RE: The gun thing again [Off Topic]
One of the problems I encountered was how do you build circuitry to survive the launch. The forces involved will destroy most electronics as they are now built. Solids state is not very solid after 15x gravitational forces. I probably sound negative, but the only way to prove it is to build one (even a small one) and see what happens. Pulling this back to the topic (sort of), would building a gun of this type on the moon facilitate the launching of deep space probes? We would eliminate the atmospheric issues and most of the acceleration issues too. Comments? Joe L. > > Most August Simians, > > Interestingly, (from a standpoint of trying to avoid the waste of > fuel-eating trajectory corrections) GS orbits need not be circular. Even > with a circular orbit, it still appears doable via a Hohmann > transfer. > > Equatorial mountain candidates for drilling the gun boreholes include > Chimborazo in Ecuador at 20,700, Kenya's Mt Kenya at 17000 + and another > in Sumatra at 12400 +. > > An example of the non-linear thinking which can be easily applied to the > gun method is that with many cargoes, the entire projectile could be > deep frozen (Say in liquid N or He) prior to launch, thereby extending > the heat tolerance. > > I was of course backward with the orientation - the bore hole would > actually be pointed a little eastward. GS (circular) orbital velocity > is about 3440 mph, eastward, so there is a little delta V (about 1400 > mph) to make up. Some portion of this would come from the vectored > rocket firing in the Hohmann transfer maneuver. > > Jack > > > -Original Message- > From: Michael Turner [mailto:[EMAIL PROTECTED] > Sent: Thursday 08 April 2004 11:48 > To: [EMAIL PROTECTED] > Subject: Re: The gun thing again > > > > Joe Latrell writes: >> Having done some experiments in gun launching (nothing to orbit mind >> you) there are a lot of factors involved that make it very >> unattractive. Heat is a really big issue. > > I've read papers that suggest a dead-mass burden of about 15% for > ablative shielding. I.e., in the same ballpark as reentry capsules. No > showstopper, at least for the optimist. Launching from higher altitudes > definitely helps, since even 14,000 feet gets you above over 25% of the > atmosphere. > >> However, the geosync inflatable station is a great idea. Using a >> transhab type design, you can launch a really big space station with >> only a few launches, assemble it (self assembly?) and then get to work > >> building probes to wherever you want to send them. > > Engineering inflatables for gun launch is an interesting idea. There > may be some kinks in it (as it were), but it seems ideal for solving > many construction problems. If you perfected rendezvous, one approach > that I think would be kinda cool is: > > 1. launch an inflatable > 2. inflate it > 3. launch another > 4. rendezvous at some orifice > 5. inflate the new one *inside* the current one >(vent residual gas to a pressure tank, and >reuse the gas for future inflation) > 6. repeat from 3 until you have enough layers >for whatever purpose desired. > > This is nice because it means you can build structures of considerable > mass within small payload limitations, and because it's fault tolerant > -- blow a launch or miss a rendezvous, and the relative cheapness of gun > launch (amortized over many launches, anyway) means just planning for a > few more launches than the absolute minimum. > > To Jack's questions: > >> > Sundry clever primates around the world > > Having met me recently, Jack, you know just how ridged a brow and > prognathous a jaw you're dealing with, in talking to me. (Thanks for > the back-shaving tips, by the way. ;-) > >> > OK, OK, I know. The gun thing won't work for orbital delivery of >> stuff to build Europan probes because one can't shave the big bump >> off of the resultant wobbling orbit ... or +- something like that. > > "The big bump"? If you mean that it starts out very elliptical, shaving > the big bumps (which I'm better at now; my back isn't as red and sore as > it used to be) amounts to circularizing the orbit. If you launch enough > fuel into the same orbit as the original projectile, you can use it to > circularize the orbit at perigee pretty efficiently, or even just head > right on out of Earth orbit, I would think. (Joe? You're the guy who > most recently did the orbital dynamics stuff, right?) > >> > However if one were to cant the trajectory of an equatorial gun back > >> > a little to the west, a projectile could be delivered which would >> "die" into a geosynchronous orbit. Granted, you'd only get one shot > >> > per gun per day, but at say a ton per shot ... > > Um. Hm. I did some rough calculations a while back, looking at > shooting straight up and using the Earth's rotation as free vector, and > I remember coming up with an orbit out past the moon. But you're > proposing something else, I re
RE: The gun thing again [Off Topic]
One or our firm's product sets is electronic sensing tools for oil well drilling. These tools must tolerate tremendous heat, pressure and rather high acceleration loads. They are continually making headway. To withstand the rigors of a gun launch (remember too that my version of the gun is >4 kilometers in length so g's are maybe not quite as high as in whatever model you are quoting), my simple answer is to embed all electrics in some sort of liquid-turned-solid epoxy material. If encased in a rigid solid, they have nowhere to go. Also, my thinking on the gun has it delivering stuff that is not so delicate - liquids, gasses, structural materials, connectors, inflatables, solid fuels, rolled sheet metals, etc. Really delicate components could be sent by STS or rockets. Re the lunar gun, a very interesting idea. I have spoken a little to oil industry people about drilling the boreholes for the guns and the steel casing to line it. They generally see it as completely feasible in the here and now - just a question of $. Jack -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Sent: Thursday 08 April 2004 14:29 To: [EMAIL PROTECTED] Subject: RE: The gun thing again [Off Topic] One of the problems I encountered was how do you build circuitry to survive the launch. The forces involved will destroy most electronics as they are now built. Solids state is not very solid after 15x gravitational forces. I probably sound negative, but the only way to prove it is to build one (even a small one) and see what happens. Pulling this back to the topic (sort of), would building a gun of this type on the moon facilitate the launching of deep space probes? We would eliminate the atmospheric issues and most of the acceleration issues too. Comments? Joe L. > > Most August Simians, > > Interestingly, (from a standpoint of trying to avoid the waste of > fuel-eating trajectory corrections) GS orbits need not be circular. > Even with a circular orbit, it still appears doable via a Hohmann > transfer. > > Equatorial mountain candidates for drilling the gun boreholes include > Chimborazo in Ecuador at 20,700, Kenya's Mt Kenya at 17000 + and > another in Sumatra at 12400 +. > > An example of the non-linear thinking which can be easily applied to > the gun method is that with many cargoes, the entire projectile could > be deep frozen (Say in liquid N or He) prior to launch, thereby > extending the heat tolerance. > > I was of course backward with the orientation - the bore hole would > actually be pointed a little eastward. GS (circular) orbital velocity > is about 3440 mph, eastward, so there is a little delta V (about 1400 > mph) to make up. Some portion of this would come from the vectored > rocket firing in the Hohmann transfer maneuver. > > Jack > > > -Original Message- > From: Michael Turner [mailto:[EMAIL PROTECTED] > Sent: Thursday 08 April 2004 11:48 > To: [EMAIL PROTECTED] > Subject: Re: The gun thing again > > > > Joe Latrell writes: >> Having done some experiments in gun launching (nothing to orbit mind >> you) there are a lot of factors involved that make it very >> unattractive. Heat is a really big issue. > > I've read papers that suggest a dead-mass burden of about 15% for > ablative shielding. I.e., in the same ballpark as reentry capsules. > No showstopper, at least for the optimist. Launching from higher > altitudes definitely helps, since even 14,000 feet gets you above over > 25% of the atmosphere. > >> However, the geosync inflatable station is a great idea. Using a >> transhab type design, you can launch a really big space station with >> only a few launches, assemble it (self assembly?) and then get to >> work > >> building probes to wherever you want to send them. > > Engineering inflatables for gun launch is an interesting idea. There > may be some kinks in it (as it were), but it seems ideal for solving > many construction problems. If you perfected rendezvous, one approach > that I think would be kinda cool is: > > 1. launch an inflatable > 2. inflate it > 3. launch another > 4. rendezvous at some orifice > 5. inflate the new one *inside* the current one >(vent residual gas to a pressure tank, and >reuse the gas for future inflation) > 6. repeat from 3 until you have enough layers >for whatever purpose desired. > > This is nice because it means you can build structures of considerable > mass within small payload limitations, and because it's fault tolerant > -- blow a launch or miss a rendezvous, and the relative cheapness of > gun launch (amortized over many launches, anyway) means just planning > for a few
RE: The gun thing again [Off Topic]
Jack, Do you have a paper on this proposal and a guess as to how much it will cost? Joe L. > > One or our firm's product sets is electronic sensing tools for oil well > drilling. These tools must tolerate tremendous heat, pressure and > rather high acceleration loads. They are continually making headway. > > To withstand the rigors of a gun launch (remember too that my version of > the gun is >4 kilometers in length so g's are maybe not quite as high as > in whatever model you are quoting), my simple answer is to embed all > electrics in some sort of liquid-turned-solid epoxy material. If > encased in a rigid solid, they have nowhere to go. > > Also, my thinking on the gun has it delivering stuff that is not so > delicate - liquids, gasses, structural materials, connectors, > inflatables, solid fuels, rolled sheet metals, etc. Really delicate > components could be sent by STS or rockets. > > Re the lunar gun, a very interesting idea. I have spoken a little to > oil industry people about drilling the boreholes for the guns and the > steel casing to line it. They generally see it as completely feasible > in the here and now - just a question of $. > > > Jack > > -Original Message- > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] > > Sent: Thursday 08 April 2004 14:29 > To: [EMAIL PROTECTED] > Subject: RE: The gun thing again [Off Topic] > > > > One of the problems I encountered was how do you build circuitry to > survive the launch. The forces involved will destroy most electronics > as they are now built. Solids state is not very solid after 15x > gravitational forces. > > I probably sound negative, but the only way to prove it is to build one > (even a small one) and see what happens. > > Pulling this back to the topic (sort of), would building a gun of this > type on the moon facilitate the launching of deep space probes? We > would eliminate the atmospheric issues and most of the acceleration > issues too. > > Comments? > > Joe L. > > >> >> Most August Simians, >> >> Interestingly, (from a standpoint of trying to avoid the waste of >> fuel-eating trajectory corrections) GS orbits need not be circular. >> Even with a circular orbit, it still appears doable via a Hohmann >> transfer. >> >> Equatorial mountain candidates for drilling the gun boreholes include >> Chimborazo in Ecuador at 20,700, Kenya's Mt Kenya at 17000 + and >> another in Sumatra at 12400 +. >> >> An example of the non-linear thinking which can be easily applied to >> the gun method is that with many cargoes, the entire projectile could >> be deep frozen (Say in liquid N or He) prior to launch, thereby >> extending the heat tolerance. >> >> I was of course backward with the orientation - the bore hole would >> actually be pointed a little eastward. GS (circular) orbital velocity > >> is about 3440 mph, eastward, so there is a little delta V (about 1400 >> mph) to make up. Some portion of this would come from the vectored >> rocket firing in the Hohmann transfer maneuver. >> >> Jack >> >> >> -Original Message- >> From: Michael Turner [mailto:[EMAIL PROTECTED] >> Sent: Thursday 08 April 2004 11:48 >> To: [EMAIL PROTECTED] >> Subject: Re: The gun thing again >> >> >> >> Joe Latrell writes: >>> Having done some experiments in gun launching (nothing to orbit mind >>> you) there are a lot of factors involved that make it very >>> unattractive. Heat is a really big issue. >> >> I've read papers that suggest a dead-mass burden of about 15% for >> ablative shielding. I.e., in the same ballpark as reentry capsules. >> No showstopper, at least for the optimist. Launching from higher >> altitudes definitely helps, since even 14,000 feet gets you above over > >> 25% of the atmosphere. >> >>> However, the geosync inflatable station is a great idea. Using a >>> transhab type design, you can launch a really big space station with >>> only a few launches, assemble it (self assembly?) and then get to >>> work >> >>> building probes to wherever you want to send them. >> >> Engineering inflatables for gun launch is an interesting idea. There >> may be some kinks in it (as it were), but it seems ideal for solving >> many construction problems. If you perfected rendezvous, one approach > >> that I think would be kinda cool is: >> >> 1. launch an inflatable >> 2. inflate it >> 3. launch another >> 4. rendezvous at some orifice >> 5
Re: The gun thing again [Off Topic]
> One of the problems I encountered was how do you build circuitry to > survive the launch. The forces involved will destroy most electronics as > they are now built. Solids state is not very solid after 15x > gravitational forces. "As they are now built" - for what? They've built nuclear explosives into artillery shells, and those devices require carefully-timed electronics. Artillery shells often have proximity fuzes. There's a lot you can do, and people have been doing it, for a long time. > I probably sound negative, but the only way to prove it is to build one > (even a small one) and see what happens. They have been built, and they have seen what happens. You can build things to take far more than 15g. Drop your watch onto a concrete floor. Keeps on ticking. Compute the likely acceleration it experienced on impact. You'll be amazed. (You probably don't have to compute it - it's probably written on the box it came in.) Gerald Bull found that wooden sabots work just fine. He also found that immersing a liquid fuel rocket in water inside the cancels almost all of the forces that you'd think would crush it. Intuitively, gun launch to space fails the intuition test. So much the worse for intuition. Do the math. > Pulling this back to the topic (sort of), would building a gun of this > type on the moon facilitate the launching of deep space probes? We would > eliminate the atmospheric issues and most of the acceleration issues too. Anything that reduces launch cost dramatically facilitates almost anything you might want to do in space. Once you can get a lot of stuff up there cheaply, many problems go away. Launching living things is the one payload category that seems off the boards, though I wouldn't be surprised if you could launch frozen ova, seeds, spores, and microbiology that ecosystems depend on, with little trouble. Ditto for food ingredients. -michael turner [EMAIL PROTECTED] == You are subscribed to the Europa Icepick mailing list: [EMAIL PROTECTED] Project information and list (un)subscribe info: http://klx.com/europa/
RE: The gun thing again [Off Topic]
Greetings Sir, Some comments on your post At 02:28 PM 4/8/04 -0500, you wrote: One of the problems I encountered was how do you build circuitry to survive the launch. The forces involved will destroy most electronics as they are now built. Solids state is not very solid after 15x gravitational forces. Actually, this is probably not a major problem. Gerald Bull put electronics in shells he launched back in the 1960's. Just packed them with sand in his shells. JPL sent two penetrator probes into Mars. The probes did not work, but evidence suggests that it was problems with the battery supply (i.e. the battery couldn't survive the long cold and still function) and not the electronics. Also, combat UAV's can pull (I believe) more that 15g's and they survive just fine. Crash Black boxes in Indy cars routinely survive probably 50-100 G's in crashs (for extremely short periods of time). So the electronics will survive. Comments? Joe L. Thanx, Gordon == You are subscribed to the Europa Icepick mailing list: [EMAIL PROTECTED] Project information and list (un)subscribe info: http://klx.com/europa/
Re: The gun thing again [Off Topic]
Check out the latest in gun-launched UAVs, courtesy of Draper Laboratories. It fits into a shroud that fits into a standard 155 mm gun barrel. Note the high g tolerances cited at the end of the quoted patent abstract. Here is an article from Electronics Design News: http://www.reed-electronics.com/ednmag/article/CA341454?industryid=2573 Seeing is believing? Take a gander: http://www.reed-electronics.com/ednmag/contents/images/341454f1.pdf The people who design these kinds of wundergadgets are not amateurs: http://www.metisdesign.com/team.html (See bio for Seth Kessler.) Here is one of the patents: --- Flyer assembly Patent # U.S. 6,392,213; Date Issued: May 21, 2002 A flyer assembly is adapted for launching with, transit in, and deployment from an artillery shell having a central void region extending along a ballistic shell axis. The flyer assembly includes a jettisonable shroud and a flyer. The shroud extends along a shroud axis, and is positionable within the central void region with the shroud axis substantially parallel to the shell axis. The flyer is adapted to withstand a launch acceleration force along a flyer axis when in a first state, and to effect aerodynamic flight when in a second state. When in the first state, the flyer is positionable within the shroud with the flyer axis parallel to the shroud axis and the shell axis. The flyer includes a body member disposed about the flyer axis, and a foldable wing assembly mounted to the body member. The wing assembly is configurable in a folded state characterized by a plurality of nested wing segments when the flyer is in the first state. The wing assembly is configurable in an unfolded state characterized by a substantially uninterrupted aerodynamic surface when the flyer is in the second state. The flyer assembly is adapted to be launched from a ballistic delivery system such as an artillery cannon, and can thus reach a target quickly, without expending system energy stored within the flyer. During launch, the flyer is coupled to the shroud so as to maintain a portion of the flyer in tension during an acceleration of the flyer along the flyer axis resulting from the launch. The flyer assembly is adapted to withstand the high g-load and high temperature environments of a cannon launch, and can tolerate a set-back g load of about 16,000 g. --- I'm working (feebly, it's true) on a book about the history of the idea of gun launch to space. And this is one of several supposed showstopper myths I want to pound a stake through the heart of: the quick and easy conclusion that gun launch means you can't put anything terribly sophisticated in the projectile. You can. You just can't buy the parts down at Space Cadets R Us. But when has that ever been true even for conventional rocket launch? Undoubtedly, gun launch entails design compromises that increase payload mass over an equivalent payload for a conventional launcher. However, at $600/lb or less to achieve orbital velocity, doubling and even tripling the payload mass to address higher accelerations is a non-issue in the context of today's high launch costs. More likely, it's a 20%-35% penalty for a given equivalent payload. Furthermore, launching"equivalent payloads" may actually make little sense if such launch economies can be achieved. Instead, you might see lots of on-orbit integration from bundles of parts, and many more designs for satellites and probes design to withstand rather small accelerations, such as those they'd experience from an ion drive doing a long-term orbital insertion. In any case, autonomous payloads of not only high electronic complexity but high electromechanical complexity can be launched from guns. The significance for cheaper space probe missions can hardly be lost on readers here. Regards, Michael Turner [EMAIL PROTECTED] P.S. If you're interested in my book project, and want to help, please do NOT send me anything except news within the last year or so. If you found some resource in 5 minutes, I probably found it myself at least 5 months ago. - Original Message - From: "Gordon Smith" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Saturday, April 17, 2004 1:06 PM Subject: RE: The gun thing again [Off Topic] > > Greetings Sir, > Some comments on your post > > At 02:28 PM 4/8/04 -0500, you wrote: > > >One of the problems I encountered was how do you build circuitry to > >survive the launch. The forces involved will destroy most electronics as > >they are now built. Solids state is not very solid after 15x > >gravitational forces. > > Actually, this is probably not a major problem. Gerald Bull put electronics > in shells he launched back in the 1960's. Just packed them with sand in his > shells. JPL sent two penetrator probes into Mars. The probes did not work, > but evidence suggests that it
RE: The gun thing again [Off Topic]
A EUROPA penetrator probe will have to survive 20,000 G on impact. Most Mars and Moon probes need only to survive about 2000 G, because there they can use rockets to brake the fall (larger payloads). We've tested a mass spectrometer to 1200 G. They tell me the electronics is not a problem at 2000 G. I think 20,000 G is more of a challenge, but then, I don't know if it is or not. There are folks doing 20,000 G experiments. Maybe you've seen some results on TV over the past year. Gary Greetings Sir, Some comments on your post At 02:28 PM 4/8/04 -0500, you wrote: One of the problems I encountered was how do you build circuitry to survive the launch. The forces involved will destroy most electronics as they are now built. Solids state is not very solid after 15x gravitational forces. Actually, this is probably not a major problem. Gerald Bull put electronics in shells he launched back in the 1960's. Just packed them with sand in his shells. JPL sent two penetrator probes into Mars. The probes did not work, but evidence suggests that it was problems with the battery supply (i.e. the battery couldn't survive the long cold and still function) and not the electronics. Also, combat UAV's can pull (I believe) more that 15g's and they survive just fine. Crash Black boxes in Indy cars routinely survive probably 50-100 G's in crashs (for extremely short periods of time). So the electronics will survive. Comments? Joe L. Thanx, Gordon == You are subscribed to the Europa Icepick mailing list: [EMAIL PROTECTED] Project information and list (un)subscribe info: http://klx.com/europa/ == You are subscribed to the Europa Icepick mailing list: [EMAIL PROTECTED] Project information and list (un)subscribe info: http://klx.com/europa/
RE: The gun thing again [Off Topic]
Gentle fellow proto-technophiles and sundry sophisticated simians, There are a lot of y'all who know a lot more about flight path manipulation, orbital physics and whatnot than do I. However, I do know more than a little about drilling holes in the earth. So let's look at a few things. To drill a fairly large diameter hole and line it with a fairly stout steel barrel is neither cheap nor expensive. The costs increase exponentially with depth, but not wildly. I think that a barrel ID of about 750 mm would fit well into current drilling technologies, based upon drilling a 915 mm hole, running a liner with a wall thickness of about 45 mm, then cementing it in place with a high density cement sheath. Query #1: To what depth should the gun hole be drilled? To drill a 1000 m hole is easy; 2000 m also easily doable. 3000 + starts getting tricky and tricky means a sudden jump in money. Would a 1000 m gun be optimal? 2000 m? Y'all tell me. Following a bit of reading, I think that conventional explosive propellants won't work, but that sequenced hydrogen/oxygen ignition will. You lower a tool into the gun barrel. Its function is to mill a row of holes into the side of the barrel. I envision that these holes would be about 150 mm in diameter and about 350 mm deep. The machine would then chamfer the hole and cut threads in the metal part of the hole. Into each of these holes would be threaded a steel cylinder, a receptacle, closed on the outer end, open on the end toward the gun barrel. They are fuel ports. They each hold an ampoule of hydrogen &/or oxygen. It is likely that the spacing and number of these fuel ports would be designed to optimize acceleration, so I sort of see them as progressively closer together as you near the surface/muzzle. So, you lower your projectile with its own little explosive initiator beneath it down into the bottom of the gun. Then you lower the fuelling machine and fill each of the fuel ports above the projectile, all the way up to the top. Note that as the fuelling machine is pulled up the gun on its fuelling mission, it is also leaving a vacuum beneath it through sealing itself on the inner bore with a series of simple external O-rings. Upon removal of the fuelling machine, a diaphragm is placed over the muzzle to preserve the vacuum and the count-down begins. A radio signal starts and confirms the initiator charge firing sequence. Upon firing the initiator, the projectile is on its way, "camming" the fuel ampoules back into their receptacles and rupturing them, sending high pressure hydrogen/oxygen into the barrel as the projectile passes. Since the muzzle is at 14000 ft altitude on an equatorial mountain, around a 1/4 of the atmosphere's interfering molecules won't contribute to heating or drag. Query #2: Some portion of the projectiles cargo would be fuel for orbital correction into a GS orbit. How much? Y'all tell me. I'm thinking that even 40% of the volume of a 6 m long projectile is still nearly 0.9 m3, or about 30 ft3. That's a lot of stuff. Some people were asking about costs. Again I can only address things drilling related, so guesses on the fuel port milling tool is a bit of a wild card. That said I have seen what the oilfield drilling industry has developed and I do have a bit of a handle on those costs. My guesses: Drilling 2000 m of 915 mm hole with very tight deviation control < $ 50,000,000 840 mm OD, 45 mm wall thickness, high strength steel liner < 9,000,000 Cementing operations and materials < 3,000,000 Road access, drilling ops base < 5,000,000 Fuel port milling device <20,000,000 Fuel port milling ops <20,000,000 Fuel port loading machine <20,000,000 Surface facilities, hoists, equipment (no launch control center) < 100,000,000 40% error <90,000,000 Total Empty Gun, Ready to Load, Privately Contracted < 317,000,000 Total Empty Gun, Ready to Load, Gov Built > 2,000,000,000 By the way, the one thing I love most about this idea is its heritage. It's a muzzle loader. I think you could put a big inflatable space station up, with food, fuel and water, with 50 shots. Hope y'all don't mind, but I'm actually from Canada; I just live in Texas and like saying y'all. Jack W. Reeve -Original Message----- From: Gary McMurtry [mailto:[EMAIL PROTECTED] Sent: Friday 16 April 2004 23:30 To: [EMAIL PROTECTED] Subject: RE: The gun thing again [Off Topic] A EUROPA penetrator probe will have to survive 20,000 G on impact. Most Mars and Moon probes need only to survive about 2000 G, because there they can use rockets to brake the fall (larger payloads). We've tested a mass spectrometer to 1200 G. They tell me the electronics is not a problem at 2000 G. I think 20,000 G is more of a challenge, but then, I don't know
RE: The gun thing again [Off Topic]
Gentle fellow proto-technophiles and sundry sophisticated simians, There are a lot of y'all who know a lot more about flight path manipulation, orbital physics and whatnot than do I. However, I do know more than a little about drilling holes in the earth. So let's look at a few things. To drill a fairly large diameter hole and line it with a fairly stout steel barrel is neither cheap nor expensive. The costs increase exponentially with depth, but not wildly. I think that a barrel ID of about 750 mm would fit well into current drilling technologies, based upon drilling a 915 mm hole, running a liner with a wall thickness of about 45 mm, then cementing it in place with a high density cement sheath. Query #1: To what depth should the gun hole be drilled? To drill a 1000 m hole is easy; 2000 m also easily doable. 3000 + starts getting tricky and tricky means a sudden jump in money. Would a 1000 m gun be optimal? 2000 m? Y'all tell me. Following a bit of reading, I think that conventional explosive propellants won't work, but that sequenced hydrogen/oxygen ignition will. You lower a tool into the gun barrel. Its function is to mill a row of holes into the side of the barrel. I envision that these holes would be about 150 mm in diameter and about 350 mm deep. The machine would then chamfer the hole and cut threads in the metal part of the hole. Into each of these holes would be threaded a steel cylinder, a receptacle, closed on the outer end, open on the end toward the gun barrel. They are fuel ports. They each hold an ampoule of hydrogen &/or oxygen. It is likely that the spacing and number of these fuel ports would be designed to optimize acceleration, so I sort of see them as progressively closer together as you near the surface/muzzle. So, you lower your projectile with its own little explosive initiator beneath it down into the bottom of the gun. Then you lower the fuelling machine and fill each of the fuel ports above the projectile, all the way up to the top. Note that as the fuelling machine is pulled up the gun on its fuelling mission, it is also leaving a vacuum beneath it through sealing itself on the inner bore with a series of simple external O-rings. Upon removal of the fuelling machine, a diaphragm is placed over the muzzle to preserve the vacuum and the count-down begins. A radio signal starts and confirms the initiator charge firing sequence. Upon firing the initiator, the projectile is on its way, "camming" the fuel ampoules back into their receptacles and rupturing them, sending high pressure hydrogen/oxygen into the barrel as the projectile passes. Since the muzzle is at 14000 ft altitude on an equatorial mountain, around a 1/4 of the atmosphere's interfering molecules won't contribute to heating or drag. Query #2: Some portion of the projectiles cargo would be fuel for orbital correction into a GS orbit. How much? Y'all tell me. I'm thinking that even 40% of the volume of a 6 m long projectile is still nearly 0.9 m3, or about 30 ft3. That's a lot of stuff. Some people were asking about costs. Again I can only address things drilling related, so guesses on the fuel port milling tool is a bit of a wild card. That said I have seen what the oilfield drilling industry has developed and I do have a bit of a handle on those costs. My guesses: Drilling 2000 m of 915 mm hole with very tight deviation control < $ 50,000,000 840 mm OD, 45 mm wall thickness, high strength steel liner < 9,000,000 Cementing operations and materials < 3,000,000 Road access, drilling ops base < 5,000,000 Fuel port milling device <20,000,000 Fuel port milling ops <20,000,000 Fuel port loading machine <20,000,000 Surface facilities, hoists, equipment (no launch control center) < 100,000,000 40% error <90,000,000 Total Empty Gun, Ready to Load, Privately Contracted < 317,000,000 Total Empty Gun, Ready to Load, Gov Built > 2,000,000,000 By the way, the one thing I love most about this idea is its heritage. It's a muzzle loader. I think you could put a big inflatable space station up, with food, fuel and water, with 50 shots. Hope y'all don't mind, but I'm actually from Canada; I just live in Texas and like saying y'all. Jack W. Reeve -Original Message----- From: Gary McMurtry [mailto:[EMAIL PROTECTED] Sent: Friday 16 April 2004 23:30 To: [EMAIL PROTECTED] Subject: RE: The gun thing again [Off Topic] A EUROPA penetrator probe will have to survive 20,000 G on impact. Most Mars and Moon probes need only to survive about 2000 G, because there they can use rockets to brake the fall (larger payloads). We've tested a mass spectrometer to 1200 G. They tell me the electronics is not a problem at 2000 G. I think 20,000 G is more of a challenge, but then, I don't know
The tether thing (for the first time?) (was Re: The gun thing again [Off Topic])
I've wondered if you couldn't cancel a lot of a Europa penetrator's acceleration by making it a counterweight to a rotating tether orbiting very close to Europa. A probe could orbit very close - Europa's "atmosphere" is mostly oxygen that (by one estimate) collides with other oxygen molecules only about 3 times on average before escaping. With "atmospheres" like this, who needs vacuum? For the sake of simplicity, consider what might be involved in dropping a probe straight down from a low altitude. Europa surface acceleration due to gravity: 1.3 m/s^2 Counteracting centripetal acceleration achieved at 1.57e+06 m from Europa center of gravity (= Europa radius plus a few km) would be at orbital velocity given by the equation a = v^2/r solving for v: v = sqrt (ra) = sqrt (1.3 m/s^2 * 1.57e+06 m) or let's about 1.5 km/s orbital speed, winging just barely above Europa's surface features. So the question is: could a tether hold, with a tip speed of 1.5 km/s? Well, flywheel tip speeds are currently in the neighborhood of 1 km/s, and that's without fullerene weaves. If they crack the fullerene fiber problem, another order of magnitude of tensile strength might emerge. One problem with this approach: the tether, having released the penetrator probe, will go flying wildly off somewhere. If, however, a counterweight incorporates an ion drive powered by flying through Jupiter's magnetic field, maybe it could retrieve itself and be reused somehow. -michael turner [EMAIL PROTECTED] - Original Message - From: "Gary McMurtry" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Saturday, April 17, 2004 1:30 PM Subject: RE: The gun thing again [Off Topic] > > A EUROPA penetrator probe will have to survive 20,000 G on impact. > Most Mars and Moon probes need only to survive about 2000 G, because > there they can use rockets to brake the fall (larger payloads). > We've tested a mass spectrometer to 1200 G. They tell me the > electronics is not a problem at 2000 G. I think 20,000 G is more of a > challenge, but then, I don't know if it is or not. There are folks > doing 20,000 G experiments. Maybe you've seen some results on TV > over the past year. > > Gary > > > >Greetings Sir, > >Some comments on your post > > > >At 02:28 PM 4/8/04 -0500, you wrote: > > > >>One of the problems I encountered was how do you build circuitry to > >>survive the launch. The forces involved will destroy most > >>electronics as they are now built. Solids state is not very solid > >>after 15x gravitational forces. > > > >Actually, this is probably not a major problem. Gerald Bull put > >electronics in shells he launched back in the 1960's. Just packed > >them with sand in his shells. JPL sent two penetrator probes into > >Mars. The probes did not work, but evidence suggests that it was > >problems with the battery supply (i.e. the battery couldn't survive > >the long cold and still function) and not the electronics. Also, > >combat UAV's can pull (I believe) more that 15g's and they survive > >just fine. Crash Black boxes in Indy cars routinely survive probably > >50-100 G's in crashs (for extremely short periods of time). So the > >electronics will survive. > > > >>Comments? > >> > >>Joe L. > > > > > >Thanx, > > > >Gordon > > > >== > >You are subscribed to the Europa Icepick mailing list: [EMAIL PROTECTED] > >Project information and list (un)subscribe info: http://klx.com/europa/ > > > == > You are subscribed to the Europa Icepick mailing list: [EMAIL PROTECTED] > Project information and list (un)subscribe info: http://klx.com/europa/ > > == You are subscribed to the Europa Icepick mailing list: [EMAIL PROTECTED] Project information and list (un)subscribe info: http://klx.com/europa/
Re: The tether thing (for the first time?) (was Re: The gun thing again [Off Topic])
Sorry, forgot the other half of the problem: limiting rotational acceleration on the penetrator probe to be dropped, when it's tethered. Say that 1000 g, or about 10,000 m/s^2, is the limit for instruments of interest. At about 1.5e+03 m/s rotational velocity on the tether (counter-rotating to match speeds with Europa's surface), you have a = v^2/r r = (1.5e+03 m/s)^2 / (1e+04 m/s^2) or a tether 'radius' (half-length) of about 200 m. I have no idea whether this is ridiculous or not. There might be some way to rev it up using Jupiter's magnetic field and some electrodynamic effect. But that's beyond my rusty physics, at this point. (In fact, so is almost all of this discussion -- fooled ya, didn't I? ;-) -michael turner [EMAIL PROTECTED] - Original Message - From: "Michael Turner" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Saturday, April 17, 2004 5:25 PM Subject: The tether thing (for the first time?) (was Re: The gun thing again [Off Topic]) > > > I've wondered if you couldn't cancel a lot of a Europa penetrator's > acceleration by making it a counterweight to a rotating tether > orbiting very close to Europa. A probe could orbit very > close - Europa's "atmosphere" is mostly oxygen that (by one > estimate) collides with other oxygen molecules only about > 3 times on average before escaping. With "atmospheres" like > this, who needs vacuum? > > For the sake of simplicity, consider what might be > involved in dropping a probe straight down from > a low altitude. > > Europa surface acceleration due to gravity: 1.3 m/s^2 > > Counteracting centripetal acceleration achieved at 1.57e+06 m > from Europa center of gravity (= Europa radius plus a few km) > would be at orbital velocity given by the equation > >a = v^2/r > > solving for v: > >v = sqrt (ra) = sqrt (1.3 m/s^2 * 1.57e+06 m) > > or let's about 1.5 km/s orbital speed, winging just barely above > Europa's surface features. > > So the question is: could a tether hold, with a tip speed > of 1.5 km/s? Well, flywheel tip speeds are currently in the > neighborhood of 1 km/s, and that's without fullerene weaves. > If they crack the fullerene fiber problem, another order of > magnitude of tensile strength might emerge. > > One problem with this approach: the tether, having released > the penetrator probe, will go flying wildly off somewhere. If, > however, a counterweight incorporates an ion drive powered by > flying through Jupiter's magnetic field, maybe it could retrieve itself > and be reused somehow. > > -michael turner > [EMAIL PROTECTED] > > > - Original Message - > From: "Gary McMurtry" <[EMAIL PROTECTED]> > To: <[EMAIL PROTECTED]> > Sent: Saturday, April 17, 2004 1:30 PM > Subject: RE: The gun thing again [Off Topic] > > > > > > A EUROPA penetrator probe will have to survive 20,000 G on impact. > > Most Mars and Moon probes need only to survive about 2000 G, because > > there they can use rockets to brake the fall (larger payloads). > > We've tested a mass spectrometer to 1200 G. They tell me the > > electronics is not a problem at 2000 G. I think 20,000 G is more of a > > challenge, but then, I don't know if it is or not. There are folks > > doing 20,000 G experiments. Maybe you've seen some results on TV > > over the past year. > > > > Gary > > > > > > >Greetings Sir, > > >Some comments on your post > > > > > >At 02:28 PM 4/8/04 -0500, you wrote: > > > > > >>One of the problems I encountered was how do you build circuitry to > > >>survive the launch. The forces involved will destroy most > > >>electronics as they are now built. Solids state is not very solid > > >>after 15x gravitational forces. > > > > > >Actually, this is probably not a major problem. Gerald Bull put > > >electronics in shells he launched back in the 1960's. Just packed > > >them with sand in his shells. JPL sent two penetrator probes into > > >Mars. The probes did not work, but evidence suggests that it was > > >problems with the battery supply (i.e. the battery couldn't survive > > >the long cold and still function) and not the electronics. Also, > > >combat UAV's can pull (I believe) more that 15g's and they survive > > >just fine. Crash Black boxes in Indy cars routinely survive probably > > >50-100 G's in crashs (for extremely short periods of time). So the > > >electronics will survive. > > > > > >>C
