric, the cube of the applied operating voltage, the cube of the operating frequency, the square of the active dielectric constant, but varies inversely with the dielectric’s loss factor (i.e., lower ac Equivalent Resistance (E-R) is better) which controls the dissipated power and temp rise of the caps for a given input power. If making a solid state Mach Lorentz thruster (MLT), the magnitude of the rectified unidirectional force is proportional to the volumetric crossed B-field in the dielectric, and the thickness of the dielectric in the direction of the applied E-field which increases the leverage arm of the applied crossed B-field. MLTs also require the use of a single cap dielectric layer to preclude Lorentz force cancellation issues that arise by using standard multilayer capacitors were the applied E-field reverses direction in each layer at a given point in time.

Given the above M-E output signal’s optimization parameter space, the desired characteristics of operational M-E energy storage devices, AKA capacitors, is as follows:

1. Relative dielectric constant (e-r)= 1,000 or greater but depends on operating voltage.
2. Dielectric density should be less than 5.6 grams/cc (BaTiO3) and preferably much less.
3. Operating frequency should be optimized for the 10-to-50 MHz range.
4. Dielectric Loss Tangent should be less than 0.5% at the operating frequency.
5. Operating voltage should be up to 100.0 kV-p (See EEStor process), but depends on obtained e-r. Higher e-r allows lower peak voltage for a given energy storage value.
6. Operating times should be measured in thousands to tens of thousands of hours. This will require using low-k plastic film caps or higher-k single crystal or nano-crystal caps.
7. For MLTs the dielectric magnetic permeability should be 10 or greater in a single layer arrangement.

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PostPosted: Fri Sep 18, 2009 7:52 pm 
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Skipjack wrote:
Quote:
This is one reason I've started to warm to the saucer shape, although the cigar shape with decks parallel to the long axis could work too.


I prefer the sphere shape. It has many advantages, e.g. pressures and structural loads are spread evenly over the surface of a sphere. The surface area versus the volume is also optimal in this configuration.
It should also be very stable when landing on legs.
With Mach Engines, I dont see any need for wings other than for heat radiation or solar arrays or something like that.
That is just my personal preference though. Each configuration has its merrits ;)

I am glad that Paul March is commenting in this thread. It is very enlightening.

Paul, do you have a roadmap for your research under ideal funding conditions, current conditions and say some compromise conditions (e.g. not billions, but a few millions, say Polywells level of funding)?
So we all get a better idea what you are planning to do, what each step would cost, etc.


We've put together several R&D plans based on several funding scenarios over the past few years, but until the M-E proof of principle tests are replicated in several other independent labs and accepted by the interested money managers, there is little hope of pursuing them. Let’s say that if the core team of ~5 people including Dr. Woodward could work full time on developing the M-E, we think we could have an R-C controlled M-E technology demonstrator that could move itself over an air hockey table, up and running within 2-to-3 years. Using current professional labor rates that equates out to a million dollars a year plus lab space rental, equipment, expendables, and lab tech time, so for around four million and three years max, I think we could convincingly demonstrate the existence of the M-E and some of its possible engineering applications.

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PostPosted: Fri Sep 18, 2009 8:07 pm 
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Betruger wrote:
I'm also curious, given Dr Woodward's health, what would happen to this research if he had to give up his work, or worse. I can't think of any perfectly polite way to say it, so I apologize for sounding so rude - but would ME research be as lucky as the Bussard Polywell research be with EMC2 picking up without too much trouble where Bussard left off?


Dr. Woodward is the heart and soul of the M-E research, but when he finally does pass on to his final rewards, and if my own health holds up in the interim, (I’m 62), I would attempt to carry on his research as best as I could considering my lesser skills in the GRT realm as compared to Jim's. I also have access to the expertise of Dr. Harold (Sonny) White’s cosmological ZPE and plasma physics knowledge, which also is applicable to this M-E field per Sonny’s STAIF-2007 paper on Quantum Vacuum Fluctuation / Magnetohydrodynamics (QVF/MHD). In my opinion the QVF/MHD approach is simply the QM based version of Dr. Woodward’s M-E work, so there is more than one way to skin this gravinertial cat. As noted before, IMO the GRT and QM worlds will ultimately be combined into a coherent “Quantum Gravity” theory that will better explain our current M-E experimental results and will lead the way to FTL interstellar flight.

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PostPosted: Fri Sep 18, 2009 8:15 pm 
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paulmarch wrote:
kurt9 wrote:
paulmarch wrote:

The current M-E experiments use COTS Vishay/Cera-Mite Y5U barium titanate alloy ceramics as the dielectric in their 500pF at 15kV cap size. It's good enough for proof of principle tests, but for a working M-E thruster, much better materials are needed with their optimized parameters dependent on the type of M-E thruster built. If it’s a rotor based UFG, then we need to extend the lifetime of the material and decrease its internal losses while keeping the e-r=5,000 or greater. For MLT's we would also need to add higher magnetic permeability to the dielectric mix as well. Smaller grain size or just going to single crystal versions like quartz crystals needs to be investigated. That's a luxury we've not been able to afford to date due to the very small resources available for this M-E research.


Please let me know the specification for the desired dielectric for both examples of M-E thrusters. Presumably these would either have to be single crystal or, if multi-crystaline, nanosized grains. If multi-crystaline, internal stress is going to be a problem. Presumably these have to be fabricated in large sizes for a working thruster.


Kurt9:

First off, is there any way to append jpg, doc, and/or pdf files to this Polywell forum? It’s a real pain in the posterior not being able to point to documents or slides that I’ve already authored for other folks who have asked similar questions, like I can at the “Next Big Future” or “NASASpaceflight.com” forums.


I'm a regular reader of the "Next Big Future" blog.

paulmarch wrote:

Now, in any M-E device, per Andrew Palfreyman’s STAIF-2006 M-E math model and a later unpublished “constrained input power” math model we created together in 2008, which are both based on Jim Woodward’s M-E derivation, the magnitude of the generated M-E derived mass/energy fluctuation signal in the energy storing dielectric is proportional to the available active dielectric mass, but inversely proportional to the density and volume of this active dielectric mass. What these three requirements translates out to is that the magnitude of the M-E delta mass/energy signal is proportional to the peak electrical and mechanical stresses applied to a given volume of the dielectric until it breaks at least. This high dielectric stress requirement limits the maximum lifetime of the dielectric so in any M-E device, a tradeoff between performance verses lifetime will have to be made. Also of note is that since the M-E signal is expressed in a cyclic manner that is in counter-(180 deg)-phase to the cap’s self-generated electrostrictive signal, using a dielectric material with a small electrostrictive constant is a big plus. Otherwise the M-E signal is cancelled out by the electrostrictive signal (E-S) until the M-E signal is driven large enough to overwhelm the E-S signal. This can happen because the M-E signal’s expression is much more nonlinear with input power than the E-S signal.

Operationally, the controlling M-E parameters of interest are the following. The dielectric’s M-E signal is proportional to the summation of the applied ac & dc bulk (relative to the distant stars) accelerations and the square of the da/dt “Jerk” accelerations. Desired peak bulk accelerations should be measured in thousands of gees or higher. Next, the M-E signal is proportional to the capacitance of the accelerated M-E cap dielectric, the cube of the applied operating voltage, the cube of the operating frequency, the square of the active dielectric constant, but varies inversely with the dielectric’s loss factor (i.e., lower ac Equivalent Resistance (E-R) is better) which controls the dissipated power and temp rise of the caps for a given input power. If making a solid state Mach Lorentz thruster (MLT), the magnitude of the rectified unidirectional force is proportional to the volumetric crossed B-field in the dielectric, and the thickness of the dielectric in the direction of the applied E-field which increases the leverage arm of the applied crossed B-field. MLTs also require the use of a single cap dielectric layer to preclude Lorentz force cancellation issues that arise by using standard multilayer capacitors were the applied E-field reverses direction in each layer at a given point in time.

Given the above M-E output signal’s optimization parameter space, the desired characteristics of operational M-E energy storage devices, AKA capacitors, is as follows:

1. Relative dielectric constant (e-r)= 1,000 or greater but depends on operating voltage.
2. Dielectric density should be less than 5.6 grams/cc (BaTiO3) and preferably much less.
3. Operating frequency should be optimized for the 10-to-50 MHz range.
4. Dielectric Loss Tangent should be less than 0.5% at the operating frequency.
5. Operating voltage should be up to 100.0 kV-p (See EEStor process), but depends on obtained e-r. Higher e-r allows lower peak voltage for a given energy storage value.
6. Operating times should be measured in thousands to tens of thousands of hours. This will require using low-k plastic film caps or higher-k single crystal or nano-crystal caps.
7. For MLTs the dielectric magnetic permeability should be 10 or greater in a single layer arrangement.


Good lord! You're not kidding about this being a high stress application. I have to chew on this a bit.

Does Dr. Woodward's site have the relevant technical information? What about the "Woodword Effect" site on the cphonx.net server?


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PostPosted: Fri Sep 18, 2009 8:26 pm 
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Quote:
I'm a regular reader of the "Next Big Future" blog.

I thought I saw you comment on there ;)


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PostPosted: Fri Sep 18, 2009 8:27 pm 
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tomclarke wrote:
I've just done some searching.

The only theoretical critique of Mach effect I have found is Robertson 2000
The case for inertia as a vacuum effect: a reply to Woodward & Mahoud

This is a strongly pro vacuum fluctuation cause of inertia but also makes quite a number of independent criticisms of Woodward's theory which do not relate to whether there is some other non-trivial explanation. They suggest that the trivial explanation - as an intrinsic property of matter - should be preferred to extrinsic effects on basis of Occam's Razor. This is debatable, I feel. They make a number of detailed criticims of Woodward's ideas.

I would like to find Woodward's reply to this?

Also Robertson 2006 has suggested that the various experiments results can be explained, given nonlinear interaction between electric & magnetic field, by a theory which seems to me on cursory reading to be totally weird since it violates conservation of momentum:
Electromagnetic Nonlinearity in the Dielectric Medium of Experimental EM Impulse-Momentum Systems in BaTiO3 dielectrics.

Finally, Woodward 2004 has a useful discussion of whether his observations could be result of some mundane effect. He concludes quite strongly that this is unlikely but I am not convinced yet that he has covered everything. His test, which has separate drives for capacitor & inductor, makes it easier to elimate other effects by varying indepndently the phase and amplitude of the two drive signals. I would have thought that a repetition of this experiment, with more powerful supplies, would have the best chances of confirming or denying Mach Effect? Paul would I am sure be able to comment on this.

Best wishes, Tom


Tom:

Do you have an e-mail address I can send you your requested reports? Jim has rebutted all the nay-Sayers a number of times now over the last 11 years I’ve known him that I'm losing count of them, but the big one came with the Oak Ridge Lab's objections that were dealt with in several papers that Jim sent out in the 2000/2001 time period. As to Tony Robertson’s ideas on this topic, well let’s say that he should probably stick to engineering issues instead of theoretical GRT issues.

BTW if you want to check out NASASpaceflight.com at the following URL, you might find some of the papers you are looking for spread out over the 39 pages of the Propellantless Field Propulsion Forum under their General Discussion/Advanced Concept header. My stuff is under my Star-Drive label.

http://forum.nasaspaceflight.com/index. ... ic=13020.0

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PostPosted: Fri Sep 18, 2009 8:41 pm 
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Paul, do you agree that if your spacecraft propulsion method turns out to be true, it will be so simple to accelerate anything close to lightspeed that relativistic weapons will be the most common weapons in the universe (in this case, I hope no et civilization comes in contact with us until we are able to expand enough to avoid extinction, since they will probably have their own relativistic arsenal and will destroy us in fear that we might do it first with our recently discovered tech)


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PostPosted: Fri Sep 18, 2009 8:46 pm 
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kurt9 wrote:
paulmarch wrote:
kurt9 wrote:
paulmarch wrote:

The current M-E experiments use COTS Vishay/Cera-Mite Y5U barium titanate alloy ceramics as the dielectric in their 500pF at 15kV cap size. It's good enough for proof of principle tests, but for a working M-E thruster, much better materials are needed with their optimized parameters dependent on the type of M-E thruster built. If it’s a rotor based UFG, then we need to extend the lifetime of the material and decrease its internal losses while keeping the e-r=5,000 or greater. For MLT's we would also need to add higher magnetic permeability to the dielectric mix as well. Smaller grain size or just going to single crystal versions like quartz crystals needs to be investigated. That's a luxury we've not been able to afford to date due to the very small resources available for this M-E research.


Please let me know the specification for the desired dielectric for both examples of M-E thrusters. Presumably these would either have to be single crystal or, if multi-crystaline, nanosized grains. If multi-crystaline, internal stress is going to be a problem. Presumably these have to be fabricated in large sizes for a working thruster.


Kurt9:

First off, is there any way to append jpg, doc, and/or pdf files to this Polywell forum? It’s a real pain in the posterior not being able to point to documents or slides that I’ve already authored for other folks who have asked similar questions, like I can at the “Next Big Future” or “NASASpaceflight.com” forums.


I'm a regular reader of the "Next Big Future" blog.

paulmarch wrote:

Now, in any M-E device, per Andrew Palfreyman’s STAIF-2006 M-E math model and a later unpublished “constrained input power” math model we created together in 2008, which are both based on Jim Woodward’s M-E derivation, the magnitude of the generated M-E derived mass/energy fluctuation signal in the energy storing dielectric is proportional to the available active dielectric mass, but inversely proportional to the density and volume of this active dielectric mass. What these three requirements translates out to is that the magnitude of the M-E delta mass/energy signal is proportional to the peak electrical and mechanical stresses applied to a given volume of the dielectric until it breaks at least. This high dielectric stress requirement limits the maximum lifetime of the dielectric so in any M-E device, a tradeoff between performance verses lifetime will have to be made. Also of note is that since the M-E signal is expressed in a cyclic manner that is in counter-(180 deg)-phase to the cap’s self-generated electrostrictive signal, using a dielectric material with a small electrostrictive constant is a big plus. Otherwise the M-E signal is cancelled out by the electrostrictive signal (E-S) until the M-E signal is driven large enough to overwhelm the E-S signal. This can happen because the M-E signal’s expression is much more nonlinear with input power than the E-S signal.

Operationally, the controlling M-E parameters of interest are the following. The dielectric’s M-E signal is proportional to the summation of the applied ac & dc bulk (relative to the distant stars) accelerations and the square of the da/dt “Jerk” accelerations. Desired peak bulk accelerations should be measured in thousands of gees or higher. Next, the M-E signal is proportional to the capacitance of the accelerated M-E cap dielectric, the cube of the applied operating voltage, the cube of the operating frequency, the square of the active dielectric constant, but varies inversely with the dielectric’s loss factor (i.e., lower ac Equivalent Resistance (E-R) is better) which controls the dissipated power and temp rise of the caps for a given input power. If making a solid state Mach Lorentz thruster (MLT), the magnitude of the rectified unidirectional force is proportional to the volumetric crossed B-field in the dielectric, and the thickness of the dielectric in the direction of the applied E-field which increases the leverage arm of the applied crossed B-field. MLTs also require the use of a single cap dielectric layer to preclude Lorentz force cancellation issues that arise by using standard multilayer capacitors were the applied E-field reverses direction in each layer at a given point in time.

Given the above M-E output signal’s optimization parameter space, the desired characteristics of operational M-E energy storage devices, AKA capacitors, is as follows:

1. Relative dielectric constant (e-r)= 1,000 or greater but depends on operating voltage.
2. Dielectric density should be less than 5.6 grams/cc (BaTiO3) and preferably much less.
3. Operating frequency should be optimized for the 10-to-50 MHz range.
4. Dielectric Loss Tangent should be less than 0.5% at the operating frequency.
5. Operating voltage should be up to 100.0 kV-p (See EEStor process), but depends on obtained e-r. Higher e-r allows lower peak voltage for a given energy storage value.
6. Operating times should be measured in thousands to tens of thousands of hours. This will require using low-k plastic film caps or higher-k single crystal or nano-crystal caps.
7. For MLTs the dielectric magnetic permeability should be 10 or greater in a single layer arrangement.


Good lord! You're not kidding about this being a high stress application. I have to chew on this a bit.

Does Dr. Woodward's site have the relevant technical information? What about the "Woodword Effect" site on the cphonx.net server?


There is some pertinent information at each site you listed buried in the various papers and presentations listed there in. You can also go to the NASASpaceflight.com Propellantless Field Propulsion Forum that I just provided to Tom and take a look at the information presented there. Pass that send a note to me and I’ll see what I can provide.

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PostPosted: Fri Sep 18, 2009 9:01 pm 
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AcesHigh wrote:
Paul, do you agree that if your spacecraft propulsion method turns out to be true, it will be so simple to accelerate anything close to lightspeed that relativistic weapons will be the most common weapons in the universe (in this case, I hope no et civilization comes in contact with us until we are able to expand enough to avoid extinction, since they will probably have their own relativistic arsenal and will destroy us in fear that we might do it first with our recently discovered tech)


I'm afraid that if the M-E thrusters work out as they seem to be working, that yes, relativistic kinetic energy weapons based on the M-E impulse drives could be the cheapest form of weapons of mass destruction (WMD)s available to any true space fairing race. We can only hope that by the time an alien race, or ourselves, obtains this kind of power and propulsion technology that they are not so paranoid as to want to take out all their interstellar neighbors in a preemptory strike! Hmmm, didn’t Anderson, Niven and/or Pournell write a sci-fi book about this topic? It also points out the need for a solar system based anti-missile system preferably using very high power laser weapons.

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I wonder if a "relativistic missile defense system" would be possible. I mean, how to detect something travelling near light speed (unless we detect the fabled tachyon emissions (if any) from such objects???

its like trying to defend against a bullet shot from a distance against your eye. The moment you see it, its only microseconds to act. But it will take more time for the visual input to even reach your brain!

anyway, keep on with the good work. May the effect turn out to be real or not, its good to have people working on alternative propulsion technics. Enough of inneficient chemical rockets.

I would be happy with nuclear pulse propulsion or even VASIMR Polywell Powered ships (reaching Mars in 30 days), what to say of reactionless drives... (or fuel recycler drives, as you said you prefered)


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PostPosted: Fri Sep 18, 2009 9:22 pm 
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Skipjack wrote:
If there are sufficient legs, it wont. I would have telescopic legs that can be adjusted to the terrain. Also I would have them be tilted outward for greater stability.


I still don't like it. Imagining this thing trying to set down on a substantial grade gives me the willies - you'd need enormously long extensible legs to stabilize it. Also, you'd probably want the centre of gravity to be fairly low, which impedes full utilization of the internal volume afforded by the shape. This (ie: putting all the heavy equipment in the bottom), combined with the large number of legs you seem to be proposing, would make it quite difficult to board (or load) this thing from the ground, limiting its usefulness outside of a well-established infrastructure.

An oblate spheroid with a polar axis half the length of the equatorial axis has about 41% more surface area and 26% more width on the ground than a sphere of the same volume. So yes, structurally there is an advantage to the sphere, but operationally, it may be outweighed by practical considerations such as landing stability and ground loading. Ground loading in particular may become important for larger vehicles.

Or maybe I just dislike the idea of a spherical spacecraft for some reason... maybe the same reason why Betruger doesn't like spaceplanes...

Now that I think about it, a spherical craft might be okay if it was quite small - a one- or two-man vehicle...


What thickness of glass/water/fused quartz/other transparency that doesn't discolour under UV bombardment would be required to protect against GCRs and CMEs? You know, for the observation deck of a Mars-bound cruise ship?


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PostPosted: Fri Sep 18, 2009 9:47 pm 
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AcesHigh wrote:
I wonder if a "relativistic missile defense system" would be possible. I mean, how to detect something travelling near light speed (unless we detect the fabled tachyon emissions (if any) from such objects???

its like trying to defend against a bullet shot from a distance against your eye. The moment you see it, its only microseconds to act. But it will take more time for the visual input to even reach your brain!

anyway, keep on with the good work. May the effect turn out to be real or not, its good to have people working on alternative propulsion technics. Enough of inneficient chemical rockets.

I would be happy with nuclear pulse propulsion or even VASIMR Polywell Powered ships (reaching Mars in 30 days), what to say of reactionless drives... (or fuel recycler drives, as you said you prefered)


You raise a good point, and I’m beginning to think than an FTL communications and tracking system at the very least may be required using the M-E wormhole term’s FTL capabilities. As one person on this forum already noted, using an M-E based micro-wormhole generator communications system and a spherical coverage set of trip-wire radar sentry posts at the perimeter of the solar system could provide several hours of warning to react to any incoming kinetic energy weapons aimed at Earth or any other human outposts in the solar system as well.

BTW, I’d be tickle pink over a VASIMR/Polywell hybrid space drive capability and I’ve been pushing that idea here at NASA/JSC/EP as a real R&D possibility for the next ten years. Of course if the M-E drives become available in that time period, I’d switch allegiances in a heartbeat, but they first have to prove themselves before I could go down that road.

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PostPosted: Fri Sep 18, 2009 9:51 pm 
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93143 wrote:
Skipjack wrote:
If there are sufficient legs, it wont. I would have telescopic legs that can be adjusted to the terrain. Also I would have them be tilted outward for greater stability.


I still don't like it. Imagining this thing trying to set down on a substantial grade gives me the willies - you'd need enormously long extensible legs to stabilize it. Also, you'd probably want the centre of gravity to be fairly low, which impedes full utilization of the internal volume afforded by the shape. This (ie: putting all the heavy equipment in the bottom), combined with the large number of legs you seem to be proposing, would make it quite difficult to board (or load) this thing from the ground, limiting its usefulness outside of a well-established infrastructure.

An oblate spheroid with a polar axis half the length of the equatorial axis has about 41% more surface area and 26% more width on the ground than a sphere of the same volume. So yes, structurally there is an advantage to the sphere, but operationally, it may be outweighed by practical considerations such as landing stability and ground loading. Ground loading in particular may become important for larger vehicles.

Or maybe I just dislike the idea of a spherical spacecraft for some reason... maybe the same reason why Betruger doesn't like spaceplanes...

Now that I think about it, a spherical craft might be okay if it was quite small - a one- or two-man vehicle...


What thickness of glass/water/fused quartz/other transparency that doesn't discolour under UV bombardment would be required to protect against GCRs and CMEs? You know, for the observation deck of a Mars-bound cruise ship?


Why not have two independent teams build both the spherical and oblate spheriod vehicle approaches and have a flyoff? That development approach works for the Air Force...

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heheh Paul, good idea.
Honestly, even if the disc won, I would still prefer the spherical shape just because it does not look quite as cheesy (though the sphere does have a certain level of cheesiness as well). Giggles ;)


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