Posted: Thu Sep 17, 2009 5:22 pm
Well, the question is whether they would be sooo common, after all they would probably be pulverized by even the smallest piece of spacedust long before they come even close to the earth.
a discussion forum for Polywell fusion
https://talk-polywell.org/bb/
with good (and big) electromagnetic shields, I think you can avoid the ship being destructed by space dust.Skipjack wrote:Well, the question is whether they would be sooo common, after all they would probably be pulverized by even the smallest piece of spacedust long before they come even close to the earth.
Yup. The stuff of our childhood dreams.Skipjack wrote:That is exactly why the possibilities are getting me so excited.
If and that is a big if it works. The thing is that this is one of those "high risk, large potential gain" investments. If someone was to invest into it.
No idea on the limits, practical or theoretical. Paul March should speak to that. It appears an artificial 1g field at minimum is envisioned, which would allow comfortable accelerations of 2Gs. 10Gs compensated is the stuff of dreams, 100Gs+ is Orgasmatron territory.Skipjack wrote:Ok, so there wont be any acceleration forces after all? Because that was my initial question.Woodward claims that artificial gravity fields should be achievable in the medium term - that means acceleration compensators.
Related. Woodward and March refer to both as "Gravinertial effects."Skipjack wrote:I am confused now. This is unrelated to the Mach effect thruster? Or is that a derived development?
Skipjack wrote:As I would understand it a "gravity compensation" in one direction would result in acceleration in the other direction. So it basically is Munchhausen pulling himself out of the swamp by his hair.
Actually, I believe you will find that shields will fail long before you get a measuarble tau factor. Indeed, in a system that could be practically built, it would fail before you got past .1c. There are a number of factors that move against you. You have to give the particles a charge before you can deflect them. As you go faster, you have less time to charge them and give your shield time to deflect. Very quickly, the field generators become a majority of your mass. Additionally, the faster you go, the more radiation you recieve as your speed is in effect bumping up the energy of the incoming radiation. As for the interstellar hydrogen, long before you got up to .99c, its energy levels would get bumped up to it being essentially antimatter. Another problem with any active shielding system is that any transient failure is lethal. Remember Dr B's ramjet? Top speed ~.4 c? That is because the magnetic field has been flattened by your ship's speed and cannot collect enough anymore to increase the speed of the ship. Your shield will have the same problem but much worse as it must do a whole lot more. And it ignores the issue of a grain of sand that has an exactly matching negative vector. You can't deflect that one. You must stop it and then move it out of the way. And what happens when you run into that rare pebble?AcesHigh wrote: with good (and big) electromagnetic shields, I think you can avoid the ship being destructed by space dust.
E= 0.5mv^2AcesHigh wrote:Im quite scared of ships travelling at lightspeed... specially if they have the potential (with this technology) to be so common.
I mean... think of a 9/11, but with a terrorist hitting Earth with a 1000 tons spaceship, at 0.99999% c.
Can anyone calculate the power of such impact?
Woodward predicts wormholes and Alcubierre warp drive effects w/in 40 years of development. Project Daedalus style front impact shields should be sufficient in the interim.AcesHigh wrote:lets not forget that fuel for electricity generation FOR PROPULSION is just a small part of what is needed... travelling at such high speeds, I would guess that we would need another fusion reactor only to create very large electromagnetic shields, very distant from the ship, to prevent collision with minor particles at near c speeds.
pfrit wrote:Actually, I believe you will find that shields will fail long before you get a measuarble tau factor. Indeed, in a system that could be practically built, it would fail before you got past .1c. There are a number of factors that move against you. You have to give the particles a charge before you can deflect them. As you go faster, you have less time to charge them and give your shield time to deflect. Very quickly, the field generators become a majority of your mass. Additionally, the faster you go, the more radiation you recieve as your speed is in effect bumping up the energy of the incoming radiation. As for the interstellar hydrogen, long before you got up to .99c, its energy levels would get bumped up to it being essentially antimatter. Another problem with any active shielding system is that any transient failure is lethal. Remember Dr B's ramjet? Top speed ~.4 c? That is because the magnetic field has been flattened by your ship's speed and cannot collect enough anymore to increase the speed of the ship. Your shield will have the same problem but much worse as it must do a whole lot more. And it ignores the issue of a grain of sand that has an exactly matching negative vector. You can't deflect that one. You must stop it and then move it out of the way. And what happens when you run into that rare pebble?AcesHigh wrote: with good (and big) electromagnetic shields, I think you can avoid the ship being destructed by space dust.
Really, .1c is increadibly fast. Everyone gets so jazzed about approaching the immovable barrier of c that they become blinded to the fact that the ultimate speed limit is way past any practical speed that we could achieve. If you have an unlimited fuel supply/reactionless engine, and you want to go really fast, what you need is to make your ship out of something that will block the radiation and sand and gas. Like a planetoid. If I remember right, it amounts to blocking the high energy cosmic rays and being able to withstand repeated nuclear bombardment. Like bigger than Phobos if you want to exceed .8c.
http://www.spacedaily.com/reports/New_A ... Light.htmlThe field equation of Einstein's General Theory of Relativity has never before been solved to calculate the gravitational field of a mass moving close to the speed of light. Felber's research shows that any mass moving faster than 57.7 percent of the speed of light will gravitationally repel other masses lying within a narrow 'antigravity beam' in front of it. The closer a mass
gets to the speed of light, the stronger its 'antigravity beam' becomes.
Yes.AcesHigh wrote: again, can anyone calculate how much energy is released by a 1000 tons ship impact at 0.99% c?
...so is this guy recommending accelerating a spaceship by throwing a star at it at three quarters of the speed of light?ravingdave wrote: http://www.spacedaily.com/reports/New_A ... Light.html
About 130,000,000 Mt.AcesHigh wrote:again, can anyone calculate how much energy is released by a 1000 tons ship impact at 0.99% c?
Hmm, I get about 955 Mt. for 99% c I do get around 120,000,000 Mt, but for 0.99% c I get 955 Mt.93143 wrote:About 130,000,000 Mt.AcesHigh wrote:again, can anyone calculate how much energy is released by a 1000 tons ship impact at 0.99% c?
Would that include the tau factor? BTW, imagine the problem with calculating a tragetory that could hit the earth at that velocity! Your mass would be such that almost anything would deflect you (you would only need the tiniest bit of deflection to miss at that velocity and distance). And virtually no time to do any course corrections. And the delta V required to move the mass! Tough problem, but probably doable. A whole lot of three body solutions, though.blaisepascal wrote:Hmm, I get about 955 Mt. for 99% c I do get around 120,000,000 Mt, but for 0.99% c I get 955 Mt.93143 wrote:About 130,000,000 Mt.AcesHigh wrote:again, can anyone calculate how much energy is released by a 1000 tons ship impact at 0.99% c?