Propulsion sans external power and matter thrown out back

[willpittenger]

Even the most efficient means of propulsion sent into space so far requires one of two following:<br /><ol type="1"><li>That we hurl matter out the back.<li>We rely on some sort of external power source.</li></li></ol><br />Hurling matter out the back causes problems because eventually, you run out of stuff to throw overboard. External power supplies have problems too. Suppose you are riding a laser from Earth with a solar sail and are now 10 light years away. Your sensors have spotted a large object (like a rock) in your path. It would take 10 years for Earth to move the laser. But you have a week. Do you leave the laser and lose all power or hit the rock?<br /><br />If we look at Star Trek, both impulse and warp drives don't rely on either problem. Granted, that was because the producers didn't have the budget of Star Wars. But, I think Star Wars would have been better off with engines that <i>don't</i> throw stuff out the back.<br /><br />Have such engines and/or power systems reach the point that we at least have something on the drawing board? <div class="Discussion_UserSignature"> <hr style="margin-top:0.5em;margin-bottom:0.5em" />Will Pittenger<hr style="margin-top:0.5em;margin-bottom:0.5em" />Add this user box to your Wikipedia User Page to show your support for the SDC forums: <div style="margin-left:1em">{{User:Will Pittenger/User Boxes/Space.com Account}}</div> </div>

 

[nyarlathotep]

No.<br /><br />I will also point out that Missions and Launches is the wrong forum for non-newtonian propulsion discussions. The correct place is Phenomena.

 

[willpittenger]

I disagree. It is not necessarily "non-newtonian". If I move the space around me, I have to move in a equal and opposite manner just as Newton predicted. If you disagree, just look in the mirror as you walk around the room. You aren't hurling matter out the back. So are you violating Newton's laws? How about a protozoan? (That is a single cell creature that uses cilia as oars.) Do they violate Newton's laws when they swim?<br /><br />We are talking about future space missions and the discussion belongs where I put it. <div class="Discussion_UserSignature"> <hr style="margin-top:0.5em;margin-bottom:0.5em" />Will Pittenger<hr style="margin-top:0.5em;margin-bottom:0.5em" />Add this user box to your Wikipedia User Page to show your support for the SDC forums: <div style="margin-left:1em">{{User:Will Pittenger/User Boxes/Space.com Account}}</div> </div>

 

[docm]

No, they don't. All motions we know of so far require thrust of some kind.<br /><br />Rockets, jets, ion and plasma drives expell mass out the rear....thank you Mr. Newton.<br /><br />The protozoan's cilia work as a whip acting as a lever against the ambient medium, just like a boat oar. Your basic lever.<br /><br />You walk by applying the thrust of your leg muscles through your foot to the floor. Levers again.<br /><br />A sailboat gets thrust from the wind just as a solar sail would get its thrust from either the suns light, solar wind or a laser. <br /><br />Magnetic propulsion's 'thrust' by pushing against the ambient solar/planetary magnetic fields not unlike an electric motors rotor acting against the stators field.<br /><br />If in the fullness of time we find a way to control gravity and/or mass (moderated by some relative of a Higgs Boson perhaps) then there will still have to be some kind of thrust involved to actually move, either by inbalanced fields or whatever.<br /><br />No thrust, no motion. <div class="Discussion_UserSignature"> </div>

 

[willpittenger]

You appear to misunderstand. As noted, the cilia does not require discarding anything or an external power source. Ditto for your legs. So its a lever. If it worked in space, it would qualify for the discussion I was attempting to start. So levers don't work there. But surely, there are possibilities that would work in space. Let's discuss those. We are not breaking or rewriting any laws of physics. So please stop accusing me of asking you to do so. <div class="Discussion_UserSignature"> <hr style="margin-top:0.5em;margin-bottom:0.5em" />Will Pittenger<hr style="margin-top:0.5em;margin-bottom:0.5em" />Add this user box to your Wikipedia User Page to show your support for the SDC forums: <div style="margin-left:1em">{{User:Will Pittenger/User Boxes/Space.com Account}}</div> </div>

 

[nyarlathotep]

<font color="yellow">You appear to misunderstand. As noted, the cilia does not require discarding anything or an external power source. Ditto for your legs.</font><br /><br />Actually, both processes consume large amounts of adenosine triphosphate. Mitochondria have to replenish it using an external supply of glucose.

 

[mikejz]

Well This might count:<br /><br />http://www.newscientisttech.com/article/mg19125681.400;jsessionid=NMGHKBGMCGMM

 

[henryhallam]

That New Scientist article is famously embarassing for the magazine - it's absolutely full of crap, breaks momentum conservation.<br /><br />The only viable "reactionless" drives are various types of solar sails and those that use the Earth's magnetic field. Of course these still react against something but you do not have to carry it with you.<br /><br />You don't need to break laws of physics and use make-believe fiction from Star Trek to have interesting and promising future propulsive methods, look at VASIMR and nuclear thermal.

 

[llivinglarge]

We should make spacecraft that use flagellate action.

 

[dreada5]

Willpittenger,<br /><br />Have fun!<br /><br />But don't blame me if your brain explodes. <img src="/images/icons/wink.gif" /><br /><br />http://www.grc.nasa.gov/WWW/bpp/<br /><br />http://www.grc.nasa.gov/WWW/bpp/overview.html

 

[henryhallam]

<font color="yellow">We should make spacecraft that use flagellate action. </font><br /><br />Would you try a spacecraft with a propellor?<br />There is nothing to push against in vacuum.

 

[vogon13]

Ooops!<br /><br />There is that damn action/reaction thing poking it's inconvenient head into things again.<br /><br /><br /><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>

 

[saurc]

I was reading about the Bussard ramjet, but that too requires matter to be 'thrown out behind' although you don't carry it with you.<br /><br />Solar sails don't work on matter momentum, rather on the momentum of photons so it is sort of 'matter less'.<br /><br />We don't necessarily rely on external energy sources, there are many radiothermal energy probes.

 

[willpittenger]

<blockquote><font class="small">In reply to:</font><hr /><p><blockquote><font class="small">In reply to:</font><hr /><p>We should make spacecraft that use flagellate action.<p><hr /></p></p></blockquote>Would you try a spacecraft with a propellor? There is nothing to push against in vacuum.<p><hr /></p></p></blockquote><br />Sure there is. Space itself. Ever hear of gravity waves? <div class="Discussion_UserSignature"> <hr style="margin-top:0.5em;margin-bottom:0.5em" />Will Pittenger<hr style="margin-top:0.5em;margin-bottom:0.5em" />Add this user box to your Wikipedia User Page to show your support for the SDC forums: <div style="margin-left:1em">{{User:Will Pittenger/User Boxes/Space.com Account}}</div> </div>

 

[willpittenger]

The problem with solar sails (and their variants that use laser energy) is that you have problems steering in deep space at high speeds. <div class="Discussion_UserSignature"> <hr style="margin-top:0.5em;margin-bottom:0.5em" />Will Pittenger<hr style="margin-top:0.5em;margin-bottom:0.5em" />Add this user box to your Wikipedia User Page to show your support for the SDC forums: <div style="margin-left:1em">{{User:Will Pittenger/User Boxes/Space.com Account}}</div> </div>

 

[tomnackid]

I disagree. It is not necessarily "non-newtonian". If I move the space around me, I have to move in a equal and opposite manner just as Newton predicted. If you disagree, just look in the mirror as you walk around the room. You aren't hurling matter out the back. So are you violating Newton's laws? How about a protozoan? (That is a single cell creature that uses cilia as oars.) Do they violate Newton's laws when they swim? <br />------------------------------------------------------------------------------------------<br /><br />A little bit of elementary physics is needed here. <br /><br />When you walk your feet push the earth backward and you react by moving forward. Since the earth is a whole lot bigger and heavier than you are for all practical purposes it seems motionless. This is what confused philosophers before Newton. He had the imagination to see that action/reaction was occurring for all motion in the universe even when it wasn't readily apparent. A microorganism moving by using cilia is no different than a boat being rowed or pushed by a propellor (depending on the type of microorganism). Water is pushed backward and the organism reacts by moving forward. <br /><br />As far as pushing space itself goes as far as we know the only way to do that is with gravity. The only way to manipulate gravity as far as we can tell right now is by moving mass around. And since gravity is by far the weakest of the known fundamental forces it takes a whole lot of mass, or a little mass moved at very, very high speeds, to make a measurable effect in the "fabric of space". A catch 22.<br /><br />Until we find a way to couple gravity with a force that we can more easily control--say electromagnetism--we don't have any theoretical basis for a so called "space drive" that works by warping space itself.<br /><br />Until then we can also move around without expending reaction mass (but still within the bounds of Newton's laws) by taking advantage of planets and the galaxies magnetic fie

 

[willpittenger]

<blockquote><font class="small">In reply to:</font><hr /><p>As far as pushing space itself goes as far as we know the only way to do that is with gravity. The only way to manipulate gravity as far as we can tell right now is by moving mass around. And since gravity is by far the weakest of the known fundamental forces it takes a whole lot of mass, or a little mass moved at very, very high speeds, to make a measurable effect in the "fabric of space". A catch 22.<p><hr /></p></p></blockquote><br />M Theory and String Theory will help there if the theories advance far enough. String Theory has the only explanation for gravity so far. In fact, when I talked about "pushing" on space, I had gravity in mind. Such "gravimetric" engines could also function as the equivalent of "tractor beams," "Shields" (by redirecting incoming objects and radiation), and sensors (by watching for gravity waves from other moving objects). <div class="Discussion_UserSignature"> <hr style="margin-top:0.5em;margin-bottom:0.5em" />Will Pittenger<hr style="margin-top:0.5em;margin-bottom:0.5em" />Add this user box to your Wikipedia User Page to show your support for the SDC forums: <div style="margin-left:1em">{{User:Will Pittenger/User Boxes/Space.com Account}}</div> </div>