# Gravtiy Tractors for NEOs

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#### Fallingstar1971

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<p>Am I the only one that sees this as impossabe?</p><p>&nbsp;How are you going to launch an object massive enough to deflect a NEO? The LEM was made of tin foil and it took the mighty saturn v to launch it. Would the Apollo command mod and the LEM together have enough mass? No, I dont think so. So where is this starship thats going to haul this mass out there?</p><p>So If the shuttle cant haul it up to space, then it would have to be built there.&nbsp; But how long would constuction take ? Would the ISS have enough mass (assuming we could move it out to the NEO)? ANd just look at how long it took to build it, and its STILL not done.</p><p>&nbsp;I think that solar sails and paint is the only workable, economical, and possible solution. But how well would paint stick to an asteriod? And could the shuttle(s) fit enough of it into there cargo bays to make it work, and will it still be light enough to launch?&nbsp;(MASS,MASS,MASS)</p><p>&nbsp;And last but not least, what if you math is off. Now you have 2 massive NEOs on a collision course with Earth. </p><p>&nbsp;</p>

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#### DrRocket

##### Guest
<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Am I the only one that sees this as impossabe?&nbsp;How are you going to launch an object massive enough to deflect a NEO? The LEM was made of tin foil and it took the mighty saturn v to launch it. Would the Apollo command mod and the LEM together have enough mass? No, I dont think so. So where is this starship thats going to haul this mass out there?So If the shuttle cant haul it up to space, then it would have to be built there.&nbsp; But how long would constuction take ? Would the ISS have enough mass (assuming we could move it out to the NEO)? ANd just look at how long it took to build it, and its STILL not done.&nbsp;I think that solar sails and paint is the only workable, economical, and possible solution. But how well would paint stick to an asteriod? And could the shuttle(s) fit enough of it into there cargo bays to make it work, and will it still be light enough to launch?&nbsp;(MASS,MASS,MASS)&nbsp;And last but not least, what if you math is off. Now you have 2 massive NEOs on a collision course with Earth. &nbsp; <br />Posted by Fallingstar1971</DIV></p><p>Lacking a definition of "this", it is rather difficult to determine if "this" is possible or not.<br /></p> <div class="Discussion_UserSignature"> </div>

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#### derekmcd

##### Guest
<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Am I the only one that sees this as impossabe?&nbsp;How are you going to launch an object massive enough to deflect a NEO? The LEM was made of tin foil and it took the mighty saturn v to launch it. Would the Apollo command mod and the LEM together have enough mass? No, I dont think so. So where is this starship thats going to haul this mass out there?So If the shuttle cant haul it up to space, then it would have to be built there.&nbsp; But how long would constuction take ? Would the ISS have enough mass (assuming we could move it out to the NEO)? ANd just look at how long it took to build it, and its STILL not done.&nbsp;I think that solar sails and paint is the only workable, economical, and possible solution. But how well would paint stick to an asteriod? And could the shuttle(s) fit enough of it into there cargo bays to make it work, and will it still be light enough to launch?&nbsp;(MASS,MASS,MASS)&nbsp;And last but not least, what if you math is off. Now you have 2 massive NEOs on a collision course with Earth. &nbsp; <br /> Posted by Fallingstar1971</DIV></p><p>Depends on what you consider to be "near", how massive it is, it's trajectory and velocity.&nbsp; If we catch it far enough away, only a very slight 'nudge' might be sufficient enough to change it's trajectory and keep it from making for a very bad day here on earth.&nbsp;</p><p>Painting it??? <img src="http://sitelife.space.com/ver1.0/content/scripts/tinymce/plugins/emotions/images/smiley-laughing.gif" border="0" alt="Laughing" title="Laughing" />&nbsp; Please tell me that was a joke... </p> <div class="Discussion_UserSignature"> <div> </div><br /><div><span style="color:#0000ff" class="Apple-style-span">"If something's hard to do, then it's not worth doing." - Homer Simpson</span></div> </div>

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#### MeteorWayne

##### Guest
<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Depends on what you consider to be "near", how massive it is, it's trajectory and velocity.&nbsp; If we catch it far enough away, only a very slight 'nudge' might be sufficient enough to change it's trajectory and keep it from making for a very bad day here on earth.&nbsp;Painting it??? &nbsp; Please tell me that was a joke... <br />Posted by derekmcd</DIV><br /><br />It's not a joke at all. Since the delta v's required to ensure a miss of earth are very small, changing the albedo of part of an asteroid can cause enough of a change in position decades down the road so that the earth and asteroid are not at the same place at the same time. It's just as valid as any other method. </p><p>&nbsp;</p> <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

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#### a_lost_packet_

##### Guest
<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Am I the only one that sees this as impossabe?&nbsp;How are you going to launch an object massive enough to deflect a NEO? The LEM was made of tin foil and it took the mighty saturn v to launch it. Would the Apollo command mod and the LEM together have enough mass? No, I dont think so. So where is this starship thats going to haul this mass out there?So If the shuttle cant haul it up to space, then it would have to be built there.&nbsp; But how long would constuction take ? Would the ISS have enough mass (assuming we could move it out to the NEO)? ANd just look at how long it took to build it, and its STILL not done.&nbsp;I think that solar sails and paint is the only workable, economical, and possible solution. But how well would paint stick to an asteriod? And could the shuttle(s) fit enough of it into there cargo bays to make it work, and will it still be light enough to launch?&nbsp;(MASS,MASS,MASS)&nbsp;And last but not least, what if you math is off. Now you have 2 massive NEOs on a collision course with Earth. &nbsp; <br /> Posted by Fallingstar1971</DIV></p><p>As with every method to counter the threat of an impending collission with an asteroid, it all depends on time.&nbsp; If you detect it early enough it's possible to alter its course by using the very slight influence a nearby mass could have on its trajectory.&nbsp; Every percentage of a degree of change will be exponentially magnified when compared with possible end/collision routes.&nbsp; Gravity doesn't take any power to generate, just mass.&nbsp; Let nature do the rest.&nbsp; The critical variable is always time.</p><p>It's possible that using methods and equipment we already have, to deflect asteroids the size of Apophis using a gravity-tractor.&nbsp; While information is at a premium, the results given a hypothetical impact with Apophis look promising, IMO. http://www.b612foundation.org/papers/wpGT.pdf</p><p>One solution will not fit all situations and much of the information necessary to firm up a solution would actually only be gained once a GT was in position and tracking the object.&nbsp; But, being pro-active has always been of benefit.&nbsp; After all, having an active, controlled tracking station situated close to a dangerous body and constantly transmitting position information would be of benefit whether or not it was acting as a GT. &nbsp; </p><p>In regards to "paint:"&nbsp; I don't think actual "paint" would be something that would be desirable to use in space.&nbsp; But, fine particulates, carbon black, dust, whatever, would do the job much better.&nbsp; It might be that a few tons of dust, released on/near the object, would cover it sufficiently to eventually alter its course due to albedo-influenced changes.&nbsp; Dispersal might be an issue as I don't know how ultrafine particulates work in such an environment.&nbsp; But, it could probably be managed. (Others here could possibly answer that question.)</p> <div class="Discussion_UserSignature"> <font size="1">I put on my robe and wizard hat...</font> </div>

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#### derekmcd

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<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>It's not a joke at all. Since the delta v's required to ensure a miss of earth are very small, changing the albedo of part of an asteroid can cause enough of a change in position decades down the road so that the earth and asteroid are not at the same place at the same time. It's just as valid as any other method. &nbsp; <br /> Posted by MeteorWayne</DIV></p><p>Interesting.&nbsp; I do vaguely recall you guys talking about changing the albedo asteroids.&nbsp; I just read up a little on the Yarkovsky effect. I'm somewhat familiar with the momentum of photons and radiation pressure and it makes perfect sense.</p><p>I guess the first picture that came to my head was a couple astronauts with coveralls over their suits with paint brushes and rollers in hand ready to apply some Sherwin-Williams eggshell colored paint. <img src="http://sitelife.space.com/ver1.0/content/scripts/tinymce/plugins/emotions/images/smiley-smile.gif" border="0" alt="Smile" title="Smile" /> </p> <div class="Discussion_UserSignature"> <div> </div><br /><div><span style="color:#0000ff" class="Apple-style-span">"If something's hard to do, then it's not worth doing." - Homer Simpson</span></div> </div>

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#### MeteorWayne

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Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Interesting.&nbsp; I do vaguely recall you guys talking about changing the albedo asteroids.&nbsp; I just read up a little on the Yarkovsky effect. I'm somewhat familiar with the momentum of photons and radiation pressure and it makes perfect sense.I guess the first picture that came to my head was a couple astronauts with coveralls over their suits with paint brushes and rollers in hand ready to apply some Sherwin-Williams eggshell colored paint. <br />Posted by derekmcd</DIV><br /><br />Yeah, "paint" is kind of a simple term for changing albedo. <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

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#### a_lost_packet_

##### Guest
<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>..I guess the first picture that came to my head was a couple astronauts with coveralls over their suits with paint brushes and rollers in hand ready to apply some Sherwin-Williams eggshell colored paint. Posted by derekmcd</DIV></p><p>You have to admit though, it'd make a heck of an ad campaign. &nbsp; Use Sherwin-Williams paint! The same paint used to save the Earth! You can't really get much more publicity than that. </p> <div class="Discussion_UserSignature"> <font size="1">I put on my robe and wizard hat...</font> </div>

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#### DrRocket

##### Guest
<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>It's not a joke at all. Since the delta v's required to ensure a miss of earth are very small, changing the albedo of part of an asteroid can cause enough of a change in position decades down the road so that the earth and asteroid are not at the same place at the same time. It's just as valid as any other method. &nbsp; <br />Posted by MeteorWayne</DIV></p><p>Do you have enough knowleldge of the orbital parameters for the asteroids and everything with which they might interact to be able to accurately predict the orbital change from such a small perturbation over such a long period of time so as to be certain of the ultimate effect ?&nbsp; Or is the state of ignorance and predictive capability such that you would be as likely to create a problem as to prevent one ?</p> <div class="Discussion_UserSignature"> </div>

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#### a_lost_packet_

##### Guest
<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Do you have enough knowleldge of the orbital parameters for the asteroids and everything with which they might interact to be able to accurately predict the orbital change from such a small perturbation over such a long period of time so as to be certain of the ultimate effect ?&nbsp; Or is the state of ignorance and predictive capability such that you would be as likely to create a problem as to prevent one ? Posted by DrRocket</DIV></p><p>You'd have to know that information for any type of intercept/interdiction mission involving anything which attempted to manipulate the course of the object.&nbsp; Even if you were going to make it go "boom" you'd need a good idea of where the debris is likely to end up and what could effect it.&nbsp; So, I wouldn't say that was a deal-killer for a GT as, I assume, it'd be necessary information for the design of any mission.&nbsp; One of the advantages of a GT is that it is, effectively, an observation platform on station, online the whole time and continues to send position information.&nbsp; With that information, position data can be constantly refined.</p> <div class="Discussion_UserSignature"> <font size="1">I put on my robe and wizard hat...</font> </div>

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#### MeteorWayne

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<p>From Live Science:</p><h2>Asteroid Gravity Tractor Idea: Funded Study</h2><h4>June 20th, 2008<br />Author Leonard David</h4><p>&raquo; Asteroid Gravity Tractor Idea: Funded Study </p><div id="art_toolbar" class="clearfix"><div class="share_grp right"><span class="yahooBuzzBadge-form"><span style="display:block;width:74px;cursor:hand;text-indent:-999em;padding-top:22px;height:0px">Buzz up!</span></span>; <div id="share_items" style="display:none"><div><img src="http://images.livescience.com/common/template_images/delicious_icon.gif" alt="Add to delicious" width="16" height="16" /> del.icio.us</div><div><img src="http://images.livescience.com/common/template_images/diggit_icon.gif" alt="Digg It!" width="16" height="16" /> Digg It!</div><div><img src="http://images.livescience.com/common/template_images/newsvine.png" alt="Save to Newsvine" width="16" height="16" /> Newsvine</div><div><img src="http://images.livescience.com/common/template_images/reddithead4.gif" alt="Add to reddit" width="16" height="16" /> reddit</div></div></div></div><div class="entry"><p>There&rsquo;s been lots of powerpoint talk and back of the envelop calculation regarding use of a &ldquo;gravity tractor&rdquo; to deflect an asteroid that might endanger Earth.</p><p>The physics behind the idea is that a spacecraft would position itself near a menacing asteroid and ever-so-slightly pull it off course thanks to the gravitational attraction between the two bodies.</p><p>But now a detailed study of the gravity tractor is underway, making use of an expert team at Jet Propulsion Laboratory and CalTech. That&rsquo;s the word from former Apollo astronaut, Rusty Schweickart - now Chairman of the Board and Founder of the B612 Foundation which is dedicated to detecting, tracking and deflecting near Earth objects (NEOs).</p><p>Schweickart spotlighted that fact in a June 15 briefing to the Secure World Foundation (SWF) in Boulder, Colorado. Full-disclosure here from this writer as I&rsquo;m a research associate with SWF, but also afraid of getting knocked in the planetary noggin by a falling space rock.</p><p>The B612 Foundation has inked a \$50,000 contract for the work to be done - a detailed performance analysis on the gravity tractor idea. Details of this work-in-progress will be given during the upcoming 10th Asteroids, Comets, Meteors meeting to be held mid-July in Baltimore, Maryland, Schweickart told me.</p><p>The assessment is looking into numerous aspects of the gravity tractor, in terms of stability required, maneuvering capability needed and how much fuel is necessary&hellip;.and just how close can you saunter up to a rotating, odd-shaped body and still maintain spacecraft control.</p></div> <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

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#### MeteorWayne

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<p>Here's a link to a report presented by NASA to Congress in March 2007 which discusses NEO mitigation methods, including the Gravity Tractor:</p><p>http://www.nasa.gov/pdf/171331main_NEO_report_march07.pdf</p><p>&nbsp;</p><p>Listed options....</p><p>&nbsp;</p><strong><p align="center">Table 3. Impulsive Deflection/Mitigation Options </p></strong><table border="1" cellspacing="0" cellpadding="7" width="461" dir="ltr"><tbody><tr><td width="50%" height="21" valign="top" bgcolor="#ffffcc"><strong><p align="left">Impulsive Technique* </p></strong>

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