How to go to the moon faster.

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holmec

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In going to the moon, it takes us 3 days. At least it took Apollo 3 days. But most of the distance of that trip was spent without any main thruster power firing. What if we changed that. I mean how hard would it be and what could the benefits be if for that constant velocity time we accelerated (half the distance) and decelerated (half the distance) with ion drives?<br /><br />I know there are people out there that don't believe in these drives. But I figure its a newer propulsion system and it seems to work. So why not find new uses for it? And the trip to the moon seems like and obvious candidate. <div class="Discussion_UserSignature"> <p> </p><p><font color="#0000ff"><em>"SCE to AUX" - John Aaron, curiosity pays off</em></font></p> </div>
 
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holmec

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"A ion drive to boost a manned trip to the Moon as you suggest would make almost no difference at all due to the small thrust and short burn time of just days."<br /><br />Perhaps present ones. Why not design one that can deliver the thrust needed to make a difference? One senario is a medical emergency. Anyway sooner or later we will want to get to the moon faster for various reasons we will most probably come up with in the future. <br /><br />Or what about for back up propulsion if main thrust just fails? But perhaps in that senario an additional craft to assist would be better. I just like to be equiped myself in an emergency or survival situation.<br /><br />Regardless a propulsion system that can span the gap that gives more thrust to the ship (saving time) and provide some consistent G forces (thus reducing the depletion of the bones) seems to be in the realm of possibility. Time in space is a factor for any mission wheather positive or negative.<br /><br />The only other type of propulsion that I know of that uses electicity (thus getting power from solar panels) other than ion drives would be and arc thruster. But ion drives are much more efficient. And we have not built a large ion drive yet. Does anyone have any numbers on ion drives? <div class="Discussion_UserSignature"> <p> </p><p><font color="#0000ff"><em>"SCE to AUX" - John Aaron, curiosity pays off</em></font></p> </div>
 
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drwayne

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"Why not design one that can deliver the thrust needed to make a difference?"<br /><br />How would you suggest changing an ion drive to increase thrust to those levels? The nature of an ion drive would seem to preclude that rather quickly, because (it would seem) that at some point the mass you are adding will take up the additional thrust. <br /><br /><br />Wayne <div class="Discussion_UserSignature"> <p>"1) Give no quarter; 2) Take no prisoners; 3) Sink everything."  Admiral Jackie Fisher</p> </div>
 
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holmec

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True but the ion drive is the most efficient propulsion we have, thus having low mass to thrust ratio. <br /><br />Also what if you make the ion engine bigger? putting out more mass at a time? <br /><br />This seems to be getting a lot of conceptual opposition. <div class="Discussion_UserSignature"> <p> </p><p><font color="#0000ff"><em>"SCE to AUX" - John Aaron, curiosity pays off</em></font></p> </div>
 
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tap_sa

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<font color="yellow">"thus having low mass to thrust ratio."</font><br /><br />You get a great deal more impulse per pound of propellant yes ie. ion drive has very good efficiency, but the engine itself has abysmal thrust to weight ratio. The best numbers I've read were 30kg heavy engine giving out 3 Newtons of thrust.<br /><br />Biggest problems in getting more thrust from ion drive is making the engine itself lighter while maintaining same power level, and coming up with powersource that has high kW/kg ratio.
 
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holmec

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OK! I concede. <br /><br />After looking at DS1 basic numbers, I basically came up with<br />0.0000734049 m/s^2 of acceleration approx. Which is quite low.<br /><br />Well, it would be nice to have a propulsion system that operated like and ion drive but gave 1G (10m/s^2) acceleration. So astonauts wouldn't loose much bone. Which would aleviate a lot of physical problems with space travel, especially to other planets. <div class="Discussion_UserSignature"> <p> </p><p><font color="#0000ff"><em>"SCE to AUX" - John Aaron, curiosity pays off</em></font></p> </div>
 
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vogon13

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If you wanted to take a solar powered aluminum smelter, some big hulking rock crushers and loaders, and some large living habitats, be thinking Orion. One launch, one trip, and you have the infrastructure for a sustainable colony.<br /><br />Doesn't much matter if that trip takes three days or 20.<br /><br /> <div class="Discussion_UserSignature"> <p><font color="#ff0000"><strong>TPTB went to Dallas and all I got was Plucked !!</strong></font></p><p><font color="#339966"><strong>So many people, so few recipes !!</strong></font></p><p><font color="#0000ff"><strong>Let's clean up this stinkhole !!</strong></font> </p> </div>
 
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tap_sa

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Besides after one big radiant Orion launch you'll <i>need</i> a sustainable colony off Earth for waiting things to cool down back home <img src="/images/icons/wink.gif" />
 
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tap_sa

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<font color="yellow">" it would be nice to have a propulsion system that operated like and ion drive but gave 1G (10m/s^2) acceleration."</font><br /><br />Indeed. VASIMR looks promising on the paper, capable of both high thrust with decreased Isp and vice versa. But the powersource problem will remain.<br /><br />Btw if you keep accelerating beyond the required minimum to hasten your trip from, say, Moon to Earth you will have more problems at the destination because of increased velocity. You'll have to fire engines retrograde to slow down and/or beef up your heatshield and prepare for increased G-forces during re-entry.
 
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jatslo

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<font color="yellow">How would you suggest changing an ion drive to increase thrust to those levels? The nature of an ion drive would seem to preclude that rather quickly, because (it would seem) that at some point the mass you are adding will take up the additional thrust.</font><br /><br />Will we could assemble the pieces in space, and the weightlessness would make inertia on mass irrelevant. Nuclear powered plasma thrusters could last for years, and all will required is docking and undocking processes. Something like this might be better suited to shuttling back and forth to and from Mars. It will give an extra boost, so to speak.
 
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nacnud

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<font color="yellow">and the weightlessness would make inertia on mass irrelevant.<br /><br /><font color="white">No it doesn't. Inertia of an object is invariant with gravity.</font></font>
 
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drwayne

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"and the weightlessness would make inertia on mass irrelevant."<br /><br />What exactly were you trying to say here?<br /><br />Wayne <div class="Discussion_UserSignature"> <p>"1) Give no quarter; 2) Take no prisoners; 3) Sink everything."  Admiral Jackie Fisher</p> </div>
 
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jatslo

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There is less gravity in space, and if you add velocity to the mix it counters gravity even more, so a more massive object would require less to push it. Of course there are two possible sources: internal and external.
 
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najab

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a) There is no less gravity in space.<br />b) Intertia is a property of mass, not weight.
 
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tap_sa

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F = ma applies in weightlesness too and the m (mass) is the same whether object experiences pull by gravity or not.
 
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drwayne

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Sorry I asked....<br /><br /><br />Wayne <div class="Discussion_UserSignature"> <p>"1) Give no quarter; 2) Take no prisoners; 3) Sink everything."  Admiral Jackie Fisher</p> </div>
 
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tap_sa

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Space travel is much easier if you rewrite the physics <img src="/images/icons/wink.gif" />
 
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drwayne

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Guys, I learned a long time ago that it is fruitless to argue with someone who feels comfortable with making up their own physics as they go along.<br /><br />Wayne <div class="Discussion_UserSignature"> <p>"1) Give no quarter; 2) Take no prisoners; 3) Sink everything."  Admiral Jackie Fisher</p> </div>
 
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jatslo

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Hi NajaB! I was wondering where you were, so I asked, and I heard you got married, so congratulations!<br /><br />Gravity is a fairy-tale like fire breathing dragons. I am talking about Electromagnetism (EM), as in strong (S); Weak (W), so the further away you get the less there is, as in casimir effect. Seems to me that you all have lots of imaginary friends. Sorry I posted here. I am not going to speak in this thread, if you all are not open to new ideas.
 
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tap_sa

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Object's inertia is proportional to strength of (some) electromagnetic field - Check.<br /><br />Does BobLazarium, the atomic element 113 negate the inertia?
 
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jatslo

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Newton's laws of motion are quite different when I observe something as oppsed to that something observing itself; however, velocity equates to G, but that depends on direction. I guess you could call it an illusion on behalf of the subject.
 
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tap_sa

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I'll take drwayne's advice now and contemplate these new interesting discoveries in silence...
 
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Swampcat

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<font color="yellow">"That is pretty rude"</font><br /><br />Depends on your POV. <img src="/images/icons/rolleyes.gif" /> <div class="Discussion_UserSignature"> <font size="3" color="#ff9900"><p><font size="1" color="#993300"><strong><em>------------------------------------------------------------------- </em></strong></font></p><p><font size="1" color="#993300"><strong><em>"I hold it that a little rebellion now and then is a good thing, and as necessary in the political world as storms in the physical. Unsuccessful rebellions, indeed, generally establish the encroachments on the rights of the people which have produced them. An observation of this truth should render honest republican governors so mild in their punishment of rebellions as not to discourage them too much. It is a medicine necessary for the sound health of government."</em></strong></font></p><p><font size="1" color="#993300"><strong>Thomas Jefferson</strong></font></p></font> </div>
 
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