Exactly 100 years ago right now...

[MeteorWayne]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>So your position is that prepositioning strategic supplies equates to "mindless undirected action"&nbsp;&nbsp; Are you saying that millions of tons of propellent would be inapropriate given the parameters of the problem?&nbsp;Do you believe that, the propellent couldn't be used for other valuable purposes?&nbsp;And I am saying that to have a workable plan we need to take actions before we get the news that&nbsp;something big is&nbsp;gonna hit in 20 months or less.&nbsp; &nbsp;&nbsp;A plan starts with concepts.&nbsp; This is a concept.I hope you are&nbsp;*planning* for the other side if I ever have to go back to war.&nbsp;&nbsp;Strategic thinking&nbsp;is obviously not one of your strong suits.&nbsp;Why do your physics say that its better to start off at ground zero with nothing, than with a million tons in orbit?&nbsp; Can you help me with the math on that one? <br />Posted by BrianSlee</DIV><br /><br />Do you know what it would cost to put millions of tons of propellant (with a limited lifetime) in orbit? </p><p>That would be a good starting point!</p><p>Yes, prepositioning straegic supplies without a strategy is indeed "mindless undirected action".</p><p>Again, the 20 month or less scenario has no workable solution, we are screwed. Period. Nothing we can do will make any difference. I thought I made that clear.</p><p>If you have another purpose for the many billions of dollars it would take, then why not use it for that purpose instead of placing it in orbit to fritter away.</p><p>And BTW, both of you, the personal insults are getting out of hand. Please stop it and address the issues, not the person....</p><p>Wayne</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>

 

[BrianSlee]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Recognition of strategic thinking seems to be a problem for you.&nbsp; It is better to start off with what you need at ground zero than to start by squandering available launch capability to pua million tons of ultimately useless junk into orbit.&nbsp; The math is simple.&nbsp; A starting point of zero, but with available resources trumps a negative starting point with resources already expended.There is a great difference between a well-planned approach to solving a problem and mindless motion.&nbsp; There is a tremendous difference&nbsp;between speed and velocity -- it is called direction. <br />Posted by DrRocket</DIV><br /><br />Hmm more sophistry and no math</p><p>&nbsp;</p> <div class="Discussion_UserSignature"> <p> </p><p>"I am therefore I think" </p><p>"The only thing "I HAVE TO DO!!" is die, in everything else I have freewill" Brian P. Slee</p> </div>

 

[DrRocket]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Hmm more sophistry and no math&nbsp; <br />Posted by BrianSlee</DIV></p><p>Actually if you look closely you can find the math.&nbsp; There is certainly no sophistry.&nbsp; You seem to have trouble recognizing either.<br /></p> <div class="Discussion_UserSignature"> </div>

 

[BrianSlee]

<h1 class="firstHeading">Strategy</h1><div id="bodyContent"><h3 id="siteSub">From Wikipedia, the free encyclopedia</h3><div id="contentSub">&nbsp;&nbsp;(Redirected from Strategic)</div><div id="jump-to-nav">Jump to: navigation, search</div><div class="dablink">For other uses, see Strategy (disambiguation).</div><p>A <strong>Strategy</strong> is a long term plan of action designed to achieve a particular goal, most often "winning." Strategy is differentiated from tactics or immediate actions with resources at hand by its nature of being extensively premeditated, and often practically rehearsed. Strategies are used to make the problem easier to understand and solve.</p></div> <div class="Discussion_UserSignature"> <p> </p><p>"I am therefore I think" </p><p>"The only thing "I HAVE TO DO!!" is die, in everything else I have freewill" Brian P. Slee</p> </div>

 

[BrianSlee]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Do you know what it would cost to put millions of tons of propellant (with a limited lifetime) in orbit? That would be a good starting point!</DIV></p><p>It would cost a lot.&nbsp; Strategic solutions are not cheap.&nbsp; e.g. We&nbsp;have been spending billions on the military for years in times of realative peace not because we had to go fight a battle today or tommorrow&nbsp;(tactical engagement) but in case of a real war (if we lose we all die or become the ex-United States of America).&nbsp; Because when you really need it, and your life really does depend on it,&nbsp;it has to be there right now.&nbsp;</p><p>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Yes, prepositioning straegic supplies without a strategy is indeed "mindless undirected action"</DIV></p><p>You are confusing strategy and tactics.&nbsp;&nbsp;</p><p>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>.Again, the 20 month or less scenario has no workable solution, we are screwed. Period. Nothing we can do will make any difference. I thought I made that clear.</DIV></p><p>Nothing&nbsp;we can do about it today does not equate to nothing we can&nbsp;do about it tommorow&nbsp;given an appropriate strategy and the resources to implement it.</p><p>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>If you have another purpose for the many billions of dollars it would take, then why not use it for that purpose instead of placing it in orbit to fritter away.</DIV></p><p>Because the survival of the species might depend it.&nbsp; i.e. It is in our "Strategic Interests"&nbsp;</p><p>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>And BTW, both of you, the personal insults are getting out of hand. Please stop it and address the issues, not the person....Wayne <br />Posted by MeteorWayne</DIV><br /><br />aww I was just starting to have fun ;O)</p><p>But I will try if Dr. Rocket does</p> <div class="Discussion_UserSignature"> <p> </p><p>"I am therefore I think" </p><p>"The only thing "I HAVE TO DO!!" is die, in everything else I have freewill" Brian P. Slee</p> </div>

 

[DrRocket]

<p>One of the items that needs to be further studied and understood is the uncertainty in our knowledge of potentially impacting asteroids.&nbsp; As Wayne has pointed out there is quite a bit of work ongoing to identify asteroids that might impact the Earth and to determine their orbital parameters.<br />http://neo.jpl.nasa.gov/risk/doc/sentry.html</p><p>One will note that at this time what is reported is a possible impact time and an assessment of the probability of a collision then.&nbsp; Now, this is not an iherently probabilistic problem.&nbsp; Either there will be a collision at some future time or there will not.&nbsp; And if&nbsp;we had adequate knowledge of the bodies in orbit around the sun we could determine whether or not a collision would occur far out into the future.&nbsp; The physics involved is completely deterministic.</p><p>Our knowledge of the orbital parameters of the various bodies is not, however, perfect.&nbsp; There is a good deal of uncertainty.&nbsp; And the models that we use to project orbital motion into the future are approximations to exact solutions.&nbsp; Consequently there are error bands around our predictions.</p><p>We also know that if we perturb the orbit of a potentially impacting asteroid sufficiently far in advance of a collision, that that a very small&nbsp;perturbation can completely avoid the collision.&nbsp; That is a useful piece of knowledge.&nbsp; But equally we know that we can make a small perturbation to a body that would completely miss the Earth and cause a collision.&nbsp; There is therefore great potential value in refining our knowledge of the orbital parameters of bodies orbiting the sun and in developing as accurate a data base as is possible to obtain.&nbsp; This may involve many observations over a long period of time.&nbsp; It also suggests the value in performing detailed simulations to determine the sensitivity of potential action taken to deflect any of those bodies.&nbsp; Studies like that can tell us how far in advance of a potential collision we might take action and be assured that it would both create an effective deflection and also be assured that we would not create a problem where none exists.</p><p>It is also important to determine what sort of action might be reasonable.&nbsp; Storing rocket propellant in space is useless if it is the wrong sort of propellant.&nbsp; There is a reason that some propellant is called storeable and some is not.&nbsp; LOX/hydrogen is not on the list of storeables, and hydrogen in particular has poor density for some applications. A few million pounds of fuel in orbit needs to be accessible, useful, and it needs to stay in orbit.&nbsp; You would want to be very sure that no perturbation of that orbit sent such a huge cache of energetic material back&nbsp;down to Earth.</p><p>So, if one wanted to deflect an asteroid, how might one do that?&nbsp; Would you use a thermonuclear propulsion sytem such as proposed for the Orion vehicle ?&nbsp; Would you use a large rocket motor, perhaps a solid with high Isp-density product ?&nbsp; Would you attemt to use explosives, either conventional or nuclear, to split the asteroid and thereby deflect each piece ?&nbsp; Could you attackthe problem very early on, and alter the absorptivity of the asteroid in an attempt to use the momentum of light (I am a bit skeptical of this, but it has been proposed)?</p><p>In any case I think it advisable to get the brain fully engaged before proceeding with expensive and possibly counter-productive action.&nbsp; A couple of million pounds of high energy rocket fuel in orbit could turn a near miss from an asteroid or comet into a gigantic bomb in a decaying orbit -- snatching defeat from the jaws of victory.</p> <div class="Discussion_UserSignature"> </div>

 

[DrRocket]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>StrategyFrom Wikipedia, the free encyclopedia&nbsp;&nbsp;(Redirected from Strategic)Jump to: navigation, searchFor other uses, see Strategy (disambiguation).A Strategy is a long term plan of action designed to achieve a particular goal, most often "winning." Strategy is differentiated from tactics or immediate actions with resources at hand by its nature of being extensively premeditated, and often practically rehearsed. Strategies are used to make the problem easier to understand and solve. <br />Posted by BrianSlee</DIV></p><p>Strategy -- Custer's plan: go forth, do good, wiin</p><p>Tactics -- Crazy Horse's plan:&nbsp; bring bullets, shoot silly white man<br /></p> <div class="Discussion_UserSignature"> </div>

 

[BrianSlee]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>One of the items that needs to be further studied and understood is the uncertainty in our knowledge of potentially impacting asteroids.&nbsp; As Wayne has pointed out there is quite a bit of work ongoing to identify asteroids that might impact the Earth and to determine their orbital parameters.http://neo.jpl.nasa.gov/risk/doc/sentry.htmlOne will note that at this time what is reported is a possible impact time and an assessment of the probability of a collision then.&nbsp; Now, this is not an iherently probabilistic problem.&nbsp; Either there will be a collision at some future time or there will not.&nbsp; And if&nbsp;we had adequate knowledge of the bodies in orbit around the sun we could determine whether or not a collision would occur far out into the future.&nbsp; The physics involved is completely deterministic.Our knowledge of the orbital parameters of the various bodies is not, however, perfect.&nbsp; There is a good deal of uncertainty.&nbsp; And the models that we use to project orbital motion into the future are approximations to exact solutions.&nbsp; Consequently there are error bands around our predictions.We also know that if we perturb the orbit of a potentially impacting asteroid sufficiently far in advance of a collision, that that a very small&nbsp;perturbation can completely avoid the collision.&nbsp; That is a useful piece of knowledge.&nbsp; But equally we know that we can make a small perturbation to a body that would completely miss the Earth and cause a collision.&nbsp; There is therefore great potential value in refining our knowledge of the orbital parameters of bodies orbiting the sun and in developing as accurate a data base as is possible to obtain.&nbsp; This may involve many observations over a long period of time.&nbsp; It also suggests the value in performing detailed simulations to determine the sensitivity of potential action taken to deflect any of those bodies.&nbsp; Studies like that can tell us how far in advance of a potential collision we might take action and be assured that it would both create an effective deflection and also be assured that we would not create a problem where none exists.It is also important to determine what sort of action might be reasonable.&nbsp; Storing rocket propellant in space is useless if it is the wrong sort of propellant.&nbsp; There is a reason that some propellant is called storeable and some is not.&nbsp; LOX/hydrogen is not on the list of storeables, and hydrogen in particular has poor density for some applications. A few million pounds of fuel in orbit needs to be accessible, useful, and it needs to stay in orbit.&nbsp; You would want to be very sure that no perturbation of that orbit sent such a huge cache of energetic material back&nbsp;down to Earth.So, if one wanted to deflect an asteroid, how might one do that?&nbsp; Would you use a thermonuclear propulsion sytem such as proposed for the Orion vehicle ?&nbsp; Would you use a large rocket motor, perhaps a solid with high Isp-density product ?&nbsp; Would you attemt to use explosives, either conventional or nuclear, to split the asteroid and thereby deflect each piece ?&nbsp; Could you attackthe problem very early on, and alter the absorptivity of the asteroid in an attempt to use the momentum of light (I am a bit skeptical of this, but it has been proposed)?In any case I think it advisable to get the brain fully engaged before proceeding with expensive and possibly counter-productive action.&nbsp; A couple of million pounds of high energy rocket fuel in orbit could turn a near miss from an asteroid or comet into a gigantic bomb in a decaying orbit -- snatching defeat from the jaws of victory. <br />Posted by DrRocket</DIV></p><p>All considerations that should be looked at before implementing a long term strategy and taking tactical actions.&nbsp; Again this is a concept so it is open to debate.&nbsp; I will maintain that it is in our long term strategic interest to have as large a logistic capability as is feasible (feasible covers a lot of area including safety and fiscal abilities) to implement for the sake of long term survival.&nbsp; I think we have ample evidence to support the hypothesis that it is not a question of if, but a question of when we will have to deal with this particular problem.&nbsp; I also believe that this approach would be useful in establishing the logistics capability to move us from where we are now i.e. Earthbound and prone to sudden extinction...to where we want to be in the future i.e. A race of beings who live among the stars&nbsp;(or at least on different planets) that would be&nbsp;safe from sudden extinction from a single event that we have little or no control over.&nbsp; I will ignore the brain fully engaged comment in the interest of getting this discussion back to a more civil tone.&nbsp; I will also say that as far as I know this is a basic physics problem with no basic solution *at the moment*.&nbsp; *If an Oort cloud object showed up today the pertinent question is what can we do right now.* We either can put enough mass in a position to make a difference or we can't.&nbsp; Not much in-between right now.&nbsp; Maybe science will devise a better method sometime in the future.&nbsp; But to my knowledge the only workable solution right now is to fight mass with mass.&nbsp; </p><p>** = edited for readability</p> <div class="Discussion_UserSignature"> <p> </p><p>"I am therefore I think" </p><p>"The only thing "I HAVE TO DO!!" is die, in everything else I have freewill" Brian P. Slee</p> </div>

 

[BrianSlee]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Strategy -- Custer's plan: go forth, do good, wiinTactics -- Crazy Horse's plan:&nbsp; bring bullets, shoot silly white man <br />Posted by DrRocket</DIV><br /><br />Not all strategies are good ones and on the other hand even&nbsp;great tactics will not win a war.&nbsp; </p><p>Even Crazy Horse (as brilliant and brave as he was) could not compete with a whole army of Custers and finally succumbed to a&nbsp;strategically superior foe.</p> <div class="Discussion_UserSignature"> <p> </p><p>"I am therefore I think" </p><p>"The only thing "I HAVE TO DO!!" is die, in everything else I have freewill" Brian P. Slee</p> </div>

 

[CalliArcale]

<p>In theory, it could be useful to have an asteroid interceptor ready to go at a moment's notice, parked in a high orbit.&nbsp; I would want it somewhere where it could pass through a Lagrangian "keyhole" fairly easily, thus reducing the amount of delta-vee (change in velocity) required to set it on its way.</p><p>But in practice, there are a lot of problems with the idea.&nbsp;&nbsp; First of all, if you don't know what your interceptor has to do (that is, you don't know the mass or trajectory of an as-yet-unknown incoming hazardous asteroid, so you don't know how much energy it has to apply to the object in order to save Earth), then you really don't know what kind of interceptor to build.&nbsp; Gravity deflector?&nbsp; That's one popular idea, in which a relatively large spacecraft is sent many years in advance so it can use its own gravity to gently push the asteroid away.&nbsp; Propulsion system which lands on the asteroid and then gives it thrust?&nbsp; Will depend on the asteroid's shape, composition, rotation rate, and whether you can take advantage of any future planetary flybys to tweak the asteroid's course.&nbsp; Furthermore, since there are no known impactors on their way, it is safe to say that we have no idea when we would need to use such a spacecraft.&nbsp; It could be tomorrow; it could be a thousand years from now; it could be never. </p><p>Basically, there are so many unknowns that in all likelihood, whatever we built and launched would never be used.&nbsp; Therefore, there is no point building it now.&nbsp; Perhaps once technology has advanced, and/or we have better characterized the threat, we could think about doing that.&nbsp; But we're not to that point yet, technologically speaking.</p> <div class="Discussion_UserSignature"> <p> </p><p><font color="#666699"><em>"People assume that time is a strict progression of cause to effect, but actually from a non-linear, non-subjective viewpoint it's more like a big ball of wibbly wobbly . . . timey wimey . . . stuff."</em>  -- The Tenth Doctor, "Blink"</font></p> </div>

 

[BrianSlee]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>In theory, it could be useful to have an asteroid interceptor ready to go at a moment's notice, parked in a high orbit.&nbsp; I would want it somewhere where it could pass through a Lagrangian "keyhole" fairly easily, thus reducing the amount of delta-vee (change in velocity) required to set it on its way.But in practice, there are a lot of problems with the idea.&nbsp;&nbsp; First of all, if you don't know what your interceptor has to do (that is, you don't know the mass or trajectory of an as-yet-unknown incoming hazardous asteroid, so you don't know how much energy it has to apply to the object in order to save Earth), then you really don't know what kind of interceptor to build.&nbsp; Gravity deflector?&nbsp; That's one popular idea, in which a relatively large spacecraft is sent many years in advance so it can use its own gravity to gently push the asteroid away.&nbsp; Propulsion system which lands on the asteroid and then gives it thrust?&nbsp; Will depend on the asteroid's shape, composition, rotation rate, and whether you can take advantage of any future planetary flybys to tweak the asteroid's course.&nbsp; Furthermore, since there are no known impactors on their way, it is safe to say that we have no idea when we would need to use such a spacecraft.&nbsp; It could be tomorrow; it could be a thousand years from now; it could be never. Basically, there are so many unknowns that in all likelihood, whatever we built and launched would never be used.&nbsp; Therefore, there is no point building it now.&nbsp; Perhaps once technology has advanced, and/or we have better characterized the threat, we could think about doing that.&nbsp; But we're not to that point yet, technologically speaking. <br />Posted by CalliArcale</DIV></p><p>CalliArcale,</p><p>&nbsp; All very good *points for discussion*.&nbsp; Given the above, would it make sense to amass a large amount of water in orbit that could also be used to:</p><p>Provide fuel for&nbsp;a nuclear steam powered rocket</p><p>Provide the basic constituents for a bi-propellant rocket i.e. Lh2 and LOX</p><p>Act as a terminal for fueling deep space exploration and colonization efforts</p><p>etc....</p> <div class="Discussion_UserSignature"> <p> </p><p>"I am therefore I think" </p><p>"The only thing "I HAVE TO DO!!" is die, in everything else I have freewill" Brian P. Slee</p> </div>

 

[MeteorWayne]

Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>CalliArcale,&nbsp; All very good *points for discussion*.&nbsp; Given the above, would it make sense to amass a large amount of water in orbit that could also be used torovide fuel for&nbsp;a nuclear steam powered rocketProvide the basic constituents for a bi-propellant rocket i.e. Lh2 and LOXAct as a terminal for fueling deep space exploration and colonization effortsetc.... <br />Posted by BrianSlee</DIV><br /><br />Why would that be a good idea if it would bankrupt the world economy? <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>

 

[BrianSlee]

Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Why would that be a good idea if it would bankrupt the world economy? <br />Posted by MeteorWayne</DIV><br /><br />I am talking about an evolutionary approach and strategic plan that could be implemented over many years.&nbsp;The idea also relies on much lower launch costs than current systems can provide or a much longer implimentation schedule.&nbsp; Either way I see no reason to bankrupt anyone in the process.&nbsp; &nbsp;*seems to me that someone on this forum has taken the position that it's not the rocket thats expensive, its the payload and the insurance to cover it.&nbsp; So how much does a bucket of water cost and how much do you want to insure it for?* <div class="Discussion_UserSignature"> <p> </p><p>"I am therefore I think" </p><p>"The only thing "I HAVE TO DO!!" is die, in everything else I have freewill" Brian P. Slee</p> </div>

 

[DrRocket]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>I am talking about an evolutionary approach and strategic plan that could be implemented over many years.&nbsp;The idea also relies on much lower launch costs than current systems can provide or a much longer implimentation schedule.&nbsp; Either way I see no reason to bankrupt anyone in the process.&nbsp; &nbsp;*seems to me that someone on this forum has taken the position that it's not the rocket thats expensive, its the payload and the insurance to cover it.&nbsp; So how much does a bucket of water cost and how much do you want to insure it for?* <br />Posted by BrianSlee</DIV></p><p>The rocket is indeed a relatively minor part of the overall launch costs.&nbsp; But what would you do with the bucket of water ?</p><p>If the idea is to find private funding to use a blimp to put a bucket of water in orbit then I say go for it.&nbsp; But don't waste my tax money.&nbsp; Bankrupt anyone in the private sector that you please.&nbsp; Or enrich them beyond their wildest dreams if you can.&nbsp; </p> <div class="Discussion_UserSignature"> </div>

 

[BrianSlee]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>The rocket is indeed a relatively minor part of the overall launch costs.&nbsp; But what would you do with the bucket of water ?If the idea is to find private funding to use a blimp to put a bucket of water in orbit then I say go for it.&nbsp; But don't waste my tax money.&nbsp; Bankrupt anyone in the private sector that you please.&nbsp; Or enrich them beyond their wildest dreams if you can.&nbsp; <br />Posted by DrRocket</DIV><br /><br />You still haven't provided a "physical" "functional" or "fiscal" basis for your assesments in the other thread and you keep running away from the questions you can't *or won't* answer&nbsp;and the facts you can't&nbsp;refute.&nbsp;*and it seems to me that you and NASA have been using my tax money for the last *50* years with what I would call less than stellar achievements in the area of space access.</p><p>*Correction Apollo 17 was the last Saturn V mission and occured in 1972 so&nbsp;the time period&nbsp;I am trying to reference&nbsp;has only been 36 years*</p> <div class="Discussion_UserSignature"> <p> </p><p>"I am therefore I think" </p><p>"The only thing "I HAVE TO DO!!" is die, in everything else I have freewill" Brian P. Slee</p> </div>

 

[DrRocket]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>You still haven't provided a "physical" "functional" or "fiscal" basis for your assesments in the other thread and you keep running away from the questions you can't *or won't* answer&nbsp;and the facts you can't&nbsp;refute.&nbsp;*and it seems to me that you and NASA have been using my tax money for the last 50 years with what I would call less than stellar achievements in the area of space access. <br />Posted by BrianSlee</DIV></p><p>I have perhaps lost track of the specific questions to which you refer.&nbsp; If you would care to restate them precisely I will answer them one by one.&nbsp; I am not particularly known for running away from questions.&nbsp; So bring 'em on.&nbsp; But please state them clearly and precisely, and don't hide behind some notion of not disclosing details that are required to be publicly published, as in a patent.</p><p>Gee, in the last 50 years we have gone from no access to space under any conditions whatever to regular launches of both satellites and humans.&nbsp; We have gone to the moon.&nbsp; We have a probe sending data from Mars.&nbsp; We have sent probes to every planet except Pluto, and a mission to Pluto is being planned.&nbsp; Our telecommunications has gone from depending on a human operator to being transmitted regularly over satellite links.&nbsp; Our weather forecasting is now based on satellite data.&nbsp; Our military knows precisely where they are because of the GPS satellites.&nbsp; Sorry you are not impressed by the progress.<br /></p> <div class="Discussion_UserSignature"> </div>

 

[derekmcd]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>*and it seems to me that you and NASA have been using my tax money for the last 50 years with what I would call less than stellar achievements in the area of space access. <br /> Posted by BrianSlee</DIV></p><p>NASA spinoff technologies:</p><p>http://www.thespaceplace.com/nasa/spinoffs.html</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>

 

[BrianSlee]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>I have perhaps lost track of the specific questions to which you refer.&nbsp; If you would care to restate them precisely I will answer them one by one.&nbsp; I am not particularly known for running away from questions.&nbsp; So bring 'em on.&nbsp; But please state them clearly and precisely, and don't hide behind some notion of not disclosing details that are required to be publicly published, as in a patent.Gee, in the last 50 years we have gone from no access to space under any conditions whatever to regular launches of both satellites and humans.&nbsp; We have gone to the moon.&nbsp; We have a probe sending data from Mars.&nbsp; We have sent probes to every planet except Pluto, and a mission to Pluto is being planned.&nbsp; Our telecommunications has gone from depending on a human operator to being transmitted regularly over satellite links.&nbsp; Our weather forecasting is now based on satellite data.&nbsp; Our military knows precisely where they are because of the GPS satellites.&nbsp; Sorry you are not impressed by the progress. <br />Posted by DrRocket</DIV><br /><br />I will not hijack waynes thread or help you do it.&nbsp; If you want to review the questions do it on your own (I am not your secratary) they are still there for you to access, and if you want to discuss it further "in a positve constructive manner'" do it in the thread I started on the subject and please quit using statements like "I don't think", please stick to statements like your math is incorrect or it won't function in that manner because (cause leads to effect).&nbsp; There is plenty of information in the threads and the white paper to evaluate the physical and functional aspects enough to determine feasability.&nbsp; And yes less than stellar,&nbsp; Since the end of the Appollo program we have achieved IMHO insignifacant gains in getting people and supplies into space.&nbsp; For all of NASA's great achievements and they have many, they have been unable to crack the code for a system that will provide the inexpensive access to space that will allow more than just a select few to get there,&nbsp;and I for one think our species will require that access to survive in a very hostile universe.&nbsp; Where would we be today if *50* years after the first flight at Kitty Hawk we had nothing to show with more capability or even the same capability as the first successful airplane Orville and Wilber designed and flew.</p><p>&nbsp;*Correction Apollo 17 was the last Saturn V mission and occured in 1972 so&nbsp;the time period&nbsp;I am trying to reference&nbsp;has only been 36 years*</p> <div class="Discussion_UserSignature"> <p> </p><p>"I am therefore I think" </p><p>"The only thing "I HAVE TO DO!!" is die, in everything else I have freewill" Brian P. Slee</p> </div>

 

[DrRocket]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>I will not hijack waynes thread or help you do it.&nbsp; If you want to review the questions do it on your own (I am not your secratary) they are still there for you to access, and if you want to discuss it further "in a positve constructive manner'" do it in the thread I started on the subject and please quit using statements like "I don't think", please stick to statements like your math is incorrect or it won't function in that manner because (cause leads to effect).&nbsp; There is plenty of information in the threads and the white paper to evaluate the physical and functional aspects enough to determine feasability.&nbsp; And yes less than stellar,&nbsp; Since the end of the Appollo program we have achieved IMHO insignifacant gains in getting people and supplies into space.&nbsp; For all of NASA's great achievements and they have many, they have been unable to crack the code for a system that will provide the inexpensive access to space that will allow more than just a select few to get there,&nbsp;and I for one think our species will require that access to survive in a very hostile universe.&nbsp; Where would we be today if 50 years after the first flight at Kitty Hawk we had nothing to show with more capability or even the same capability as the first successful airplane Orville and Wilber designed and flew. <br />Posted by BrianSlee</DIV></p><p>?<br /></p> <div class="Discussion_UserSignature"> </div>

 

[Mee_n_Mac]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Do you know what it would cost to put millions of tons of propellant (with a limited lifetime) in orbit? That would be a good starting point!Yes, prepositioning straegic supplies without a strategy is indeed "mindless undirected action".Again, the 20 month or less scenario has no workable solution, we are screwed. Period. Nothing we can do will make any difference. I thought I made that clear.If you have another purpose for the many billions of dollars it would take, then why not use it for that purpose instead of placing it in orbit to fritter away.And BTW, both of you, the personal insults are getting out of hand. Please stop it and address the issues, not the person....Wayne <br />Posted by <strong>MeteorWayne</strong></DIV><br /></p><p>What's the likely composition of our Oort cloud nemesis ?&nbsp; How much delta V, in either it's direction of motion or orthogonal to it, would be needed to make a hit into a miss ? Just rough numbers here .... </p><p>Can we discuss the feasibilty of some future system to gather the Sun's light and focus it on our problem body ?</p><p>&nbsp;</p> <div class="Discussion_UserSignature"> <p>-----------------------------------------------------</p><p><font color="#ff0000">Ask not what your Forum Software can do do on you,</font></p><p><font color="#ff0000">Ask it to, please for the love of all that's Holy, <strong>STOP</strong> !</font></p> </div>

 

[DrRocket]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>What's the likely composition of our Oort cloud nemesis ?&nbsp; How much delta V, in either it's direction of motion or orthogonal to it, would be needed to make a hit into a miss ? Just rough numbers here .... Can we discuss the feasibilty of some future system to gather the Sun's light and focus it on our problem body ?&nbsp; <br />Posted by mee_n_mac</DIV></p><p>I don't think anybody knows the answer to all of your questions.&nbsp; The delta V will depend on when and where it is applied.&nbsp; A little bit in the Oort cloud could go a long way.&nbsp; Nearer the sun more delta V would be needed.&nbsp; If Wayne has a representative set of numbers for a Oort cloud body, it might be interesting to calculate what a Hohman transfer might look like to circularize the orbit.&nbsp; That obviously would be really difficult to do in practice, but it would perhaps provide a gauge for what might be done with what I suspect is a little bit of impulse.&nbsp; If I have time maybe I'll try to cook up a purely hypothetical example.&nbsp; <br /></p> <div class="Discussion_UserSignature"> </div>

 

[CalliArcale]

<p>BrianSlee,&nbsp; your questions deserve a line-by-line reply; the automatic reply thingie tends to kind of glom stuff together.&nbsp; So I'm going to boldface what I quote of your post for clarity.</p><p>All very good *points for discussion*.&nbsp; Given the above, would it make sense to amass a large amount of water in orbit that could also be used to:</p><p>Provide fuel for&nbsp;a nuclear steam powered rocket</p><p>Maybe once we've developed a nuclear steam powered rocket, know how much propellant mass it needs in order to be useful, and have developed a means of storing it and transferring it ot the rocket in a useful fashion.&nbsp; Water is tricky in orbit.&nbsp; It's volatile in space.&nbsp; Here on Earth, water's easy to deal with, but get the pressure low enough and it just boils away like carbon dioxide does on Earth.&nbsp; (That's one of the problems with surface water on Mars; water can't stay liquid.&nbsp; It actually goes straight from solid to gas.)&nbsp; It also freezes at a relatively high temperature, so you'd have to keep it pretty warm to be able to transfer it into a rocket -- even if we *did* have a rocket that took water as its propellant.</p><p>Basically, in theory it could work, but sticking water up there now is putting the cart before the horse.&nbsp; We should figure out how we're going to use the water before we invest a lot of money into putting it up there.&nbsp; Heck, right now we don't even know that it's the best propellant choice.&nbsp; It'd be a shame to spend billions putting a bunch of water up there that we'd never use. </p><p>Really, at present the only long-term storable propellants are those used by ion drives (extremely low thrust, but high specific impulse) and hypergolics (relatively high thrust, low to middling specific impulse; hypergolics are also used by launch vehicles such as the Proton and the now-retired Titan).&nbsp; These cooperate well with the conditions in space, though you do need to keep the hypergolics warm enough that they don't freeze, so you're looking at adding a heater for those too.&nbsp; Wouldn't be as bad as trying to keep water in orbit, though.&nbsp; The hypergolics have some other penalties, the worst of which is that they're fairly heavy, and corossive, which means you need to beef up seals and things.&nbsp; One bit upside is that engines using hypergolic propellants are simpler and thus less failure prone; you don't need an igniter, for one thing. </p><p>Provide the basic constituents for a bi-propellant rocket i.e. Lh2 and LOX</p><p>LH2 and LOX are extremely volatile, which is why they are seldom used on orbit, and then only in the very earliest stages of the mission.&nbsp; They boil off too quickly, and you'd end up losing too much of it before you'd get a chance to use it.</p><p>Storing the water is only slightly better, and then you'd have to spend energy performing electrolysis to break it into hydrogen and oxygen, after which you would need to spend *more* energy liquifying it so it would be sufficiently dense to use as rocket propellant. Actually, did you know that LH2 for cryogenic rockets here on Earth, like the Space Shuttle, is *not* made from water?&nbsp; Seriously.&nbsp; It's made from petroleum, because that process is cheaper.&nbsp; I believe the LOX is made from atmospheric oxygen, though I'm not 100% sure of that. </p><p>Act as a terminal for fueling deep space exploration and colonization efforts</p><p>Long term, maybe, though I'm not convinced that *water* is neccesarily the best choice.&nbsp; It's got a good shot, but it's got fairly serious engineering problems to overcome first.&nbsp; Right now, though, there are no deep space exploration or colonization efforts in the works which need a propellant dump in low Earth orbit.&nbsp; Sad, perhaps, but true.&nbsp; It makes no sense to build a gas station that nobody's going to use, especially if you build it to provide only unleaded gasoline, but then in twenty years, when you finally get customers, they're all driving hydrogen fuel cell vehicles. </p><p>The main problems that have far has stymied this sort of effort in low&nbsp; Earth orbit have been these:</p><p>1) Not enough vehicles are going out there for a fuel dump to be worth the cost;&nbsp; it's cheaper just to give them a little bit of extra fuel from the start and launch them from the ground.</p><p>2) Truthfully, starting from low Earth orbit is only marginally better, in terms of delta-vee, than starting from the ground.&nbsp; The tiny gain is just not worth the expense, especially since relying on an orbiting "gas station" means you are constrained from the&nbsp; outset to the specifications of the gas station.&nbsp;</p> <div class="Discussion_UserSignature"> <p> </p><p><font color="#666699"><em>"People assume that time is a strict progression of cause to effect, but actually from a non-linear, non-subjective viewpoint it's more like a big ball of wibbly wobbly . . . timey wimey . . . stuff."</em>  -- The Tenth Doctor, "Blink"</font></p> </div>

 

[neilsox]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>What's the likely composition of our Oort cloud nemesis ?&nbsp; How much delta V, in either it's direction of motion or orthogonal to it, would be needed to make a hit into a miss ? Just rough numbers here .... Can we discuss the feasibilty of some future system to gather the Sun's light and focus it on our problem body ?&nbsp; <br />Posted by mee_n_mac</DIV><br />A solar mirror cannot produce a small spot except at very close range, but a solar mirror could pump an array of lasers which could produce a small spot up to&nbsp;ten? million miles away. If the spot is small enough, rock or iron would be vaporized, producing reaction mass which would propel nemesus in the opposite direction, slightly. Not much&nbsp;orbit changes is needed to change a likely hit of Earth to a likely miss years later.</p><p>If we appropriate a billion dollars this year (wisely) and double the spending each subsequent&nbsp;year, we can (in my opinion) have a dozen mirror laser arrays in solar orbit by 2030, with some of them in the Oort cloud by 2060. The laser arrays going to the Oort cloud need to be nuclear powered as sun light is too weak in the Oort cloud. The laser arrays would have several other uses besides deflecting nemesis, especially if we have a human presence in the solar system.&nbsp;ie search light to help find asteroids and comets, communications, terriforming,&nbsp;a laser type radar, space solar power www.spacesolarpower.wordpress.com&nbsp; &nbsp;Neil.</p>

 

[DrRocket]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>What's the likely composition of our Oort cloud nemesis ?&nbsp; How much delta V, in either it's direction of motion or orthogonal to it, would be needed to make a hit into a miss ? Just rough numbers here .... Can we discuss the feasibilty of some future system to gather the Sun's light and focus it on our problem body ?&nbsp; <br />Posted by mee_n_mac</DIV></p><p>Just for grins here are some numbers.&nbsp; Assume that you have a body from either the Oort cloud or the Kuiper belt orbiting the sun.&nbsp; We'll take the apogee of the orbits to be 5000 AU and 55 AU respectively.&nbsp; We'll also take the orbital parameter (semi-Latus rectum) to 1 Au in either case -- highly&nbsp;elliptical orbits.&nbsp; It is feasible to calculate the velocities at&nbsp; apogee by hand for a given orbit.&nbsp; In this case I calculated the velocities for the elliptical orbit and for a circular orbit a the same apogees -- the difference being what would be required to circularize the orbits in what is known as a Hohman transfer.&nbsp; Actually performing a Hohman transfer is a bit impractical, but perhaps the numbers are illustrative.&nbsp; And if you could literally circularize the orbit of such a body, there is no chance of a collision with the Earth or any other planet, and no reasonable future perturbation of the orbit with anything the body is likely to encounter (other than a passing rogue planet or a star and then we have a whole new set of problems) would cause a collision either.</p><p>So, here are the numbers.&nbsp; For the Oort clould body the required delta V to circularize is 13.225 m/s -- not much.&nbsp; And for the Kuiper Belt body the delta V needed is 118.4 m/s -- still reasonably modest for such a major orbit change.&nbsp; </p><p>While those speed changes are relatively modest, for a large body they would still be difficult to impart.&nbsp; A body 1 km in diameter&nbsp;with &nbsp;a specific gravity of 1 would have a mass of about 5.24*10^11 kg so to circularize an orbit in the Oort Cloud would require an impulse of 6.925 quadrillion N*s, and that is quite a bit of impulse. about 1.56*10^12 lb*s.&nbsp; If you had a rocket with propellant providing and Isp of 440 sec, that would require 3,54 billion pounds of propellant.&nbsp; With SRBs that number is closer to 5.6 billion pounds, give or take a few.&nbsp; </p><p>What all of this does show is that a relatively minor velocity change, far out in the orbit, can make a huge change in the orbital shape.&nbsp; It also points out that even small velocity changes in large bodies require a lot of momentum change.&nbsp; </p><p>For those not familiar with a Hohman transfer, it is an idealized impulsive burn that instantaneously increases velocity at the apogee of an orbit.&nbsp; The direction of the burn is tangent to the circularized orbit and in the direction of motion of the original orbit.&nbsp; It is the optimal strategy in terms of fuel consumption to go from an elliptical to a circular orbit.</p> <div class="Discussion_UserSignature"> </div>

 

[BrianSlee]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>BrianSlee,&nbsp; your questions deserve a line-by-line reply; the automatic reply thingie tends to kind of glom stuff together.&nbsp; So I'm going to boldface what I quote of your post for clarity.All very good *points for discussion*.&nbsp; Given the above, would it make sense to amass a large amount of water in orbit that could also be used torovide fuel for&nbsp;a nuclear steam powered rocketMaybe once we've developed a nuclear steam powered rocket, know how much propellant mass it needs in order to be useful, and have developed a means of storing it and transferring it ot the rocket in a useful fashion.&nbsp; Water is tricky in orbit.&nbsp; It's volatile in space.&nbsp; Here on Earth, water's easy to deal with, but get the pressure low enough and it just boils away like carbon dioxide does on Earth.&nbsp; (That's one of the problems with surface water on Mars; water can't stay liquid.&nbsp; It actually goes straight from solid to gas.)&nbsp; It also freezes at a relatively high temperature, so you'd have to keep it pretty warm to be able to transfer it into a rocket -- even if we *did* have a rocket that took water as its propellant.Basically, in theory it could work, but sticking water up there now is putting the cart before the horse.&nbsp; We should figure out how we're going to use the water before we invest a lot of money into putting it up there.&nbsp; Heck, right now we don't even know that it's the best propellant choice.&nbsp; It'd be a shame to spend billions putting a bunch of water up there that we'd never use. Really, at present the only long-term storable propellants are those used by ion drives (extremely low thrust, but high specific impulse) and hypergolics (relatively high thrust, low to middling specific impulse; hypergolics are also used by launch vehicles such as the Proton and the now-retired Titan).&nbsp; These cooperate well with the conditions in space, though you do need to keep the hypergolics warm enough that they don't freeze, so you're looking at adding a heater for those too.&nbsp; Wouldn't be as bad as trying to keep water in orbit, though.&nbsp; The hypergolics have some other penalties, the worst of which is that they're fairly heavy, and corossive, which means you need to beef up seals and things.&nbsp; One bit upside is that engines using hypergolic propellants are simpler and thus less failure prone; you don't need an igniter, for one thing. Provide the basic constituents for a bi-propellant rocket i.e. Lh2 and LOXLH2 and LOX are extremely volatile, which is why they are seldom used on orbit, and then only in the very earliest stages of the mission.&nbsp; They boil off too quickly, and you'd end up losing too much of it before you'd get a chance to use it.Storing the water is only slightly better, and then you'd have to spend energy performing electrolysis to break it into hydrogen and oxygen, after which you would need to spend *more* energy liquifying it so it would be sufficiently dense to use as rocket propellant. Actually, did you know that LH2 for cryogenic rockets here on Earth, like the Space Shuttle, is *not* made from water?&nbsp; Seriously.&nbsp; It's made from petroleum, because that process is cheaper.&nbsp; I believe the LOX is made from atmospheric oxygen, though I'm not 100% sure of that. Act as a terminal for fueling deep space exploration and colonization effortsLong term, maybe, though I'm not convinced that *water* is neccesarily the best choice.&nbsp; It's got a good shot, but it's got fairly serious engineering problems to overcome first.&nbsp; Right now, though, there are no deep space exploration or colonization efforts in the works which need a propellant dump in low Earth orbit.&nbsp; Sad, perhaps, but true.&nbsp; It makes no sense to build a gas station that nobody's going to use, especially if you build it to provide only unleaded gasoline, but then in twenty years, when you finally get customers, they're all driving hydrogen fuel cell vehicles. The main problems that have far has stymied this sort of effort in low&nbsp; Earth orbit have been these:1) Not enough vehicles are going out there for a fuel dump to be worth the cost;&nbsp; it's cheaper just to give them a little bit of extra fuel from the start and launch them from the ground.2) Truthfully, starting from low Earth orbit is only marginally better, in terms of delta-vee, than starting from the ground.&nbsp; The tiny gain is just not worth the expense, especially since relying on an orbiting &quot;gas station&quot; means you are constrained from the&nbsp; outset to the specifications of the gas station.&nbsp; <br />Posted by CalliArcale</DIV><br /><br />CallieArcale,</p><p>&nbsp; I understand what you are saying and agree that there are a lot of engineering challenges involved.&nbsp; All of the points you present would definitely need to be addressed before implementing any long term strategy.&nbsp; I am simply trying to explore options, that I think make some sense and are actually in the can do column and that we can at least start on sometime between now and the near future i.e. the next 10 to 15 years, or less if the technology allows.&nbsp; I don't know what our current launch capability is in terms of mass delivery potential, but I have a feeling it would be wholly inadequate to take on a planet killer that showed up unexpectedly.&nbsp; If strategic pre-positioning isn't the answer, what else could we do in the near term to increase our launch capabilities to the point of standing at least some chance of survival.&nbsp; If the whole world pulled together to build and launch rockets, could we produce enough in 20 months or less to get it done (I have to question that probability)? And given the low probability of an occurrence today or tomorrow how can we&nbsp;craft a strategic solution that provides benefits in other areas like inexpensive access to space to help justify the costs?&nbsp; IMHO we need every conceivable advantage that we can get to even think about surviving an event of this nature.</p><p>Also I apologize to the forum for my lack patience and decorum in dealing with Dr. Rocket.</p> <div class="Discussion_UserSignature"> <p> </p><p>"I am therefore I think" </p><p>"The only thing "I HAVE TO DO!!" is die, in everything else I have freewill" Brian P. Slee</p> </div>