...Use the physics package as a "normal" nuke...Based on that, I don't see the utility of the laser device. We already have nuclear warheads that can be launched into space that could achieve the same result without the intermediate step of generating a laser beam.
aftercolumbia - 23/3/2007 1:01 AM
It would be effective against targets on Earth unfortunately, if used in two manners:
1. Shoot the gamma beam at Earth. The atmosphere will absorb energy, that's for sure, but the energy is still there, in the atmosphere. If the atmosphere absorbed all the energy, you'd wind up with a Tunguska like explosion. It is more likely that several hundred kilotons worth would make it to the ground (where it would actually have a smaller area of effect.)
2. Use the physics package as a "normal" nuke. This results in a plain Jane 3MT nuke.
Chelomei might consider this a "small explosion"...the guy who origininally designed Proton as a 100MT class missile.
joema - 23/3/2007 3:47 PMQuote...Use the physics package as a "normal" nuke...Based on that, I don't see the utility of the laser device. We already have nuclear warheads that can be launched into space that could achieve the same result without the intermediate step of generating a laser beam.
If the asteroid is discovered far enough out (years), various non-nuclear methods could be employed: gravity tractor, kinetic impactor, etc.
If it's discovered close (weeks-months), an ICBM modified for a precision stand-off detonation could deflect it without fragmentation. Virtually all ICBMs can reach earth escape velocity with a reduced payload. If that failed, you have a redundancy factor of several hundred. Just try again. By contrast if the laser is a highly specialized very complex device. Presumably you'd have only one, or maybe a single backup? If malfunctioned, underperformed, or the launch vehicle failed, it's "game over".
It's technically interesting. The purpose of this forum is to discuss items like that. However it would appear to have very high development costs and limited redundancy relative to other options.
Olga - 23/3/2007 4:40 PMThat is incorrect. An ICBM is simply a launcher with a payload sized for suborbital delivery. Many such ICBMs have (or had) 10 warheads of of 300 kiloton EACH, plus a post-boost maneuvering bus, plus a heavy inertial guidance platform.
Existing ICBMs can NOT be launched some far deep into space for interception purposes.
Olga - 23/3/2007 4:40 PMA stand-off detonation is absolutely ineffective because of lacking an air blast in space – the base of sticking factor.A stand-off detonation is very effective -- the immediate X-ray and neutron burst simply vaporizes a thin layer of material from the asteroid surface which propulsively nudges the body in the opposite direction, without fragmenting it.
Olga - 23/3/2007...what will you do with the “reduced payload”? What will it be enough for?...This has already been studied in great detail. For an asteroid the size/mass of Apophis, a stand-off detonation of a small 30 kiloton nuclear warhead would deflect it (without fracturing) about 15 centimeters/second, which is enough move it out of the gravitation "keyhole" (about 640 meters wide) in 1.2 hours (1.2 MB .pdf): http://www.llnl.gov/planetary/pdfs/I...n/04-Solem.pdf
joema - 24/3/2007 3:16 AMQuoteOlga - 23/3/2007 4:40 PMA stand-off detonation is absolutely ineffective because of lacking an air blast in space – the base of sticking factor.A stand-off detonation is very effective -- the immediate X-ray and neutron burst simply vaporizes a thin layer of material from the asteroid surface which propulsively nudges the body in the opposite direction, without fragmenting it.
bhankiii - 23/3/2007 5:15 PM
Have you considered putting this thing on the back of the moon? There's no atmosphere to get in the way, and it's always pointed away from the earth, so there are fewer political ramifications. Whatever damage you do to the back side of the moon would be considered acceptable, if it saved the earth.
joema - 23/3/2007 6:16 PM
Striped down to a single 300 kt warhead, a Peacekeeper-class ICBM could easily achieve earth escape velocity.
aftercolumbia - 25/3/2007 8:02 PMQuotejoema - 23/3/2007 6:16 PM
Striped down to a single 300 kt warhead, a Peacekeeper-class ICBM could easily achieve earth escape velocity.
The Minotaur IV manual at www.orbital.com does not agree with you. The Minotaur IV is a booster derivative of the Peacekeeper MX with Orbital's Orion 38 added as a fourth stage. The highest energy performance quote is 2246m/s short of escape speed.
aftercolumbia - 25/3/2007 2:02 PMThe Minotaur IV can put about 3,800 lbs (1,723 kg) into a 100 nm LEO.
The Minotaur IV manual at www.orbital.com does not agree with you. The Minotaur IV is a booster derivative of the Peacekeeper MX with Orbital's Orion 38 added as a fourth stage. The highest energy performance quote is 2246m/s short of escape speed.
khallow - 26/3/2007 11:28 PM
At least, this is a device that could be deployed ahead of time. Say as a backup "plan B" that could be promptly executed.
meiza - 25/3/2007 1:38 PMQuoteaftercolumbia - 25/3/2007 8:02 PMQuotejoema - 23/3/2007 6:16 PM
Striped down to a single 300 kt warhead, a Peacekeeper-class ICBM could easily achieve earth escape velocity.
The Minotaur IV manual at www.orbital.com does not agree with you. The Minotaur IV is a booster derivative of the Peacekeeper MX with Orbital's Orion 38 added as a fourth stage. The highest energy performance quote is 2246m/s short of escape speed.
With what payload? Approaching zero?
joema - 26/3/2007 8:42 AMI'm glad someone paid more attention to that end of the curve.Quoteaftercolumbia - 25/3/2007 2:02 PMThe Minotaur IV can put about 3,800 lbs (1,723 kg) into a 100 nm LEO.
The Minotaur IV manual at www.orbital.com does not agree with you. The Minotaur IV is a booster derivative of the Peacekeeper MX with Orbital's Orion 38 added as a fourth stage. The highest energy performance quote is 2246m/s short of escape speed.
ICBMs are simply launch vehicles. In general, the escape velocity payload for a booster is roughly 20-25% of the LEO payload. Examples:
Proton LEO payload: 22,000 kg; escape velocity payload: 5,800 kg
Titan IV LEO payload: 21,680 kg; escape velocity payload: 5,660 kg
The Atlas ICBM booster that launched John Glenn into orbit had a LEO payload capacity of about 1,354 kg. This is less LEO capability than the Minotaur IV has. The Atlas-Agena version of this booster launched Mariner IV to Mars, payload about 260 kg.
It seems obvious that a large ICBM can launch a meaningful payload to escape velocity, since it has already happened.
The question then becomes what does the warhead weigh, and how this compares with the available payload capacity. Nuclear weapon yield-to-weight ratio for real-world devices is about 350 kg per megaton. So for a booster in the Atlas/Peacekeeper class, about 500 kilotons, with the rest for ancillary packaging.
The Peacekeeper used ten W87 300 kiloton warheads, about 400-600 lbs (181-272 kg) each. A single W87 warhead with associated packaging for deep space should be well within the earth escape payload capability. If not, you'd just use a smaller (hence lighter) warhead.
kevin-rf - 26/3/2007 9:49 PMAs described above, a stand-off detonation from a very small 30 kt nuclear warhead would deflect an Aphophis-size asteroid by 15 cm/sec, without fracturing. Details in this research paper (1.2MB .pdf): http://www.llnl.gov/planetary/pdfs/Interdiction/04-Solem.pdf
Sending a real nuke to nudge an asteroids orbit would take longer since it needs to cover the distance between earth and the offending asteroid/comet to have any impact on it. And then time is needed for the nudge to move it enough to miss us. How many months?....Sending a gravity tug requires planning and years of advance notice....How many years?...Ablating the surface with a focused laser or microwave beam or solar beam will take even longer...Last I check no really good gamma ray optics (mirrors or lenses) existed. State of the art seems to be grazing incident mirrors which absorb a fair percent of the gamma rays and will be vaporized by the pulse...
meiza - 27/3/2007 3:36 PM
what would be required to increase the range of the laser?
I’m a bit surprised that nobody asked a question or expressed his doubts that there exists a technology which allows obtaining a radiation density of 66 Hiroshima’s within 6 square centimeters.
kevin-rf - 27/3/2007 3:59 PMExactly. You're still launching a nuclear warhead on an asteroid intercept course. Only when it gets close, you detonate the nuke, which pumps the laser, which strikes the asteroid. You still have most of the launch vehicle performance issues, guidance issues, etc. Plus you add the complexity of the laser itself. I don't see the big advantage of this vs just doing a precision stand-off detonation.
...If this thing has to get fairly close to an asteroid or comet it will need a spacecraft with a guidance system. If the spacecraft can intercept an asteroid with degree of accuracy this thing requires it should be able to do the same with a standard nuke not requiring the fancy gamma ray laser on the front end of the nuke...
joema - 28/3/2007 3:27 AMQuotekevin-rf - 27/3/2007 3:59 PMExactly. You're still launching a nuclear warhead on an asteroid intercept course. Only when it gets close, you detonate the nuke, which pumps the laser, which strikes the asteroid. You still have most of the launch vehicle performance issues, guidance issues, etc. Plus you add the complexity of the laser itself. I don't see the big advantage of this vs just doing a precision stand-off detonation.
...If this thing has to get fairly close to an asteroid or comet it will need a spacecraft with a guidance system. If the spacecraft can intercept an asteroid with degree of accuracy this thing requires it should be able to do the same with a standard nuke not requiring the fancy gamma ray laser on the front end of the nuke...
E_ E_ H - 27/3/2007 4:49 PM
Launching ICBMs, even stripped out one way ticket systems, is daft because the object would not be "blasted" off course. It would probably be broken up.
Olga - 27/3/2007 10:15 PM
3. Your political views are quite funny and one-sided.
Despite existing among different countries suspicions a possible collision of an asteroid with the Earth is a world-wide issue. It is not possible for one country, even for Russia or America to overcome such a challenge alone.
Olga - 28/3/2007 2:15 PM
1. It was discussed in previous postings that using such a device for military purposes is not effective (at least in comparison with existing nukes).
2. As for international cooperation, there is at least one international organization which could solve the issue. I believe some American people still remember its name.
3. Your political views are quite funny and one-sided. If you need a big discussion you can open your thread on that. May be I would even post something reminding you some details on new and modern history.
Olga - 28/3/2007 3:15 PM
2. As for international cooperation, there is at least one international organization which could solve the issue. I believe some American people still remember its name.
aftercolumbia - 29/3/2007 3:09 AM
Gamma rays are incredibly hard to focus, and they do have military applications in the guts of advanced nuclear weapons (which means that most of the knowledge base on how to do it is behind locked doors.)
Olga - 27/3/2007 11:02 PM
As for optics, the device does not require any optics or focusing. Optics’ functions are performed by crystalline planes of a crystal (ttp://www.rufund.ru/Docs/laser/RU_2243621_C1_ENG.zip (1.5MB)). Moreover it is difficult to imagine optics for a beam of such a power (if you have a sufficient physico-mathematical skills you could have look at a patent)
Olga - 28/3/2007 12:15 AM
Despite existing among different countries suspicions a possible collision of an asteroid with the Earth is a world-wide issue. It is not possible for one country, even for Russia or America to overcome such a challenge alone.
vda - 29/3/2007 2:27 AM
I do not see why US (or Russia) cannot build asteroid busters alone. If it will be perceived a real threat, funds will be found at once. Currently US citizens spend more on New Year gifts than on space program.
Olga - 29/3/2007 6:31 AM
I don’t know how much I’m clear in English, but as nobody pays attention to my technical comments may be I chose wrong place to discuss it?
Why is it 'obviously correct'? Is US unable to build nukes? How much will it cost to develop a 25 MT nuke? Or US wants to finance someone else's asteroid buster?
Did Olga's country participated in Spacewatch or otherwise how did they help finding/tracking Earth-crossing asteroids? Or helping (financing?) constructing of new big telescopes capable of doing so? I don't remember big news about this.
I will tell you why it should be obvious -- because we need to mobilize the resources of all the developed countries to complete not just the NEO survey mandated by Congress but also to maintain an ongoing space survey looking for objects that are slightly smaller than that NEO criteria heading for Earth which might only shatter a few cities and kill millions of people. We need eyes and instruments looking out into space from every portion of the planet -- not just the good old USA. This is a task that humanity will have to perform as long as we live on this planet -- we better get used to it. Additionally, it doesn't take much imagination to anticipate that if we do have the good fortune to see something before it hits us, there is a very good chance are we are going to have very little time to mobilize a response and we are going to have to be absolutely certain it will work. To do that I suggest -- no, I don't suggest, I state as a fact -- that we will need the best minds and capabilities on this planet regardless of their nationality. Moreover, we need to take these steps NOW -- not once we feel the breath of impending doom. We need to get international cooperation and I don't care who's asteroid buster we end up financing -- just as long as it works. If it was only your existence at risk, I would tell you to go ahead and take your chances. Unfortunately, it is also mine and everyone else on this planet. And that cannot be put at risk to satisfy anyone's paranoia. By the way, I am sure the Russians would be just as skeptical of working with us as you are toward working with them.
Whether or not Russia participated in Spaceguard in the past is irrelevant to our discussion of the need for their future cooperation. Russia clearly has space capabilities approaching our own. We need to get them involved now and in the future. Olga clearly isn't a representative of the Russian government, so lets try to avoid beating her up with arguments that are nothing but a litany of past grievances between nations. It is the future we need to worry about, not rehashing the past.
Stargazer777 for president.Thank you (wild applause in background), thank you. Contributions to my campaign can be sent directly to my web address. Contact me directly for bribes....
meiza - 30/3/2007 11:07 AM
A conventional nuclear bomb has to travel all the way to the asteroid and possibly match the speed, while this laser can blast the asteroid from a distance away, distance comparable to the earth-moon distance?
Olga - 30/3/2007 2:48 AMQuotemeiza - 30/3/2007 11:07 AM
A conventional nuclear bomb has to travel all the way to the asteroid and possibly match the speed, while this laser can blast the asteroid from a distance away, distance comparable to the earth-moon distance?
Yes. But it's not the only advantage. I'll reply more in the nearest future.
meiza - 30/3/2007 2:07 AMA nuclear warhead doesn't need to match speed with the asteroid or comet it's targeting, any more than a World War II anti-aircraft shell with a radar proximity fuze needed to match speed with its target: http://en.wikipedia.org/wiki/Proximity_fuze
A conventional nuclear bomb has to travel all the way to the asteroid and possibly match the speed....
joema - 30/3/2007 7:54 PMQuotemeiza - 30/3/2007 2:07 AMA nuclear warhead doesn't need to match speed with the asteroid or comet it's targeting, any more than a World War II anti-aircraft shell with a radar proximity fuze needed to match speed with its target: http://en.wikipedia.org/wiki/Proximity_fuze
A conventional nuclear bomb has to travel all the way to the asteroid and possibly match the speed....
As you'd expect, technology has progressed a bit since WWII, and there are various ways of employing independent redundant fuzing methods to ensure proper operation -- laser, radar, infrared, etc.
The laser isn't useful to shoot the asteroid as it passes close to the earth. By that time the necessary deflection couldn't be achieved.
The laser and the nuclear warhead that powers it must be launched on a high performance booster and accurately guided through deep space to within several thousand km of the asteroid. This must take place long before the asteroid gets close to earth.
Those requirements are very similar to simply using the warhead directly in a non-fragmenting stand-off detonation.
A stand off detonation does require precise terminal guidance and redundant fuzing. However that technology has been well understood for a long time.
The laser requires development of entirely new technology. Testing would require nuclear detonations, which is not allowed under the current test ban treaty: http://en.wikipedia.org/wiki/Comprehensive_Test_Ban_Treaty
The same treaty would also theoretically prohibit direct use of nuclear weapons against an asteroid headed straight at earth, but presumably if there were no other choice than a global apocalypse the devices would be used.
By contrast the laser requires nuclear detonations for developing and testing the gamma ray laser years in advance, when there is no asteroid imminently threatening. It's probably a harder sell from that standpoint.
meiza - 30/3/2007 2:20 PM
Nah, this is about the "keyhole" thing, when the asteroid first passes near earth and it's determined that it will hit earth on a later round. As mentioned in previous messages.
And it's a pretty hard problem to intercept an asteroid if you don't match speeds, since the velocities are so big. Sure, deep impact did it with a well known "easy" one. I don't know much about this problem. You have to be at the right side of the asteroid at the right distance and detonate at the right time. With the laser it's not so precise as you can track the asteroid as it moves, it is enough if you're some tens of thousands of kilometers on the right side of it.QuoteThe laser and the nuclear warhead that powers it must be launched on a high performance booster and accurately guided through deep space to within several thousand km of the asteroid. This must take place long before the asteroid gets close to earth.
not necessarily, see above
joema - 30/3/2007 1:54 PM
The laser requires development of entirely new technology. Testing would require nuclear detonations, which is not allowed under the current test ban treaty: http://en.wikipedia.org/wiki/Comprehensive_Test_Ban_Treaty
The same treaty would also theoretically prohibit direct use of nuclear weapons against an asteroid headed straight at earth, but presumably if there were no other choice than a global apocalypse the devices would be used.
meiza - 30/3/2007 11:07 AM
To summarize, is the main advantage of the laser that it can shoot at the asteroid when it passes earth close by?
And when doing this, it can hit the asteroid even if the last position updates come only minutes before the pass?
A conventional nuclear bomb has to travel all the way to the asteroid and possibly match the speed, while this laser can blast the asteroid from a distance away, distance comparable to the earth-moon distance?
lambda0 - 30/3/2007 2:36 PM
However, I wonder about the conversion efficiency of the energy of the explosion to useful gamma rays. Lasers have generally a low efficiency (a few percents), and I saw in your document that the emission of gamma rays comes from a quite complex sequence of events and energy conversion processes that may generate losses at each stage.
What is the real conversion efficiency ? It is based on experiments, or only on theoretical calculations ?
publiusr - 31/3/2007 12:40 AM
Olga, I heard about some weapon called an "Ellipton" some years ago. Would that have been something similar?
kevin-rf - 30/3/2007 5:07 PM
Unless you can bring that gamma ray laser to a really sharp focus over a large distance you will still have to get pretty close the mole hill for it to work.
Not as close as with a nuke, but still within a stones throw. You will still need roughly the same DeltaV and time to reach said mole hill.
kevin-rf - 30/3/2007 5:07 PM
Considering how hard it is to focus gamma rays I don't see have you can generate a focused beam out of the taper.
kevin-rf - 30/3/2007 5:07 PM
Leaving a bunch of Zenit,Atlas,Delta Heavy,Arianes V, or H-2 rockets in a wharehouse waiting for said rock is not cost effective and actually reduces your chance of mission success.
kevin-rf - 30/3/2007 5:07 PM
What needs to be done.
1. Figure out how to encapsulate a nuke so it is still in it's comfort zone after several months in space.
2. Figure out how to encapsulate a nuke so we do not have a radiation release if things go wrong on launch.
meiza - 5/4/2007 3:20 AM
Why not use gyro for panning to hit the asteroid in a constant spot? I understand attitude control that way can be very precise, space telescopes use it?
Stargazin2nite - 6/4/2007 1:48 AM
"Unfortunately Energia does not participate in this project. Everything is limited to Krikalev (as a private person only). Your fantasy is misleading the public."
Stargazin2nite - 6/4/2007 1:48 AM
I think it is ironic that you are accusing someone else of promoting a "fantasy misleading the public". YOU are the one proposing a system designed around technology (gamma ray lasers) that doesn't exist!!
kevin-rf - 5/4/2007 10:27 PM
Ummm where are you getting these times from? Lasing for 0.001 seconds is a very long time frame for a laser pulse. I don't care if a nuclear pulse is exciting the thing. If the device is 2 meters long it would imply the shock wave from a nuclear explosion traveling at 2000 m/sec. Or half the speed of sound in steal... I would expect a pulse duraton on the order of micro seconds if not single digit nano seconds.
kevin-rf - 5/4/2007 10:27 PM
An ordinary gyro can be used because you will be relying on the mass interia of the system to keep it accurately pointed. Spinning the device arround the focus is an excellent way to get your pointing accuracy.
kevin-rf - 5/4/2007 10:27 PM
These events are rare enough that one can properly design the intercept trajectory so it will be a non issue. Your 70 km/s intercept speed assumes you are intercepting at 90 degrees. If this is a last ditch effort you are more likely going at or past the target at 70 km/s and you left right translation will be much less than 70 km/s so it will become a non issue.
Stargazin2nite - 6/4/2007 1:48 AM
Unfortunately, another collaboration composed of researchers from Argonne National Laboratory, Los Alamos National Laboratory, and Lawrence-Livermore National Laboratory used the very intense and sophisticated X-ray source at Argonne National Laboratory to perform the same experiment and announced that it could not reproduce the results reported by the Texas group. Furthermore, the experiment at Argonne sets limits on the effect more than a thousand times below the magnitudes reported in the Texas papers.
Stargazin2nite - 6/4/2007 1:48 AM
With regard to your proposal, please point us to any peer-reviewed research that demonstrates your technology concept of a gamma ray laser is even remotely feasible. Here's the peer-reviewed science that indicates it most likely is not feasible:
(1) I. Ahmad et al., Physical Review Letters 87, 072503-1 (2001).
(2) I. Ahmad et al., Physical Review C 67, 041305 (R) (2003).
Olga - 10/4/2007 2:37 PM
Read the document: http://www.rufund.ru/Docs/laser/RU_2243621_C1_ENG.pdf
You will find all the answers there.
Nobody guarantees “comfortable” trajectories. We should be prepared for the worst. Then we could be sure that in simple cases everything goes as it was planned. As for the velocities I mentioned a project “Vega” earlier.
kevin-rf - 11/4/2007 1:03 AM
Why don't you quote the relevant points from the document instead. I have read it more than once. It is lacking. This is an untested device that is not the answer to life the univese and everything.
kevin-rf - 5/4/2007 10:27 PM
Ummm where are you getting these times from? Lasing for 0.001 seconds is a very long time frame for a laser pulse. I don't care if a nuclear pulse is exciting the thing. If the device is 2 meters long it would imply the shock wave from a nuclear explosion traveling at 2000 m/sec. Or half the speed of sound in steal... I would expect a pulse duraton on the order of micro seconds if not single digit nano seconds.
kevin-rf - 11/4/2007 1:03 AM
We have had probes fly by, return comet dust, and even send a copper slug into the heart of a comet. This proven technology. You brush it aside as it is to hard to do.
kevin-rf - 11/4/2007 1:03 AM
If it is to late, we need to start mass evacuations, sheltering in place in areas that can not evac in time.
kevin-rf - 11/4/2007 1:03 AM
Yes your laser is interesting, but one has never been built or tested. Actually it was presented by Stargazin2nite as it might not work and you say trust us it will.
...
What is your goal here? To talk about one approach among many or raise money to fund the device for the devices sake? As many keep pointing out it is not the only approach.
Stargazin2nite - 11/4/2007 4:58 AM
...with the level of arrogance you are displaying...
Stargazin2nite - 11/4/2007 6:49 AM
Also the patent is dated 2004 -- why sit on this revolutionary technology for 2+ years???
Stargazin2nite - 11/4/2007 11:24 PM
The links I provided are relevant to the most recent claims regarding stimulated emission of gamma rays. You are correct that they do not explicity discredit your approach, however they do illustrate the persistent difficulties that the scientific community has encountered while attempting to achieve a demonstratable GRASER -- i.e. a "holy grail" of physics.
[...] but based on current scientific understanding and a mountain of published research over the past 60 years, I cannot convince myself that a GRASER will ever be a viable method of dealing with NEO's.
Stargazin2nite - 11/4/2007 2:24 PM
"Recoilless gamma-ray lasers", George C. Baldwin and Johndale C. Solem, Theoretical Division, Los Alamos National Laboratory, Reviews of Modern Physics, Vol. 69, No. 4, (1997)pp1085-1117.