NASA's Next 50 Years

Discuss life, the universe, and everything with other members of this site. Get to know your fellow polywell enthusiasts.

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djolds1
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Post by djolds1 »

Skipjack wrote:I do know what the thrust to weight ratio is, but I do not quite know where you get your information Duane.
According to Astronautix at least one of the various configurations that were designed and or tested had a Thrust to Weight ratio of 7.46.
http://www.astronautix.com/engines/nerva.htm
Winchell Chung's "Atomic Rocket" page(s). Usually accurate math, always easy to access. Does not detail the variations as well as the Encyclopedia Astronautica. Given that DUMBO has a thrust of 3.5 Meganewtons and a T:W of 71.0...
Skipjack wrote:Further I would like to point out that the US was not the only country considering this kind of engine. The Soviets originally wanted to use simillar engines for their N1 heavy lift rocket.
http://www.astronautix.com/lvs/n1.htm
The Soviets were never shy about using nuclear power in space.

Duane
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Skipjack
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Post by Skipjack »

Yeah, why be shy about it anyway?
Even Carl Sagan was a proponent of it.

I am still not sure whether you actually agree or disagree with me ;)

Skipjack
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Post by Skipjack »

In any case, NERVA could be much improved uppon with todays tech, I am sure.
The problem for me has always been more a political one than a technical one. With a polywell based propulsion system, the political implications would be a matter of the past as well and door to space will finally open really wide... provided "that deng theing works".

djolds1
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Post by djolds1 »

Skipjack wrote:Yeah, why be shy about it anyway?
Even Carl Sagan was a proponent of it.
The early years?
Skipjack wrote:I am still not sure whether you actually agree or disagree with me ;)
Agree. I'd ride an Orion.
Skipjack wrote:In any case, NERVA could be much improved uppon with todays tech, I am sure.
The US DoD reexamined solid NTRs in the late '80s/early '90s as part of the Star Wars program. Their notional studies came out with Isps of 1000 seconds, theoretical max.

Note that LOX/LH2 rockets have not seen significant improvements in thrust or Isp since 1960. Fifty years. Certain technologies have hard limits. Several meganewtons of thrust, 800-900 seconds of Isp, and T:Ws of 20+ would be very nice today. Its not the high Isp seen in the better systems, but is a significant improvement for manned flight.
Skipjack wrote:The problem for me has always been more a political one than a technical one.
That's the reason I like the near term achievable megaprojects. They short circuit the nuclear fears, are national egotrips, and give cheap access.
Skipjack wrote:With a polywell based propulsion system, the political implications would be a matter of the past as well and door to space will finally open really wide... provided "that deng theing works".
I'm still concerned that the word "nuclear" will cause a reflexive retreat. :(
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Skipjack
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Post by Skipjack »

Yeah, one has to make sure to never mention the word nuclear and polywell in one sentence, or presentation. I dont know about government officials in the US, but in Austria the ones making the decision would never get the difference between fission an fusion. Dont even mention anything about Orion anywhere near them, they would burn you at the stake.
I remember that back when there where the very early and at the time quite casual discussions with the responsible politician about ITER being built in Austria. Not only did the guy not understand what it was about, he behaved so dum that after 3 sentences from him, the topic was dropped and never brought up again ;)
I think you have to have half of you brain removed in order to become a successful politician.

On Carl Sagan: Yeah sure, he was supporting Orion even, even in his "Cosmos" TV series.

djolds1
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Post by djolds1 »

Skipjack wrote:Dont even mention anything about Orion anywhere near them, they would burn you at the stake.
Perhaps they'd like to see a launch from the business end? :D

Irony is that the Nuclear Salt Water Rocket makes Orion look clean and comfy by comparison.
Skipjack wrote:I remember that back when there where the very early and at the time quite casual discussions with the responsible politician about ITER being built in Austria. Not only did the guy not understand what it was about, he behaved so dumb that after 3 sentences from him, the topic was dropped and never brought up again ;)
Sounds like the idiots who thought firing up the LHC would create a black hole and end the world. Even if one was created, it would evaporate into the aether almost instantly.
Skipjack wrote:I think you have to have half of you brain removed in order to become a successful politician.
No. But you do have limited time, so many issues almost need to be pre-digested down to sound bites just to be able to minimally comprehend them.

OTOH, I doubt FPO & BZO will have that problem in the Nationalrat. :twisted:
Skipjack wrote:On Carl Sagan: Yeah sure, he was supporting Orion even, even in his "Cosmos" TV series.


Probably the 10 meter NASA Orion. Loft it on a Saturn 5. A 100 metric tonne item. The original ground launched Orion Planetary was 4000 metric tonnes. 8)

http://www.astronautix.com/graphics/o/orionsco.jpg
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djolds1
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Post by djolds1 »

Betruger wrote:Duane,
Go to the space.com forums and search for a thread started by user 'Keermalec' titled something like 'Mars, 8 tons at a time'. He has crunched the essential numbers to make it work. There was another preceding thread that you might find technicaly interesting in the old uplink.space.com forums, too.

Here's one of those..
Thanks! :)
Betruger wrote:And if anyone with plasma physics knowledge ( :wink: ) has an hour or two of free time .. Check out this irresistible force vs. immovable object debate on the physics of the sun.. Skipping to the last few dozen pages and limiting yourself to the plasma circuits arguments could possibly be helpful in pulling the discussion out of its trenches.
:(

Page no longer present. And the Internet Archive returns a 404.

Duane
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Skipjack
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Post by Skipjack »

I think he wanted "the big version".

Way OT:
This is very difficult to explain. Let me just say the following:
Austria has issues. The leading parties kept ignoring them. Austria has an immigration problem. At least one leading party admitted that during the last election also. The leading parties kept putting the well being of others ahead of the well being of their own people.
Austria has had the worst inflation in 60 years. The big parties kept nice talking it. Gasoline costs 50% more than it does in the US, the big parties kept nice talking it. Foodprices climbed by up to 50% in the last 6 years, the big parties kept nice talking and ignoring it. And with all that, we are wasting money on people that are not ours.
All this did not go well with the general public here.
Yet the big parties together still make more than 50% of the votes. So to put this into relation.
Also, the big parties here are ideoligally handicapped to no avail. It is a tragedy. BZO and FPO also have ideological problems though. They are just not always quite as unscientific as the others.
Also to put this into relation: G.W. Bush makes Joerg Haider look like Oliver Twist. Even Joe Biden would be considered a right wing radical here. I mean death penalty is something that none of our politicians would ever consider and even the hardest immigration laws that any member of any of these two parties ever considered are ridiculously mild compared to the ones the US currently has and has always had. Proposing laws like these in todays Austria would be unthinkable.
Just to put things into the right perspective.

djolds1
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Post by djolds1 »

Skipjack wrote:I think he wanted "the big version".
Sagan is the man who campaigned against the terror of the nuclear winter that WW3 would cause. I have severe trouble seeing him being in favor of Orion ground launches.

OTOH, the NASA 10m Orion and HUGE interstellar designs are perfect for exploration, colonization, and even get rid of all those evil weapons grade fissionables.
Skipjack wrote:Way OT:

Austria has had the worst inflation in 60 years. The big parties kept nice talking it. Gasoline costs 50% more than it does in the US, the big parties kept nice talking it. Foodprices climbed by up to 50% in the last 6 years, the big parties kept nice talking and ignoring it. And with all that, we are wasting money on people that are not ours.
All this did not go well with the general public here.
Much the same in the States. Every time I hear a pol or presscritter say "we have a strong economy" I try not to grind my teeth. Even if correct in the abstract, that is not the reality people are living in, and simply saying it is an insult.
Skipjack wrote:Yet the big parties together still make more than 50% of the votes. So to put this into relation.
Also, the big parties here are ideoligally handicapped to no avail. It is a tragedy. BZO and FPO also have ideological problems though. They are just not always quite as unscientific as the others.
Borderline neofascist, yes? Haider is back with BZO, and together FPO & BZO took 30% of the election.

I'm seeing good indicators that intense anger is boiling just under the surface in the entire Piedmont-Wien corridor.

You in Wien?
Skipjack wrote:Also to put this into relation: G.W. Bush makes Joerg Haider look like Oliver Twist. Even Joe Biden would be considered a right wing radical here. I mean death penalty is something that none of our politicians would ever consider and even the hardest immigration laws that any member of any of these two parties ever considered are ridiculously mild compared to the ones the US currently has and has always had. Proposing laws like these in todays Austria would be unthinkable.
:)

Yup. Reactionary Euro rightwingers who move to the US are odd if they manage to end up in the middle of our Left. Tho there are certain bloody minded people I like who want to see the Somali pirates lined up against a wall and shot.

Downside for Europe is no tradition of assimilation. Makes integrating any significant number of newcomers much more difficult.

Duane
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Skipjack
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Post by Skipjack »

You know, if you consider Haider fascist, then what is any US politician?
Not that I particularily like him or his party(he is a populistic hypocrit that would do and say everything to get himself some votes), but me and many other Austrians dont quite enjoy the way things are made to appear by certain press and certain political fractions.
Now, dont get me wrong I am very antiideological myself and not a particular fan of any of our parties here, since they all tend to disregard science to often in favor of ideologies or populism. That is just political reality though.
The immigration problem in Europe is a big one. The US will most likely get aware of it when the amount of muslims here in Austria, France, England and Germany exceeds the critical mass and becomes a political power factor. There is a German politician called Erbakan. He is originally from Turkey and casually said recently "we will take over this place in 20 years". Now that does not sound to much of a desireable thing to me. Personally though, I think that it is already to late to do something about it anyway (by 10 or even 15 years), so I am making sure I will be outa here before that happens. Preferably to the US of course (where I will have to fight with the rather strict immigration laws then ;) ).

Skipjack
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Post by Skipjack »

To get back on topic though...
I think that Carl Sagan was referring to the huge interstellar designs, not the one taking off from the ground. I remember him referring to this like this "it is certainly the best use for nuclear bombs I can imagine". I wholeheartedly agree with him on this. I cant think of a better use for nuclear bombs either. I would rather all of them were up there propelling interstellar, or at least interplanetary spaceships than down here, playing doomsday machines ;)

rj40
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Post by rj40 »

What happens in 50 years? If Polywell works as hoped, I suppose people use that to accelerate the exploration of the solar system; if a reason can be found to convince politicians. But if it doesn’t, who knows. People think He3 might be useful for fusion energy, and apparently there is a lot of the stuff on the moon. That might be just the reason needed to return. In that case, I see big fights over the lunar poles.

1. Probable water supply as ice (for people and for rocket engines)
2. Constant sunlight for solar power nearby (to split the H and O for fuel and to power outposts until fusion generators get up and working)

Water is heavy, whoever controls that on the moon, probably controls the moon and perhaps the solar system. People need it to live and rockets will most likely need it for some time – even with fusion.

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Post by MSimon »

rj40 wrote:What happens in 50 years? If Polywell works as hoped, I suppose people use that to accelerate the exploration of the solar system; if a reason can be found to convince politicians. But if it doesn’t, who knows. People think He3 might be useful for fusion energy, and apparently there is a lot of the stuff on the moon. That might be just the reason needed to return. In that case, I see big fights over the lunar poles.

1. Probable water supply as ice (for people and for rocket engines)
2. Constant sunlight for solar power nearby (to split the H and O for fuel and to power outposts until fusion generators get up and working)

Water is heavy, whoever controls that on the moon, probably controls the moon and perhaps the solar system. People need it to live and rockets will most likely need it for some time – even with fusion.
There is plenty of water in space. It is bombarding the earth all the time.
Engineering is the art of making what you want from what you can get at a profit.

djolds1
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Post by djolds1 »

rj40 wrote:What happens in 50 years? If Polywell works as hoped, I suppose people use that to accelerate the exploration of the solar system; if a reason can be found to convince politicians. But if it doesn’t, who knows.
Nice thing about having nearly 200 countries on Earth.

If the US & EU freeze, Brasil, India, China, Argentina and some of the less savory states are still going to want the prestige and power of exploration & colonization. And if Bussards are as cheap as they look to be, those countries can run QED rocket programs with riskier & less reliable designs than the US/EU would insist on.

That's one reason I've quipped about buying my Bussards from "Energia de la Argentina" in the past. If the North Atlantic countries freeze in Precautionary Principle fear, others will not.
rj40 wrote:People think He3 might be useful for fusion energy, and apparently there is a lot of the stuff on the moon. That might be just the reason needed to return. In that case, I see big fights over the lunar poles.
Once in space, mining the outer gas giants is easy. Reliable notional designs have been worked up using NERVA nuclear engines. Bussard QEDs offer an order of magnitude improvement.
rj40 wrote:1. Probable water supply as ice (for people and for rocket engines)
2. Constant sunlight for solar power nearby (to split the H and O for fuel and to power outposts until fusion generators get up and working)
Possible. But baking volatiles off earth-crossing carbonaceous asteroids would probably be more reliable.
rj40 wrote:Water is heavy, whoever controls that on the moon, probably controls the moon and perhaps the solar system. People need it to live and rockets will most likely need it for some time – even with fusion.
Water is relatively easy. Carbonaceous asteroids and ice moons are everywhere. The pain is nitrogen for breathing gas dilutant. Ceres has some ammonia clays, and Titan is drenched in the stuff. But everywhere else the concentration is either low or hard to access.
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rj40
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Post by rj40 »

True that water rich asteroids or comets won’t take all that much more energy to get to once in orbit. True also, that it will be easier to leave them wrt the Moon. But it will most likely take more time. Plus you have to wait around for one to get in a favorable position with respect to Earth or Earth orbit. Sure, you have to wait for the moon to be positioned for a favorable Lunar transfer, but the time lag is much less and the trip is shorter (faster turn-around time). Also, if go to the lunar poles you know right where the stuff is, there is more of it per unit area – so far as we know, and you don’t have to wait for the next water rich asteroid/comet to be optimally positioned. With working BFRs using Boron, not as big a deal, but if BFRs are never able to do pB11, I think a large source of water AND He3 off Earth (but near it!), with access to constant solar energy, becomes more important.

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