John Slough gets NIAC PhaseII award!

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Skipjack
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Re: John Slough gets NIAC PhaseII award!

Post by Skipjack »

GIThruster wrote:
Skipjack wrote:Musk has talked about nuclear thermal engines for mars transportation in the past. The problem is that they are almost impossible to develop and aquire for non government entities. The fusion driven rocket is simpler, cheaper and better. I would be suprised if Musk did not look into it for the long term. He is planning to colonize mars after all.
I think you may be conflating a memory of Musk being asked after a TED talk about nuclear propulsion, to which he responded he was not familiar with any significant proposals but would look into it. If you're aware of any statements he's made publicly beyond this I'd love to see them. I agree, he is the sort to look into this and so invest himself, and from what I see of Slough's work this may indeed be cheaper to develop than TRITON, but there are very serious challenges. Have you seen for instance what the fule costs are for the FDR? For most systems fuel is not an significant driver of cost, but with this. . .I'm not so sure.
Yes, there was a poster by SpaceX once that showed steps to mars colonization. One of them was nuclear thermal propulsion.
It was a long time ago and Musk has not talked much about it since then. I think he is focusing on more near term problems right now (gotta get to LEO cheaply first).

I dont think that the fuel would be that hard to come by or that expensive. It is not THAT much fuel per trip either. It certainly will be more pricy than conventional rocket fuel, but the cost of that is completely negligible anyway.

AcesHigh
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Re: John Slough gets NIAC PhaseII award!

Post by AcesHigh »

well, obviously to colonize Mars this particular fusion propulsion is not adequate. You would need something on the order of Orion, which envisioned BASE designs 56 meters in diameter and 90 meters in height, able to take 6 thousand tons to LEO or 5 thousand tons to Mars (AND RETURN!)

or of course, the fusion "version of Orion", Daedalus, which envisioned 100 fusion reactions (by laser inertial confinement of deuterium pellets) per second.

Skipjack
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Re: John Slough gets NIAC PhaseII award!

Post by Skipjack »

AcesHigh wrote:well, obviously to colonize Mars this particular fusion propulsion is not adequate. You would need something on the order of Orion, which envisioned BASE designs 56 meters in diameter and 90 meters in height, able to take 6 thousand tons to LEO or 5 thousand tons to Mars (AND RETURN!)

or of course, the fusion "version of Orion", Daedalus, which envisioned 100 fusion reactions (by laser inertial confinement of deuterium pellets) per second.
Why do that, when you could just as well take several smaller ones of these fusion driven rockets, which are cheaper and easier to build than Orion. Completely disregarding that orion is completely out of the question for political reasons anyway.

mvanwink5
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Re: John Slough gets NIAC PhaseII award!

Post by mvanwink5 »

Anyone have an idea what the mechanism and magazine would look like that would be able to load the aluminum (or lithium) foil liners (hoops) into position for magnetic driven collapse? Could they come off a roll onto a drum? Maybe get ahold of some Budweiser engineers?
Counting the days to commercial fusion. It is not that long now.

hanelyp
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Re: John Slough gets NIAC PhaseII award!

Post by hanelyp »

mvanwink5 wrote:Maybe get ahold of some Budweiser engineers?
Unless there have been some developments I'm not aware of, aluminum beverage cans are formed with a die extrusion process from a flat sheet. A miracle of mass produced aerospace worthy precision.
The daylight is uncomfortably bright for eyes so long in the dark.

Skipjack
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Re: John Slough gets NIAC PhaseII award!

Post by Skipjack »

mvanwink5 wrote:Anyone have an idea what the mechanism and magazine would look like that would be able to load the aluminum (or lithium) foil liners (hoops) into position for magnetic driven collapse? Could they come off a roll onto a drum? Maybe get ahold of some Budweiser engineers?
I asked them that question during the fall NIAC symposium. Best check out the last 2 minutes of this video here (if you havent done so, you should watch the rest of it as well):
http://www.youtube.com/watch?v=5aiVPJo2suw

mvanwink5
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Re: John Slough gets NIAC PhaseII award!

Post by mvanwink5 »

Skipjack,
Thanks for that link. So, they have thought about liner reload methods and frequency of reloads (spay on, deposition, extrusion-Budweiser?, didn't suggest unspooling from a roll though), and put in a generous weight for it in their Mars mission mass budget. I guess the engineers will just have to step up and design it. Thanks again for the link.
Counting the days to commercial fusion. It is not that long now.

AcesHigh
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Re: John Slough gets NIAC PhaseII award!

Post by AcesHigh »

Skipjack wrote:
AcesHigh wrote:well, obviously to colonize Mars this particular fusion propulsion is not adequate. You would need something on the order of Orion, which envisioned BASE designs 56 meters in diameter and 90 meters in height, able to take 6 thousand tons to LEO or 5 thousand tons to Mars (AND RETURN!)

or of course, the fusion "version of Orion", Daedalus, which envisioned 100 fusion reactions (by laser inertial confinement of deuterium pellets) per second.
Why do that, when you could just as well take several smaller ones of these fusion driven rockets, which are cheaper and easier to build than Orion. Completely disregarding that orion is completely out of the question for political reasons anyway.
1 - Orion would be theoretically much cheaper
2 - Orions were supposed to take off from Earth
3 - these huge Orions were supposed to be built in shipyards... almost no regard for the weight. What was important was a sturdy structure
4 - Orions were supposed to be able to be built with 60s technology. How come fusion rockets would be cheaper and easier?

mvanwink5
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Re: John Slough gets NIAC PhaseII award!

Post by mvanwink5 »

Orion died because of signing nuclear test ban treaties (which Freeman Dyson supported, knowing it would be the end of Orion).
Counting the days to commercial fusion. It is not that long now.

Skipjack
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Re: John Slough gets NIAC PhaseII award!

Post by Skipjack »

AcesHigh wrote:
Skipjack wrote:
AcesHigh wrote:well, obviously to colonize Mars this particular fusion propulsion is not adequate. You would need something on the order of Orion, which envisioned BASE designs 56 meters in diameter and 90 meters in height, able to take 6 thousand tons to LEO or 5 thousand tons to Mars (AND RETURN!)

or of course, the fusion "version of Orion", Daedalus, which envisioned 100 fusion reactions (by laser inertial confinement of deuterium pellets) per second.
Why do that, when you could just as well take several smaller ones of these fusion driven rockets, which are cheaper and easier to build than Orion. Completely disregarding that orion is completely out of the question for political reasons anyway.
1 - Orion would be theoretically much cheaper
2 - Orions were supposed to take off from Earth
3 - these huge Orions were supposed to be built in shipyards... almost no regard for the weight. What was important was a sturdy structure
4 - Orions were supposed to be able to be built with 60s technology. How come fusion rockets would be cheaper and easier?
You are acting as if nuclear bombs can be built for free. It is quite expensive, especially since you need many. Orion would also not make access to space more routine. You would have less frequent flights with larger payloads, when the opposite is desirable.
You want to build an infrastructure that supports frequent and cheap transportation on demand.

AcesHigh
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Re: John Slough gets NIAC PhaseII award!

Post by AcesHigh »

Its desirable for SOME applications. To colonize another planet, the desirable is BIG SHIPS like the ones from Orion.

Imagine if europeans had tried to colonize the Americas with small 5-10 people boats.


Also, notice I said LIKE the ones from Orion. Because in the first post I mentioned Orion, I also mentioned Daedalus project style fusion propulsion.

In sum, any kind of SSTO propulsion capable to reach Mars in a short time and taking 100 people each voyage.

GIThruster
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Re: John Slough gets NIAC PhaseII award!

Post by GIThruster »

Skipjack wrote:You are acting as if nuclear bombs can be built for free. It is quite expensive, especially since you need many.
Agreed and there's always the observation that solutions like Orion are simply never going to be built for the obvious reasons. Even if you can't accept the notion that "bombs for rockets" is a stupid idea for dozens of reasons, especially including it has people flying around with bombs (a solution no world government could possibly ever accept), you can at least look at the last 60+ years and note, we're not building this stuff. Orion was never a practical solution.

At least with Slough's work, there's some small possibility we'll find out if such thrusters are theoretically possible given the constraints of current materials science. What people tend to assume wrongly is that just because the thing is "just engineering" does not mean it is really possible. For these thrusters to be useful in any way, they need to be durable enough to be reused again and again with minimal maintenance. That's a huge materials science challenge that we've yet to see addressed and in fact, the vast bulk of any real development program. NERVA and ROVER did not teach us anything about practical systems, so all the real engineering is yet to come. I'd say Slough has his work cut out for him.
"Courage is not just a virtue, but the form of every virtue at the testing point." C. S. Lewis

AcesHigh
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Re: John Slough gets NIAC PhaseII award!

Post by AcesHigh »

Please, HALT this discussion and re-read the start of the argument. It was less about Orion itself and more about the need, IF WE WANT TO TRULY COLONIZE ANOTHER PLANET, to have SSTO ships with ultra high ISPs... and ships that can be BIG.

We will need to be taking 100 people each trip if we want to colonize Mars.

THAT´s why I mentioned Orion. I did not say Orion should become a reality or that it did not have a few fallout problems. I was simply talking about high thrust high ISPs SSTO ships, that could be scaled to be big.

Again, notice I talked about DAEDALUS. Thats not "nuclear bombs". Its fusion of deuterium pellets. But one hundred per second instead of 1 each ten seconds.

Now, if you think it´s possible to colonize Mars (or some Jupiter/Saturn moon) by taking 5 people at a time, taking them from Earth on a rocket then moving them to a low thrust fusion rocket like John Slough´s, then ok. It´s your opinion. I do not think its viable.



ps: what would be the thrust of John Slough´s engine if it could fuse 1000 times each 10 seconds, like Daedalus was "supposed" to do?

AcesHigh
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Re: John Slough gets NIAC PhaseII award!

Post by AcesHigh »

and of course, the BEST solution to colonize Mars would be to Woodward to make a ship fly with his Mach Effect... btw, long time we dont have updates, right GIT?

paperburn1
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Re: John Slough gets NIAC PhaseII award!

Post by paperburn1 »

I would settle for cheap to LEO , then everything else is math and if necessary brute force.
I am not a nuclear physicist, but play one on the internet.

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