> Assuming active sensors for targeting, make that triple!
I had been thinking about this also. In addition I would like to offer
computing time for the targeting. At this level even very short periods of
time will have a huge impact. You have a huge distance to the target and
rather (we can assume) fast speads (of both target and shooter). Besides, at
rather large distances after you start adding all these factors in you get the
problem that if your weapon is off by even the smallest fraction it will
translate to huge misses at the other end.
I would like to add a few other thoughts. It seems that a lot is being said
about 'fighters' and then I read the length of '1000 meters'. Now, that seems
like a rather large fighter to me:)
I also would like to bring up the other measurements of the ship. We are
talking (at least the calculations so far indicate) about a 1000 meter long
ship. But, how wide is it and how tall is it? I think this should be taken
into account because who says your going to get a hit on it long ways. I would
suggest that as soon as enemy craft are detected you would rotate your ship to
bring the smallest target to bear against them.
Most of the discussion has also involved lasers. Now, I would also suggest
that a laser is going to have to hit a specific point on a ship for a period
of time in order to do any real damage (at least as I understand it). What if
you had your ship rotating? It would seem that this would spread the beams
contact over the hull, at least to me. Even if it only took a very short
period of time for the laser to do damage, after you add in ship movement and
rotation (both being changed in a random pattern as much as possible I would
guess) it might be harder to do the ship damage farther out.
Heck, make your ship round and out of ice. Have it rotating and smooth.
I
would think that this would help you survive a hit somewhat. I have this
really cool image in my head of someone doing welding repair work on ice
:) I would think the ice would be harder to detect than metal and would have
other uses besides easy repair (emergency fuel perhaps).
All kinds of other things to take into account for that long range beam shot.
Electronic measures will be taken into account. If you are using radar all
kinds of fun can be had if you have a ship that you are willing to dedicate to
the purpose. You could easily toss out reflective junk to scatter the laser
before it hits you (it would fly along the course you are
moving - the one the enemy is tracking also, so it would be deflecting
in exactly that one small area you might need it the most). Just a lot of
things to take into account.
I suggest that we will see lasers (of some type) for close in work and
missiles (of some type) for extended distances.
Probably going to see three range brackets. One in which beams will play an
offensive role (short), one in which both beams and missiles will have
extended roles (med) and one in which missiles will play the prime role
(long). All this assumes two moving ships of course. Against a stationary
target just throw a big rock :) (and yes, I realize it is a bit more
complicated than that:):)
Chad (the none scientist, so have mercy on me with your response if I have
missed any big things:)
> Thomas Barclay wrote:
Or like fleet battles in the "Mote in Gods Eye" by Niven and Pournell, I takes
a while for laser fire to overload a ship's sheilds and score a kill. A space
battle is described as a black golbes(sheilds) floating in space connected but
red lines of laser fire, broken up by the occasional energy torpedo. The point
is that ships don't dodge, the just take it, untill the energy becomes to
much, then either flee or face damage
later
Hi there!
I have been doing some number crunching on how difficult it would be to hit a
ship with lasers once the targeting system had locked on and I thought I would
share it with you. This is by no means exhaustive but it is accurate for the
premises.
1. The target ship is 1000 feet long (sorry if you use metric but I was raised
with feet even though Canada is officially metric now).
2. The target ship is moving 10,000 miles per hour relative to the
targeting system. Comparing that to B5 and other sci-fi shows that is
VERY fast.
3. The target ship is moving along the long axis ie. it's bearing is the same
as it's heading.
4. Laser light travels at 186,000 miles per second.
10,000 miles per hour equals 2.777777 miles per second 2.777777 miles per
second equals 14,611.11 feet per second
therefore a 1,000 foot long ship would cover its own length in 1/14
second
This would mean that targetting the centre of the ship and firing would hit
somewhere along its length
as long as the beam didn't take more than 1/28 of a second. Therefore
it would hit at a distance of 186,000 divided by 28 or 6,642.85 miles. Now I
am not suggesting that targeting systems or laser beams would be effective at
that distance but
it does show that at a range of 100-200 miles you are going to hit as
long as you push the button and are targeted on the enemy. You can play with
this by changing the target speed, angle of the target, how well weapons are
aligned to the target (and that will have some effect) but if you can target
it you will hit it. It also means if the laser is pointing at a fighter which
is closing to kill the laser will hit every time as at that distance the laser
is just travelling too fast to miss.
This doesn't mean though that I will change the way I play the games,
this is after all sci-fi
> On Tue, 24 Feb 1998, BEST, David wrote:
> I have been doing some number crunching on how difficult it would be to
Some problems here. If the target ship is moving at constant speed, then
you can aim for any point you like - it's just the same as if it were
standing still. What makes targetting difficult is _manoeuvre_ ability.
Best bet is to compare the transit time of the beam (0.03 seconds for 6,000
miles, for example) with the velocity change the ship can manage
in that time (0.005 m/s if it has 1G acceleration).
It's still the case that, normally, if you can target it you can hit it. The
beam transit time only becomes significant enough to prevent a hit at much
longer distances (or higher accelerations).
Roger spake thusly upon matters weighty:
> Best bet is to compare the transit time of the beam (0.03 seconds for
I would imagine futuristic combat vessels would require either 1. outrageous
ECM suites to fool the enemy targetting 2. high maneouvre caps (crew inside
liquid or foam suspension capsules to cushion against G shock or some such. I
saw one book where they suggested replacing blood with a synthetic that took G
compression better and modifying space crew bone structure etc). I
would think this would be on the order of 5-10 Gs if not more.
Probably a lot of #1 and at least some of #2.
Tom.
/************************************************
> How about simple leading the target?
> At 15:58 24/02/98 -0500, you wrote:
Nice calculation. What you have deduced is perfectly reasonable. You are also
correct that the the closer the ship the easier it is to hit (in fact, if you
look at it in vector terms, as the ship gets closer the relative
tracking speed - the angle you have to move the laser through to keep it
on
target - approaches zero). The problem with this in the real world is
keeping the beam on exactly the same spot for that 1/28th of a second,
rather than just within your 1,000 foot diameter. After all, it's probably
doable to vapourise a (say) one foot circle of hull in 1/28th of a
second, but a lozenge 1 foot in width and 1,000 feet long? Heck of a lot more
energy required.
While we are vaguely on the subject, anyone who can find a copy should check
out the Colonial Marines Tech Manual (I think it's called), a piece of
licenced fluff from the Alien movies. It has a section on space combat (purely
narrative and 'factual') which is most interesting, along with some
SGII/DSII relevant things to say about infantry combat in the age of
mobile sentry guns, smart mines, laser rifles etc etc...
TTFN
Jon
> I would imagine futuristic combat vessels would require either
> 2. high maneouvre caps (crew inside liquid or foam suspension
As I remember it a properly trained fighter pilot in a pressure suit can
take short bursts well over 5G - I think the standard figure is 8 for
very short maneuvers. A theory I always had was it would be possible to fit
future air/space pilot with some sort of cybernetic/nanotech 'blood
pressure relgualtor' which would stop the effects of blood pooling (blackouts
and redouts). Then you have only to worry about broken bones etc, which is a
very high G sustainability.
TTFN
Jon
Hi Roger!
My point was that at the combat distance we are concerned with - maybe
200 miles - you probably are not going to miss. Even with the possible
acceleration rates.
David Best
> ----------
> Roger Burton West wrote:
Are you guys taking into account the transit time from the target to
your sensors in your overall on-target timing calculation? That should
at least double the response time, even assuming that target processing is
instantaneous.
On Wednesday, February 25, 1998 1:18 PM, BEST, David
> [SMTP:dbest@shl.com] wrote:
Taking one MU = 1000km (the official unoffical MU scale) then an A battery
goes out to 36,000 km, futher than 200 miles but still near instant for light.
I'd always thought that a 1000 metre ships going to be a very small target at
36,000 km. Even a very small movement of the laser barrel will transfer to
several Km the other end, it was this slack in the targeting system and
weaponary mechanics that gave us the possibility of missing the taget. Also
offensive particle beams will probably be a fraction slower than C (speed of
light) and will probably loose
power over distance as they de-focus (attenuate?).
Our most accurate current similar pointy targetting devices *now* I suppose
are telescopes. I don't know how long it takes to lock onto a small fast
moving target in earth orbit such as a satellite or MIR but suspect its not
that easy?
sincerely
Hi Roger
This is incorrect. Depending on the distance the target ship will have moved
but the beam will be travelling in a straight line. It won't be like the
target is standing still unless it is very slow or very close. Also targetting
systems would take into consideration target acceleration.
> On Wed, 25 Feb 1998, BEST, David wrote:
> This is incorrect. Depending on the distance the target ship will have
Sure. My point, though, is that it's not possible for the target ship to
get out of the way of the beam unless it has a lot of _random_
acceleration in the plane perpendicular to the beam, or unless the distance
over which the beam is fired is very long.
I recommend to anyone who can get hold of them the last GDW Traveller books
(the "after the fall" ones), which had a lot of discussion on this subject.
Jonathan spake thusly upon matters weighty:
> Are you guys taking into account the transit time from the target to
Good point. I don't think they'd thought about that. And whatever reading you
have, the quality increases as the target grows closer (less likelihood the
target has changed course in the lag time). At close ranges, this target to
ship to target time might not be long indeed, but it will (I assume)
effectively double the misalignment you calculate using the method the other
folks were using.
Mind you, I don't think it dispells the point that at visual ranges
(200-500 km with optics ? ), your fighters would be meat if they
didn't have visual stealth or hyper manoevrability at high Gs. If
they had visual and EM stealth, and/or manoevre (random walk
perhaps?) evasions, then they might still have a decent chance of
surviving. Even some low level ablative shielding - enough to let
them take a short hit while they attack - could be replaced on
carrier landings... would probably be enough to stop the hits they might take
on closing with the enemy.....
Tom.
/************************************************
> Taking one MU = 1000km (the official unoffical MU scale) then an A
De-focus. Attenuation would not be a problem in space.
> Our most accurate current similar pointy targetting devices *now*
Radar is far more accurate for targetting/tracking than a telescope. The
narrow field of vision inherent in telescope design make them unsuitable for
this sort
of application. Coupling the targetting/tracking system to the weapon is
the more difficult task.
> sincerely
> Our most accurate current similar pointy targetting devices *now*
Actually, with the proper systems, it shouldn't be that much of a problem. If
you have a fast enough computer to analyze what you're tracking, a sensitive
enough detector, and a fast enough drive mechanism, you ought to be able to
lock onto anything within your operating parameters.
Visual-type
telescopes (I'm assuming that's what you're referring to above) wouldn't be
what you'd want, though. For the most part, their field is too restricted.
Radar would be far preferable. Radar can cover an area of sky, and report to
the computer where the targets are, which can tell whatever it needs to tell
where something is. But you prolly already figured that bit out. ;-)
While I don't have direct experience with them, I'm sure NORAD uses a battery
of radars to keep track of the God-knows-how-many objects that are
floating around in orbit up there, and I *think* they track things as small as
a quarter, maybe a bit smaller. Impossible to do visually.
Mk
> Actually, with the proper systems, it shouldn't be that much of a
Visual-type
> telescopes (I'm assuming that's what you're referring to above)
wouldn't be
> what you'd want, though. For the most part, their field is too
One thought, would this not lead to stealth muntions, muntions which are
harder to detect and therefore intercept. Or muntions which on closing with
the target or being hit with a radar beam of a certain strength ( ie active
tracking vers passive search) deploy a large number of warheads, some decoys
etc to swamp the defenses.
> While I don't have direct experience with them, I'm sure NORAD uses a
A-yup. Which meant the technology of the detecting/tracking system would
then have to improve to compensate, which means the munitions would have
to re-stealth themselves, ad nauseum. :-)
Mk
How about simple leading the target?
> On Wed, 25 Feb 1998, Darren Douglas wrote:
> One thought, would this not lead to stealth muntions, muntions which
Fighters would probably stay thousands of km away from th target. If
anti-fighter defenses are so potent at ranges of .01 light seconds or
less then the obvious answer is not to get that close. I would predict an
increase in stand-off weapons that would allow fighters/bombers/attack
craft to remain outside of the most effective defenses a ship could mount.
These might incude stealth munitions such as hyper-velocity stealth
missiles that would have a really fast burn, maybe something that imparts a
velocity of several thousand km per hour and then coast into short range
of the target before firing a single pulse x-ray or particle beam
(Needle missile?) or detonating a large fusion warhead (normal missile) Or
conversely since the fighter does not have as difficult a time in tracking a
ship (just how fast can a 1000 ton craft move sideways...) you could mount a
fairly large laser on a fighter that would place it out of range of the ship's
AF lasers or at least force the opponent to mount bigger
lasers than necessary (c-batts instead of ADAF's)
Fighters would definitely have to be heavily stealthed to have a chance to
survive. Although NORAD can track objects in orbit that are about the siz of a
golfball, these are metallic, highly radar reflective
objects. The F-117A for instance has the same radar signature as a
metallic golfball a massive decrease in radar signature. I would assume
that the B-2 has a similar reduction in radar profile. The radar
profile on these planes has been reduced so much that IR and visual aspects
become bigger problems. In space it would be much harder to reduce the IR
signature of a fighter, active missile or even a ship since there is no easy
way to diffuse the exhaust. Perhaps using multiple engines that are baffled
from all directions except the rear might be a solution but the
enemy is still going to know that you're coming - a heat source of
thousands of degrees kelvin showing up against a backdrop of 3 or 4 degrees
kelvin is going to kinda hard to miss, unless you dive out of the
sun...:)
To sum it up, fighters of the future are either going to be
non-existant or basically small missile carriers with really short life
expectancies.
--Binhan
> Are you guys taking into account the transit time from the target to
Assuming active sensors for targeting, make that triple! 1) Time for sensor to
reach target 2) Time for reflection of sensor to reach firing ship 3) Time for
fire to reach target ship
> Christopher Pratt wrote:
> Tony Christney wrote:
s
> It's not possible to lead the target with a laser due to the speed of
How so? If a target is x kms away (say farther than the beam could travel in a
second), and going along X course, then you can get a predicted location where
the ship will be in shoot at it. By the time the laser gets out there it will
hit the target. Do you think these 1000 meter long vessels can turn on a dime?
> BEST, David wrote:
> Hi there!
Snipage!
> if you can target it you will hit it. It also means if the laser is
In one of the last few Challenge Mags, the Frank Chadwick (the dude who was
running GDW at the time...) Wrote an artical about this. He was saying
somthing like the focusing lens for the laser would have to be 6 meters across
(!) to hit a target 1000 kilometers away... I am not sure of the numbers, I
don't have the mag in front of me right now.
I just assume that someone somewhere in the game universe did the research,
and solved problems like this...
Brian spake thusly upon matters weighty:
> > Good point. I don't think they'd thought about that. And whatever
Albeit that a passive solution doesn't reveal you, but it takes more time to
build, resulting in greater delays and more likelihood of a miss. Good for
ambushes with stealthed ships (anyone from SFB say "Passive Fire Control"?).
The active solution, I'm assuming, is the default in FT. Special rules for
passive solutions and running 'silent' could be invented if they don't exist.
Tom.
/************************************************
Binhan spake thusly upon matters weighty:
> Fighters would probably stay thousands of km away from th target. If
Or else have so many fighters that they cloud the spacelanes.... (But that
wouldn't be practical in any sane universe....)
> These might incude stealth munitions such as hyper-velocity stealth
And the missiles would have some limited manoevre capability themselves so
that a straight ballistic track didn't work....
> Fighters would definitely have to be heavily stealthed to have a
BB I had heard. Golfball is the B-2. But I also heard that was only
effective against modern radars and that by some quirky property the older
radars would see it better (but that is a rumor).
I would assume
> that the B-2 has a similar reduction in radar profile. The radar
Carry compressed liquid nitrogen or something and mix it with the exhaust....
(or something). Or get the fantastica drive that doesn't
emit.....
Perhaps using multiple engines that are
> baffled from all directions except the rear might be a solution but
Why do I feel like yelling Torah! Torah! Torah! and putting on a rising sun
headband..... *Always check six, and watch for him to come in out of the
sun....*
/************************************************
On Wednesday, February 25, 1998 6:44 PM, Tony Christney
> [SMTP:acc@uvic.ca] wrote:
The narrow
> field of vision inherent in telescope design make them unsuitable for
Oops,
What I meant was assume the telescope is analagous to the weapon, as its a big
heavy thing that focuses light, how good are current technoogies for getting a
telescope on a target and tracking it? If you see the target in the centre of
the 'scope then you just shot it. Could a terresterial 'scope track MIR for
instance.
I don't know if there are any active telescope tracking systems that use radar
maybe NORAD has one for eyeballing the space junk?
I wasn't saying use the telescope as the fire control tracking system., thats
silly.
Anyway looks like this threads is way due to diediedie now anyway.
> Or else have so many fighters that they cloud the spacelanes.... (But
I can think of only one universe where this would be practical: 1) The only
way to travel between the stars is through fixed jump gates
2) Fuel is the most limiting factor in space travel due to cost. In this style
of universe, ships would carry just enough fuel to get to the jump gate and
from the gate to the destination. A 1 degree change in vector could cause a 3x
or more cost in fuel to get back to the correct
course or destination. Pirates/Ambushers would place ships or fighters
along the most cost effective route from the planet to the jump gate. Granted
if fuel is the biggest cost, fighters would not be used as they burn fuel more
quickly.
> Radar is far more accurate for targetting/tracking than a telescope.
The narrow
> field of vision inherent in telescope design make them unsuitable for
Well, as I noted in another msg yesterday, I know amateur astronomers who
*hand-track* on Mir... ;-) And at the right orientations they have
reported
they can make out the rough shape (one of my co-workers even took a
blurry photo of the Mir and shuttle docked a few years ago; you *can* make out
the basic shapes)
> Anyway looks like this threads is way due to diediedie now anyway.
B'bye!
:-)
Mk
> You naked inside your fear wrote:
Quick note: Mir doesn't dodge violently, evading missiles and beam
weapons fire. (8-) Though, there are systems that can take a
'snapshot' of a target, and follow it down. Maverick and several
other Electro-optical guided missiles/bombs are examples of this.
Actually, would anybody know what the tolerances on these systems are?
(And if so, could they actually tell us? (8-) )
J.
Jerry spake thusly upon matters weighty:
Though, there are systems that can take a
> 'snapshot' of a target, and follow it down. Maverick and several
I assume to some extent, and based off Mr.TV, that these systems us IR
tracking as well as optical, and use high speed sampling rates and
a technology similar to anti-jitter technology used in hand held cam
corders - the high speed imaging grabs two sequential frames, and
looks for changes. In the case of the anti-jitter - it takes out
small vibrations. In the case of tracking, it probably moves the array and
recentres on the new centre. If the array can track as fast as the target is
moving, and if it has a high enough rate of acquiring frame data (ie it
doesn't take five minutes to build a frame hence observations about movement
are near meaningless), then it should track okay. Mind you this style of
tracking is an 'after
the fact style' - where the target WAS a little piece ago (1 frame
back). It isn't (but probably could be made) predictive - it won't
guess where the target is going. It could, and if it did, you'd be stuck with
the quality of the 'guesses' your software made and the longer the lag between
frame acquisition, the more problematic this would become.
Here's another one - interesting scenario for FT - one force heavy,
the other force light. The light force catches the heavy force in the
middle of shakedown on new SW or HW which is problematic - as a
result they perform with enough penalties to let the light guys have an
advantage or at least so things are even. (ie "Dammit Jones, those NSL
destroyers are coming in! Get that targeting array online or we'll have to
fire by Eyeball Mark One!" "I'm trying captain, but every time I try to target
something, I get a blue screen with register information and a Contact Your
Software Vendor message....")
Tom.
/************************************************