
U.S. Air Force has shot down multiple air-launched missiles in a test - SEJeff
https://www.thedrive.com/the-war-zone/27795/the-air-force-just-shot-down-multiple-missiles-with-a-laser-destined-for-fighter-aircraft
======
gingabriska
Don't we simply need a missile covered with mirrors to defy these lasers?

It's just a light bean albeit concentrated one, how hard can it be to deflect
it?

Edit: don't understand the downvoting, please enlighten. Your wisdom is not
obvious to me. Thanks

~~~
thaumaturgy
No, it doesn't work like that. The military is of course tight-lipped about
exactly how powerful SHiELD is, but at least one site claims that the goal is
50kw [1]. That's a lot of power. A few years ago, a 30kw laser test made the
rounds in news outlets for destroying a few targets during testing. [2]

Mirrors don't perfectly reflect light in all frequencies. Mirrors are designed
to reflect mostly visible light, lasers at this power level are infrared. Any
imperfections in the reflective surface would immediately heat up, damaging
the reflective surface, which would then heat up even more. And even if it
were perfect, and were designed to reflect whatever frequency of radiation the
laser's putting out, it's still not going to reflect 100% of the laser's
output, and you've probably got yourself a material that's pretty impractical
for a rocket.

[1]: [https://phys.org/news/2018-03-air-fighter-mounted-laser-
summ...](https://phys.org/news/2018-03-air-fighter-mounted-laser-summer.html)

[2]: [https://newatlas.com/lockheed-martin-laser-
truck/36377/](https://newatlas.com/lockheed-martin-laser-truck/36377/)

~~~
Retric
50kw is actually not that powerful in terms of lasers. Petawatt systems are
being built. The real question is how how much power you can deliver to a
target.

In that context rotating reflective missiles make this much harder as does
slightly thicker casings. Anything you deploy optimized for today’s missiles
is easy to design around, so you need to design for countermeasures.

~~~
coredog64
Building a useful air launched missile that spins at a rate capable of being a
countermeasure is difficult.

~~~
Retric
On it’s own I agree, but even fairly slow rotation such as 1 RPM becomes
useful on edge cases. That’s not hard to achieve.

My point is if you find the minimum power output to be X kw, you want to
deploy something at ~4x power output to deal with fairly easy modifications.

PS: Stealth capabilities is probably a bigger long term issue, but that’s a
large modification.

------
rdiddly
All the acronyms are over the top. Have they heard of my Project SCIMITAR?
(Symbolically Capturing Information by Making Inane Trite Acronyms to
Rememberstuff)

Joking aside, if they can get this into a compact form that can be adequately
supplied and cooled, it'll be a quantum leap in weaponry. You're talking about
going from hurling chunks of matter that in turn impart kinetic and thermal
energy, to being able to project energy directly.

~~~
dba7dba
The Scimitar? The name was already taken for a military project/equipment
before you were even born. It is an armoured reconnaissance vehicle (sometimes
classed as a light tank) used by the British Army, fielded starting in 1970s.

It is both amazing and slightly terrifying... Imagine when this weapon can be
hand carried by an individual soldier. Or even a crew served weapon like a 'Ma
Deuce".

~~~
rdiddly
Hey I was born pre-moonwalk, and not just the Michael Jackson kind either.
(Don't let my immaturity fool you.)

Scimitar link:
[https://en.m.wikipedia.org/wiki/FV107_Scimitar](https://en.m.wikipedia.org/wiki/FV107_Scimitar)

------
S_A_P
Question: say one of these planes is flying above me and someone shoots a
surface to air in the general direction of this plane, and in the process of
destroying said missile an errant laser beam strikes me as I watch from the
ground. What happens to me? Mainly curious as to the power of the beam as a
thought experiment.

~~~
mr_overalls
This scenario has been carefully explored since the mid-1980s. For
clarification, are you made of popcorn?

[https://www.youtube.com/watch?v=rthHSISkM7A&t=16s](https://www.youtube.com/watch?v=rthHSISkM7A&t=16s)

~~~
S_A_P
That was one of my first thoughts too. I am curious if/how deadly the lasers
are, and I have resisted the Dr Evil quote fingers until now.

------
sdrothrock
I imagine Israel would be at the top of the list of interested parties for
this technology -- it sounds much cheaper than the Iron Dome since I assume
there isn't a real per-shot charge other than the energy required.

It would also be much faster than their current interceptors.

I just wonder how well it would work against low-tech targets.

~~~
azernik
It also would be well-suited to shorter-range attackers - Iron Dome can only
intercept missiles with a _minimum_ range of about 2.5km.

Israel is pursuing its own high-energy laser defense program, Iron Beam (yes,
not so creative). From public sources, it's not clear if the thing is 1-2
years from deployment, or if it's in development hell; the US is uniquely
public about these high-budget prestige projects for internal political
reasons.

~~~
chmod775
> the US is uniquely public about these high-budget prestige projects for
> internal political reasons.

I don't know if there's prestige in being _7 years_ late to the party.

Rheinmetall demonstrated this tech in 2012.

[https://newatlas.com/rheinmetall-laser-
test/25504/](https://newatlas.com/rheinmetall-laser-test/25504/)

~~~
adventured
That's pretty amusing. The US has been far ahead of everyone else in military
laser tech for decades.

Rheinmetall didn't demonstrate what you're implying. You're conflating two
entirely different systems.

The US has so many laser programs that predate the Rheinmetall example, it's
hard to decide where to start. HELLADS, AN/SEQ-3, Boeing YAL-1, HEL-MD, THEL,
MLD, etc.

Like this one:

"On March 18, 2009 Northrop Grumman announced that its engineers in Redondo
Beach had successfully built and tested an electric laser capable of producing
a 100-kilowatt ray of light, powerful enough to destroy cruise missiles,
artillery, rockets and mortar rounds."

Or:

Precursor to the Boeing YAL-1: "The Airborne Laser Laboratory was a less-
powerful prototype installed in a Boeing NKC-135A. It shot down several
missiles in tests conducted in the 1980s"

THEL:

"The Tactical High-Energy Laser, or THEL, was a laser developed for military
use, also known as the Nautilus laser system. The mobile version is the Mobile
Tactical High-Energy Laser, or MTHEL. In 1996, the United States and Israel
entered into an agreement to produce a cooperative THEL called the
Demonstrator, which would utilize deuterium fluoride chemical laser
technologies. In 2000 and 2001 THEL shot down 28 Katyusha artillery rockets
and five artillery shells. On November 4, 2002, THEL shot down an incoming
artillery shell. The prototype weapon was roughly the size of six city buses,
made up of modules that held a command center, radar and a telescope for
tracking targets, the chemical laser itself, fuel and reagent tanks, and a
rotating mirror to reflect its beam toward speeding targets. It was
discontinued in 2005"

------
noobermin
Laser weapons might have their uses, just hope that the it isn't a cloudy day,
or say, the enemy uses something like a mirror for that specific frequency, or
even better, something that emits a dust cloud that eats the energy. Missiles,
of course, can fly through dust clouds.

~~~
wnkrshm
Scattering by droplets/aerosols is an effect that drastically reduces the
capability of an optical system to focus at range, it's like shining a
flashlight through milk - not the same as variations in air density that you
could maybe partially compensate for using adaptive optics.

In rain, common LIDAR wavelengths, like 905nm and 1550nm lose about 0.1-1% of
their power due to scattering per meter travelled and on top of that 0.1-1%
due to absorption. Of course, this will not scale linearly with higher power
but it's a lot even if it's ten times less.

For laser weapons to be effective you need a clear line of sight in the
respective wavelength.

------
naval-gazer
Power efficiency makes lasers in fighters problematic. The current cutting
edge lasers have 35 percent efficiency. If you heat the target with 100 kW
power, the fighter absorbs 300 kW of heat. You can use fuel to absorb the heat
but heat exchangers adds lots of weight and extra complications.

~~~
Symmetry
I'd tend to assume that the airflow a fighter has to work with would help a
lot with managing the heat it deals with.

~~~
hindsightbias
The F-35 cools avionics by running lines through the fuel tanks and already
has had thermal issues. Removing the heat of a ~50-100kw laser via a heat
exchanger onto surface airflow is going to make a nice heat signature/target.

------
GistNoesis
How wide is the beam ? How long does it need to stay focus on roughly the same
point ? Wouldn't spinning your missile prevent a beam to being focused always
on the same point ? Does adding random jitter to your missile trajectory
prevent focusing ?

~~~
asdff
At what point do we have a pilot match speed with the missile and cast a net?

------
tomphoolery
Anyone else getting a "Real Genius" vibe from this turret?

I feel like Val Kilmer is about to make an epic bowl of popcorn with this
thing.

~~~
jeffrogers
The whole thing has Real Genius written all over it. I can only hope the
Lockheed test engineers put a large JiffyPop out for target practice.

------
danmaz74
> A directed energy weapon also has an effectively bottomless magazine.

Is this true for a laser mounted on an airplane? How is the energy stored?

~~~
onion2k
_How is the energy stored?_

Presumably as jet fuel, and the laser is charged by the plane's engines.

~~~
consp
Most extreme high power lasers are chemical in nature, but these are probably
somewhat similar to the setup in [1] by the laser power mentioned. I would
guess using an APU to control conditions but it does not rule out your guess
of using the onboard systems.

1\.
[https://en.m.wikipedia.org/wiki/AN/SEQ-3_Laser_Weapon_System](https://en.m.wikipedia.org/wiki/AN/SEQ-3_Laser_Weapon_System)

------
Causality1
I wonder if there's any chance this could spur development of effective anti-
ICBM laser systems. Considering that nuclear ICBMs are the only real
existential threat to the United States, I'm often surprised they don't spend
a huge chunk of their defense budget neutralizing that threat.

~~~
TeMPOraL
I worry if a single nation would be first to develop effective ICBM
countermeasures, the whole MAD doctrine would collapse on the spot and we'd
have a next world war on our hands.

~~~
Shivetya
MAD only works if the other side is concerned about the welfare of its people.
I know that many would prefer to think otherwise but the USSR was just as
concerned about their own people as the United States was. They don't have
oceans on both sides as a buffer.

that out of the way, it is regimes that don't show a real concern for their
people that is the danger. the only hold on them is the vulnerability of those
making the decision. once they show disregard for their own welfare is when
everyone should be worried.

~~~
Udik
> regimes that don't show a real concern for their people that is the danger.

I doubt that these exist, "look, these people are crazy and suicidal and don't
even care about their own children" is a common propaganda statement, with the
clear purpose of de-humanising the enemy. Even the most ferocious dictators
care about some of the people, and about their own cultural heritage, and the
country they rule. Nobody wants to be wiped off the face of the earth.

~~~
azernik
And even if they don't care about any of those things, their people are the
source of their power.

------
sandworm101
Take this all with some massive grains of salt. The language is very vague.
When it comes to "shooting down" a missile much depends on definitions and
locations.

An inbound air-to-air missile is a very tricky target. It is face-on. Your
laser cannot target the explosive bits of the missile (the rocket motor that
is active for the first few seconds of flight). But that doesn't matter.
"Shooting down" can mean jamming the missile's IR sensor or damaging its radar
dome, both of which would stop it as a threat. The real problem imho is the
size of the emitting aperture. Focusing a laser tightly at any distance
requires a device probably too large for a fighter aircraft.

Shooting down a missile from the side, from the ground or form an escort
aircraft is another matter. Get it during the boost phase (the first few
seconds after launch) and even a pinprick through the side of the rocket motor
will cause it to explode. But in that scenario why wait for the missile to be
launched? If you can burn through the rocket motor after launch, you can do so
_before_ launch. My point: any weapon capable of explosively shooting down
misses in flight is also capable of shooting down the launching aircraft
before it gets a chance to fire.

Oh, and don't forget that such weapons are probably illegal under various
treaties. If it can shoot down a missile a one mile it can blind a pilot at
ten. Pointed at the ground it could blind scores of troops. Some legal hoops
would need to be jumped before one could ever deploy such a laser.

~~~
DuskStar
> The real problem imho is the size of the emitting aperture. Focusing a laser
> tightly at any distance requires a device probably too large for a fighter
> aircraft.

Focusing a laser onto a 100mm point at 5km does not seem like it would take
that large of an aperture, and that should be all you need to kill the seeker.

> Get it during the boost phase (the first few seconds after launch) and even
> a pinprick through the side of the rocket motor will cause it to explode in
> a true "shoot down".

IIRC most air to air missiles have a boost phase far longer than that - I
think most will still be burning at intercept for shots inside the killbox.
That's part of the selling point of the Meteor [0] - it can throttle, so it'll
almost always be burning at intercept.

> But in that scenario why wait for the missile to be launched? If you can
> burn through the rocket motor after launch, you can do so before launch.

It's a lot easier to argue that the other side shot first when you blow up the
missile AFTER it leaves their plane. Not to mention the case where the
responsible aircraft wasn't detected until after launch...

0:
[https://en.wikipedia.org/wiki/Meteor_(missile)](https://en.wikipedia.org/wiki/Meteor_\(missile\))

~~~
sandworm101
>> 100mm point at 5km does not seem like it would take that large of an
aperture.

It gets trickier than that. From the perspective of the target missile the
laser is a pinpoint source, easily ignored/blocked. You have to hit is with
enough power to actually do damage. 50KW over a 10cm seeker head won't be
enough. A missile is supersonic. That seeker head is already being bombarded
by plenty of IR/heat and is actively cooled. You need to focus down to far
less than a centimeter to start burning things.

~~~
DuskStar
If it's an IR seeker, the cooling might be able to prevent damage, but is it
enough to prevent heating the seeker sufficiently to cause the missile to lose
lock? What happens if the laser turns off/loses track at 2 km while dropping
flares - can your missile differentiate between flares and the skin of a plane
in that scenario?

And I can't help but think that a pinpoint source coming from your target is
harder to ignore than one coming from anywhere else.

Either way, at mach 4 it takes ~3.5 seconds to cover 5km. 50kw * 3.5s = 175kj,
42 grams of TNT equivalent. That's still a fair bit to mitigate. (but also not
nearly as much as I was thinking)

------
dba7dba
Everyone thought a huge laser taking up a dedicated 747 (Boeing YAL-1) was a
stupid idea but looks like it was a good starting point.

~~~
dingaling
The YAL-1 ( horribly nonstandard designation ) was addressing a different and
much harder problem; destroying ballistic missiles in the ascent phase at
considerable range.

However destroying magnitude-smaller, nearby air-to-air missiles is much more
achievable and was demonstrated by the NKC-135 / Airborne Laser Lab project
back in 1979-85. Yes, 40 years ago.

------
baybal2
R73 missile was credited with shooting down other A2A missile back in
eighties. So it is not the first time it was done somehow

------
Symmetry
Now that off-boresight missiles are coming into service I wonder how long
it'll be before fighters can use missiles to shoot down missiles like you see
in modern naval engagements.

Also, I know the F-35 has the power plant to run one of these but could one be
mounted on an F-22?

------
amelius
Wondering what kind of recoil force this laser gun generates.

[https://www.physicsforums.com/threads/does-a-laser-have-a-
re...](https://www.physicsforums.com/threads/does-a-laser-have-a-
recoil.379922/)

~~~
wnkrshm
You get about 1 Newton per 300MW of photon flux, it's not dependent on
wavelength. So here with 50kW of continuous photon flux, the magnitude is
about 166mN, the gravitic force of about 50 grains of rice, less than a
paperclip.

------
gnode
It seems pertinent to mention "laser" in the title. My initial thought was "so
what? Missile defence is nothing new."

------
gandutraveler
I am thinking what if enemies just shoot fake projectiles and wait for the
defense system runs out of missiles.

~~~
Symmetry
I'm not really sure what the point would be? Getting a hunk of metal moving
quickly towards the target is most of what a missile does. In a conflict where
airframes are a limited resource I don't see why it would make sense to waste
payload on decoys when you could just load up more missiles.

~~~
hedora
You only need to get one nuke through.

Also, compared to building additional missiles, having your missile split into
a bunch of decoys and a few warheads is fairly inexpensive.

~~~
Symmetry
Wait, where are nukes entering into this? The article was about tactical
defenses for warplanes, I don't think anybody still has nukes in their air-to-
air arsenals after the 70s. When you're talking about ICBMs with MIRVed
warheads decoys can make a lot of sense because in space a 10 kg balloon looks
a lot like a 500 kg warhead. But in the atmosphere they're very easy to tell
apart and nobody talks about decoy _missiles_.

------
Haga
Make love not war on rainy days

------
Circuits
So have we rounded up enough sharks so we can mount all these lasers or what??

------
b_tterc_p
I feel like blinding sensors or pilots might be easier?

~~~
jws
Easier, but prohibited by treaty.

See “The Protocol on Blinding Laser Weapons, Protocol IV of the 1980
Convention on Certain Conventional Weapons”

[https://en.m.wikipedia.org/wiki/Protocol_on_Blinding_Laser_W...](https://en.m.wikipedia.org/wiki/Protocol_on_Blinding_Laser_Weapons)

It’s quite short and to the point. No weapons designed to permanently blind
people are allowed. Incidental blindness is ok, also if you get blinded while
looking through binoculars that’s fine. Blinding sensors is also fine.

~~~
b_tterc_p
This one seems odd. If this weren’t explicitly allowed, it could rather easily
stop most aerial operations. While it is nice for pilots, it seems to cancel
out the potential to just make sending pilots on military runs in feasible in
the first place.

------
Paraesthetic
So its just like the iron dome?

~~~
azernik
Very different systems.

Iron Dome uses ground-launched interceptor missiles, tied in to a theater-
level control net, to intercept short-to-medium-range surface-to-surface
ballistic missiles.

This uses a self-contained, at-some-point-aircraft-mounted laser, to shoot
down guided, powered, maneuvering air-to-air or surface-to-air missiles.

------
credit_guy
So, here's who WW3 will unfold, about 20 years from now. Once the USAF can
mount laser weapons on a plane, not long after they'll be able to put them in
missiles. And more precisely in those missiles that perform the anti-ballistic
missile defense function. Currently the equation governing the ABM defense is
that you need about 2 kinetic vehicles to destroy one warhead launched at you.
If you replace this with one laser-equipped missile can zap 10 incoming
targets, that's a complete different ballgame. The MAD concept can become very
unstable. Instead of needing a many, many thousands of missiles to obtain
impenetrable defense, two hundred missiles-mounted lasers could do the job (a
single Ohio class submarine can carry up to 24 Trident-II SLBM's with up to
288 multiple independent re-entry vehicles; if you replace each such nuke with
a laser, you are all set).

When will the US have this capability? I would ball-park this at about 15
years for now.

What options does Russia have. By my cont 3 options (hardware-based; I'm not
counting cyber-warfare and psychological and subversive warfare).

1\. Deterrence in numbers. Currently Russia deploys 1600 warheads, and has a
total of 6500 (deployed+stockpiled+retired). If they go to 20-30k warheads, in
an all out war a few dozens might still find their way to some large urban
areas in the US, and so even a 99.9% ABM capability might still leave a few
tens of millions of Americans dead.

2\. Laser-equipped anti-anti-missiles. If you can zap a nuke out of the sky,
you can zap the missile carrying the laser too. Provided you have the
technology. I expect Russia to have a delay in implementing this technology,
maybe 5 to 10 years

3\. Alternate threats that are immune to this defense. This is exactly what
Russia demonstrated one year ago: a hypersonic nuclear-capable, nuclear-
powered missile that can travel in the lower atmosphere (where the effective
range of a laser is reduced, due to light absorption) plus a mega-nuke
delivered by an autonomous submarine that purportedly can create a 500-foot
tsunami that would wipe NYC from the map.

Where does that leave us? The US will enjoy the maximum military gap about 20
years from now and this will provide a huge incentive to perform a
decapitation strike. Would this be palatable to the US population? Only if it
can be demonstrated that the collateral damage would be insignificant. Is that
possible? What do you need to do? You need to take out the missile silos, the
strategic nuclear submarines, and the strategic bombers (the nuclear triad).
The silos are traditionally the targets of some nukes; in the past these nukes
had about one megaton yield, but with the increase in missile accuracy the
current US yield is about 100kt; this is still 5 times larger than Nagasaki.
Is it possible to use a smaller nuke with an increased accuracy? A rule of
thumb is that a 10-fold increase in accuracy can reduce the necessary
effective yield by 100. Starting this year (2019) the US Navy will have a 5-7
kt nuke in its arsenal (W76-2 [1]). This type of nuke could ensure essentially
zero civilian casualties, while still being able to destroy most missile
silos. Oh, and it would also be a good anti-strategic-submarine weapon too.

So, about 20 years from now, the US will have a once-in-a-century opportunity
to break the mutually-assured-destruction stalemate, and potentially rid the
world of nuclear weapons. All with minimal loss of life (especially civilian
life). But the window of opportunity will be very short, Russia will be able
to close the MAD gap in a few years. Which will make this opportunity a very
difficult one to pass on.

[1] [https://www.theguardian.com/world/2019/jan/28/us-nuclear-
wea...](https://www.theguardian.com/world/2019/jan/28/us-nuclear-weapons-
first-low-yield-warheads-roll-off-the-production-line)

~~~
kyboren
This is crazy talk.

> The US will enjoy the maximum military gap about 20 years from now and this
> will provide a huge incentive to perform a decapitation strike. Would this
> be palatable to the US population? Only if it can be demonstrated that the
> collateral damage would be insignificant. Is that possible? What do you need
> to do?

A decapitation strike couldn't be debated. It would have to be _done_. The US
population would only accept it--and only in part, as some segments would
never accept it--as a _fait accompli_ if there were zero US casualties, few
foreign civilian casualties, no/minimal residual health risks, and limited
reputational damage to the US. I highly doubt any, let alone all, could be
accomplished with a nearly sufficient degree of confidence, even with
groundbreaking missile defense systems.

The risks of miscalculation are staggering, and the immorality of attempting
or even seriously considering (as a policymaker) such a "decapitation strike"
in the current or foreseeable future global context is indisputable.

~~~
credit_guy
> This is crazy talk.

Quite succinct and accurate. I have to admit, reading my own words, I do sound
like a crank.

So, let me give a more nuanced view. I think the probability of an all-out
nuclear exchange is still quite reduced, but if the capability gap between
Russia and the US extends considerably, this probability will increase from
the current infinitesimal level to a non-negligible one. Other events that
were once considered unthinkable (DJT, Brexit) have come to pass, so never say
never.

With that said, how can we get to such an extreme event as a nuclear exchange?
I think that whenever there is a military crisis in the world (Iran
threatening to resume uranium enrichment ?) the POTUS asks his advisors for
options. The spectrum of options ranges from PR spin machine, to diplomatic
pressure, to military operations. All options will have listed their pros and
cons, their best, base and worst outcomes. They will be judged in isolation
and weighed against each other. After this careful comparative cost-benefit
analysis, the POTUS makes the decision.

Now all things being equal, if the military gap between the US and the
opponent is larger, the armed response options will comparatively have a
better cost-benefit ratio. The more impenetrable the ABM defense becomes, the
more the military option will look like the better deal.

Now the vicious cycle is that, as the military option is chosen more often
(how long did it take DJT to send an aircraft carrier towards Iran?), the more
tensions will appear, and the more crisis situations will emerge. Some of them
will be de-escalated, but some will escalate to various levels. Sometimes cool
heads will prevail, but sometimes the grown-ups will have left the room
already. One day Russia might do something that would trigger Nato's article 5
[1], and the US will have to respond. You could say that we've been in many
situations like that in the 60's, 70's and 80's, but the military gap between
the US and the Soviet Union was never close to what it's now, and what will
become in the coming decades.

Ok, ok, but nuclear, you say? Well, the US has dropped about 100 bombs in
Nevada, just 60 miles from Las Vegas, and it was no big deal. A few (hundred)
small-ish nukes going boom in the middle of Siberia will result in some
condemnations from some pacifist organizations, but as long as there is some
reasonable casus belli and minimal civilian collateral damage, people will
move on quite soon.

[1] [https://www.rferl.org/a/explainer-nato-
articles-4-and-5/2462...](https://www.rferl.org/a/explainer-nato-
articles-4-and-5/24626653.html)

------
klausjensen
"...In a test"

------
saneshark
While this seems promising it seems like it will be a short lived phenomenon.
Missles will just become obsolete and then you have to come up with a
deterrent for lasers.

Is anyone actively working on laser deflector shields?

~~~
mattmanser
I don't get your reasoning? Lasers need line of sight and hit a very small
area, missiles can travel long distances and hit a massive area.

~~~
TeMPOraL
Go high enough, and you can have LOS to anything within half the planet of
you. Wait for the world to spin a bit, and you have LOS to the other half.

~~~
arethuza
Perhaps the catch being that if you have LOS to half the planet then half the
planet has LOS to you and presumably its a lot easier to build and operate a
high energy laser on the ground rather than in high orbit.

~~~
dredmorbius
Missile-launched laser platforms.

You don't have to loiter for all time.

~~~
TeMPOraL
Loitering in space is near-free.

That said, I'm thinking pumped-laser-tipped missiles could be very effective
as e.g. anti-ship weapons. You could launch one straight up from your
territory, and have it snipe the enemy ship from far away. The enemy would
have to monitor a large portion of the sky for relatively small objects _and_
react instantly with lasers of their own to counter that.

EDIT: I suspect these could be made into pumped-laser _shells_ ; good luck
countering one that's launched from beyond the horizon.

~~~
arethuza
Ships would appear to have access to an idea anti laser countermeasure - spray
lots of water into the air!

~~~
TeMPOraL
Water is also a good RF screen, so such shield would also effectively blind
and cripple the ship. Even discounting the energy use, no way they could keep
that up continuously. Ramp-up time is probably large enough too (on the order
of seconds), making surprise attacks very feasible. Not an _ideal_
countermeasure, though I'm not sure what would be, beyond packing more
ablative armor.

~~~
dredmorbius
If you're in a position to be aware of an imminent attack, ramp-time is
probably within reason. Power reqirements are fairly modest by military
standards -- a small fireboat can pump impresive quantities of water, and
since the goal in defence / obscuring is to blind (and absorb energy), a finer
atomised mist would be more effective. Filter and system fouling is likely a
bigger concern.

True bolt-from-the-blue attacks are rare, though possible.

The spray profile could be modified to enable sensor detection, or alternative
(off-ship, buoy, balloon, drone, ...) sensor placement could enable both eyes
_and_ shields.

