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General Discussion => Advanced Concepts => Topic started by: Olga on 03/18/2007 02:11 pm

Title: Earth defense from asteroid and comet hazard using super-power gamma-laser
Post by: Olga on 03/18/2007 02:11 pm
Dear all,

We are launching a new web-site concerning several projects in Russia. Among those projects there is one called “A system for Earth defense from asteroid and comet hazard on the base of super-power gamma-laser”. We would appreciate your feedback on the related document: http://rufund.ru/Docs/laser/Doclad_laser_ENG.zip

Title: Re: Earth defense from asteroid and comet hazard on the base of super-power gamma-laser
Post by: khallow on 03/22/2007 01:41 pm
Glancing through the document, I see that this appears to be a one-time emergency device (among other things, it appears that use of the device results in a small nuclear fission explosion). Namely, it's intended for a case where a collision with the threatening comet or asteroid is near at hand and large changes in the trajectory are needed. There are several problems that seem relevant here. First, there is the possibility that the device would need to be used near Earth. EMP mitigation might need to be considered. Second, this could generate a lot of debris which is one of the reason explosions (which are similar in effect) aren't considered desireable. Even if the debris isn't an issue for Earth, it greatly increases the risk of impacts in near Earth space. Third, this device has some obvious uses as a weapon (in addition to the considerable ability to deflect asteroids) and that would be an obstacle to its deployment.

Come to think of it, there's also a technical matter (assuming I understand the operation of this device sufficiently well). Given that there's a lot of natural neutron sources both on Earth and in space, it appears to me that you'd want to store this device in a subcritical (and stable) configuration and somehow snap it together just prior to firing. But the alignment of this process would appear to me that it needs to be very precise. Given that among other things, the device will probably experience both large acceleration loads (from getting launched into space) and heating cycles (from solar radiation), you need to have an alignment process that can handle that.
Title: Re: Earth defense from asteroid and comet hazard on the base of super-power gamma-laser
Post by: Olga on 03/22/2007 06:30 pm
Dear khallow,

Thank you for your posting. I’ll try to be consecutive in my answer.

First of all, energy of the beam is equivalent to about 1 megaton at a trinitrotoluol. A thermonuclear explosion (at 30% coefficient of efficiency) is about 3 mt. Is there someone who considers it is a small explosion? :-)

Secondly, the device is not only for close in interception cases. It is for ANY case, including super difficult cases when a dangerous object has an embarrassing trajectory.

The assumption that there will be needed an explosion near the Earth is incorrect. In the Earth’s magnetosphere, to be precise, closer than one million kilometers from the Earth (according some sources – 5 million kilometers) it is acceptable to perform such “small” explosions as a last resort. The reason is not an EMP only. An appearance of an artificial radiation belt is more harmful.  

Thirdly, the device does not destroy a big object. We can talk about an object’s destruction if it’s dimensions are tens meters, in which case, its debris will be destroyed in the atmosphere.

Fourthly, yes, this device could be used as a weapon, a space weapon. Its use against objects on the Earth would not be effective because the atmosphere would absorb the beam’s energy. The effect of such a weapon on the Earth’s surface would be similar to the effect of the explosion of a 3 megaton bomb in space. The question of deployment of a “space weapon” is a political one and should be solved internationally. ANY deflecting asteroid device could be used as a weapon just by deflecting some asteroid toward an “Evil Empire”.

As for technical issues: issues of thermoregulation, acceleration loads, protection from high-energy particles are solved in many variants. The precise of alignment for such devices is a solvable task (a precise of alignment is not a big issue).  One real problem, however, is maintaining precision at the moment of the explosion.  To overcome this problem a precession of the device could be used at the fire moment.
Title: Re: Earth defense from asteroid and comet hazard on the base of super-power gamma-laser
Post by: aftercolumbia on 03/22/2007 09:01 pm
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.
Title: Re: Earth defense from asteroid and comet hazard on the base of super-power gamma-laser
Post by: joema on 03/23/2007 11:47 am
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...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.
Title: Re: Earth defense from asteroid and comet hazard on the base of super-power gamma-laser
Post by: on 03/23/2007 01:15 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.
Title: Re: Earth defense from asteroid and comet hazard on the base of super-power gamma-laser
Post by: stargazer777 on 03/23/2007 06:18 pm
As Olga mentioned, any device sufficiently powerful to change the trajectory of a onrushing comet or asteroid would, inevitably, make a powerful weapon that could be used against Earth.  That is a risk we are just going to have to take.  I can't make a judgment on its scientific or engineering feasibility, but I wouldn't close the door on any option that might enable us to save our collective derriers from such a catastrophe.  When it comes to the survival of our species -- remember, "pride cometh before the fall."
Title: Re: Earth defense from asteroid and comet hazard on the base of super-power gamma-laser
Post by: Olga on 03/23/2007 07:59 pm
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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.

1. Unfortunately, an interaction of a gamma-beam of such energy with a medium is not researched enough. There is a set of nuclear, quantum, wave and thermodynamic processes. According to the modern estimations it is possible to say that, indeed, a shoot of the beam to the atmosphere will create appearances similar to the processes of Tunguska but scales of them will be in 50-100 times less.    Just to remind, energy of the beam is about 1 megaton and the energy in the region of Podkamennaya Tungusska according to the modern estimations was about 40-50 mt.


Yes, in top layers of the atmosphere, starting from 80-100 km when the beam will pass in a target direction there appears a wisp of hot plasma. More there, a part of exposure’s products concentrated in a beam as well will reach the target.  However the most part of the energy will be scattered in top layers of the atmosphere in contrast to Tungusska’s phenomenon where a part of substance (the beam has no any) reached lower layers of the atmosphere. An air blast is the basic damaging factor and it can not be powerful coming from a great height. The result will be a zone of total destruction on the Earth’s surface with dimensions of about one half of a football ground. Don’t forget that to do it you will need to set off a charge of 3 mt in the nearest space which will destruct your satellite system as well as will make impossible any space missions for months or even years because of powerful artificial radiation belts in the magnetosphere. Do you think a destruction effect costs that?


2. For what? There are mentioned by you “normal” nuke which besides more effective and cheaper. Let’s agree that a space vehicle with the device will be based on the Earth in a subcritical and stable configuration under an international control. At Baikonur  might be guarded by American, Chinese and Russian military,  at Franch Gviana  or at Canaveral – Japanese, French, Indian and so on. Systems of international controls ate technically and organizationally are developed.  

Title: Re: Earth defense from asteroid and comet hazard on the base of super-power gamma-laser
Post by: Olga on 03/23/2007 08:40 pm
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joema - 23/3/2007  3:47 PM

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...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.

In one Russian comedy film there is one scene when one of the heroes looking to a meadow turns to another hero and asks: “Do you see the gopher?  No?  But it exists.” I mean if you don’t see something it doesn’t mean the thing does not exist.

Existing ICBMs can NOT be launched so far into deep space for interception purposes. They can NOT even achieve 0.01 of a result which is achievable by the proposed laser. To do that you would need a superpower thermonuclear charge which would go deep into an object. A stand-off detonation is absolutely ineffective because of lacking an air blast in space – the base for destroying an object.  Also such charges should be constructed before so they could withstand accelerative forces of tens of thousands of G’s.

The laser beam in fact settles a rocket engine on an asteroid and combines a power of deep thermonuclear explosion with advantages of a remote impact.  The issue of utilization of normal nukes was discussed broadly by specialists. You can easily find information about that in the Internet.

You say that ICBMs can reach earth escape velocity with a reduced payload. That is true. And how long they will travel at this velocity to a interception point? At which distance do you want to intercept an object? And when a rocket is there what will you do with the “reduced payload”? What will it be enough to do? Don’t forget that the aim of the “reduced payload” is to give a stone mountain an additional velocity which should allow this mountain to miss Earth by at least 6400 kilometers (one Earth radius) within days before a collision. If you fail, there are no second chances?

Have you ever seen a “plain” nuclear device or a space device?  Even the first satellite was not so “plain”. Any specialized and complex device may be tested including its elements if you can develop it to a certain reliability.

Nobody says we are talking about one device. A group of such devices would be about in 100 times cheaper than gravity tractor, kinetic impactor, etc.
Title: Re: Earth defense from asteroid and comet hazard on the base of super-power gamma-laser
Post by: Olga on 03/23/2007 08:59 pm
Dear stargazer777,

Thanks  :)
Title: Re: Earth defense from asteroid and comet hazard on the base of super-power gamma-laser
Post by: joema on 03/23/2007 11:16 pm
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Olga - 23/3/2007  4:40 PM
Existing ICBMs can NOT be launched some far deep into space for interception purposes.
That 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.

Striped down to a single 300 kt warhead, a Peacekeeper-class ICBM could easily achieve earth escape velocity. In fact the Titan II ICBM launched the Clementine probe into lunar orbit, which included the additional propellant burden of lunar orbit insertion: http://en.wikipedia.org/wiki/Clementine_mission


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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.

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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

If an asteroid the mass/speed of Apophis is detected closer, missing the keyhole isn't sufficient -- you have to alter the trajectory to totally miss earth. A single 30 kt detonation 1 year out would do it in most cases. For closer detections, multiple detonations would be required, each changing the asteroid velocity about 15 cm/sec. In theory you could deflect it sufficiently (without fracturing) with only a few weeks advance notice by using 10-20 such stand-off detonations. There are many variables, but the technology already exists and could be deployed within weeks or months if necessary.
Title: Re: Earth defense from asteroid and comet hazard on the base of super-power gamma-laser
Post by: Olga on 03/24/2007 03:58 pm
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joema - 24/3/2007  3:16 AM


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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.



If you insist I’ll try to give more arguments.  
At first let’s consider a high altitude thermonuclear explosion. Utilization of a thermonuclear explosion for defense from hazardous space objects was suggested for the first time in Hyde R. A., 1984. Cosmic bombardment. - Special report UCID-20062, Lawrence Livermore Nat. Lab. Resulted from the thermonuclear explosion decay products, X-ray and gamma-radiation and a neutron flux arrange an air-blast. The main role belongs to the neutron flux (Hammerling P., Remo Y. L., 1992. NEO Interaction with X-ray and neutron radiation. - In: IW-92, p. 186.), which gets at a depth of 20 cm under a surface of an object at a density of ?=2g/cm3 and average atom weight of a substance equal to 25. A part of substance will be “blown-off” (here is a source of origin English terms “blow-off” and “stand-off” for this type of thermonuclear explosions) and a space object will get an additional impulse.

At an optimal height of explosion over a surface (Ahrens Th. J., 1992. Deflection and fragmentation of Near-Earth- As-teroids. - IW-92, pp. 89-111) equal to


h=D((v2 - 1)/2)˜0.2D

0.3 of its surface will undergo radiation. For all that explosion energy equal to f=0.28 gets to the surface. A share of explosion energy transmitted to a neutron radiation is equal to e=0.32. For all that a velocity of a blown-up particle is equal to v =feW/CP, where W is a power of thermonuclear explosion in kilotons; CP = 2 km/s – is a velocity of spreading a neutron blast wave, and a velocity v is directed orthogonally to the object’s surface. At accepted values v = 44 m/c for each of kiloton of the charge. A reduction of v for a direction of object’s motion gives  vr =0.7 v = 31 m/c for each of 1 kt of the charge (for D = 100 m a drift speed is 5.3 cm/s).

As a result the object with a mass M will get a velocity DV (m/s) equal to


?V=?D2d?fvreW/M=2*107?D2W/M

 where W in kt, D in m, in g/sm, M in g.  

The consequence is that by explosion equal to 300 kt you will give to a “medium” in his density asteroid with a diameter of 1 km increase of velocity about 2-3 cm/s.

Variants of stand-off and immediately surface explosions give similar results in a diapason up to 20 mt. I will save you your calculations of different variants. You can use an average value of 106-108(t m/s)/Mt. For the rest be so kind as to calculate yourself. If you meet any difficulties I can provide you with diagrams for explosions of various power and asteroids of various dimensions, just to save you from a necessity to use sources like http://en.wikipedia.org or kids’ encyclopedias.

As for ICBM I consider the format of this forum is not appropriate to give lectures on space ballistic and etc. It requires some time to invent a situation with a dangerous space object where this carrier would be useful and when it would be worthy to use it (heavy space types of it for instance 3C has better chances). And if you care a little about consequences for ecology after ICBM utilization then it’s better to forget about military toys all together.  

Here is a typical, even optimistic case: a long-period comet-type object from a remote area of the Solar system is discovered. The core’s diameter is about 8 km. An inclination to ecliptic’s plane is 65 degrees. A direction of revolution round the Sun is reverse to the Earth revolution at its orbit. A velocity relative to the Sun while crossing an Earth orbit is about 30 km/s. Time to a possible collision is 6 months (we were lucky). Estimations of collision’s probability are 60% (after 10 days of observation). After three months from discovering the comet became active, a trajectory is corrected; the core’s decay is predicted for one large (90% of mass) and few small fragments. Estimations of collision’s probability become higher up to 90% (after 90 days of observation).
Is there anything incredible?  Now let’s suggest NASA use Titan. Can you guess where they will advice you to allocate it? I can’t use rude words here, but you can ask me via private mail. Or do you hope that we will need to deflect only those objects which will be “comfortable” to deflect? May be you would ask asteroids to be polite and check with us their trajectories and dimensions in advance?
Title: Re: Earth defense from asteroid and comet hazard on the base of super-power gamma-laser
Post by: Olga on 03/24/2007 05:10 pm
I’ll start with a fact that Apophis is not a limitation. Secondly, data from “one year out” taking into account a required precise will not allow you to answer a question “in what direction to deflect”? Deflecting “somewhere” may push it directly to the Earth, when without yours interference it would pass beside the Earth. And this is only one reason. You said “A single 30 kt detonation 1 year out would do it in most cases”. I’ve suggested one situation in the previous posting – try to push it from “falling down” trajectory.

To deflect “with only a few weeks advance” in fact means that at a point from where there are few weeks before a collision there is already a group (10-20) of space devices (which need to be designed, constructed, launched, to fly) which will consistently (“just” 10-20 nuclear explosions) deflecting an asteroid. For all that the devices were not tested because they were made “quick and dirty” within “few weeks or months”. Who will win do you think? I would stake on asteroid :)

I’ll try to give a graphic example. A difference between mentioned by you nukes and the proposed laser is the same as between infantryman with a grenade and infantryman with a bazooka in a fight against a tank. At certain circumstances, if fortunate, the first one with a grenade can shoot down the tank, however, is it reasonable for his commanders to expect he succeeds?

Sorry for short answers. Reaction to all aspects would end up with very long texts.
Title: Re: Earth defense from asteroid and comet hazard on the base of super-power gamma-laser
Post by: Olga on 03/24/2007 05:35 pm
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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.


I confess that we did not consider this variant :)

I should remind you that a theoretical firing distance of the device is about 100 000 km (one third of the Moon orbit’s radius). A real firing distance taking into account difficulties with pointing and keeping stable the beam is unlikely to be more than 30 000 km. Asteroids in their turn have an annoying property not to take into consideration our preferences regarding their trajectories and won’t go straight “to ambush”  (then it is better just to hope that the Moon will be on their way). With the same result you can allocate a nuclear mine somewhere in a deep space hoping to detonate it if some asteroid will pass close by.
Title: Re: Earth defense from asteroid and comet hazard on the base of super-power gamma-laser
Post by: aftercolumbia on 03/25/2007 07:02 pm
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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.

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.
Title: Re: Earth defense from asteroid and comet hazard on the base of super-power gamma-laser
Post by: meiza on 03/25/2007 07:38 pm
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aftercolumbia - 25/3/2007  8:02 PM

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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.

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?
Title: Re: Earth defense from asteroid and comet hazard on the base of super-power gamma-laser
Post by: joema on 03/26/2007 02:42 pm
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aftercolumbia - 25/3/2007  2:02 PM
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.
The Minotaur IV can put about 3,800 lbs (1,723 kg) into a 100 nm LEO.

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.
Title: Re: Earth defense from asteroid and comet hazard on the base of super-power gamma-laser
Post by: Olga on 03/26/2007 04:12 pm
The question is not whether it is possible to use a nail file to tighten a screw or not :)
Title: Re: Earth defense from asteroid and comet hazard on the base of super-power gamma-laser
Post by: khallow on 03/26/2007 07:28 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.

aftercolumbia, the Minotaur IV puts about 1700 kg into orbit (according to their fact sheet (http://www.orbital.com/NewsInfo/Publications/Minotaur_IV_Fact.pdf)). The fourth stage must be quite heavy compared to a single W87 warhead (http://nuclearweaponarchive.org/Usa/Weapons/W87.html) (which is apparently used in the Peacekeeper) which weights somewhere around 200 to 400 kg.
Title: Re: Earth defense from asteroid and comet hazard on the base of super-power gamma-laser
Post by: Olga on 03/26/2007 08:09 pm
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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.


Sorry, I think I missed something. Do we have any "plan A" already?
Title: Re: Earth defense from asteroid and comet hazard using super-power gamma-laser
Post by: Olga on 03/26/2007 08:31 pm
Since you started to discuss launch vehicles, an integrated launch vehicle using Zenit-2S seems to be the most appropriate in the nearest future (according announced characteristics). In case it will be developed towards acceptable level of reliability and modified according specific requirements to an interceptor.

As for modern ICBM they were constructed for other purposes with other requirements and limits.  It is not reasonable to talk about them as about effective NEO interceptors. (You could propose Patriots as well which were quite successful for Saddam’s Scad’s :)) .

Deflecting NEOs is very complicated and complex (not only technically) issue. Any complicated issue has simple, clear for understanding and INCORRECT solutions. Think about.
Title: Re: Earth defense from asteroid and comet hazard on the base of super-power gamma-laser
Post by: aftercolumbia on 03/27/2007 12:33 am
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meiza - 25/3/2007  1:38 PM

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aftercolumbia - 25/3/2007  8:02 PM

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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.

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?

700kg.  The minimum energy payload is about 2200kg.
Title: Re: Earth defense from asteroid and comet hazard on the base of super-power gamma-laser
Post by: aftercolumbia on 03/27/2007 12:42 am
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joema - 26/3/2007  8:42 AM

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aftercolumbia - 25/3/2007  2:02 PM
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.
The Minotaur IV can put about 3,800 lbs (1,723 kg) into a 100 nm LEO.

I'm glad someone paid more attention to that end of the curve.

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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.

All of these add stages to their low energy editions.

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It seems obvious that a large ICBM can launch a meaningful payload to escape velocity, since it has already happened.

The ICBMs we are talking about have design energies some 700 to 1000m/s short of LEO.  This is why Minotaur IV sports the Orion 38...making it a booster with four stages, each with a different manufacturer!  It is pretty obvious that more needs to be done (and already has been done) than simply stripping nine warheads off.

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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.

Also remember that this mission, unlike that of an ICBM (with it's 30 minute duration) is a full blown spacecraft, complete with star trackers and solar power.  The model it really ought to be operating on is Deep Impact...lithium deuteride instead of copper, so you get that H-bomb level bang.  (I've been misunderstood before, so let me clarify that I'm not suggesting driving such a warhead headlong into the surface.)
Title: Re: Earth defense from asteroid and comet hazard using super-power gamma-laser
Post by: kevin-rf on 03/27/2007 02:49 am
I think it is a solution in need of a problem.

It has some advantages,

If developed and stuck in a silo somewhere in Kansas it can be launched on short notice and used at a stand off distance. It will take what? Three days to get far enough from the earth to be used without wiping out everything else in orbit.

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. It will require a fair amount of fuel since it not only has to intercept the asteroid but also change its path so as to match the asteroids path through space. How many years?

Ablating the surface with a focused laser or microwave beam or solar beam will take even longer and only be useful when the offenders orbit faces the correct end towards us and we have said lasers/microwaves/solar beams.

The problem is you still need to develop a vehicle to cradle and point the gamma ray laser during its flight. Unless you fly it really close to the offender you have to some how focus the gamma ray laser to a really tight spot on the target. At a few million km out how large is a 1 km asteroid in degrees? If you don't focus then most (99 point what percent) of your energy is wasted. 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. This is one of the problems that killed using 157nm (deep UV) light sources for semiconductors. You had optics to handle 193nm light, but the materials broke down at 157nm and instead the node was deleted and replaced with a combination of 193nm liquid immersion optics and electron beam technologies. Sadly I do not see how you will be able to focus that laser of yours.

There is more than one way to skin this cat...

Asteroid/Comet defense has to be layered.

The first line is intelligence. Frequent and constant dedicated earth and deep space based searches for asteroids and comets. One of the big holes in our knowledge is how many unknown objects orbit mostly inside of the earths orbit and therefore are lost in the suns glare? The sooner we know an asteroid/comet is on its way the better chances we have.

The second line is deflection. To date many people have provided many ideas on how to do it. Many will work to a limited degree. I am very partial to gravity tugs. They are 'simple' and will not generate debris that will pepper earth and any spacecraft in orbit around earth.

We need long term deflection where we have detected and predicted an impact in advance and have time to use a slow deflection method. Tugs, Lasers, Impactors...

We need short term deflection where the object was detected to close to impact to do something without drastic measures. This is where nukes, impactors, and gamma ray lasers may come into play. A good example here is comets since they are really falling into the solar system from the outer solar system at a good clip. When you detect one it will already be lined up for a collision with earth some months later.

We need a plan for when an object is detected to soon before impact to do anything. If we have a day or more of notice we can do things to protect the people in the effected areas and reduce the amount of lives lost. Sitting on a side walk drinking a coffee and looking up and going 'oh my' is less than ideal.  

Interesting site ( http://www.rufund.org/ ), looks like someone is trying to make some money off of some Russian technologies. Kind of reminds me of an article ( http://www.thespacereview.com/article/824/1 ) about Energia. Whose name is all over this laser. As for the other technologies. Yes they are novel, but there was already a needle free blood sugar monitor on the US market. It was withdrawn a few years back due to technical calibration issues. It was some sort of IR spectrograph and the the technic had some repeatability issues. The third item is interesting, but why do I want a high efficiency toaster oven when I can buy a low efficiency one for five bucks at walmart? And before I get the rash of not being eco sensitive I drive a hybrid, only buy energy star appliances and am a card carry member of (and gives time to) more than one  environmental group...
Title: Re: Earth defense from asteroid and comet hazard using super-power gamma-laser
Post by: joema on 03/27/2007 02:53 pm
Quote
kevin-rf - 26/3/2007  9:49 PM
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...
As 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

Typical warhead yield-to-weight is 350 kg per megaton, so you'd need only 10.5 kg for the warhead itself, plus ancillary equipment. A wide variety of available boosters -- including but not limited to modified ICBMs -- are capable of boosting that to escape velocity.

The 478 kg New Horizons probe was boosted by a production Atlas V to 36,200 mph (16.21 km/sec): http://en.wikipedia.org/wiki/New_horizons It could just as easily been an asteroid-deflecting warhead used in a stand-off detonation.

At that speed it passed the moon's orbit in nine hours (vs three days for Apollo).

So off-the-shelf technology exists to intercept an asteroid in deep space within days of launch, not months. The deflection required obviously varies based on asteroid mass, trajectory, and intercept distance.

There are two basic deflection scenarios:

(a) A small deflection to miss the gravitational "keyhole" -- a tiny region in space through which the asteroid must pass to hit earth on a subsequent encounter. This typically requires detection a year or more out. In that case you wouldn't necessary need nuclear deflection, although designing and building a non-nuclear method would add to the lead time required.

(b) A larger deflection to miss earth if on a direct impact course. In this case, if detected less than a year out, nuclear stand-off deflection is about the only option.

Laser deflection of asteroids has been discussed many times previously. Many laser, kinetic, and nuclear deflection methods are studied in these papers: http://www.llnl.gov/planetary/

The mirror or beam divergence problem is significant, and tends to limit the feasible range of lasers. Consider one of the most powerful lasers ever built -- the 1 megawatt COIL laser used in the Boeing ABL: http://en.wikipedia.org/wiki/Airborne_Laser

It supposedly will be able to fire about 20 rounds of (maybe) several seconds each. If we take 3 sec/round as typical, that's 60 sec total firing time. Total energy emitted would be about 60 million joules, but you'd lose some energy from atmospheric absorption, even if adaptive optics maintained focus. Yet 60 megajoules is only about the energy of 1/2 gallon of gasoline.

The beam divergence of a 1.35 micron, 1.5 meter dia COIL laser is about 1.15 microradians. At distances of more than a few thousand km, the beam would be much wider than the asteroid.

So whether surface-based, airborne, or space-based, beam divergence of any laser will tend to limit the useful range. For visible and near-IR, we at least know how to focus that and manage power levels in the megawatt range. It took many years of research to achieve that.

The nuclear-pumped gamma-ray laser described in the paper Olga mentioned avoids this by launching it into space on an intercept course for the asteroid. It must come within 10E8 meters, maximum, of the asteroid. At that point the warhead detonates, creating the laser which strikes the asteroid.

If you're going to launch a nuke into space on an asteroid intercept course, why add the additional development and efficiency burden of carrying a laser? You're already launching a megaton-class nuclear warhead on an asteroid intercept course, but when you approach the asteroid using the nuclear detonation to pump a gamma-ray laser. Why not just use the nuke itself, do a precision stand-off detonation? The technology already exists for that.
Title: Re: Earth defense from asteroid and comet hazard using super-power gamma-laser
Post by: kevin-rf on 03/27/2007 04:31 pm
So if we discovered an inbound asteriod that will mash the misty isles into puridge by easter we could mount a defense with off the shelf components? The problem is a system similar to existing spacecraft with a warhead inside is theory. No one has done the design work yet. The space probe and rocket do not exist. At least not that has been publically funded or published.
Title: Re: Earth defense from asteroid and comet hazard using super-power gamma-laser
Post by: Olga on 03/27/2007 07:02 pm
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.    

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)

Unfortunately Energia does not participate in this project. Everything is limited to Krikalev (as a private person only). Your fantasy is misleading the public.  

Development of a web-site www.rufund.ru/org is at the very beginning. I have a great wish to answer you regarding other projects but I have to control myself and not send something “off-top” the current thread. I would like to advice you the same. I would be happy to answer all your questions at forum of the mentioned web-site which will be available in a few weeks.


Title: Re: Earth defense from asteroid and comet hazard using super-power gamma-laser
Post by: meiza on 03/27/2007 08:36 pm
what would be required to increase the range of the laser?
Title: Re: Earth defense from asteroid and comet hazard using super-power gamma-laser
Post by: kevin-rf on 03/27/2007 08:59 pm
Quote
meiza - 27/3/2007  3:36 PM

what would be required to increase the range of the laser?

Being able to focus a 1 megaton (should actually be converted to mega/giga joules) gamma ray laser...

Quote
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.

Why is such a device for sale on the open market? ;) Wasn't the mass converted to energy at Hiroshima on the order of the mass of a penny? It's just the machine to do the conversion weighs much more than a penny. I would assume the 'package' is the trigger and fusion is going on in the laser taper... So I believe 6 cm. The point is coupling a nuke to the laser, not making a baseball sized nuke to toss out at the world series. If this thing has to get fairly close to an asteriod or comet it will need a spacecraft with a guidance system. If the spacecraft can intercept an asteriod 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.

I think you'll have a harder time selling a space nuke to the general public than other methods of asteriod deflection.
Title: Re: Earth defense from asteroid and comet hazard using super-power gamma-laser
Post by: joema on 03/27/2007 11:27 pm
Quote
kevin-rf - 27/3/2007  3:59 PM
...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...
Exactly. 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.

It's true the gamma ray laser can be thousands of miles from the asteroid, but in astronomical terms that's tiny. You still must intercept it pretty far out, likely many millions of km. That requires precision guidance over the long journey, even if you use a laser when approaching the asteroid vs just detonating closer.

Various types of nuclear pumped lasers have been studied for many years. Space-based nuclear pumped X-ray lasers were initially the centerpiece of the American SDI program.

I'm not doubting a nuclear pumped laser is possible, only that I don't see the point of using the intermediate laser with the attendant cost, complexity and reliability issues. In either nuclear intercept case (laser or not) you've got to launch a high speed precision-guided nuclear warhead at an intercept course to the asteroid.
Title: Re: Earth defense from asteroid and comet hazard using super-power gamma-laser
Post by: Olga on 03/28/2007 05:33 am
Quote
joema - 28/3/2007  3:27 AM

Quote
kevin-rf - 27/3/2007  3:59 PM
...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...
Exactly. 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.

Firstly, creation of a hole in an asteroid and flowing out gas are more effective to deflect the asteroid than an explosion, even a stand-off one.

Secondly, it is not always possible to achieve a surface of the object. For instance comets may be surrounded with clouds of dust particles, also there could take place calculation mistakes, evolution of the object’s trajectory or too high relative velocities.

I would appreciate if you’d go through my postings on the first page and answer to them.
Title: Re: Earth defense from asteroid and comet hazard using super-power gamma-laser
Post by: vda on 03/28/2007 07:39 pm
Quote
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.

The idea is to detonate them close to the surface and vaporize/expell a lot of rock, creating a puff of "rocket" exhaust. This will slow down asteroid a bit, making it miss the earth.

Jacket of thermonuclear stage can be designed to leak most of the power of the blast (in the form of gamma rays) asymmetrically, in this case - direct it to asteroid. Sort of very poorly focused gamma laser, but with asteroid being less than 300 feet from the bomb you don't need to focus much.

Not impacting it and detonating inside. *That* is a last resort - "lets try to produce as much vapor/thrust as we can, even if we risk getting big fragments".
Title: Re: Earth defense from asteroid and comet hazard using super-power gamma-laser
Post by: Olga on 03/28/2007 07:40 pm
May be I'm not very good in English, but I belive there is some difference between "feedback" and "observation".
Title: Re: Earth defense from asteroid and comet hazard on the base of super-power gamma-laser
Post by: Olga on 03/28/2007 08:15 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.

Mentioned by you political problems are not of this level.

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.

Title: Re: Earth defense from asteroid and comet hazard on the base of super-power gamma-laser
Post by: vda on 03/28/2007 10:27 pm
Quote
Olga - 27/3/2007  10:15 PM
3. Your political views are quite funny and one-sided.

Yup, everyone's political views tend to be one-sided - to one of the many possible sides. My views say that helping Russia build nuclear weapons is not sane. Call me paranoid.

Quote
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.

We (I mean both US and Russia) managed to build tens of thousands nukes without cooperation. IIRC Tsar bomba was designed and built in fourteen weeks.

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.
Title: Re: Earth defense from asteroid and comet hazard on the base of super-power gamma-laser
Post by: aftercolumbia on 03/28/2007 11:09 pm
Quote
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).

It has also been discussed in previous postings that existing nukes are effective enough to render this device not worth developing.

Quote
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.

I doubt it.  I'm not entirely certain which organization you refer to, but I suspect that it's either NATO, or the EU.  The UN moves far too slowly to administer this sort of a system.  Also, the UN leaves me with an overwhelming impression of being bureaucratically lazy, and woudn't want to administer such a system.

Quote
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.

Someone else's I'm guessing.  I'm from a more pragmatic persuasion.  I believe the best near term solution to asteroid deflection is to launch existing nuclear warheads on commercial boosters with Deep Impact style flyby/guidance monitoring stages.  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.)
Title: Re: Earth defense from asteroid and comet hazard on the base of super-power gamma-laser
Post by: kevin-rf on 03/29/2007 02:15 am
Quote
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.

You do not need an international comittee. All you need is one of the many space fairing nation that has nukes to decide to spend the money.

It could be Europe (ESA), Russia, the US, China, or India. I would also not count out japan, they have touched an asteriod...

All have nukes (except Japan), all have or are working on deep space missions.

It is a matter of money and political will.

Even though the US has carried out the largest number of asteriod/comet missions to date, it would most likely be more acceptable to all US haters if the ESA or India nuked the asteriod(s). No one would say they are using it to test a new evil nuke with which they will enslave the world. Of course, even if the US developed and tested a gravity tug people would complain that it is just a front for BMD proof unstopable super WMD.
Title: Re: Earth defense from asteroid and comet hazard on the base of super-power gamma-laser
Post by: Olga on 03/29/2007 05:16 am
Quote
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.)

If it is written unclear in English just let me know and I'll tryto restate in a different way:


Quote
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)

Title: Re: Earth defense from asteroid and comet hazard on the base of super-power gamma-laser
Post by: Olga on 03/29/2007 05:31 am
Quote
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.



Quote
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.

I was not referring to technical or funding issues only. I just don't believe that any country may take the responsibility alone. This is actually about what you are saying - Russians would not appreciate the idea that USA will develop something (and USING to deflect asteroids (where?)!) as well as Chinese, Indians, Japanese, Europe, and Israel and so on. There are too many suspicions for too high responsibility.

I don't really want to discuss political issues in this topic as they concern the idea of defense in general, for any means (laser, nukes, tractors and so on).

I would like to get some professional feedback for a technical side of the topic, but it looks like nobody listen to my arguments   (regarding focusing and etc.). 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?
Title: RE: Earth defense from asteroid and comet hazard using super-power gamma-laser
Post by: Chris Bergin on 03/29/2007 02:15 pm
*Politics alert* :o

Everyone, let's try and keep the political talk to a minimum please.

I'll tidy up this thread.
Title: Re: Earth defense from asteroid and comet hazard using super-power gamma-laser
Post by: Jim on 03/29/2007 02:24 pm
A thread  going bad and I wasn't involved?  I must be slipping
Title: Re: Earth defense from asteroid and comet hazard on the base of super-power gamma-laser
Post by: Chris Bergin on 03/29/2007 02:27 pm
Quote
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?

Your English is excellent. I will watch this thread and make sure no one responds off topic.
Title: Re: Earth defense from asteroid and comet hazard using super-power gamma-laser
Post by: stargazer777 on 03/29/2007 03:03 pm
I think Olga's comments that effective asteroid defense will require international cooperation is obviously correct.  Whatever issues of mistrust linger between nuclear and space faring nations will have to be put aside on the indisputable basis that an asteroid or comet impact anywhere on the planet would be a world-wide catastrophe -- threatening the survival of human civilization and perhaps of our entire species.  That alone should be enough to stop all the pointless flag waving and focus our attention on the steps we need to take NOW to prepare an effective and prompt defense before it is too late.  International agreements can easily be formed to safeguard whatever technologies are developed to protect the planet.  And perhaps -- just perhaps -- it will be a long overdue step in reminding all of our people that our fates on this planet are inextricably linked and we can no longer ignore that fact.

I also want to second Chris's comment -- Olga's English is excellent and her contribution to this forum is very valuable.
Title: Re: Earth defense from asteroid and comet hazard using super-power gamma-laser
Post by: stargazer777 on 03/29/2007 10:22 pm
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.  

Title: Re: Earth defense from asteroid and comet hazard using super-power gamma-laser
Post by: Marcus on 03/29/2007 10:43 pm
Stargazer777 for president.

Does anyone really expect that we can--without fail--maneuver a nuclear device to within a useful distance of a comet or asteroid using current launch vehicle technology? Where are you going to get the Delta-V for the necessary gawdawful orbit crank to match velocities with the space rock? It's all well and good that you can push a nuke up to escape velocity, but if we're talking about a solar-diving comet or something similiar that's going to be one hell of an encounter speed.

Can we really reliably maneuver a nuclear-armed spacecraft to within 300m of a lumpy rock with a closing velocity of 12km/s AND equip it with enough shielding to survive any impacts from potential surrounding debris?

Seems to me that a standoff device--even if it only buys us a few hundred kilometers--makes a lot of sense.
Title: Re: Earth defense from asteroid and comet hazard using super-power gamma-laser
Post by: stargazer777 on 03/29/2007 10:54 pm
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....
Title: Re: Earth defense from asteroid and comet hazard using super-power gamma-laser
Post by: meiza on 03/30/2007 07:07 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?
Title: Re: Earth defense from asteroid and comet hazard using super-power gamma-laser
Post by: Olga on 03/30/2007 07:48 am
Quote
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?

Yes. But it's not the only advantage. I'll reply more in the nearest future.
Title: Re: Earth defense from asteroid and comet hazard using super-power gamma-laser
Post by: lambda0 on 03/30/2007 10:36 am
Hello
I read your document, and I find this concept original.
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 ?






Title: Re: Earth defense from asteroid and comet hazard using super-power gamma-laser
Post by: kevin-rf on 03/30/2007 01:07 pm
Quote
Olga - 30/3/2007  2:48 AM

Quote
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?

Yes. But it's not the only advantage. I'll reply more in the nearest future.

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.

Considering how hard it is to focus gamma rays I don't see have you can generate a focused beam out of the taper. The device in the paper is an expanding wave front going through what amounts to a pinhole the diameter of the taper. To be brought to the proper focus it needs a second properly shaped lense/mirror.  That beam will be expand as it travels. At what distance does it become larger than the nasty little rock?

The advantage of nuke/nuke lasers/slugs is you don't have to slow down when trying to move the small mountain. A gravity tug needs to reach said mole hill, change it's speed to match said mole hill, and hover over it for a period of time.

As I said before several countries have proven capabilities to send a probe to an asteriod and comet. Most of these countries (with the exception of Japan) have the ability to produce a nuke. Such a mission will not take anymore effort than any of the past comet/asteriod mission. It is a matter of one of the many space groups deciding that a rock presents enough of a threat to pony up the money to mount a mission. The key is all this takes time. Meaning the emphasis ($$$) should be on early detection so we can propery plan and execute such a mission.

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. You are better off building what ever the current in production rocket is. That is what the currently trained launch crews are familar with. An old dusty rocket will not have all the same mods as a new rocket and will not be handled the same way as a new one. Imagine trying to dust off an old thor (I think 12 where left over at the end of the program) and fly it off a Delta II pad. It does mean the min. reaction time is what ever it takes to place a rocket order and integrate the 'probe'.

Some people have mentioned in the past that Lockheed, now ULA keeps a 'spare' atlas in the factory so they can fill any potential order on short notice (time frame of 6 to 9 months). The only US rocket larger than a 551 is a Delta Heavy.

Yes there is potentially one asteriod on the way in 2036. Now is the time to start planning that mission, but not yet the time to order the booster and probe. We still do not know which way to shove it.

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.
3. Design a reference platform on which said nuke will rest.

When we see a mole hill that will turn into a mountain we can build the rocket and probe.

The sky is falling, but if we do it right we have time to react and take the proper action.
Title: Re: Earth defense from asteroid and comet hazard using super-power gamma-laser
Post by: joema on 03/30/2007 06:54 pm
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meiza - 30/3/2007  2:07 AM
A conventional nuclear bomb has to travel all the way to the asteroid and possibly match the speed....
A 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

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.
Title: Re: Earth defense from asteroid and comet hazard using super-power gamma-laser
Post by: meiza on 03/30/2007 07:20 pm
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joema - 30/3/2007  7:54 PM

Quote
meiza - 30/3/2007  2:07 AM
A conventional nuclear bomb has to travel all the way to the asteroid and possibly match the speed....
A 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

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.

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.

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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.

not necessarily, see above

Quote
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.

Yes, the laser seems outright very expensive and otherwise problematic. I just think that it possibly proposes a solution for the "last ten thousand kilometers" problem, if the asteroid is hard to match speeds with and/or its trajectory is only known shortly before the pass near earth.
Title: Re: Earth defense from asteroid and comet hazard using super-power gamma-laser
Post by: Marcus on 03/30/2007 07:34 pm
What about the time it takes for a fusion device to develop the fireball? If the fireball propogation time is too slow, the comet or asteroid may pass the detonation before it's had a chance to impart significant thrust through surface material evaporation and expansion. Plus, the most effective application of force is going to be perpindicular to the line of travel of the asteroid, so there's still the problem of getting the weapon close enough to a (likely) poorly-defined irregular rotating body without actually accidentally impacting the asteroid. Your nuclear device might develop a very high radiation flux on the asteroid, but it's only going to be acting for--at best 1/12th of a second on a km-long asteroid--and a fraction of that will actually act on a vector that goes through the asteroid's center of mass. A lot of the energy is going to be wasted on vectors that induce more of a rotation than an actual orbit change. Now, I don't know. Maybe durations on the order of 1/100th of a second is enough time. Maybe the laser only acts for half that time.

A standoff laser still has the merit of being able to direct whatever % of energy it can focus directly through the center of mass of the asteroid and on a nearly perfectly perpindicular (depending on the standoff distance and velocities involved) vector to the asteroid's direction of travel.
Title: Re: Earth defense from asteroid and comet hazard using super-power gamma-laser
Post by: kevin-rf on 03/30/2007 07:56 pm
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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.

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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.

not necessarily, see above

You are assuming

1. The offending asteriod is detected before it hits the magic 'keyhole'
2. The 'keyhole' encounter is with earth and not Mars, or Venus, or even Jupiter.

Even if we have years of advance notice, the asteriod may not have a 'near' earth encounter before impact. Especially if it has a comet levy like encounter with jupiter and the orbit is greatly altered... You have to be prepared to send your interceptor half way across the solar system.

High speed intercept would require the space probe be able to do the last mile navigation on its own to place itself either in front or behind the asteriod. Remember we are not talking about the nuke/laser coming in physical contact with the asteriod, but close enough to give the sucker enough of a shove to move it the right way. Joema has a link to a nice paper on how close you need to be. If you can knock down an ICBM with another ICBM you can place a nuke in the correct position.

It is doable, deep impact touched a comet, other probes have played a nice game of russian roulet with comets imaging the cores and even collecting dust. How many asteriod fly bys have there been now? I have lost count. A few missions have even touched an asteriod. The tehnology is there now.

As much as I feel gravity tugs are a better option, the nuke option does have merits.

Still you are better off finding the offender with proper survey and then coming up with the correct corrective action. If the survey is robust enough, you have years to develop the proper corrective action. Which would only require one, two probes to shove the asteriod out of the way.
Title: Re: Earth defense from asteroid and comet hazard using super-power gamma-laser
Post by: kevin-rf on 03/30/2007 08:01 pm
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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.

Actually the United States has signed but not ratified the CTBT. So they are free to nuke an asteriod.

Still I would like to see the required enviromental impact statement for nuking one ;)
Title: Re: Earth defense from asteroid and comet hazard using super-power gamma-laser
Post by: publiusr on 03/30/2007 08:40 pm
Olga, I heard about some weapon called an "Ellipton" some years ago. Would that have been something similar?
Title: Re: Earth defense from asteroid and comet hazard using super-power gamma-laser
Post by: Olga on 03/31/2007 09:38 am
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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?

Shooting at the asteroid when it passes the Earth close by is not very good idea (as I mentioned previously). Efficiency of the beam’s impact is comparable with nuclear explosion performed deep in the object and it is possible to blast the asteroid from a distance way not matching velocities of the asteroid with the device.
Title: Re: Earth defense from asteroid and comet hazard using super-power gamma-laser
Post by: Olga on 03/31/2007 09:40 am
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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 ?

The real conversion efficiency of the X-beam according existing calculations will be about 30% (may be less). For such a device it is a significant amount. Also if the NEO’s trajectory allows matching velocities (at least for 1-2 km/s) this NEO would experience a blast of other fission products though their velocities are much less of the velocity of light.
As for experiments the technology of production presented in the device crystal already exists. Such crystals were produced before (with much less dimensions) and their properties were researched. Of course experiments were not performed (how do you imagine it? :)). The next step we see is a complex mathematical modeling of processes in the device and of the beam’s impact to NEO.

Title: Re: Earth defense from asteroid and comet hazard using super-power gamma-laser
Post by: Olga on 03/31/2007 09:41 am
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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?

Sorry, I've never heard about that.
Title: Re: Earth defense from asteroid and comet hazard using super-power gamma-laser
Post by: Olga on 03/31/2007 10:37 am
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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.


How much to be close depends on precision of a guidance system of the space device.  In theory it may be as I wrote before about 100 000 km. But even for a distance of 30 000 km a possibility to be saved before a blast has no comparison with contacting methods.  I can give some examples like Vega  (6.3.1986, minimal distance from a comet was  8,9 thnd.km), Vega II (9.3.1986, 8 thnd. Km from Galea comet) and Giotto (14.3.1986,  about 600 km). A velocity was about 80 km/s as I remember. All the devices almost had not suffered. In July 1992 Giotto managed to get photos of Grigg-Skjellerup from a distance of 200 km. Is it enough to forget about stones? There are also were Stardust, 01.2004, Wild-2, 240 km.


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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.

I remind ones more that there is no need to focus the beam in this device. A diameter of the taper is 3 cm. Diffraction scattering is less than 10-10 (this is a starting point for the distance of 100 000 km). All these data are available in the document from the first posting. If you want to know more read http://www.rufund.ru/Docs/laser/RU_2243621_C1_ENG.zip  (1.5 MB) where you could find a physics of the processes.


I absolutely agree about early detection. This is a base for any deflecting system. But I consider this as another topic for discussion.  





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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.

There is such a problem but we could develop a system of storage. An experience with liquid rockets partly could help.

“Potentially one asteroid on the way in 2036” is a particular problem. We need a general system so not to think about it each time (when it may be too late actually).


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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.

I agree with you. Mentioned by you requirements should be implemented for any deflection by means of nuclear devices. Technologies of encapsulating already exist but need to be adopted for the device.  
Title: Re: Earth defense from asteroid and comet hazard using super-power gamma-laser
Post by: Olga on 03/31/2007 04:36 pm
Actually this forum is the first place for public discussion of the technology. There have been no official publications yet (including Russia) concerning this question.

For further development of the project there is needed a complex mathematical modeling of the processes in the device and physical phenomenon which appear due to interaction of the beam with a NEO. The purpose of such a research is a confirmation of implemented models and specification of interaction physics with NEO.

Next step is a preliminary draft of the device and an interceptor, selection of schemes for internal and external dynamics for the interceptor, control means and systems, thermoregulation, protection system for crash cases at the moment of launching or maneuvering.

I would like to make an emphasis once more that this device is not supposed to be a weapon ageists people or something created by people. The inventors would be happy to make it an international project.

How ever there are few technical issues which have been still unsolved. In particular the precision of orientation of the interceptor with the device in space may be achieved by means of dynamic compensation and accurate mechanics, the question is how to keep the X-beam at the NEO’s center of mass at the moment of blast.

The problem is that a velocity of the device relatively a NEO may achieve 70 km/s and more (Vega project (1986) may be an example of high mutual velocities). The beam irradiates within a period of time about 0.001 seconds. For this period in case of shooting from one side the NEO will pass a distance of 70 meters relatively the interceptor. So you need not only to hit close to the center of mass but as well to keep the beam at the same place until it is generated. At that moment a front of vaporization due to a nuclear explosion will pass the device and the interceptor. That’s why it will be a complicated thermodynamic system.

Today one of the ideas for solving this problem is next. Before a start the interceptor revolves on the axis of the X-laser (the axis should go through the center of mass of the interceptor). By the apparatus of the interceptor there is calculated an angular value of a length at which the beam should be kept at the NEO. In the process of revolution taking into account the value there would be arranged a certain precession angle of revolution by orientation means of the device. The angle would be chosen in such a way so the angel of revolution during the beam’s irradiation outlines a curve at the NEO close to a vector of displacing center of NEO’s mass relatively the interceptor.


Here is an illustration, where:
1 - a vector of displacing center of NEO’s mass
2 – center of NEO’s mass at the starting moment when X-beam irradiates to the NEO (moment T0)
3 – NEO
4 – the beam of X-laser at the T0 moment
5 – an interceptor
6 – controlled precession angle of revolution of the interceptor
7 – center of mass of the interceptor
8 – the beam of X-laser at the moment when irradiation stops (moment T1).



Has anyone other ideas?

Please, do not hesitate to tell me if something is not clear due to mistakes in my English.
Title: Re: Earth defense from asteroid and comet hazard using super-power gamma-laser
Post by: Olga on 04/01/2007 08:15 pm
To whom it may concern. I will be back at this forum on Wednesday.
Title: Re: Earth defense from asteroid and comet hazard using super-power gamma-laser
Post by: Olga on 04/04/2007 03:31 pm
Well, it seems there was need in previous posting :-)
Title: Re: Earth defense from asteroid and comet hazard using super-power gamma-laser
Post by: meiza on 04/04/2007 11:20 pm
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?
Title: Re: Earth defense from asteroid and comet hazard using super-power gamma-laser
Post by: Olga on 04/05/2007 05:51 pm
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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?

An ordinary gyro can not be used due to explosion. In the concept discribed in my previous posting (with a picture) device itself is some kind of a gyro. The question is how about other ways to solve this problem.
Title: Re: Earth defense from asteroid and comet hazard using super-power gamma-laser
Post by: kevin-rf on 04/05/2007 06:27 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.

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.

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.
Title: Re: Earth defense from asteroid and comet hazard using super-power gamma-laser
Post by: Stargazin2nite on 04/05/2007 09:48 pm
"Unfortunately Energia does not participate in this project. Everything is limited to Krikalev (as a private person only). Your fantasy is misleading the public."


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!!    

At present, a gamma ray laser is a *hypothetical* device which would generate coherent radiation in the range 0.005-0.5 nanometer by inducing radiative transitions between isomeric nuclear states.  To provide some background, in 1999 C.B. Collins of the University of Texas at Dallas caused a stir in the physics world when his group reported that irradiating samples of Halfnium-178 with X-rays produced by a dental x-ray machine (yes, you read it correctly - a dental xray machine) produces a several percent enhancement of gamma ray emission by the isomer.  This experiment suggested that the isomer could be triggered to release its energy by irradiating it with a much lower-energy beam.  

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.  

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).


So, before you get too excited about moving an asteroid by harnessing fantasy gamma ray laser technology, perhaps we should think about increasing the NEO detection program to include objects down to the 100m range.  Beyond that, the gravity tractor concept appears to be a far more feasible, particularly since we have already shown that we can rendevous with asteroids (e.g. Hayabusa mission).    

 



Title: Re: Earth defense from asteroid and comet hazard using super-power gamma-laser
Post by: Olga on 04/10/2007 05:52 pm
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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."

I imagine a spiteful howl in case we would have an announcement from Energia IN ADVANCE. Russians design a huge space gun!  How about requiring a written approval from Mr. Putin and a separate budget line in the state budget?


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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!!    

Let’s discuss it step by step.

Firstly, strictly speaking, there is NO ANY technology to intercept NEOs nowadays.  Or you have already intercepted a dozen and I missed something? Is there any trial test for intercepting? Only when you will manage to intercept a couple then you can say you HAVE a technology.

Every technology proposed at the moment for the issue may be researched with more or less interest as a pretender to a “pick list”. All these gravity tractors and nukes are for LESS interest due to few simple reasons. The tractors are not good initially (mainly because of the time limits). The nukes do not achieve the result (I don’t want to say here about costs, efficiency and other aspects). The proposed device if it fits announced characteristics (I will write more about it later) is good enough for intercepting as an element of a defense system both for the initial problem specification (for reasonable range of uncertainties as well) as well as for the final problem specification (deflecting effect for reasonable costs).

I will answer later to other parts of your posting
Title: Re: Earth defense from asteroid and comet hazard using super-power gamma-laser
Post by: Olga on 04/10/2007 07:37 pm
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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.

Read the document: http://www.rufund.ru/Docs/laser/RU_2243621_C1_ENG.pdf
You will find all the answers there.

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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.

We need a prescribed angular motion of a rod-crystal after the moment when an external gyro transforms into plasma and the crystal itself is in a process of vaporization.  The solution is to rotate the rod itself together with the device and to set a precession angle just before an explosion.

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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.

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.
Title: Re: Earth defense from asteroid and comet hazard using super-power gamma-laser
Post by: Olga on 04/10/2007 08:01 pm
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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.  

READ THE PATENT. Everything mentioned by you is already there: http://www.rufund.ru/Docs/laser/RU_2243621_C1_ENG.pdf

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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).


These articles are about absolutely different technology. Strictly speaking the proposed device is NOT A LASER in usual terms because a coherence of X-quantums is achieved not directly as it used in lasers but indirectly – through coherence of a neutron wave. Mentioned by you links can not help in solving the issue. With the same result you could provide some links for gardening.

We have reviews, in particular from the specialists of Kurchatov Institute. But these reviews will be published in a certain time. But what kind of a review would you like? A review which approves a correctness of formulas? The text is available. In the device description there are no calculations which are not in frames of usual quantum equations. Approved by you specialists could tell what is wrong. I think you would not ask for tests of the device to ensure you personally? The thing which is really needed is a complex mathematic modeling of the processes in the device. This stage is in preparation process. Calculation experiments will allow getting the results very close to a real explosion and they are widely used because of moratorium for nuclear tests.

[to be continued...]
Title: Re: Earth defense from asteroid and comet hazard using super-power gamma-laser
Post by: kevin-rf on 04/10/2007 09:03 pm
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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.

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.

There are multiple different options for handling this problem. The best is a layered defense with detection being on the forefront. We will be lucky if we have one asteriod strike the earth in our life time. It is a rare event on the time scale of human life. If we can detect and track the incoming we have time to develop and deploy more sure fire approaches.

If time is on your side you can deflect with gravity tractors, nukes, or even high speed copper slugs. Probes have done flybys, orbits, and touched asteriods. 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.

If it is to late, we need to start mass evacuations, sheltering in place in areas that can not evac in time. The better the scanning techniques the smaller the object has to be to slip through the surveys and surprise us.
 
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.

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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.

If you have an inbound asteriod/comet that will strike earth, the intercept vector will be similar to vector of the inbound. You will not have a high intercept angle. If you are intercepting at a high angle then the deadly encounter will be a future encounter and you have years for your nudge to take effect.

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.

Building a bunch of these sticking them in a warehouse waiting for the day that they will be needed is not the best idea. You are better off developing the techniques needed, running practice asteriod/comet sample return missions, and building the equipment when an incoming asteroid has been found. Otherwise you have an ancient rocket that know one remembers how to fly using an ancient space probe design that none remembers how to steer. Relying on having my great great grand children trying to figure out who in which elder home is capable of launching the antique does not instill confidence.
Title: Re: Earth defense from asteroid and comet hazard using super-power gamma-laser
Post by: Stargazin2nite on 04/11/2007 12:58 am
Olga -- sounds like this ignorant physicist should just hand you the Nobel Prize in physics right now, huh?  

Let me see if I have this correct:

Your fantasy system/device claims a power density that is ~ 770 times GREATER than the power density at the target location of of the National Ignition Facility (NIF) at Lawrence Livermore -- which will be the most powerful coherent energy source in the world upon completion of construction in 2009.  That facility is a $1.1B project that has utilized the previously acquired domain knowledge from the NOVA laser - i.e. it's performance claims are VERIFIABLE.  The facility will be utilized full-time for many, many years.  

Of course, with the level of arrogance you are displaying, I am certain that your purely theoretical concept (supported by ZERO verifiable experimental results) will certainly work!  Quick Mr. Putin, write the check now!!  Do honestly think you can develop 50+ of your theoretical systems, verify, validate, qualify, and maintain them when there is a 1 in 10^6 chance that they will ever be used in the next 100 years?  Good luck getting your funding for that project!

Oh, and here is the link to the gardening website you so flippantly requested (you should have plenty of time to explore it while waiting for your projects' funding):

http://www.garden.org/home



Title: Re: Earth defense from asteroid and comet hazard using super-power gamma-laser
Post by: kevin-rf on 04/11/2007 02:03 am
Stargazin2nite thanks for the gardening link, I need to do some research on how to splice a thermostat into some solar powered fans for the green house. Maybe this will be the year I have some luck with the peppers and cukes. !@##%$@ Beetles and Slugs....

As for the asteroid battle plan. A thought just occurred to me. For an asteroid to be detected with only a few days notice it must be smaller than current surveys are looking for. The better the surveys the smaller the objects must be. This puts an upper limit on how large an asteroid can sneak up on us. Based upon past surveys it is safe to say no asteroids larger than 100km is on a collision course with us. Based upon current surveys it is not safe to say the same about .1 km asteroids.

One of the down sides of better surveys is the really small stuff will be really close to earth before we detect it. Our warning time may be less than a day. On the plus side without the surveys we would have zero warning.

Better surveys will obsolete the fancy nuke. The better the survey the more time we will have for other deflection methods. It will put upper limits on the size of the smaller the objects we are missing. These small surprise asteroids will not be detected with enough notice to do more than shelter in place. Sorry that is where the money needs to go.
Title: Re: Earth defense from asteroid and comet hazard using super-power gamma-laser
Post by: Stargazin2nite on 04/11/2007 02:49 am
Kevin-rf -- no prob on the gardening link....good luck with your garden this year!  (I myself have no capabilities in that arena!).

1)  I 100% agree with you on improving detection;  knowledge is power.

2)  Incidentally, did you look at the "patent" referred to above?  I especially enjoyed the disclaimer on the bottom of p.31, which states that the information contained in the document could be wrong due to "human or mechanical error, as well as other factors".  Also the patent is dated 2004 -- why sit on this revolutionary technology for 2+ years???

I shall cease and desist on this thread at this point.
Title: Re: Earth defense from asteroid and comet hazard using super-power gamma-laser
Post by: Olga on 04/11/2007 05:16 pm
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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.

Dear Kevin-rf,

I really appreciate that you have an interest to the document. But quoting the relevant points (with formulas which is difficult to post here) won’t help if not everything is clear in the document. This means you will require more explanations and this thread will move from the space thematic to something  different.


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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.

Pulse duration is determined by the velocities of thermal neutrons (105 cm/s).


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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.

A rendezvous mission is not a deflection mission. There is no proven technology for deflection.

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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.

Do you imagine yourself evacuating London? I can do hardly.

And also, don’t you find it is difficult to have a separate plan for each “if”? As I noticed it is a very popular word here regarding asteroid deflection. Why not to have the only one approach which is applicable for all “if”?



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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.

The purpose of this thread is not to ensure everybody that the device works. In the first posing I asked for some feedbacks, but now I see I had to put some limits. The question is: if the device is FEASIBLE do you find that it is better/worse than other approaches and why?
Title: Re: Earth defense from asteroid and comet hazard using super-power gamma-laser
Post by: Olga on 04/11/2007 05:19 pm
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Stargazin2nite - 11/4/2007  4:58 AM

...with the level of arrogance you are displaying...

I’ve pointed that you provided wrong links to approve that the device is not feasible. If this displays my level of arrogance then I’m surprised.


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Stargazin2nite - 11/4/2007  6:49 AM

Also the patent is dated 2004 -- why sit on this revolutionary technology for 2+ years???

May be because we are not the guys from the University of Texas at Dallas   :)
Title: RE: Earth defense from asteroid and comet hazard using super-power gamma-laser
Post by: Stargazin2nite on 04/11/2007 07:24 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.

To the best of my knowledge, the most recent comprehensive review of gamma ray laser research covering all current approaches was published in 1997:  

"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.

Perhaps you are doing something other than what has been already tried? I simply have great skepticism about your claims of achieving something that no one else has been able to do for the past 60 years.

Incidentally, Dr. George Baldwin, now 89, is a legend in gamma ray laser research and recently wrote an insightful book about his scientific career at Los Alamos and elsewhere.  

There is an online interview with him published Jan. 27, 2007 (http://blogcritics.org/archives/2007/01/27/212655.php) where here was asked the question,  "Is the graser any closer today that it was in the '70s?".  His response was "No, not really. We thought it would be relatively easy to create - unfortunately many of the obstacles that we faced are still there. Today the Graser is much less likely to be realized than when we thought it might be easy. The problems are many; in fact I do not think that it is feasible to build a Graser. I have spent over 60 years trying to create the Graser - I cannot see a way around some of the engineering issues."

I do wish you luck in your research, 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.

   


Title: RE: Earth defense from asteroid and comet hazard using super-power gamma-laser
Post by: Olga on 04/15/2007 05:47 pm
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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.


The proposed laser is NOT a developed version of what you mentioned. It is a new approach which was not researched before. Your logic is not very clear for me because if there was nothing new in this field for recent 60 years it doesn’t mean there can not be anything at all.

To Russian speakers of this forum (I know there are some :) ): if you would like to discuss the physics of the device, you can visit a Russian forum which is just launched: http://forum.rufund.ru/viewforum.php?f=2

A forum for English speakers is coming soon.
Title: RE: Earth defense from asteroid and comet hazard using super-power gamma-laser
Post by: Stargazin2nite on 04/16/2007 05:11 pm
Hope springs eternal, doesn't it?

Just tell us where to send your Nobel Prize!   :)
Title: Re: Earth defense from asteroid and comet hazard using super-power gamma-laser
Post by: Olga on 06/23/2007 06:33 pm
English version of the site is now available: www.rufund.org :-)
Title: Re: Earth defense from asteroid and comet hazard using super-power gamma-laser
Post by: MTKeshe on 06/24/2007 08:25 am
By physical reality  and nature of  asteroids, these are all solid objects, in trying to hit them with powerful gamma ray is a good option, but what happens if the matter is big enough that can absorb the energy.

As these objects are on a fast tract motion and in entering any gravitational field like earth, they lose some of their energy absorbed to the magnetosphere of the earth by large extent, then the destruction by using gamma ray will be impractical.

This is quite real possibility.

What is the backup option , a second ray,  warhead launch.

This looks like the old star war policy technology of the late American president off the hip shooter Mr Ragon.

The gamma ray system to do the job you are talking about is  impossible to target.

In your second comment on this thread you talk about a small object of about  so many centimetres.

The reality is how are you going to see and detect such an object from one million kilometres from earth as you say.

I think you have to become more realistic , then you can have support, otherwise this is a  few Phd job support talk.

I have done a lot of analysis for destruction of an object in motion in space.

Nothing comes up to be correct in what you are trying to do.

In space line concentration energy deployment due to fast motion of objects like asteroid, is impossibilities.

You have to have field saturation support technology.

What this means , you need to create  a large magnetic field high energy  like a net to allow the object to pass through, and during this time energy saturate the object that it disintegrates.

This is a real possible technique, as in reality you create a magnetosphere a head of the object for it to hit before reaching the earth.

This is realistic and practical.

Your gamma technology as the first commenter in this thread said has been tried for 60 years and the most expert scientist is telling us the system is no go.



Title: RE: Earth defense from asteroid and comet hazard using super-power gamma-laser
Post by: publiusr on 07/07/2007 05:38 pm
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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.



He gave us the Medusa/orion nuke pulse concept IIRC. That might be a better way of dealing with large slug-type nickel-iron impactors. Fasten the end of Medusa into the asteroid, deploy the large 'chute, and place the nuke in between.