Lasers a Go Go

Must admit to not covering lasers a great deal but the US (and Germany for some inexplicable reason) seem to be pushing forward.

The US Navy plans to deploy a solid state laser test system aboard the USS Ponce this year

The eye opening quotation from that video is at the beginning, a couple of dollars per shot combined with a couple of hundred thousand dollars per shot for missiles.




This video from General Atomics, paints of course a rosy picture, but the concept is interesting, lasers in support of SEAD/DEAD missions and a glimpse of their potential in the Air to Air role. Imagine a group of networked unmanned aircraft providing mutually supporting fire with onboard lasers then the bomb trucks tucking in behind.

Rheinmetall are developing a laser system

This is based on combining multiple laser sources and has been tested in various forms and on various platforms

Boxer HEL
Boxer HEL

HEL_Air-Defence-HEL-Effector-30kW HEL_Mobile-HEL-Effector-Container

Read more here and here

Where is the UK on this game changing paradigm shifting technology?



H/T Eric

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February 18, 2014 9:45 pm

How game changing is this really?

At the moment, aircraft don’t fly close to ships because they don’t want to receive a missile for the trouble; this is just more disincentive to enter line of sight. In terms of point defence, requiring a second or so for each target i’m not sure that this is much of an improvement over existing systems at the currant stage of development.

The real question with this is how much does it cost, and what does it require for deployment, because if a sloop could do a similar job to a T45 for a fraction of the price then it’s going to give aircraft a really bad day, and lasers are only going to keep getting more powerful.

February 18, 2014 10:48 pm

The interesting bit for me was General Atomics describing their UCAV as a compliment to manned air power. Perhaps the tide of opinion in the US shifting back towards manned flight already?

Chris Werb
Chris Werb
February 19, 2014 12:04 am

Missiles don’t all cost a couple of hundred thousand dollars each. The latest SM-6 (RIM-174 Standard Extended Range Active Missile (ERAM)) SAMs come in at around $4,300,000 a piece. OK, the missile is non-line of sight capable and I would assume less affected by environmental conditions than a laser, but even so…

February 19, 2014 2:59 am

From the first vid, it looks like 8 seconds from target hit to a catastrophic burn through. That’s a painfully long time to tie up your gun. I can see this as a last ditch defence system, but in that case, is it better compared to a single hit to kill medium calibre A-gun used in an air defence role?

Missiles can intercept as many missiles simultaneously as your radar can handle and your ready use ammo limit, a gun is limited to one at a time.

Chris, think that one was designed as an anti-ICBM missile, exo-atmospheric capable. Translation, it’s the Ferrari of all anti-missile defences. Think the ASTER 30s which is a more reasonable benchmark come in at approximately a million a piece, which sounds scarily costly until you realise that anti-ship missiles also cost about the same, so in essence you’re throwing equal value missiles (money) at each other. Unless the ship goes down of course, in that case, it’s a bargain for the attacker.

February 19, 2014 9:25 am

@Obsever – I assume that the 8 second burn time will drop a little bit as the lasers power efficiency improves.

From what has been put out there at the moment, this is definitely been considered as a long ranged CIWS rather than a replacement for Medium/Long range SAMs.

Chris Werb
Chris Werb
February 19, 2014 10:15 am

A million a copy is still quite a lot more than a few dollars :) Unless things have changed dramatically, it was also the case that SAMs did not have 100% kill probability, therefore you usually had to fire more than one at an incoming missile to “ensure” a kill (although you would obviously never achieve a 100% probability regardless of how many SAMs you shoot or how good your point defence systems were).

February 19, 2014 10:52 am

Actually Chris, think for missiles you might actually be able to fire it one at a time per target to ensure lack of wastage, depending on how far away the enemy AShM is detected, you can actually fire, wait to see the results, then fire again. At the Mach 3 ballpark where a lot of AShMs are, it’s 1km per second, so if you popped a round off at 120km, that’s a full 2 min to wait and see.

Think you got 3 shots at the target before you’re forced to go to guns. 120km missile fired, 60km interception (intercept 1), miss, 60km missile fired, 30km interception (intercept 2) miss, 30km missile fired 15 km interception (intercept 3). This is a bit conservative as it assumes that the interceptor missile also travels at Mach 3, actual speed for it is a bit higher.

As for the laser, I’m curious to know the range at which the tests were conducted. The further away, the greater the energy loss. For all we know, past 1km, it might be nothing more than “angry flashlights”. For a practical CIWS, we can already see that the laser has to be effective starting at 9km for it to blow the missile at 1km. The last km is for debris to hit the sea instead of the defending ship. Not to deride it as useless for all eternity, but for it to become practical, there seems to be a need for a bit more work and improvements.

And IIRC, battery energy storage density was the limiting factor for a lot of current day energy weapons.

February 19, 2014 10:58 am

Obs – maybe the purpose is not just to blow the incoming round to shards, but also to fry the guidance system? A blind self-guided missile may be as ineffective as a pulverized one? I suspect the guidance components might be more delicate than the missile structure.

February 19, 2014 11:04 am

I think you might be right Chris. Combine with other ECM and decoys, could make for very effective protection.

February 19, 2014 11:13 am

From the first vid, it looks like 8 seconds from target hit to a catastrophic burn through. That’s a painfully long time to tie up your gun.

This is true. But I think that the key will be that you have more than one laser per ship – so you can hit each target with several beams, and that’ll cut the dwell time you need for a kill right down. (like the Germans are doing on land.) Power’s not too much of a problem – these lasers have outputs in the tens of kilowatts, so (conservatively, assuming about 10% efficiency) they’ll need power input in the hundreds of kilowatts. An electric-drive ship will have generator output in the tens of megawatts. No reason (other than cost) not to have, say, fifteen or twenty of these units on each broadside. Even if they take power from the screws, it’s only for a few seconds.

The abiding problems remain detection of the targets (you still have to get them on your radar to know they’re there) and atmospherics reducing range (laser light not good with fog, spray or smoke).

The Other Chris
February 19, 2014 11:47 am

UK’s interest in Directed Energy Weapons is kept relatively quiet. You’ll find the MOD have practically no public records on file for detailed comment under FOI as a starting point. DSTL have a few papers recommending investment and development in recent years.

Known systems deployed or that reached late stages of testing include dazzling weapons (deployed but not used in 1982) and High Power Microwave weapons (tested aboard five US BQ-145A drones in the early 2000’s).

Given how hushed EXACTOR was…

We then have the flip side of the coin in the deployment of Laser Eye Protection, initially for pilots. The likes of Maurice Ward and his legendary (mythical?) Starlite “paint” (believed to be an organic derived powder suspended in PVA for his Tomorrow’s World demonstrations) is at the very least alleged to have inspired development from UK companies of other organic compounds that can provide a more permanent thermal boundary layer.

For engaging smaller drones at low altitude the UK also has the L128A1 and L74A1 man portable systems available…

As an aside, the MoD have recently purchased 7,000 Vario-Ray designators for use on Rifles from Rheinmetall.

February 19, 2014 12:06 pm

Indeed if DEW, specifically laser weapons, become ubiquitous then that might finally signal the end of the Mk1 Eyeball as sensor of choice – indirect electronic vision protects the viewer from harm. Moderately achievable in vehicles, but the infantry are a bit more difficult – I suppose a blanked out visor & helmet cam work? That or putting each in a private armoured shell with sensors and weapons built in…

February 19, 2014 12:33 pm

Let us not go borrowing trouble when none exist as yet. Most lasers, even military ones, are fairly eye safe and the Geneva Convention specifically bans lasers that damage eyes. Not to mention that energy requirements are such that practical laser weapons are limited in usage and effectiveness. Yet to see a laser cut through an IFV or even a Humvee and if you want to pot UAVs, a 25mm-35mm would do just as well and is more flexible in target choices to boot. Or TOC’s “other man portable systems”.

a, multiple lasers focusing on a single target only works if the lasers hit the same spot, otherwise it is just burning 2 different holes in 2 different spots. No difference in practical effects. Think the really big ones use an array of 6+ beams not for the focusing effect but to create a thermal “tunnel” for the center beam to hit for better effect without too much inverse square energy loss. But that was a long time ago, tech could have changed since then.

Gloomy Northern Boy
Gloomy Northern Boy
February 19, 2014 2:56 pm

…presumably one of the potential benefits of lasers is that provided the power source is sufficient and stable they don’t need reloads…and how far off is something capable of firing a laser or energy pulse, as opposed to a continuous beam?

Answers on a postcard please

Galactica Gloomy

The Other Chris
February 19, 2014 3:45 pm

Plenty of scientific and industrial laser research going on. It’s the weaponisation details in the UK that’s lacking.

Orion you’ve already mentioned. Any collider or fusion ignition test lab dotted around Cambridgeshire. Some of our Universities have large units too. Given the strong recommendations from the likes of DSLT over the years I’d be gobsmacked if there isn’t a program or three abounds, “joint” or otherwise.

Note that physics is moving beyond[1] flat inverse square laws and other accepted “brute force” limits. Key amongst those, to me at least, are material science advances that are providing the ability to create emitter structures such as Spatial Light Modulators on the sub-nano wavelength scale. These scales allow stimulated light to be emitted by what is in effect a phased array – think analogous to an AESA – allowing the emission of constructive and destructive interference patterns which can be varied in real-time.

In practice, this reduces the impacts of the affects of air, dust, moisture, blooming, etc.

Cooling is still one of the largest problems with Directed Energy Weapons. We’re behind the scale when it comes to Thermal Efficiency, when your Smartphone stops warming up after streaming a long video you’ll know we’re beginning to get somewhere with Radio-scale wavelengths at least!

Some other points that might be non-obvious and/or interesting [2]:

– It’s possible for a beam to diffuse wider than some imagine, instead of burning a tight “point” on the target.
– Thermal effects on a target increase the chance of detection by, err, thermal detection systems.
– Similarly scanning of a beam can result in a LIDAR effect.
– Damaging optics etc. has already been mentioned.
– Thermally deforming or damaging a flight or aerodynamic surface can be catastrophic for the target.
– Likewise weakening the surface of an explosive or fuel store can have devastating affects.
– Responses to DEW’s will likely be thermal or energy protection to the target, coatings, cooling, materials etc.
– DEW’s are likely to be included as part of a layered offensive/defensive system, not the sole system.
– “Dazzling” laser weapons that do not damage the eyes have already been deployed by Allied forces.

[1] For a very recent example, last month details of the creation of a synthetic monopole emerged. If verified, it confirms a number of particle behaviours including that of photons amongst other headline grabbing applications starting with the letter Q.

[2] Or maybe not.

The Other Chris
February 19, 2014 3:50 pm


Pulses are already out there to varying degrees.

February 19, 2014 3:52 pm

Gloomy – many lasers in use are pulsed. Repetition rates can be higher than the eye registers though so appear a solid continuous beam. Exciting stuff here: noting the 100kW NG military laser (that one might be their C-RAM device mounted in a Phalanx-like assembly) but then note the two scientific high power lasers quoted at 7,000,000 and 13,000,000 times the military laser power, both at Lawrence Livermore Labs. Those would hurt.

Gloomy Northern Boy
Gloomy Northern Boy
February 19, 2014 4:01 pm

Cheers chaps…live and learn… :-)


Rocket Banana
February 19, 2014 4:10 pm

Particle CIWS = end of BVR missile advantage = end of RN outer-layer air defence with F35B = reliance on SAMs = pointless because of particle CIWS

Let’s just hope I’m totally wrong and no-one is developing particle based CIWS… argh!

February 19, 2014 4:13 pm

I could never quite get the theory behind the cooling laser and the Sisyphus effect, but then it was only covered in pretty broad brushstrokes before I went into biology instead.

TOC, diffused emitter array? Very interesting. Maybe the next gen lasers might just be a flat plane like an AESA radar plate. Or even a combined array. Would make AWACs rather tough to kill.

The Other Chris
February 19, 2014 4:25 pm


The F-35B becomes the perfect base model for your Solid State Laser Gunship.

Remove the LiftFan and replace with your DEW equipment. You have a geared and clutched shaft driven by the low speed spool of a megawatt class gas turbine available for your power generation, with air intake facilities into the new equipment bay and models already devised for your cooling needs.

Although I am skipping one or three design and test steps first of course…

Rocket Banana
February 19, 2014 5:38 pm


Oh, I see. You’ve strapped a “strike laser” onto the thing. Nice :-)

Once they figure out how to overcome blooming and absorption you might be onto something.

Mike wheatley
Mike wheatley
February 19, 2014 8:14 pm

The neat thing about the Rheinmetall demo is that they had a 2-laser turret and a 3-laser turret all hitting the same spot on the same target. Very impressive.

Lasers are odd things: being coherent light, they diffuse a lot less, but they still diffuse. The optics serve to overcome this, and focus the power onto a spot. As a result, the range of the weapon depends on the frequency and the diameter of the optics (or, of you prefer, the ratio of the diameter to the wavelength). Within the resulting range, they work at almost full effect, and they become ineffective almost immediately beyond it.

The use of adaptive optics has already been mentioned in passing – there has been a lot of input from ground based astronomy here – the idea is to flex the mirror to cancel out distortions in the atmosphere.

8 second dwell time is based on the current, demo, lasers: a proper beastie will at least 10 times as powerful, so do the job in user a second.

The T-beam is significant: a conventional long range shot requires waiting for your missile to merge with the inbound, and then evaluating the result: 120km range at launch, 60km range at intercept, evaluate, make additional shots, etc.
Whereas, with a laser: you fire, it immediately hits, <1 second to burn through, you have a huge telescope pointing at it with which to evaluate the results, repeat firing as necessary.

To me, their characteristics make excellent long range anti-air weapons, given a ship big enough to mount some large optics[1]. There will still be a risk of 4 sea-skimming sky hawks / 18 shipwrecks coming over the horizon – I would expect a laser to struggle to kill them all fast enough – but that is where CAMM (and other active seeker point defence missiles) are at their best.

Lasers likewise also have a big advantage against crossing or fleeing targets: instant launch to impact.

I'm just not sure about laser armed aircraft…
Consider: the reasons airpower is so significant in the past 75 – 100 years (as compared to fast light things historically, e.g. horse cavalry,) is due a lot of positive feedback:
– The range of the weapon is enhanced by the altitude of the launcher relative to the target.
– The range of the weapon is enhanced by altitude full stop.
– The range of the weapon is enhanced by the speed of the launcher.
– The probability of the weapon hitting is decreased for targets able to move at comparable speeds.
– A fast target can run the weapon (missile) out of fuel, whilst a slow one (ship) cannot.
– The preferred weapons and their launchers are easy to fit into aerodynamic shapes.
This all means that the best counter to a fighter is another fighter.
But, none of these things apply to laser weapons.
– An F-35 trading laser with a T-45 is never going to be able to sink the ship, but the ship can easily render the aircraft un-flightworthy.
– The ship can mount wider optics – and so get the first shots in.
– The ship can afford armour, of at least harder-to-cut metal construction, whilst the aircraft cannot.
– The height, speed, and manoeuvrability of the fighter provide no benefit.
– The ship can carry enough fuel=ammo for the entire war, no need to land to rearm.
…and that is without looking at the surrounding water as a resource for anything novel.

Has anyone seriously evaluated an orbit-to-ground laser – even if it costs as much as a CVN, it might still be worth it?


[1] Take a T-45. Replace the Sampson with 4 fixed arrays slightly further down on the mast. Use the dome for the laser optics. Done.

February 20, 2014 11:23 am

a, multiple lasers focusing on a single target only works if the lasers hit the same spot, otherwise it is just burning 2 different holes in 2 different spots. No difference in practical effects

That’s not as difficult as it might seem, though. The spot, at that kind of range, will be quite big – it won’t be a pinpoint. Let’s assume an infrared laser with a wavelength of ten microns and an aperture of 200 mm. The diffraction equation is sin theta = lambda over d = two in ten thousand, so at a range of 8 km the spot will be 40 cm wide. Not that difficult to get those to overlap.

February 20, 2014 11:31 am

Has anyone seriously evaluated an orbit-to-ground laser – even if it costs as much as a CVN, it might still be worth it?

Inverse-square law is nasty here. If you need a 10 kW beam to do something useful at 2 km range, then from low orbit – 100 times as far – you will need something ten thousand times as powerful. 100 MW. So you’ll need a gigawatt of power input. This isn’t just “let’s put a submarine reactor in orbit”, it’s more like “let’s put Sizewell B in orbit”.
Current lightweight reactor technology gives you 200 kW output for every ton of reactor (the SAFE-400) so you’d need to lift five thousand of those. You know the International Space Station? Like that, but ten times as big.

And, once they’re up there, it’s in low orbit, which means it’ll only be overhead for a minute or two every half hour…

Mike Wheatley
Mike Wheatley
February 21, 2014 1:04 am

@ a
Lasers don’t obey the inverse square law (well, they do, but only over absurd distances).
Also, I was thinking more in terms of Really Big Mirrors, rather than increasing the power input.


The beam divergence angle θ is calculated like this:
θ = 1.22 L/RL

θ = beam divergence angle (radians)
L = wavelength of laser beam (m, see table above)
RL = radius of laser lens or reflector (m)
Note that this is the theoretical minimum size of the divergence angle, it will be larger with inferior lasers.

Next we decide upon the beam power BP, then calculate the beam intensity at the target (the beam “brightness”):

BPT = BP/(π * (D * tan(θ/2))2)

BPT = Beam intensity at target (megawatts per square meter)
BP = Beam Power at laser aperture (megawatts)
D = range to target (meters)
θ = Theta = Beam divergence angle (radians or degrees depending on your Tan() function)
π = Pi = 3.14159…

For example:
a laser with a ten meter radius mirror operating on a mid-infrared wavelength of 2700 nanometers (0.0000027 meters) has a divergence angle of (1.22 * 0.0000027) / 10 = 0.00000033 radians or 0.000019 degrees.

If the laser has an aperture power of 20 megawatts, and the target is at a range of four megameters (4,000,000 meters), then the beam brightness at the target is 20 / (π * (4,000,000 * tan(0.000019/2))2) = 15 MW/m2 or 1.5 kW/cm2.

…That website even links to helpful spreadsheets!

February 21, 2014 2:31 am

Actually, anything which radiates has to obey the inverse square law, but that is also purely in a vacuum. In atmosphere there is also the thermal bloom a mentioned.

There were orbital weapon satellites researched in the past, most notable were the proposed Thor weapon satellites and the Brilliant Pebbles SDI defence satellites. I think the Thor still shows the best promise.

Rocket Banana
February 21, 2014 9:54 am

If anything spreads with a divergence angle it will obey the inverse square law because the divergence is over a plane (two dimensions).

Add to that the idea that the laser will be refracted through just about anything in the air (H2O, O2, CO2, N2, etc). Also, a high-powered laser will “boil” the air (this is what the US did to fire a lightning bolt down the middle). Once boiled the energy that was absorbed by the boiled (or plasma-fied) air will be re-emitted isotropically (every direction) further dissipating the incident energy on the target.

There is therefore a bit of a problem making lasers work over long ranges.

Take it all into space and it’s a different box of bananas ;-)

February 21, 2014 11:41 am

a high-powered laser will “boil” the air (this is what the US did to fire a lightning bolt down the middle).

It’ll also, literally, boil the water. A few seconds after it starts to play on the target, if it’s hitting water as well (as it would if it’s aiming at a target over the water from above) there’ll be a cloud of steam absorbing and scattering the laser light…

February 22, 2014 2:29 pm

Forgive my ignorance but don’t you just need to polish your missile until it is mirror shiny, so the laser just reflects away? And the ground target just needs a laser detector and an efficient smoke making system?

February 22, 2014 3:55 pm

@ ChrisM,

Bigger problems might be getting the laser to dwell sufficiently on a rapdily twitching target like an incoming missile, or correcting for aiming errors at long ranges.

And with a powerful enough laser, one that has the potential to do a lot of damage if it misses the intended target, the ROE could end up being hilariously complicated.

Mike Wheatley
Mike Wheatley
February 23, 2014 3:33 pm

@ Observer, Simon,

Remember when you were a kid, using a magnifying glass to fry ants? Think about the intensity of the light between the lens and the ant: that isn’t obeying inverse-square, now is it?
Inverse-square applies to point sources, which very few things really are, but most things can be approximated as if they were point source. However, lasers, together with lens / mirror based systems, are one of the few things that really can’t be approximated as point sources, and inverse-square cannot be applied to them.

It is also worth remembering the physics of prisms (including rainbows) – lenses refract by an amount that depends on the wavelength of the wave. So, for normal light, the blue light has a focal point that is closer to the lens than the red light. At long ranges, white light source (as used in a search light) would have its energy spread out by wavelength (unless you use some very fancy optics). But of course a laser is only one wavelength, so a lens or mirror system can focus all the energy onto a spot at very long ranges.

February 23, 2014 3:55 pm

Mike Wheatley,
Mathematically speaking, all your examples are subject to an inverse square proportionality if you look at them in a particular way. The difference between them and an idealised point-source is the other factors in the equation. In the case of focussed light, the point of focus is your point source, from there on it diverges, and anything that diverges has to obey an inverse-square proportionality.

For systems where you are focussing a beam of light, the key relationship is based on the area of the projected spot at the distance you are interested in (aka the target). The accuracy of the optics is such that at extreme ranges (Where the focussing optics are infinitesimally small compared to the distance between the source and the target) the difference in angle between focussed and diverging is too small to control, so inevitably the spot will not be precise.

You are not wrong, but Simon and Observer aren’t entirely incorrect either.

Red Trousers
Red Trousers
February 23, 2014 4:48 pm

All wars are fought in shitty weather (and at the edges of 4 maps, with the Kevins using a different datum from the Army or the Andrew).

All of the inverse square malarkey is useless when you can’t see shit. Please remember that when spending fantasy £squillions when instead you could buy some remarkably cheap recce wagons and decent training for land forces.


February 23, 2014 4:58 pm

*points above*

If a beam attenuates over a long distance in vacuum, it’s a sign of the inverse square law in effect, and even if they call it a “laser”, nothing we have now can hold its energy in a vacuum to infinity. In fact, some very old lasers are point sources radiated in all directions but only with the rest of the tube blocked out (ruby crystal or neon arc lasers come to mind). It’s still coherent comprising of a single frequency, but it still obeys the inverse square law. Of course nowadays you can play a lot more games with light, including destructive and constructive interference but the basic fundamental properties still stand.

BTW, if they don’t do something about that 8 sec burn time, the counter to the laser is simple then. Rotate the missile at <16 sec. Once the part heated is on the other side, the beam has to heat a new patch all over again.

Wonder if alternate wavelengths might give better effects. Masers (microwave lasers) and X-ray lasers have long been possible.

Edit: Damn it RT, I was pointing at mrfred’s statement, you’re in my line of fire. :P

Red Trousers
Red Trousers
February 23, 2014 5:18 pm

@ Observer,

Your fire was attenuated over 8,000 miles from Singapore, plus it went off into deep space somewhere due to the curvature of the earth…. Unless your laser is 10,000 kms above Singapore, in which case you do have a LOS shot…


February 23, 2014 5:52 pm

Nope, my “finger of death” flies nape of earth. :P

John Hartley
John Hartley
February 23, 2014 5:56 pm

Its a long time ago, but I seem to remember that X-ray lasers were the most promising part of SDI. Need a small nuclear bomb to power them though. Remember that Project Orion to build a huge robust steel spaceship, powered by large numbers of small nuclear bombs. Could have gone to Mars or Jupiter, but canned for fallout reasons. Anyway, they came up with a way to build large numbers of small nuclear bombs cheaply.

February 23, 2014 7:03 pm

Chris, mirrors or reflective finishes don’t stop lasers.

It’s been tried, mirrors only reflect away a certain percentage of the inbound energy. The rest causes the mirror to deform quickly, and within milliseconds it’s not a mirror any more and your back to getting burn-through again. Unless a material with massively high reflectivity (>99%) and incredible thermal resistance is discovered then mirrors aren’t going to be an anti laser solution anytime soon.

Red Trousers
Red Trousers
February 23, 2014 8:53 pm

@ Observer,

If it really is doing nap of the earth, I should bottle the algorithms and the secret bending sauce and sell them to someone. Bending light is a bit tricky.

Lasers to me have battlefield utility for measuring distances. Not for killing things. You need big wattage to do that, so it cannot be done by battlefield wagons, nor can it be done BLOS, so it is a bit spastic.

February 23, 2014 9:02 pm

There are some bits of kit that utilise sophisticated heat beams, otherwise known as “Lasers”, that are usable on the battlefield and are exceptionally good at killing optical devices. (and only incidentally the eyes of anyone looking through them, because doing it deliberately would be illegal.)

John Hartley
John Hartley
February 23, 2014 10:39 pm

“Diamonds are Forever” got it right in 1971. A laser weapon is best placed in orbit. Though blowing up SSBNs in deep ocean is unlikely. Striking the airliner of a foreign dictator cruising at 40,000 ft, is scarily do-able. Above most of the atmosphere that could scatter the beam & able to strike at near light speed with no warning or defence. Except to destroy the laser sat, perhaps by launching your own crude sat ahead of it & blowing it up, then allowing the laser sat to be destroyed by the debris.

February 23, 2014 11:56 pm

RT, when did my finger emit light? It’s strictly physical. :P

JH, you don’t really need nuclear bombs for an X-ray laser, it’s a frequency not a power setting. As for the Orion drive, it was less about fallout and more about “WTF are we going to do in space?” Beyond the moon race, which was a Democracy/Communist prestige project at that time (and still is looking at the Chinese), there is very limited utility in “long” distance space travel. Even the Mars habitation projects are put on hold, there were calls for volunteers then nothing more and Biosphere went nowhere. As for intergalactic travel, I remember reading a study on the energy it would take to send a ship to the nearest star and it was calculated that even 1:1 anti-matter energy conversion was insufficient for the ship to reach its destination in a decent timeframe, especially when you have to bring along the mass needed for the reaction to take place too, so you get a death spiral. (More mass needed = bring more mass = more energy needed for propulsion = more mass needed etc). Not to mention the annual production of anti-hydrogen in the world can be measured in pico-grams. With the production budget of a big country’s entire GDP. Fascinating stuff, but ultimately not very usable.

And NO, NO, NO to debris weapons! We got too much junk up there and a single collision can shut down our near space for years!! The situation is actually near critical, enough that new satellites are required to either de-orbit or get boosted to a graveyard orbit.

February 24, 2014 2:03 pm

“I seem to remember that X-ray lasers were the most promising part of SDI. Need a small nuclear bomb to power them though”

Gamma ray lasers (aka grasers) were the ones that had to be pumped by a nuclear bomb. Not really a practical weapon of war…

John Hartley
John Hartley
February 24, 2014 6:55 pm

Obs & others. X-ray laser. Yes you can power one with a particle accelerator, but its not really viable to launch a 10+ mile loop into orbit. Now I am doing this from memory, but I seem to remember in the late 80s?, Something that looked like a WW2 sea mine. A round satellite with spikes on it. The small bomb exploded & an X-ray pulse was generated by the spikes in that instant before they were destroyed by the explosion. The spikes would be pointed at the target. The X-ray laser delivers a punch, rather than the burn through of a normal laser. Re a debris satellite weapon. I am not advocating one, but some countries see them as a way of addressing the US technical advantage. I think there was a proposal for a de junking satellite. Again this is a ropey memory, but I think the idea was to act like flypaper, get the debris to stick to it. Once you were full, de orbit the satellite & let it burn up the junk.
As for interstellar travel, NASA had a “breakthrough propulsion physics” study looking at exotic stuff. If you could get a bubble of negative energy round a spaceship, it could do hyperlight speeds without breaking the lightspeed/Einstein limit.
Plus of course, BIS came up with a proposal in the 70s for an unmanned probe to the nearest stars at 10% of lightspeed (Daedalus?).

The Other Chris
March 7, 2014 5:35 pm

Best place for this news (other than the Open Thread) especially for those who understand multiple point waveforms and particle natures:

Successful EXCALIBUR Test Brings DARPA Closer to Compact High Energy Lasers