Date: Mon, 4 Mar 1996 08:04:53 -0500To: "L. Parker" <lparker@destin.gulfnet.com>From: kgstar@most.fw.hac.com (Kelly Starks x7066 MS 10-39)Subject: Re: tentative hybrid design.Cc: kgstar@most.fw.hac.com (Kelly Starks x7066 MS 10-39)Bcc: X-Attachments: At 5:59 PM 3/1/96, L. Parker wrote:>At 12:22 PM 3/1/96 -0500, you wrote:>>At near light speed? Wouldn't it at least cause a flare? >Who was the SF author that coined the phrase "c-fractional missiles"? Idon't think even he (or she) quite envisioned THAT much mass at near lightspeed! The venerable E.E. Doc Smith would have appreciated this one... >Lee ParkerCertainly not the most mild mannored way to enter a star system. ;)Kelly===============================================Date: Mon, 4 Mar 1996 08:30:44 -0500To: Brian Mansur <bmansur@oc.edu>From: kgstar@most.fw.hac.com (Kelly Starks x7066 MS 10-39)Subject: Re: MARS HYBRID DESIGN II (First Draft)Cc: interstellar drive group <bmansur@oc.edu>, David<David@InterWorld.com>, hous0042 <hous0042@maroon.tc.umn.edu>,KellySt <KellySt@aol.com>, kgstar <kgstar@most.fw.hac.com>, lparker<lparker@destin.gulfnet.com>, rddesign <rddesign@wolfenet.com>, SteveVanDevender <stevev@efn.org>, "T.L.G.vanderLinden"<T.L.G.vanderLinden@student.utwente.nl>Bcc: X-Attachments: At 4:57 PM 3/1/96, Brian Mansur wrote:>>From Brian>March 1, 1996>Here it is: the detailed design I promised (as detailed as I can make it atthe moment anyway). But first: does the "interstellar drive group"selection that I now see on my address book now account for everyone inthe discussion team? Okay, on with the show. >Note that this is my first draft. The lab is about to close and I have a lotmore ideas to cover but they may have to wait a bit. Things like sailshielding and mirror array design are among them. Sill I'm going to sendwhat I've got to let you all have some fun ripping it apart :) >MARS HYBRID DESIGN II (Kevin already submitted the first this morning) >Total mission time: 50+ years>Pathfinder(s) mission flight time: 40+ years Asimov flight time: 24+years>Asimov exploration phase time: Undetermined If its going to take 50 year to get there. I think people would put it offuntil they could think up a faster ship. Or just lose interest in the project. >ASSUMPTIONS:>It is assumed for this mission plan that a high degree of roboticautomation has already made possible the production of at least 1E18 Wneeded to power 1E7 masers without much human supervision. It is alsoassumed that this maser array is totally dedicated to the mission and thatthe beam will be left throughout the mission. >PHASE 1: LAUNCH OF PATHFINDERS>At least one heavy pathfider vessel will be sent before the Asimov usingmaser sail to reach a terminal velocity of 1/3c. Pathfinder carries severalthousand, heavy duty, heavy weight, individually targetable, disassembledmirror arrays that will be deployed roughly 30 years later near TC (seereflectors in an upcoming posting). These arrays (probably making aneffective 1000 km+ wide reflector) will reflect maser energy back to theAsimov for the deceleration phase. The Pathfinder may or may not have acrew depending on the level of automation available at the time of launch. >Also, it may or may not carry emergency supplies for the Asimov shouldthey choose to match speed and dock during the deceleration phase. Are you assuming the beam would be tight enought to be reflected after 11light years. Not to mention assuming a mirror could hit the ships sail withthe reflected beam, a few light years away? >PHASE 2: LAUNCH OF THE ASIMOV>The Asimov is maser pushed to a high %c terminal velocity. It is hopedthat the maser propulsion system will be efficient enough to push theAsimov to a speed at which the effects of time dialation will be useful tothe crew. At the very least, a max speed of .75c is assumed here. >This ship will consist of an ion drive for in system shuttling around TC.It will also carry the exploration team and their supplies for the mission.Among the supplies already mentioned in other discusions are seed robots.They will be used to start a robot workforce that will help construct,among other things, a precision mirror array to reflect the maser energyfrom Sol back to the Asimov's maser sail when the exploration phase iscompleted.>PHASE 3: DECELERATION OF THE ASIMOV>The exact process has many variations. If there are several Pathfinders,each, the one closest to the Asimov will deploy its reflector array andthen move to a safe range from the beam path. The array will enter thebeam path and redirect the maser energy back to the Asimov. The Asimov,of course, will have turned its sail around (a slow and delicate process). Itwill also have moved slightly to the side the maser beam coming from Solto prevent blocking of the array. I assume 'array' refers to the reflectors on the pathfinders. If the Pathfinders are reflecting the beam off to one side. They will bepushed out of the beam in the other direction, and accelerated forward.Given that the beam presure is strong enough push the ships in the firstplace, it would be to strong for the ships thrust against. >Some method of periodic or even continuous course correction on both theAsimov's part and the array's will be required to correct for the angle atwhich the maser beam must be reflected. The Asimov may simply angle itssail slightly with the edge furtherest from the Sol to array beam tiltedback toward Sol. The array will have to use built in rockets, or else tiltfrom time to time in the proper direction to allow vectorial force to pushit back into the center of the beam.This might be complicated given the main sail would be curved like aparachute, not flat. >Now, assuming that the doplar effect will cause problems with reflectionof the maser beam, another Pathfinder could deploy it's array and continuethe decelation process. Note that I don't know if the most efficient thingthat the Asimov can do with the redirected maser beam will be to simplybounce it back to space or to power a ion drive. The exhaust from an iondrive would make for nice shielding against large particles. >One final note. As the Asimov and Pathfinder speeds reach equilibriumthey have the option of docking (assuming the deceleration of the Asimovbrought it close to the Pathfinder when speed equilibrium was reached. Atthis point, any crew on the Pathfinder could cross over. Note that theAsimov could dock with only one Pathfinder. It could dock with more than one. But that wold depend on their speeds andrelative positions. >PHASE 4: SYSTEM EXPLORATION/CONSTRUCTION OF MASER REFLECTOR >The Asimov enters the Tau Ceti star system's Kupier Belt. At this point itdisassembles its sail and starts scouting for a low gravity, metal richKupier body that is not too far from the maser beam path. Once such a bodyis located, the seed robots are deployed to begin a robot community. >Since the Kupier body will be too far away from Tau Ceti for solar energycollection, it is assumed that the robots will be powered by fusion reactorthat must be brought along (in addition to the fuel). Depending on theautomation technology at the time of launch, these robots will at least beresponsible for construction of a mirror platform needed forreacceleration to Sol.Why so far out? That doesn't sound like and area we'ld want to do most ofour exploring at. So why make the base there? You could fuel the fusion reactors with fuel avalible were you set up theoperations. Again, having a mirror reflect back the beam from sol sems unlikely. Notonly would the sol beam be spread out over huge distences and diffuse. Ifit wasn't soread out a random orbit in the Kuniper belt would quickly driftout of the beam path, and if it stayed in the beam it would be aboutimpossibly to reflect the beam that precisely. >The Asimov leaves the Kupier outpost to continue its exploration of thestar system. Whatever number of crew is needed to oversee constructionstays behind. As the maser reflector nears completion. The array must besomehow weighted down to keep it from flying off. Keeping it tethered tosomething like the weight of Phoboes would be nice but then Sol wouldhave to track it to keep the beam on target. It will probably be better tosimply give it enough weight to prevent it from blowing away too fastwhile reaccelerating the Asimov. I only hope that the required weightwon't be beyond out ability to put to space. Also, this entire array willhave to be able to maintain its position inside the maser beam whichmeans some powerful rockets or some angling of the array as mentioned inPhase 3. >PHASE 5: REACCELERATION OF THE ASIMOV/RETURN TO SOL >This final phase is pretty self-explanitory. The Asimov's sail (havingbeen patched up from the flight to TC we hope) is redeployed is manuveredinto the path of the redirected maser beam. Again, it is hoped that a highterminal velocity will be possible. As the Asimov nears Sol, the array isturned around and the masers focus straight on to the tatered sail. Missionends as the Asimov pulls into the local Starbase. The array is the mirrors on the pathfinders. The whole time the beam ispointing straight at T.C. at the reflectors. The ship is riding that beamstraight back from Tau. I.E. the Tau reflection is shining on its back andthe stronger direct source from sol on its frount. This makes acceleratingout of Tau, much less getting to high speed, very difficult. Kelly===============================================Date: Mon, 4 Mar 1996 15:31:29 -0500To: Brian Mansur <bmansur@oc.edu>From: kgstar@most.fw.hac.com (Kelly Starks x7066 MS 10-39)Subject: Re: MARS HYBRID DESIGN II (First Draft)Cc: Brian Mansur <bmansur@oc.edu>, kgstar <kgstar@most.fw.hac.com>,David <David@InterWorld.com>, hous0042 <hous0042@maroon.tc.umn.edu>,KellySt <KellySt@aol.com>, lparker <lparker@destin.gulfnet.com>, rddesign<rddesign@wolfenet.com>, Steve VanDevender <stevev@efn.org>,"T.L.G.vanderLinden" <T.L.G.vanderLinden@student.utwente.nl>Bcc: X-Attachments: At 1:03 PM 3/4/96, Brian Mansur wrote:>>From Brian,>>>At 4:57 PM 3/1/96, Brian Mansur wrote: From Brian>>>March 1, 1996>>>MARS HYBRID DESIGN II (Kevin already submitted the first this morning) >>>Total mission time: 50+ years>>>Pathfinder(s) mission flight time: 40+ years Asimov flight time: 24+years>>>Asimov exploration phase time: Undetermined >Kelly Says:>>If its going to take 50 year to get there. I think people would put it offuntil they could think up a faster ship. >I'll tell you right now that it will take you at least fifty years to think upand build the support systems for another faster ship. Live with 50 yearsor else we don't go at all!Oh really? It took less than 50 years to go from the Wright Brothers flierto supersonic flight; or from the first mass market cars to the exodusfrom the cities to the constructed subburbias. Come to think of it we arenow celibrating the 50 year of the computer. 50 years is a long time in technology. Also remember that fifty yearswould put this mission into the 22nd century! By then phisisists will havediscovered a lot more tricks then Anti-matter. They might have thought ofwarp drives for all we know. (Well actually they already thought of them,but have no practical idea how to do them.) >>Or just lose interest in the>>project.>Okay, listen up people of America. Unless we can create anti-matter incopius quantities or build a lot more than 1E7 masers plus solar energycollectors to power them all so that we can overcome doplar shift on thereflector, you're going to have to be patient. Half a century really isn'tthat long for this kind of a mission.Thats a very long time to wait around for first initial survey reports! At61 years (2111) you'ld get you first report back from Tau. If you were thatpatient, you wern't that interested. You might as well have just done photorecon from orbiting 1000 kilometer telescope arrays. You'ld get a lot ofthe data, 60 years earlier. If your 60 years patent, you probably arn't interested enough to pay the bigbill for this stuff. >And remember that twenty-five of the fifty+ years will be an unmannedpart of the mission where the slow moving deceleration mirror gets intoposition so that we can send a fast moving ship with the exploration crew.They will take 12+ years to get to TC and 12+ years to get back and Ifigure that they will be there for at least 10. Now if that isn't good enoughfor you, I don't know what is. Just how fast do want to go? Warp speed? ;( >>ASSUMPTIONS:>>It is assumed for this mission plan that a high degree of roboticautomation has already made possible the production of at least 1E18 Wneeded to power 1E7 masers without much human supervision. It is alsoassumed that this maser array is totally dedicated to the mission and thatthe beam will be left throughout the mission. >>PHASE 1: LAUNCH OF PATHFINDERS>>At least one heavy pathfider vessel will be sent before the Asimov usingmaser sail to reach a terminal velocity of 1/3c. Pathfinder carries severalthousand, heavy duty, heavy weight, individually targetable, disassembledmirror arrays that will be deployed roughly 30 years later >near>>TC (see reflectors in an upcoming posting). These arrays (probablymaking an effective 1000 km+ wide reflector) will reflect maser energyback to the Asimov for the deceleration phase. The Pathfinder may or maynot have a crew depending on the level of automation available at the timeof launch. >>Also, it may or may not carry emergency supplies for the Asimov should >they>>choose to match speed and dock during the deceleration phase. >Kelly Says:>>Are you assuming the beam would be tight enought to be reflected after11 light years.>I'm assuming that we can send a mirror the width of Jupiter if we wantedto. >And when I get time to write up the specifics on this idea, you'll see thatthe mirror can actually be thousands of individually targeted mirrorsguided by the same kinds of gyros that Kevin uses to aim the masers. Kev was aiming the beam electronicly, not mechanically. Also givenorbital mechanics your Jupiter sized mirror array would move out of thebeam. I don't know about out in the jovians, but things here at 1AU moveabout a light minutte a week in their orbits. >>Not to mention assuming a mirror could hit the ships sail with thereflected beam, a few light years away? >Remeber the gyros.>>PHASE 2: LAUNCH OF THE ASIMOV>>The Asimov is maser pushed to a high %c terminal velocity. It is hopedthat the maser propulsion system will be efficient enough to push theAsimov to a speed at which the effects of time dialation will be useful tothe crew. At the very least, a max speed of .75c is assumed here. >>This ship will consist of an ion drive for in system shuttling around TC.It will also carry the exploration team and their supplies for the mission.Among the supplies already mentioned in other discusions are seed robots.They will be used to start a robot workforce that will help construct,among other things, a precision mirror array to reflect the >maser>>energy from Sol back to the Asimov's maser sail when the explorationphase is completed.>>PHASE 3: DECELERATION OF THE ASIMOV>>The exact process has many variations. If there are several Pathfinders,each, the one closest to the Asimov will deploy its reflector array andthen move to a safe range from the beam path. The array will enter thebeam path and redirect the maser energy back to the Asimov. The Asimov,of course, will have turned its sail around (a slow and delicate process). Itwill also have moved slightly to the side the maser beam coming from Solto prevent blocking of the array. >Kelly says:>>I assume 'array' refers to the reflectors on the pathfinders. >I just realized that you can launch the reflective mirror without stickingit on a pathfinder. The pathfinder was supposed to just be a convientlyprotected package for the mirror. But if some shielding ideas that I'vebeen kicking around are at all worth our time, we can forego the idea ofthe pathfinder completely.>Kelly Says:>>If the Pathfinders are reflecting the beam off to one side. They will bepushed out of the beam in the other direction, and accelerated forward.Given that the beam presure is strong enough push the ships in the firstplace, it would be too strong for the ships thrust against. >I'm not sure I understand the last sentence. The beam holds the projected momentum needed to push our obserdlyheavy ship. If said ship isn't in the beam, the reflectors in the beam willhave to angle relative to the beam. That will mean that the thrust angleson the reflectors and the receaving ship, will also be angled. Since thethrust isn't paralell to the beam/course. The ship and reflectors will bepushed out to the sides. I.E. off the beam, and off course. ------------\//\-------->Brian Says:>>Some method of periodic or even continuous course correction on boththe Asimov's part and the array's will be required to correct for the angleat which the maser beam must be reflected. The Asimov may simply angleits sail slightly with the edge furtherest from the Sol to array beamtilted back toward Sol. The array will have to use built in rockets, or elsetilt from time to time in the proper direction to allow vectorial force topush it back into the center of the beam.>Kelly Says:>>This might be complicated given the main sail would be curved like aparachute, not flat.>Good point. Of course the angle of vectorial force will be tiny consideringthe reflector and the Asimov are several AU apart. Oh, I forgot you couldn't do that with the reflectors and get the beam tothe ship. Also targeting on a moving ship when you get a few light monthsapart is dangerous. >Brian Says:>>Now, assuming that the doplar effect will cause problems withreflection of the maser beam, another Pathfinder could deploy it's array >and>>continue the decelation process. Note that I don't know if the mostefficient thing that the Asimov can do with the redirected maser beamwill be to simply bounce it back to space or to power a ion drive. Theexhaust from an ion drive would make for nice shielding against largeparticles. >>One final note. As the Asimov and Pathfinder speeds reach equilibriumthey have the option of docking (assuming the deceleration of the Asimovbrought it close to the Pathfinder when speed equilibrium was reached. Atthis point, any crew on the Pathfinder could cross over. Note that theAsimov could dock with only one Pathfinder. >Kelly Writes:>>It could dock with more than one. But that would depend on their speedsand relative positions.>Have to think about that more, I guess. Gotta go to class. I'll finishreplies after 5 CT. Kelly=========================================================Date: Mon, 4 Mar 1996 16:24:01 -0500To: Brian Mansur <bmansur@oc.edu>From: kgstar@most.fw.hac.com (Kelly Starks x7066 MS 10-39)Subject: Re: MARS HYBRID DESIGN II (First Draft)Cc: Brian Mansur <bmansur@oc.edu>, kgstar <kgstar@most.fw.hac.com>,David <David@InterWorld.com>, hous0042 <hous0042@maroon.tc.umn.edu>,KellySt <KellySt@aol.com>, lparker <lparker@destin.gulfnet.com>, rddesign<rddesign@wolfenet.com>, Steve VanDevender <stevev@efn.org>,"T.L.G.vanderLinden" <T.L.G.vanderLinden@student.utwente.nl>Bcc: X-Attachments: At 3:00 PM 3/4/96, Brian Mansur wrote:>>From Brian,>Brian Says:>>PHASE 4: SYSTEM EXPLORATION/CONSTRUCTION OF MASER REFLECTOR >>The Asimov enters the Tau Ceti star system's Kupier Belt. At this pointit disassembles its sail and starts scouting for a low gravity, metal richKupier body that is not too far from the maser beam path. Once such a bodyis located, the seed robots are deployed to begin a robot community. >>Since the Kupier body will be too far away from Tau Ceti for solarenergy collection, it is assumed that the robots will be powered by fusionreactor that must be brought along (in addition to the fuel). Depending onthe automation technology at the time of launch, these robots will atleast be responsible for construction of a mirror platform needed forreacceleration to Sol.>Kelly Says:>>Why so far out? That doesn't sound like and area we'ld want to do mostof our exploring at. So why make the base there? You could fuel the fusionreactors with fuel avalible were you set up the operations.>The reason for putting the base so far out is because whatever Kupierbody we find near the maser beam is going to be orbiting TC very slowly.It will give us time to set up our reflector and get it into position withthe least amount of effort. It just occured to me that if you find an objectfurther inside the system whose orbit would be just right at certain timesto let you do the same thing. Of course that also depends upon the orbitalplane of TC.Object that far out areactually moving faster than orbits closer in. Theyjust have farther to go. You also have to remember that if the beam ispowerfull enough to push the ship at 10m/s, it will push the lightermirror faster. Good point about the orbital plane. Ods are Sol won't be in it. >Let me see if I can make this more clear. Once the mirror is built, it willhave to be put into the maser beam and it will have to be able to staythere. So any orbital momentum it has must be overcome by either rocketsor the acceleration force of the maser. Let's face it. We won't have enoughtime to weight the mirror down enough to keep it from accelerating. Butby putting the reflector in deep space, it should also be relatively free ofgravitation distraction from TC and other objects, at least until it getsfast enough that it won't matter. So in some ways the acceleration isgood. >About getting fusion fuel from the rock we're already mining. We mightbe able to if we can build a surplus of robot workers. As I pointed out inthe summary intro, this whole mission depends on a revolutionary degreeof automation.>Kelly Says:>>Again, having a mirror reflect back the beam from sol sems unlikely. Notonly would the sol beam be spread out over huge distences and diffuse. Ifit wasn't soraed out a random orbit in the Kuniper belt would quickly driftout of the beam path, and if it stayed in the beam it would be aboutimpossibly to reflect the beam that precisely. >See above for how we plan to tackle this problem. Also, the mirrorcomponents might be equiped with rockets. Not only do they adjustposition, but they add weight as well. On the downside, they are also yetanother item that must be built in system.>I'm beginning to see that if we can do all the things I'm saying we'regoing to have to, we might just go ahead and make another maser arraycomplete with solar energy collectors. The whole reason for botheringwith a reflective mirror is to give the Asimov something that is supposedto be simpler to assemble at TC than a maser array. So unless ourautomation is almost 100% automated, we're not going to get muchexploring done. >Unfortunately, I'd don't see a better alternative on the table than todevelope this automation.>That reminds me of a quote: "So you say you want a revolution. Well youknow. We don't want to change the world but . . . well, all right." >>The Asimov leaves the Kupier outpost to continue its exploration of >the>>star system. Whatever number of crew is needed to oversee constructionstays behind. As the maser reflector nears completion. The array must besomehow weighted down to keep it from flying off. Keeping it tethered tosomething like the weight of Phoboes would be nice but then Sol wouldhave to track it to keep the beam on target. It will probably be better tosimply give it enough weight to prevent it from blowing away too fastwhile reaccelerating the Asimov. I only hope that the required weightwon't be beyond out ability to put to space. Also, this entire array willhave to >be>>able to maintain its position inside the maser beam which means somepowerful rockets or some angling of the array as mentioned in Phase 3. >>PHASE 5: REACCELERATION OF THE ASIMOV/RETURN TO SOL >>This final phase is pretty self-explanitory. The Asimov's sail >(having>>been patched up from the flight to TC we hope) is redeployed ismanuvered into the path of the redirected maser beam. Again, it is hopedthat a high terminal velocity will be possible. As the Asimov nears Sol,the array is turned around and the masers focus straight on to the tateredsail. >Mission>>ends as the Asimov pulls into the local Starbase. >Kelly says:>>The array is the mirrors on the pathfinders. >No, the pathfinders are history (somewhere in deep, deep space by now)and the deceleration arrays are with them.>Kelly says:>>The whole time the beam is>>pointing straight at T.C. at the reflectors. The ship is riding that beamstraight back from Tau. I.E. the Tau reflection is shining on its back andthe stronger direct source from sol on its frount. This makes acceleratingout of Tau, much less getting to high speed, very difficult. >I left out the detail of saying that the Asimov will again be riding theredirected be just to the side of the incoming beam from Sol, thusavoiding the drag your worried about. And, of course, we'll have to makecourse corrections on the Asimov and the reflector. >I'll go ahead and put a few ideas I had for mirror and ship coursecorrections here. We could have the Asimov detach its ion drive and cableconnect it to an edge of the wire mesh sail and the hab section. The drivecould then gently pull the whole set up back onto the beam path. We couldalso, perhaps have the maser array at Sol periodically decrease power toallow this tug to do its job without being microwave fried. We would haveto do something about shielding the tug, of course. >Perhaps the tug could be a pair light rockets hanging onto opposite sidesof >1000km+ wide sail. They could have their own shielding and would be inexcellent positions to do their jobs.You have to remember these tugs would have to pump out thousands, tohundreds of thousands of tons of thrust. That's too much to just hang offthe sail. Kelly=============================================================Date: Tue, 5 Mar 1996 08:36:33 -0500To: David@interworld.com (David Levine)From: kgstar@most.fw.hac.com (Kelly Starks x7066 MS 10-39)Subject: Re: MARS HYBRID DESIGN II (First Draft)Cc: Kelly Starks x7066 MS 10-39 <kgstar@most.fw.hac.com>, Brian Mansur<bmansur@oc.edu>, hous0042 <hous0042@maroon.tc.umn.edu>, KellySt<KellySt@aol.com>, lparker <lparker@destin.gulfnet.com>, rddesign<rddesign@wolfenet.com>, Steve VanDevender <stevev@efn.org>,"T.L.G.vanderLinden" <T.L.G.vanderLinden@student.utwente.nl>Bcc: X-Attachments: At 4:35 PM 3/4/96, David Levine wrote:>Kelly Starks x7066 MS 10-39 wrote:>>Thats a very long time to wait around for first initial survey reports! At61 years (2111) you'ld get you first report back from Tau. If you were thatpatient, you wern't that interested. You might as well have just done photorecon from orbiting 1000 kilometer telescope arrays. You'ld get a lot ofthe data, 60 years earlier.>>If your 60 years patent, you probably arn't interested enough to pay thebig bill for this stuff.>I agree. If you launch a mission that will not return scientific results inyour lifetime (assume you are in your 30s or 40s when you send themission off), most people would probably just say "why not let them do it-then-, instead?" >The payoff is too distant for most corporations, and the bill too big forgovernments to justify to the people when considering the length of timeinvolved. >If we can't do it faster, we're not going to do it. I'm tending toward the steping stone idea. Try a few of the near by starsnow, and strech when you can. >Too bad we don't have a target system with already-contacted ETs.Deceleration seems to be our biggest problem. They could construct an in-system maser decelerator... Of course, assuming they trusted us. I don'tknow what we'd do if an alien civilization contacted us and asked us tobuild a maser array to decelerate their spacecraft.>Interestingly, many people say that interstellar travel is so amazinglydifficult (and we are seeing part of it) that it won't be accomplished formillenia, if at all. One of the responses to the Fermi Paradox. But lately Ithink we'd agree that interstellar travel is, in fact, possible, but athorrendous cost. If we had a pre-existing deceleration system (i.e.cooperative aliens in the target system), however, interstellar travel mayactually not be too difficult. It makes me think of an area of the galaxywhere civilizations may arise frequently, and there is some sort of traderoute set up with masers. You could travel easily between stars if therewere lots of aliens around... But, if (like us) you seem to be alone, youmight be stuck at home. Interesting paradox - if there are places tocolonize, you can't go there. If everywhere is filled up already, you can gothere. >Just rambling.>DavidYeah.Interesting point about Star travel. The whole idea of the radio search ofthe galaxy is that phyisical star travel is impossible. So civilizationswould have to content themselves with randomly transmiting (possibly forhundreds of thousands of years!), until someone in the galaxy decides tolisten and reply. We have shown that it is possible; not practical yet, butpossible. Given that what civilization would wait hundreds of thousands ofyears for an answer, when they could just go look for themselves. So in a way, we haven't come up with a doable concept yet, but we've donebetter than Carl Sagen and friends. Kelly=======================================================Date: Tue, 5 Mar 1996 09:15:22 -0500To: Brian Mansur <bmansur@oc.edu>From: kgstar@most.fw.hac.com (Kelly Starks x7066 MS 10-39)Subject: Re: MARS HYBRID DESIGN II (First Draft)Cc: kgstar <kgstar@most.fw.hac.com>, David <David@InterWorld.com>,hous0042 <hous0042@maroon.tc.umn.edu>, KellySt <KellySt@aol.com>,lparker <lparker@destin.gulfnet.com>, rddesign <rddesign@wolfenet.com>,Steve VanDevender <stevev@efn.org>, "T.L.G.vanderLinden"<T.L.G.vanderLinden@student.utwente.nl>Bcc: X-Attachments: At 3:39 PM 3/4/96, Brian Mansur wrote:>>From Brian 3:34 PM CT 3/4/96>At 1:03 PM 3/4/96, Brian Mansur wrote:>>>From Brian,>>>>At 4:57 PM 3/1/96, Brian Mansur wrote: From Brian>>>>March 1, 1996>>>>MARS HYBRID DESIGN II (Kevin already submitted the first thismorning) >>>>Total mission time: 50+ years>>>>Pathfinder(s) mission flight time: 40+ years Asimov flight time: 24+years>>>>Asimov exploration phase time: Undetermined >>Kelly Says:>>>If its going to take 50 year to get there. I think people would put it >off>>>until they could think up a faster ship. >>Brian Says:>>I'll tell you right now that it will take you at least fifty years to thinkup and build the support systems for another faster ship. Live with 50years or else we don't go at all!>Kelly Says:>>Oh really? It took less than 50 years to go from the Wright Brothersflier to supersonic flight; or from the first mass market cars to theexodus from the cities to the constructed subburbias. Come to think of itwe are now celibrating the 50 year of the computer. >>50 years is a long time in technology. Also remember that fifty yearswould put this mission into the 22nd century! By then phisisists will havediscovered a lot more tricks then Anti-matter. They might have thought ofwarp drives for all we know. (Well actually they already thought of them,but have no practical idea how to do them.) >Okay, to avoid a hashed argument (and I apologize for coming down sohard on my time comment), I concede to your point of possibly being ableto build something faster. It sounds like your idea is improbable but thenI'm proposing that we'll be able to create near 100% autonomous robotworkforces. I'm only saying that, right now, this hybrid idea is the best Ican think of. Of course, as your argument hints, who knows but we mightbe able ourselves to find something better given a few more weeks ormonths. >Brian Says:>>>Or just lose interest in the>>>project.>>Okay, listen up people of America. Unless we can create anti-matter incopius quantities or build a lot more than 1E7 masers plus solar energycollectors to power them all so that we can overcome doplar shift on thereflector, you're going to have to be patient. Half a century really isn'tthat long for this kind of a mission.>Kelly Says:>>Thats a very long time to wait around for first initial survey reports! At61 years (2111) you'ld get you first report back from Tau. If you were thatpatient, you wern't that interested. You might as well have just done photorecon from orbiting 1000 kilometer telescope arrays. You'ld get a lot ofthe data, 60 years earlier.>I see where our differences in opinion are coming from. You and I havedifferent ideas as to what a kind of human universe this hybrid idea willbe taking form. And I admit that it is my fault here because you aresticking to the LIT charter and I'm not qualifying my designs by notingthat I am not limiting my technology to what would be available to 2050.Sorry. Thats ok. Its an old argument in the group. As I mentioned in those draftweb pages I sent around (and got no responce to!). If you slip the timetable to a cetury from now, you have to start guessing what newtechnologies, and Physcics! will be avalible. A hundred years ago Fusion,fission, relativity, momentum transfer of momentum, and a bunch morewere not enve theories. Physisists (sp?) are currently mutering aboutinertian and kinetic energy (i.e. what the hell are they), mater conversion,controled distortion of space and time, alternate dimentions, faster thanlight travel, and even freakier stuff. By 2050 a lot of these mutteringswill be hardened theories, and our designs will look like a Saturn-V thesize of a mountain fueled by burning coal. But, if you don't know what we'll get, you got to plan conservativly. >As for using 1000 km telescope arrays to scan TC. Given the level oftechnology and space infrastructure that I think any of our close toworkable designs are needing, we would have done that already. >Question. Isn't there a wavelength resolution limiting how much detailyou can gather on distant objects. What I'm wondering is whether or nottelescopes have the same limitations that light microscopes have whentrying to view objects with detail smaller than the wavelength (in nm) ofthe object they are observing.The wave length limit would be the same. We couldn't resolve objectssmaller than a wavelength of light. Not that thats a big issue in studinginterstellar planets. ;) >Kelly Says:>>If your 60 years patent, you probably arn't interested enough to pay thebig bill for this stuff.>With the amount of automation I'm assuming here, its the robots who willbe paying the bill. And they don't care (we hope given depending if AI's areneeded for my ideas).>>And remember that twenty-five of the fifty+ years will be an unmannedpart of the mission where the slow moving deceleration mirror gets intoposition so that we can send a fast moving ship with the exploration crew.They >will>>take 12+ years to get to TC and 12+ years to get back and I figure that >they>>will be there for at least 10. Now if that isn't good enough for you, Idon't know what is. Just how fast do want to go? Warp speed? ;( >>>ASSUMPTIONS:>>>It is assumed for this mission plan that a high degree of roboticautomation has already made possible the production of at least 1E18 Wneeded to power 1E7 masers without much human supervision. It is alsoassumed that this maser array is totally dedicated to the mission and thatthe beam will be left throughout the mission. >>>PHASE 1: LAUNCH OF PATHFINDERS>>>At least one heavy pathfider vessel will be sent before the Asimovusing maser sail to reach a terminal velocity of 1/3c. Pathfinder >carries>>>several thousand, heavy duty, heavy weight, individually targetable,disassembled mirror arrays that will be deployed roughly 30 years later >>near>>>TC (see reflectors in an upcoming posting). These arrays (probablymaking an effective 1000 km+ wide reflector) will reflect maser energyback to >the>>>Asimov for the deceleration phase. The Pathfinder may or may not havea crew depending on the level of automation available at the time oflaunch. >>>Also, it may or may not carry emergency supplies for the Asimov should >>they>>>choose to match speed and dock during the deceleration phase. >>Kelly Says:>>>Are you assuming the beam would be tight enought to be reflected after11 light years.>>Brian Says:>>I'm assuming that we can send a mirror the width of Jupiter if wewanted >to.>>And when I get time to write up the specifics on this idea, you'll see >that>>the mirror can actually be thousands of individually targeted mirrors >guided>>by the same kinds of gyros that Kevin uses to aim the masers. >>Kelly Says>>Kev was aiming the beam electronicly, not mechanically. Also givenorbital mechanics your Jupiter sized mirror array would move out of thebeam. I don't know about out in the jovians, but things here at 1AU moveabout a light minutte a week in their orbits.>Brian Says:>If the reflector is construction at Kupier Belt distance, it won't bemoving any faster than Pluto. That is until we put the mirror into thebeam path. >Then it will slowly accelerate. With relatively minor course corrections,it will stay in the beam.Pluto moves MUCH faster than Earth. Your mirror would quickly move outof the beam. even if the beam was larger than Earths orbit. >>>Kelly Says:>>>Not to mention assuming a mirror could hit the ships sail with thereflected beam, a few light years away? >>Brian Says:>>Remeber the gyros.>>>PHASE 2: LAUNCH OF THE ASIMOV>>>The Asimov is maser pushed to a high %c terminal velocity. It is hopedthat the maser propulsion system will be efficient enough to push >the>>>Asimov to a speed at which the effects of time dialation will be usefulto the crew. At the very least, a max speed of .75c is assumed here. >>>This ship will consist of an ion drive for in system shuttling around TC.It will also carry the exploration team and their supplies for the mission.Among the supplies already mentioned in other discusions are >seed>>>robots. They will be used to start a robot workforce that will helpconstruct, among other things, a precision mirror array to reflect the >>maser>>>energy from Sol back to the Asimov's maser sail when the explorationphase is completed.>>>PHASE 3: DECELERATION OF THE ASIMOV>>>The exact process has many variations. If there are severalPathfinders, each, the one closest to the Asimov will deploy its reflectorarray and then move to a safe range from the beam path. The array willenter the beam path and redirect the maser energy back to the Asimov. TheAsimov, of course, will have turned its sail around (a slow and delicateprocess). It will also have moved slightly to the side the maser beamcoming from Sol to prevent blocking of the array. >>Kelly says:>>>I assume 'array' refers to the reflectors on the pathfinders. >>Brian Says:>>I just realized that you can launch the reflective mirror withoutsticking it on a pathfinder. The pathfinder was supposed to just be aconviently protected package for the mirror. But if some shielding ideasthat I've been kicking around are at all worth our time, we can forego theidea of >the>>pathfinder completely.Then how do you slow down the packaged mirrors without the pathfinderrockets? Or is this the expendable set? I'm confused. >>Kelly Says:>>>If the Pathfinders are reflecting the beam off to one side. They will bepushed out of the beam in the other direction, and accelerated forward.Given that the beam presure is strong enough push the ships in the firstplace, it would be too strong for the ships thrust against. >>Brian Says:>>I'm not sure I understand the last sentence. >>Kelly Says:>>The beam holds the projected momentum needed to push our obserdlyheavy ship. If said ship isn't in the beam, the reflectors in the beam willhave to angle relative to the beam. That will mean that the thrust angleson the reflectors and the receaving ship, will also be angled. Since thethrust isn't paralell to the beam/course. The ship and reflectors will bepushed out to the sides. I.E. off the beam, and off course. >------------\>/>/>\-------->Brian Says:>Understood as inevitable. Here are some ideas I put into an e-mail sent toyou just a little earlier today which address the problem. Begin Excerpt>I'll go ahead and put a few ideas I had for mirror and ship coursecorrections here. We could have the Asimov detach its ion drive and cableconnect it to an edge of the wire mesh sail and the hab section. The drivecould then gently pull the whole set up back onto the beam path. We couldalso, perhaps have the maser array at Sol periodically decrease power toallow this tug to do its job without being microwave fried. We would haveto do something about shielding the tug, of course. >Perhaps the tug could be a pair light rockets hanging onto opposite sidesof >1000km+ wide sail. They could have their own shielding and would be inexcellent positions to do their jobs.>End ExcerptHanging them on the sails doesn't matter. The weight after all is in theship, not the sail. Given the power levels of the beam, the lateral thrusters on the ship andmirror assembly would need to be incredable. Possibly prohibativly so. >>Brian Says:>>>Some method of periodic or even continuous course correction on boththe Asimov's part and the array's will be required to correct for the >angle>>>at which the maser beam must be reflected. The Asimov may simplyangle >its>>>sail slightly with the edge furtherest from the Sol to array beam tiltedback toward Sol. The array will have to use built in rockets, or else >tilt>>>from time to time in the proper direction to allow vectorial force topush it back into the center of the beam.>>Kelly Says:>>>This might be complicated given the main sail would be curved like aparachute, not flat.>>Brian Says:>>Good point. Of course the angle of vectorial force will be tiny >considering>>the reflector and the Asimov are several AU apart. >>Kelly Says:>>Oh, I forgot you couldn't do that with the reflectors and get the beam tothe ship.>Brian Says:>Huh? I don't understand this.If you angle the mirrors to counter thrust you back into the beam, you'ld bereflecting the beam away from the ship not toward it. Trying to anticipatewhere the ship is relative to the mirror array would be a problem too. Themirrors obviously can't 'aim' in the conventional sence due to the timedelay. You might try a secondary set of sails rigged to provide lateral thrust.After all. Only a tiny fraction of the beam will hit the reflectors (Thebeam would after all be pretty spread out), and only a fraction of thereflected beam would hit the main sail (since you can't aim accuratly,shotgun the area). >>Kelly Says:>>Also targeting on a moving ship when you get a few light months apartis dangerous.>Brian Says:>See my above question on just how well Kev's gyroes could be adapted towork for mechanical reflection. If this isn't solvable for aiming mirrrors,I guess its back to the drawing board.=============================================================Date: Tue, 5 Mar 1996 09:21:21 -0500To: Brian Mansur <bmansur@oc.edu>From: kgstar@most.fw.hac.com (Kelly Starks x7066 MS 10-39)Subject: Re: MARS HYBRID DESIGN II (First Draft)Cc: kgstar <kgstar@most.fw.hac.com>, David <David@InterWorld.com>,hous0042 <hous0042@maroon.tc.umn.edu>, KellySt <KellySt@aol.com>,lparker <lparker@destin.gulfnet.com>, rddesign <rddesign@wolfenet.com>,Steve VanDevender <stevev@efn.org>, "T.L.G.vanderLinden"<T.L.G.vanderLinden@student.utwente.nl>Bcc: X-Attachments: At 3:48 PM 3/4/96, Brian Mansur wrote:>>From Brian At 3:45 CT 3/4/96>>At 3:00 PM 3/4/96, Brian Mansur wrote: >>>From Brian,>>Brian Says:>>>PHASE 4: SYSTEM EXPLORATION/CONSTRUCTION OF MASER REFLECTOR >>>The Asimov enters the Tau Ceti star system's Kupier Belt. At this pointit disassembles its sail and starts scouting for a low gravity, >metal>>>rich Kupier body that is not too far from the maser beam path. Oncesuch >a>>>body is located, the seed robots are deployed to begin a robotcommunity. >>>Since the Kupier body will be too far away from Tau Ceti for solarenergy collection, it is assumed that the robots will be powered by fusion >reactor>>>that must be brought along (in addition to the fuel). Depending on theautomation technology at the time of launch, these robots will at least beresponsible for construction of a mirror platform needed for >reacceleration>>>to Sol.>>Kelly Says:>>>Why so far out? That doesn't sound like and area we'ld want to do mostof our exploring at. So why make the base there? You could fuel the fusionreactors with fuel avalible were you set up the operations.>>Brian Says:>>The reason for putting the base so far out is because whatever Kupierbody we find near the maser beam is going to be orbiting TC very slowly.It >will>>give us time to set up our reflector and get it into position with the >least>>amount of effort. It just occured to me that if you find an object furtherinside the system whose orbit would be just right at certain times to letyou do the same thing. Of course that also depends upon the orbital planeof TC.>>Kelly Says:>>Object that far out areactually moving faster than orbits closer in. Theyjust have farther to go. You also have to remember that if the beam ispowerfull enough to push the ship at 10m/s, it will push the lightermirror faster.>Brian Says: I'm sick of writing says. From now on its just the name of theperson.>Brian:>Doh! Oh well. Guess that just means that we'll have to use an extra100,000 tons of fuel to slow the array down to keep it inside the beam.You know, when I joined LIT I really never thought that getting to anotherstar system would be so hard. Back then I thought you could just say"engage" and the engines would start up and "whosh." You'd be there afterthe commercial break. Ugh!Yeah, reality sucks some times. MOst of LIT thought we'ld have the drivesystems ironed out in a couple of months. That was nearly 2 years ago. >[Much discusion deleted]>Brian:>>I'll go ahead and put a few ideas I had for mirror and ship coursecorrections here. We could have the Asimov detach its ion drive and cableconnect it to an edge of the wire mesh sail and the hab section. The drivecould then gently pull the whole set up back onto the beam path. We couldalso, perhaps have the maser array at Sol periodically decrease power toallow this tug to do its job without being microwave fried. We would haveto do something about shielding the tug, of course. >>Perhaps the tug could be a pair light rockets hanging onto opposite sides >of>>1000km+ wide sail. They could have their own shielding and would be inexcellent positions to do their jobs.>Kelly:>>You have to remember these tugs would have to pump out thousands, tohundreds of thousands of tons of thrust. That's too much to just hang offthe sail.>Okay, new twist. Leave the blasted maser beam on full and use powerfrom the masers to convert to electricity and let the tug boat ionaccelerator eat cake (the kind made up of one ion variety of course). Youcan tell I'm getting frustrated here.Many sore head ponding on this wall. We certainly didn't come up with thiscrazy interstellar microwave beam sail trick because it sounded easy! Kelly=========================================================Date: Tue, 5 Mar 1996 09:28:33 -0500To: Brian Mansur <bmansur@oc.edu>From: kgstar@most.fw.hac.com (Kelly Starks x7066 MS 10-39)Subject: Re: MARS HYBRID DESIGN II (First Draft)Cc: David <David@interworld.com>, Kelly Starks x7066 MS 10-39<kgstar@most.fw.hac.com>, hous0042 <hous0042@maroon.tc.umn.edu>,KellySt <KellySt@aol.com>, lparker <lparker@destin.gulfnet.com>, rddesign<rddesign@wolfenet.com>, Steve VanDevender <stevev@efn.org>,"T.L.G.vanderLinden" <T.L.G.vanderLinden@student.utwente.nl>Bcc: X-Attachments: At 4:12 PM 3/4/96, Brian Mansur wrote:>---------->From: David>To: Kelly Starks x7066 MS 10-39>Cc: Brian Mansur; hous0042; KellySt; lparker; rddesign; SteveVanDevender; T.L.G.vanderLinden>Subject: Re: MARS HYBRID DESIGN II (First Draft) Date: Monday, March 04,1996 4:35PM>Brian 4:08 CT 3/4/96>Kelly Starks x7066 MS 10-39 wrote:>>Thats a very long time to wait around for first initial survey reports! >At>>61 years (2111) you'ld get you first report back from Tau. >Brian:>Actually, it will take 50 years. That assumes 35 to 40 years from thetime of the deceleration mirror launch to the final deceleration of theAsimov. >Remember that the Asimov will be launching just 15 to 25 years afterthe reflector has been sent up before it. After final deceleration andexploration begins, the first survey reports will be received 12 yearslater around the year 2100 (assuming a decel reflector launch date of2050 which I am not).Opps, were sorry.>I would like to point out that I haven't seen an answer to my questionabout the doplar shift effect on a fast moving reflector. If the doplareffect simply decreases efficiency of the beam before it reaches theAsimov, that can be compensated for by using more power. Of course thatmeans building more solar panels and masers but then I'm assumingincreadible automation capability where there is virtually no human cost. Don't have numbers, but yes the shift will whipe out most of the power. >>Kelly:>>If you were>>that patient, you wern't that interested. You might as well have just >done>>photo recon from orbiting 1000 kilometer telescope arrays. You'ld get alot of the data, 60 years earlier.>>If your 60 years patent, you probably arn't interested enough to pay thebig bill for this stuff.>>David:>>I agree. If you launch a mission that will not return scientific results inyour lifetime (assume you are in your 30s or 40s when you send themission off), most people would probably just say "why not let them do it-then-, instead?" >>The payoff is too distant for most corporations, and the bill too big forgovernments to justify to the people when considering the length of timeinvolved. >Brian:>Who was that one European prince that started looking for a route toIndia by sailing around Africa? Didn't it take about 50 years for his dreamto come true. And that after he died? Of course most of us aren't thatpatient.They never made it to China. Ironicly the Chineese were coming around theother side of Africa at the same time. They gave up because the outsideworld was full of infearious that wern't worth talking to. (The governmentalso though sailers were to uppity.) So they never made it to europe. None of them of course is used to the tech of ten years from now beingdrasticly better than that of now. We KNOW we will be able to do it muchbetter later. >David:>>If we can't do it faster, we're not going to do it. >Brian:>This lack of patience on the part of human society is starting really tobug me. Of course I've no right to complain seeing as how I should havebeen patient enough to do my Calculus before replying to these e-mails. Its not a limitation. Its just not trying to be stupid and wastfull. >>David:>>Too bad we don't have a target system with already-contacted ETs.Deceleration seems to be our biggest problem. They could construct an in-system maser decelerator... Of course, assuming they trusted us. I don'tknow what we'd do if an alien civilization contacted us and asked us tobuild a maser array to decelerate their spacecraft.>Perhaps let them come but I'd certainly make sure that they'd have to gothrough serious customs checks before we let them anywhere near Earth. >Can't have illegal aliens running about now can we? ;)Kelly===========================================================Date: Tue, 5 Mar 1996 11:26:50 -0500To: Brian Mansur <bmansur@oc.edu>From: kgstar@most.fw.hac.com (Kelly Starks x7066 MS 10-39)Subject: Re: Mirrors (first draft)Cc: David <David@InterWorld.com>, hous0042<hous0042@maroon.tc.umn.edu>, jim <jim@bogie2.bio.purdue.edu>, KellySt<KellySt@aol.com>, kgstar <kgstar@most.fw.hac.com>, lparker<lparker@destin.gulfnet.com>, rddesign <rddesign@wolfenet.com>, SteveVanDevender <stevev@efn.org>, "T.L.G.vanderLinden"<T.L.G.vanderLinden@student.utwente.nl>, zkulpa<zkulpa@zmit1.ippt.gov.pl>Bcc: X-Attachments: At 5:12 PM 3/4/96, Brian Mansur wrote:>Brian 5:10 CT 3/4/96>Okay, here it is. The mirror paper.>First off. I'd like to thank everyone for the comments on the MARS HybridII (first draft). Although it has been mangled and shot through, I think itstill has a chance of working. This is because I'm already assuming amiracle in robotics to make it happen. Why not a few more? But to make itmore believable, here are some ideas on the mirrors to perhaps add (oreliminate) credibility.>MASER BEAM REDIRECTING MIRROR:>This component of my hybrid design was originally meant to bedisassembled and launched aboard a protective pathfinder shell. This isbecause the mirror will have to be precision crafted to reflect maserenergy back to the Asimov during its deceleration phase. Whether or notthe mirror will be curved overall I am not knowledgable enough todetermine. But to allow flexiblitity for the design, I planned on making theentire mirror a composite of individually targetable mirrors of say 10kmto a side. Thats kind of the problem with these big structures. They won't stayprecice under these loads. They will flex. Probably need to be flexible likefabric. >Since the total reflective area will span a diameter of at least 1000km,this mirror will also have to be extremely thin. I figure that by the timewe decide to launch this mission, we should have come up with somesuperstrong, superlightweight plastics for the support structure andreflective surface. This is necessary to make this array light enough topush. A point of confusion for me is just what a microwave reflectorwould be like in terms of the reflective surface. I have heard that areflective sail could be made like chicken wire with spaces of say 1 mmbetween wires. >That would certainly lighten the load.A looser mesh than that, possibly up to 1/2 cm mesh. But varies alotdepeding on transmitted frequency and dopler shift. >Refiguring my reflector ideas, I decided that the mirror could beprotected against the interstellar debris using a lightweight solid shield. >See Shielding below for an explanation. If this can be accomplished, thenwe could use the mirror as its own sail, pushing it via masers. It would beheavy but that is actually good because it means less acceleration duringthe Asimov's decel phase and so less distance between the two to aimacross. >Aiming the array would be accompished by applying the same kinds ofgyros that are employed on the masers to keep the beams on target fromthe Sol end. I hope this is adaption can be made because my entiredeceleration scheme really depends on it. I note that these gyros will needsome kind of protection from the maser beam and that is something I'venot yet worked out.>In flight course corrections will be needed for this reflector to work.This will have to be accomplished with onboard rockets. Just howpowerful they must be and how much fuel they must carry depends on howlight we can get the mirror structure. If the mirror is chicken wire, thisshouldn't be much of a problem.>SHIELDING:>Here's my proposal on shielding. Make a bag out of chicken wire and fill itwith superlightweight ping pong balls or with a superlightweight foam.These substances would act like a dust or gas barrier but would stayinside the bag. Anything that hits the bag will probably cause a sizableexplosion so replenishment of these materials will be needed. Robots canscout the surface of the bag to patch and reknit gaping holes. The size ofthe bag depends on how much shielding we want. >It just occured to me that this idea may not work very well because thechemical structural of the pp balls or the foam will probably be altered bythe tremendous heat from collisions. Kelly, I believe, had proposed keepinga plasma in a bag several km in thickness. I don't know how to containplasma in such a thin bag as chicken wire even it the wire was producing ahefty field. Also, how do we keep the plasma a plasma. How about a "less"energetic charged dust cloud. Would that stay in a magnetic field better? >Could we keep it charged. Wouldn't we have static electricity problems? My shield wasn't a plasma shield. I just assumed the ship launched a cloudof electrostatically charged dust ahead of the ship. Given the charge. Thecloud would spread out a bit, but wouldn't clump up on the ship. Dustplowing back past the ship would need to be scooped up before it got outpast the sides, and relaunched forward. On the other hand your huge frontal area mirrors wouldn't need to worryabout that. You might even just ignore the shield and assume a certain % ofthe mirror mesh will be eroded during the flight, and carry extra mirrors. >So much for bolstering my hybid design. By the way. From now on I'mgoing to officially call it an ARGOSY class starship. Since I'll probablyhave nothing better to do over spring break (like relaxing?), I'll see if Ican improve my design. Expect to see a lot of ideas borrowed from theExplorer design. I should at least be able to give the group a decentdescription along with a critic of the problems associated with the thing.Oh, and a long list of assumptions as well.Great! I was hoping we'ld get a fleet of compeating ship designs! We cantry to cross link our pages when they are uploaded by Dave. Let me know if you want copies or help.Kelly==========================================================Date: Tue, 5 Mar 1996 11:41:23 -0500To: Brian Mansur <bmansur@oc.edu>From: kgstar@most.fw.hac.com (Kelly Starks x7066 MS 10-39)Subject: Re: MARS HYBRID DESIGN II (First Draft)Cc: David <David@interworld.com>, kgstar <kgstar@most.fw.hac.com>,Brian Mansur <bmansur@oc.edu>, hous0042 <hous0042@maroon.tc.umn.edu>,KellySt <KellySt@aol.com>, lparker <lparker@destin.gulfnet.com>, rddesign<rddesign@wolfenet.com>, Steve VanDevender <stevev@efn.org>,"T.L.G.vanderLinden" <T.L.G.vanderLinden@student.utwente.nl>Bcc: X-Attachments: At 10:03 AM 3/5/96, Brian Mansur wrote:>Brian 9:56 CT 3/5/96>David:>>Just rambling.>>David>Kelly>>Yeah.>>Interesting point about Star travel. The whole idea of the radio search ofthe galaxy is that phyisical star travel is impossible. So civilizationswould have to content themselves with randomly transmiting (possibly forhundreds of thousands of years!), until someone in the galaxy decides tolisten and reply. We have shown that it is possible; not practical yet, butpossible. Given that what civilization would wait hundreds of thousands ofyears for an answer, when they could just go look for themselves.>>So in a way, we haven't come up with a doable concept yet, but we'vedone better than Carl Sagen and friends.>Brian>So how does it feel to be on the cutting edge ;) of starship design? What'ssad is that we are the only ones who really look at this problem from atleast a semi-real perspective. And whats sadder is that we're finding thatwe have to be completely unrealistic (by today's tech standards) to thinkup anything that would get us to TC.Well there have been some serious attempt to do this. They ran into mostof the same problems. But, we've stuck at it longer, and are more widelyvisible given the web. So we might keep more discusion going. Kelly================================================================Date: Tue, 5 Mar 1996 11:43:09 -0500To: Brian Mansur <bmansur@oc.edu>From: kgstar@most.fw.hac.com (Kelly Starks x7066 MS 10-39)Subject: Re: MARS HYBRID DESIGN II (First Draft)Cc: David <David@interworld.com>, Kelly Starks x7066 MS 10-39<kgstar@most.fw.hac.com>, Brian Mansur <bmansur@oc.edu>, hous0042<hous0042@maroon.tc.umn.edu>, KellySt <KellySt@aol.com>, lparker<lparker@destin.gulfnet.com>, rddesign <rddesign@wolfenet.com>, SteveVanDevender <stevev@efn.org>, "T.L.G.vanderLinden"<T.L.G.vanderLinden@student.utwente.nl>Bcc: X-Attachments: At 10:21 AM 3/5/96, Brian Mansur wrote:>Brian 10:15 CT 3/5/96>>Kelly Starks x7066 MS 10-39 wrote:>>Pluto moves MUCH faster than Earth. Your mirror would quickly move outof the beam. even if the beam was larger than Earths orbit. >>David>>Pluto's mean orbital velocity is 4.74 km/sec. Earth's mean orbitalvelocity is 29.79 km/sec. >Why is the mean orbital velocity of Pluto 4.74 compared to a much larger29.79. Did you get the numbers mixed up. I'm confused. So am I. This does fit with my understanding and exerience with orbitalmechanics. Kelly==========================================================Date: Tue, 5 Mar 1996 12:50:32 -0500To: Brian Mansur <bmansur@oc.edu>From: kgstar@most.fw.hac.com (Kelly Starks x7066 MS 10-39)Subject: Re: MARS HYBRID DESIGN II (First Draft)Cc: Brian Mansur <bmansur@oc.edu>, kgstar <kgstar@most.fw.hac.com>,David <David@InterWorld.com>, hous0042 <hous0042@maroon.tc.umn.edu>,KellySt <KellySt@aol.com>, lparker <lparker@destin.gulfnet.com>, rddesign<rddesign@wolfenet.com>, Steve VanDevender <stevev@efn.org>,"T.L.G.vanderLinden" <T.L.G.vanderLinden@student.utwente.nl>Bcc: X-Attachments: At 10:48 AM 3/5/96, Brian Mansur wrote:>>From Brian 10:40 AM CT 3/5/96>[Much discussion deleted]>>Kelly Says:>>>Thats a very long time to wait around for first initial survey reports! >At>>>61 years (2111) you'ld get you first report back from Tau. If you werethat patient, you wern't that interested. You might as well have just >done>>>photo recon from orbiting 1000 kilometer telescope arrays. You'ld get alot of the data, 60 years earlier.>>Brian>>I see where our differences in opinion are coming from. You and I havedifferent ideas as to what a kind of human universe this hybrid idea will >be>>taking form. And I admit that it is my fault here because you aresticking to the LIT charter and I'm not qualifying my designs by notingthat I am >not>>limiting my technology to what would be available to 2050. Sorry. >>Kelly>>Thats ok. Its an old argument in the group. As I mentioned in those draftweb pages I sent around (and got no responce to!). If you slip the timetable to a cetury from now, you have to start guessing what newtechnologies, and Physcics! will be avalible. A hundred years ago Fusion,fission, relativity, momentum transfer of momentum, and a bunch morewere not enve theories. Physisists (sp?) are currently mutering aboutinertian and kinetic energy (i.e. what the hell are they), mater conversion,controled distortion of space and time, alternate dimentions, faster thanlight travel, and even freakier stuff. By 2050 a lot of these mutteringswill be hardened theories, and our designs will look like a Saturn-V thesize of a mountain fueled by burning coal. >>But, if you don't know what we'll get, you got to plan conservativly. >Brian>I'm hoping that conservative includes future automated industry thatmakes today's automated factories look like how the first Englishfactories do compared to today's.I'm kind of dubious on that one. You are talking about fully self replicatingmachines, constructing power transmitters with billions of times thepower of Earths current electric grid, and and mirrors the size of planets,all fielded in 50 years. I'ld kind of think that was a non conservativeassumption. >[Much more discussion deleted]>>Brian Says:>>If the reflector is construction at Kupier Belt distance, it won't be >moving>>any faster than Pluto. That is until we put the mirror into the beam path. >>Then it will slowly accelerate. With relatively minor coursecorrections, it will stay in the beam.>>Kelly>>Pluto moves MUCH faster than Earth. Your mirror would quickly move outof the beam. even if the beam was larger than Earths orbit. >Brian>(imitating Homer Simpson's voice) Doh! Doh! Doh! Doh! Doh! Doh! Doh! Doh!Doh! Doh! Doh! Doh! Doh! Doh! Doh! Doh! Doh! Doh! Doh! Doh! >Doh! Doh! Doh! Doh! Doh! Doh! Doh! Doh! Doh! Doh! Doh! Doh! Doh! Doh! Doh! Doh!>David gave me these numbers>Pluto's mean orbital velocity is 4.74 km/sec. Earth's mean orbitalvelocity is 29.79 km/sec. >Are these right? They seem backwards.I'ld agree. It seems odthat you'ld accelerate out from the inner system to aslower velocity. I suppose you might be losing the dif to potential energychanges. But I suppose it isn't critical for our discusion. Assumeing a beamdiameter 40 times the dimeter of earth. 4.76Km/s will still have youcross the beam in 31 hours. >>Kelly>>Then how do you slow down the packaged mirrors without the pathfinderrockets? Or is this the expendable set? I'm confused. >Brian:>The decel mirrors are expendable. Again, considering the automation levelof the civilization necessary just to put together such mirrors and maserarrays to launch them, I'm not worried about the cost. I've noticed the cost isn't discused much by us. Stark raving fear perhaps? >>>Kelly Says:>>>>If the Pathfinders are reflecting the beam off to one side. They will bepushed out of the beam in the other direction, and accelerated forward.Given that the beam presure is strong enough push the ships in the firstplace, it would be too strong for the ships thrust against. >>>Brian Says:>>>I'm not sure I understand the last sentence. >>>Kelly Says:>>>The beam holds the projected momentum needed to push our obserdlyheavy ship. If said ship isn't in the beam, the reflectors in the beam will >have>>>to angle relative to the beam. That will mean that the thrust angles onthe reflectors and the receaving ship, will also be angled. Since the thrustisn't paralell to the beam/course. The ship and reflectors will be pushedout to the sides. I.E. off the beam, and off course. >>------------\>>/>>/>>\-------->>Brian Says:>>Understood as inevitable. Here are some ideas I put into an e-mail sentto you just a little earlier today which address the problem. Begin Excerpt>>I'll go ahead and put a few ideas I had for mirror and ship coursecorrections here. We could have the Asimov detach its ion drive and cableconnect it to an edge of the wire mesh sail and the hab section. The drivecould then gently pull the whole set up back onto the beam path. We couldalso, perhaps have the maser array at Sol periodically decrease power toallow this tug to do its job without being microwave fried. We would haveto do something about shielding the tug, of course. >>Perhaps the tug could be a pair light rockets hanging onto opposite sides >of>>1000km+ wide sail. They could have their own shielding and would be inexcellent positions to do their jobs.>>End Excerpt>Kelly:>>Hanging them on the sails doesn't matter. The weight after all is in theship, not the sail.>>Given the power levels of the beam, the lateral thrusters on the ship andmirror assembly would need to be incredable. Possibly prohibativly so. >Brian>Are you saying that the power level of the beam will keep us frommanuvering? If so, we can periodically turn it off like I suggested. Well my thought was that the main beam would throw the ship and mirroroff to the side very quickly. Assuming a 1% lateral thrust, thats a .1 m/saccell. You'ld drift 373,000 kilometers and get a lateral speed of 8.6kilometers per secound, after 1 day. (Well ok you'ld exit the beam after acouple hours and stop accelerating.) Rockets that could push back againstthat load would rival the stardrive for powe. But of couse you can't thrustlaterally without twisting the mirrors (no known material can stayoptically flat over that distence under any load.) So if everything isn't precisely balenced and trimed you'ld get radicallyout of alignment. If that happens not only do you lose power and have ahell of a time geting back aligned. Since the ships could be light monthsapart, you couldn't correct your aim for where the ship really is. >What we need is a powerful enough rocket, probably ion drives that canperiodically tug the Asimov, its sail, and the tugs themselves, perhaps afew thousand km back toward the beam every now and then. Lets assumethat the tug accelerator weighs 10 tons/m, and the drive needs to be 1000m long. >This does not account for fuel because I don't know what that will be:hopefully 10ton/m is an overestimate. Two accelerators will weigh20,000 together. By the way. At rest, I figured we might put them along anaxis perpendicular to the direction we want to tugs to tug. >What we need to do is find exactly how many km we'll have to adust overthe flight. Then we can find better weight values. To find the kmdisplacement, lets say that for safety, the Asimov is traveling 100,000km to the side of the beam. Also assume that the decel reflector (duringdecel phase) and the reaccel mirror (durring reaccel phase) never comecloser than 1 AU from the Asimov. Can anyone do the trig here? I'll see if Ican find the time get the numbers myself, but I don't make promises evenwhen relatively simple mathmatics are involved. >I also have an idea to add to my mirror paper. I'll probably reprint thisnext paragraph in it later but here it is anyway. How about putting aFresnel lens in the path to TC to refocus our beam. The lens could be of thethin variety, although I believe we would have some power losses throughthe lens.>The lens could be launched and stopped at the desired position if weattached detachable reflective sail blankets on both sides. One side wouldreflect maser energy for acceleration. The other would be the surfacefacing TC to which a decel mirror. The decel mirror would be like the kindenvisioned for the Asimov and so would probably be launched separately. Iguess this idea would add several more years to our launch time-tableassuming we only had enough masers and power to launch the weight of 1reflective mirror at a time. By the way, I have little conception as to howmuch this Fresnel lens would weigh and I don't know if it wouldexperience acceleration while refocusing. For aiming I suggest the famousWaveguide gyros simply because I don't have any better ideas. >>>Brian Says:>>>>Some method of periodic or even continuous course correction on boththe Asimov's part and the array's will be required to correct for the >>angle>>>>at which the maser beam must be reflected. The Asimov may simplyangle >>its>>>>sail slightly with the edge furtherest from the Sol to array beamtilted back toward Sol. The array will have to use built in rockets, or else >>tilt>>>>from time to time in the proper direction to allow vectorial force to >push>>>>it back into the center of the beam. >>>Kelly Says:>>>>This might be complicated given the main sail would be curved like aparachute, not flat.>>>Brian Says:>>>Good point. Of course the angle of vectorial force will be tiny >>considering>>>the reflector and the Asimov are several AU apart. >>>Kelly Says:>>>Oh, I forgot you couldn't do that with the reflectors and get the beam tothe ship.>>Brian Says:>>Huh? I don't understand this.>>Kelly>>If you angle the mirrors to counter thrust you back into the beam, you'ldbe reflecting the beam away from the ship not toward it. Trying toanticipate where the ship is relative to the mirror array would be aproblem too. The mirrors obviously can't 'aim' in the conventional sencedue to the time delay.>Brian>Don't we already have computers that could be programed to reasonablyfigure this aiming problem out?They could given current accurate info. But given that the info has totravel at the spped of light, it would be months out of date by the time themirror systems got it. Given that the actuall rates will varry back andforth a bit durring the interveaning time (given random flexing of the sail,and random variations of the beam), and we can't predict what thesevariations will be. The aiming calculations will be precise calculationsbases on very bad information. I.E. computer generated guesses. Evenassuming not one unexpected thing ever happens on the ship or mirror. Ifyou guess wrong even once. You're aiming the beam into empty space andthe ship is racing away from where you think it is. Just to complicate things. The mirror is moring at a high fraction of thespeed of light. So relatavistic distortion will distort the beam, mirror,and apparent space. >>Kelly>>You might try a secondary set of sails rigged to provide lateral thrust.After all. Only a tiny fraction of the beam will hit the reflectors (Thebeam would after all be pretty spread out), and only a fraction of thereflected beam would hit the main sail (since you can't aim accuratly,shotgun the area).>Brian>I'm not sure I follow you here? I think I need a diagram. ----------\/ ///\--------A little hard to folow I know, but you have a secound set of sailsconnected to each mirror and sail, angled to the beam shining on them.These are angled to provide lateral thrust against the main lateral thrustof the main mirror/sails . They would use parts of the beam that pass tothe side of the areas that the mirror and sail would see (yes that meansthe beam would need to be huge, which would waste the vast majority ofits power. Probably 99%- 99.99% of it). Oh, and you have to make sure the cross thrust dosen't distort theoptically perfect surfaces or the mirrors. >>>Kelly Says:>>>Also targeting on a moving ship when you get a few light months apartis dangerous.>>Brian Says:>>See my above question on just how well Kev's gyroes could be adapted to >work>>for mechanical reflection. If this isn't solvable for aiming mirrrors, Iguess its back to the drawing board.>Brian>So does anyone know if these gyros will work. Kev? Haven't heard fromyou yet bud.Even if the gyros would work, how flat can you keep hundreds of miles ofunsupported (you are in spec) chicken wire being blown down wind underVERY high thrust loads? Kelly============================================================Date: Tue, 5 Mar 1996 12:55:24 -0500To: Brian Mansur <bmansur@oc.edu>From: kgstar@most.fw.hac.com (Kelly Starks x7066 MS 10-39)Subject: Re: Mirrors (first draft)Cc: Brian Mansur <bmansur@oc.edu>, kgstar <kgstar@most.fw.hac.com>,David <David@InterWorld.com>, hous0042 <hous0042@maroon.tc.umn.edu>,jim <jim@bogie2.bio.purdue.edu>, KellySt <KellySt@aol.com>, lparker<lparker@destin.gulfnet.com>, rddesign <rddesign@wolfenet.com>, SteveVanDevender <stevev@efn.org>, "T.L.G.vanderLinden"<T.L.G.vanderLinden@student.utwente.nl>, zkulpa<zkulpa@zmit1.ippt.gov.pl>Bcc: X-Attachments: At 10:57 AM 3/5/96, Brian Mansur wrote:>Brian 10:50 AM CT 3/5/96,>Thanks for the comments. I'll try to reply to them in a day or two (I'll bebusy for the rest of this week on School Club activities and homework).But here's a little something.>[much discussion deleted]>>Brian>>So much for bolstering my hybid design. By the way. From now on I'mgoing to officially call it an ARGOSY class starship. Since I'll probablyhave nothing better to do over spring break (like relaxing?), I'll see if Ican improve my design. Expect to see a lot of ideas borrowed from theExplorer design. I should at least be able to give the group a decentdescription along with a critic of the problems associated with the thing.Oh, and a long list of assumptions as well.>>Kelly>>Great! I was hoping we'ld get a fleet of compeating ship designs! We cantry to cross link our pages when they are uploaded by Dave. >>Let me know if you want copies or help. >Brian>A word of warning is that I still have to work with BMP. I'm afraid that Iwasn't able to download the GIF program you gave me so all I can do fornow is send bit demons. I can do some decent drawings with the bithowever and I will over the break. I was wondering if you could compressthem and send them on to the rest of the group so that their hard drivesdon't explode. I'm not sure I can handel BMP files. I'm sure I didn't send you a programgiven that my stuff is all Macintosh, and it sound like you are an IBMer. >Glad to hear that you're enthusiastic about the idea. I'm beginning to seealready that much of the ARGOSY design will be vague, however. It figurethat it will at least have a similar summary as see in my Hybrid firstdraft plus troubleshooting points.>By the way, something I also plan to get to is an e-mail discussing thedecel problems with the EXPLORER. Its a great idea if drag can beovercome with minimal power losses. Loading the decel/reacel track isalso a pain. Stoping these things is a nightmare! We can't carry enough fuel (unless theships get EXTREEAME), and we can't beam it, because the beam only pushesone way. Perhaps we're using these beams wrong? hummm. Kelly