NewSpace 2010: Polywell and Vasimr

[GIThruster]

I'm always happy to be corrected. Show me a reasonable launch cost for hundreds of miles of cable and I'll retract my sentiments.

All of the rational I have seen in support of the concept has again relied upon the notion that launch costs will be driven down by their volume. If you tell me the entire elevator will fit on an Atlas, cool. Then all you need to do is convince the masses that it won't fall out of the sky.

But it can't fit in an Atlas. Or two. Or twenty, IIRC.

You start to see the problem. . .problems we don't have if we simply pursue the proper physics and get what we really want/need--propellantless thrust.

[paulmarch]

I'm always happy to be corrected. Show me a reasonable launch cost for hundreds of miles of cable and I'll retract my sentiments.

All of the rational I have seen in support of the concept has again relied upon the notion that launch costs will be driven down by their volume. If you tell me the entire elevator will fit on an Atlas, cool. Then all you need to do is convince the masses that it won't fall out of the sky.

But it can't fit in an Atlas. Or two. Or twenty, IIRC.

You start to see the problem. . .problems we don't have if we simply pursue the proper physics and get what we really want/need--propellantless thrust.

Ron:

It's not hundreds of miles of carbon fiber cable. It's more like ~30,000 miles of carbon nanotube cable that needs to be lofted to GEO that is then tied to a small asteroid as the required counter balance. My biggest problem though with this concept is what happens the first time this cable is snapped by a wayward aircraft, orbital debris or terrorist attack and then everything attached to it below a certain altitude goes streaking off at 1,000 mph before its starts falling. Last item of concern is how does one cope with the electrical currents induced in the cable by the relative motion of the cable with regards to the Earth's B-field, especially when solar flares are in progress. Do we not remember what happened to the Italian tether experiment from the Space Shuttle with only 12 km of cable reeled out? We still have a very poor understanding of the electrodynamic environment surrounding this planet…

[Skipjack]

Are you familiar with Dr. Woodward's Mach-Effect conjecture and the experimental data-set backing it? It's by no means fully proven yet, but this body of work is far more real than "magic space pixes"...

Hey Paul! Cool to see you are still lurking arround here! I am glad that the politics here did not scare you away
I think most people here are aware of the interesting research that you and Dr Woodward are doing.
How is that coming allong? Got any news for us?
It would sure be a dream come true for me any I am sure a lot of others here too.

[Tom Ligon]

Paul,

Yes, every time I hear speculations about space elevators or other tether experiments (several slingshot approaches have been proposed) I wonder if they have gotten to the bottom of that surprise blowout of a relatively short tether.

The last I heard they thought they could use induced current in conducting tethers to de-orbit spacecraft.

A space elevator cable probably won't induce as much current per unit length as one in LEO (no motion relative to the surface, although the dynamic magnetic field during each day would have an effect). But with tens of thousands of miles sticking straight out the opportunity to discover new modes of disaster are intriguing.

[Betruger]

Are you familiar with Dr. Woodward's Mach-Effect conjecture and the experimental data-set backing it? It's by no means fully proven yet, but this body of work is far more real than "magic space pixes"...

Hey Paul! Cool to see you are still lurking arround here! I am glad that the politics here did not scare you away
I think most people here are aware of the interesting research that you and Dr Woodward are doing.
How is that coming allong? Got any news for us?
It would sure be a dream come true for me any I am sure a lot of others here too.

Also if there's been any news from Cramer's retrocausality experiments..

[GIThruster]

". . .with tens of thousands of miles sticking straight out the opportunity to discover new modes of disaster are intriguing."

Heh!

This is why I can't even remember the numbers and to be fair, not all designs use an asteroid. There's more than one, but none of them make any sense.

BTW, I think Dr. Woodward is sneaking into the lab this week to try a first run for the Fall season. He's still in CO for the summer but travels back to LA every 10 days or so for chemo and tinkers a little each time. I think he said he's about ready to run.

Paul, if you want to try to run one of my ALTAS wafers, I'd be thrilled. Looks like Bruce will be busy for months yet and the actuators I have will run on your Ham stuff so long as it's matched. Just let me know and I'll build you a thruster.

[paulmarch]

Are you familiar with Dr. Woodward's Mach-Effect conjecture and the experimental data-set backing it? It's by no means fully proven yet, but this body of work is far more real than "magic space pixes"...

Hey Paul! Cool to see you are still lurking arround here! I am glad that the politics here did not scare you away
I think most people here are aware of the interesting research that you and Dr Woodward are doing.
How is that coming allong? Got any news for us?
It would sure be a dream come true for me any I am sure a lot of others here too.

Guys:

No news yet as G/I-Thruster remarked. Jim is slowly revamping his shuttler experiment taking into account the required driving electronics, the 1-omega (w) & 2-w BW filtering, with some help from me in the circuit analysis/simulation front.

I'm still fighting with RF engineering issues in regards to testing my MLT-2010 after I found out that its as-wound inductor had a self-resonant frequency (SRF) of 2.05 MHz when I had hoped for at least double that figure. (I was trying to operate it in the 1.8 to 2.0 MHz, 160 meter Ham communications band.) Oh well, I could rebuild it or use what I've got, so I've decided to use what I've got and run it at its current R-L-C resonant frequency of 1.62 MHz. Of course, my ICOM 746Pro transceiver doesn't operate at that low a frequency, so I'm having to build up a Medium Frequency (MF) transmitter system that will be battery driven and be able to fit in the MLT-2010's tin-can Faraday shield. I hope to have this assembly put together and ready for some preliminary tests by the end of this coming September. Murphy allowing of course…

[paulmarch]

". . .with tens of thousands of miles sticking straight out the opportunity to discover new modes of disaster are intriguing."

Heh!

This is why I can't even remember the numbers and to be fair, not all designs use an asteroid. There's more than one, but none of them make any sense.

BTW, I think Dr. Woodward is sneaking into the lab this week to try a first run for the Fall season. He's still in CO for the summer but travels back to LA every 10 days or so for chemo and tinkers a little each time. I think he said he's about ready to run.

Paul, if you want to try to run one of my ALTAS wafers, I'd be thrilled. Looks like Bruce will be busy for months yet and the actuators I have will run on your Ham stuff so long as it's matched. Just let me know and I'll build you a thruster.

Ron:

Thanks for the ATLAS wafer offer, but one thing at a time please. If the MLT-2010 ends up being a bust, I may take you up on your offer in the October/November time frame.

[TallDave]

Of course, my ICOM 746Pro transceiver doesn't operate at that low a frequency, so I'm having to build up a Medium Frequency (MF) transmitter system that will be battery driven and be able to fit in the MLT-2010's tin-can Faraday shield. I hope to have this assembly put together and ready for some preliminary tests by the end of this coming September. Murphy allowing of course…

Good luck! I hope you're able to get a good signal-to-noise ratio.

[TallDave]

GT,

I think the current thinking is most of the cable is built by crawlers.

I agree there are many Unknown Unknowns in a SE, which will probably doom initial attempts. But, like the Panama Canal, the benefits are big enough that the first few disastrous attempts probably won't prevent it from eventually happening -- unless of course we get some crazy specific impulse fusion drives first.

[WizWom]

We need propellantless propusion and as long as dread, dopey engineers hang out for less, we won't see funding for what's real--the M-E thruster.

We need magic space pixies, to wave their wands! Woohoo!

Are you familiar with Dr. Woodward's Mach-Effect conjecture and the experimental data-set backing it? It's by no means fully proven yet, but this body of work is far more real than "magic space pixes"...

With all due respect, Dr. March, while i appreciate the attempt to model the origin of mass by Mach, I find that his explanation adds complexity without adding clarity.

You're playing around with rather interesting RF effects in a fairly strong electromagnetic field; I'd be surprised if you could NOT get some sort of effect from the Earth's 100V & .3 gauss field.

At this point, your experiments are in the same realm as Pons & Fleishmann in 91.

But, P&F Colf fusion eventually WAS shown to be duplicable, just trivial.

Nothing would please me more than you finding a way to do a massless thruster, EVEN if it just used the Earth's EM field and had limited applicability above 5 miles. Those first 5 miles are a very real problem for rockets, and it would be revolutionary.

[cc]

Well, I had a fairly long post that the forum just ate when I hit the preview button. If you have concerns, the book I referenced will almost certainly address them.

In summary, space elevators may be long, but they are not nearly as massive as people expect, and the seed ribbon is small enough for existing launchers. After that is deployed, it is progressively widened by successive climbers, which along with excess ribbon, also act as the counterweight. (no asteroid or additional launch capacity required)

A key point though, is that rockets must provide the entire energy for the delta-V, which is further compounded by the much smaller payload fraction. With the elevator, you only provide a modest amount of potential energy; the vast remainder is taken from the Earth's angular momentum. Releasing from the ribbon past GEO allows direct access to other destinations, virtually for free.

To appreciate the scale of the elevator, the entire projected cost for the first ribbon and supporting infrastructure is less than that of ITER.

[GIThruster]

With all due respect, Dr. March, while i appreciate the attempt to model the origin of mass by Mach, I find that his explanation adds complexity without adding clarity.

I'm surprised to hear this. Can I ask, where do you think inertia comes from?

Since gravitic and inertial effects seem identical at times, it appears to me quite simplifying to say that inertia comes from gravity. Einstein liked the idea so much he coined the term Mach's Principle.

The only way I can see to reduce the complexity of the issue is to treat it as a non-issue by failing to ask where inertia comes from. Did you want to say that it's an intrinsic property of matter or did I misunderstand you?

[pfrit]

". . .with tens of thousands of miles sticking straight out the opportunity to discover new modes of disaster are intriguing."

Heh!

This is why I can't even remember the numbers and to be fair, not all designs use an asteroid. There's more than one, but none of them make any sense.

Actually, most of the tether and virtually all of the tether mass would not fall if it broke. The nd away from the Earth would move away.

My problem with it is that it would by definition pass through the Van Allen belts. It will pick a charge. This charged cable would them pass through the ozone layer and the rest of the atmosphere. The ozone would eat it because of the charge and it would attract a lot of lightning. I just don't buy the idea that it could survive for long with any kind of charge or that somehow you could isolate the charge.

[icarus]

With the elevator, you only provide a modest amount of potential energy; the vast remainder is taken from the Earth's angular momentum.

I see an environmental flaw here, who asked Gaia if you could take some of her angular momentum and what do you intend to do about paying it back?