The Slow Speed of Light

[kafka47]

Naturally, there are system buoys, beacons, and patrols. That is how the Imperium can maintain a relatively full employment economy...massive government spending on useless projects through expensive procurement from from the Megacorporations which are controlled by the Nobility.

Emperor Stephon: What do you mean...50MCr for a lighbulb...??? I can go to Palace Depot and get for 2Cr (italics as I am sure that the Emperor may use more creative language)

Prime Minister: The Ministry of Exploration assures us that all possible sources have been researched and for this special type of lightbulb, it will be have to at this cost and assures me it is a bargin. Plus, factor in the installation, fuel costs, crew salaries, Danger pay, etc. You would not want the Station above Capital to shine less brightly, would you, Sire?

Emperor: I guess not...#$%^&@! Scouts, Navy, E#R%^ I just don't understand why they failed to notice the burnt out bulb last week?

PM: They did, your Highness, but if they replaced it last week what would they have to do this week?

In all serious, Marc's points are right on the mark and I think he has spelled out what many of us have just been using.

There is however the need for adventure in Traveller (despite that I think there is a rule somewhere)...that would determine that much of a system is merely Wilderness or wild. Space is really big. If our own world can be a microcosm. I have hiked through parts of the Appalchians and not run into other people for several days or gone through Maine and only encountering communities with one telephone. I would say that I was have been lost, if were not for my "sensors" - trail maps. So even now if I would employ a GPS, I could still get lost and far off course due to terrain and the batteries breaking down. And, this in the United States...supposively the most technologically advanced nation on the planet.

Therefore, I see Traveller being no different. Sensors, buoys, etc are there as you need them. Higher the Starport & TL, the more amenities there are but essentially apply the rule of profit...they might be there for a cost or simply reserved. Only the Imperium provides these public goods for the public good...which is more dictated by other factors.

 

[Patron Zero]

Cinematic Moments

Accepted that everyone will have opinions whether the film, Wing Commander could be considered to depict a Traveller universe or for that matter it's namesake source material PC game. That said I do think the scene involving the vessel CS Tiger Claw powering down and laying on the 'bottom' does illustrate the gist of the thread's discussion.

However credit should be given to the eternal classic film, Run Silent, Run Deep for visualizing the knuckle-biting tension of being pinged in combat.

 

[Commander Truestar]

I said I read a lot, not I do a lot, and yes I know there is a big difference. Still, I wouldn't have gone active in response to an active ping and actually if the Sensors and Tac officers know their stuff they should be able to suss out the type and such of the offending ping and work out the math as most of that stuff can be found in a good copy of Jane's, but again that's just Mr. Armchair speaking.

Of course Mr. Armchair does happen to have a copy of Jane's ASW book.

Really...
So from one quick set of hits you can determine...even after significant dispersion...what type of equipment the enemy has. This, I assume, is based on Psi-reading the offending sensor operator's thoughts to know if they are varying their power output to mask their system type....
And of course, EVERY variation of starship system and Pirate or local shipyard up-grade can be found in Jane's ships of the stars..

And knowing that, despite the fact that you only got hit by one wave of active pings you can not only tell where the enmy was hours ago(which is what the math WILL tell you if you can solve the variables above) but also figure out where they are going at what speed, etc..

Remember, in a Sub you get all sorts of passive stuff like screw sounds and the like which you will not get in space. At the distances of sensor contact in Traveller vis-light is not an option and even if it was, It took years for Sharon Shoemaker to spot S-L 9. You have hours at best...

Oh, and you are a very skilled sub sonar tech with a significant sensors background, even if you do filter everything through your water-based experience..

These are players, some of who are ex-military but, who do not have your experience.

I feel they did fine in that they did not take any damage and took out their foe. In even the most basic of space battles, that is rarely the case if even possible.

Marc

 

[Commander Truestar]

Marc:
Keep in mind that signal drop off over distance is an exponential function, and thus the differential as a fraction of the stronger signal antennae's power gives the position on the curve distance, AND the timing differential between the antennae gives the bearing. By knowing where in the curve one falls, one can back-calculate the signal strength at source, as well.

OK, so you know where(through triangulation) and how much power I put into my signal...though not how much power I "Can" put into it. Those are 1.5 answers to the many questions including:
-from there, where did I go?
-At what speed?
-Am I even now changing vectors?
-am I a big ship with average sensors or a small ship with big ears or a HUGE ship barely using any power?

The number of questions you do not answer are legion and the one answer you think you have(power setting) may be erronious

So where are you without an active ping of your own.

Most of you seem to be saying that the active ping give you everything when it gives you little more than a single point. No one can define a line from a point.

as far as sub sensor tech is concerned, I am betting that you are counting on a whole lot of passive data which you can get underwater...but not likely get in space.

So if he has active pinged you and knows everything about you already, you'd might as well return the favor before scrambling your position if you are the average adventurer and not a sonar expert.

Marc

 

[aramis]

Given a mere few seconds of observation, I can observe your current vector; based upon emmission spectra, I can likely confirm closing speed, and determine a probable location, and it only takes two hits to establish speed and direction; all I have to do is saturate that area where you could be. At 0.1 LS, anything over 100 tons and under 8G's is effectively direct-fire targetable, since you can only get so far out of the way. IIRC, when I did the math in the 90's, 6G's and 800 tons was still direct shot at 0.2LS.

Remember ∆D=0.5ATT
6G is A=60 (in traveller) (and 58.8 in real life)
T=2xRange (in LS) + tracking time (in sec)

So, given 0.1 sec tracking and 0.1LS, that's T=0.3, which means ∆D=0.5(60)(0.3)(0.3)=30*0.09=2.7m... your 6G ship can only be 3m change of vector from where your vector would leave it. That's not enough to take a center of known surface area of minimum profile on a Type S hull... I can direct fire, and hit you, unless your speed is relativistic... in which case I need to integrate the additional time to intercept. Kind of stuff a modern computer can do in fractions of a econd.

 

[tbeard1999]

Given a mere few seconds of observation, I can observe your current vector; based upon emmission spectra, I can likely confirm closing speed, and determine a probable location, and it only takes two hits to establish speed and direction; all I have to do is saturate that area where you could be. At 0.1 LS, anything over 100 tons and under 8G's is effectively direct-fire targetable, since you can only get so far out of the way. IIRC, when I did the math in the 90's, 6G's and 800 tons was still direct shot at 0.2LS.

Remember ∆D=0.5ATT
6G is A=60 (in traveller) (and 58.8 in real life)
T=2xRange (in LS) + tracking time (in sec)

So, given 0.1 sec tracking and 0.1LS, that's T=0.3, which means ∆D=0.5(60)(0.3)(0.3)=30*0.09=2.7m... your 6G ship can only be 3m change of vector from where your vector would leave it. That's not enough to take a center of known surface area of minimum profile on a Type S hull... I can direct fire, and hit you, unless your speed is relativistic... in which case I need to integrate the additional time to intercept. Kind of stuff a modern computer can do in fractions of a econd.

Yup. In reality, space battles will be quite unlike naval battles for the simple reason that even passive sensors can detect enemy ships at extreme ranges:

If the spacecraft are torchships, their thrust power is several terawatts. This means the exhaust is so intense that it could be detected from Alpha Centauri. By a passive sensor.

The Space Shuttle's much weaker main engines could be detected past the orbit of Pluto. The Space Shuttle's manoeuvering thrusters could be seen as far as the asteroid belt. And even a puny ship using ion drive to thrust at a measly 1/1000 of a g could be spotted at one astronomical unit.

This is with current off-the-shelf technology. Presumably future technology would be better.

I'd add that current astronomy instruments can do a complete spherical sky search in about 4 hours. So your incredibly bright engine (or heat radiators for life support) can't really get lost in the "big sky".

And powering down won't get it done either. A ship the size of an Oscar class submarine with engines powered down will be visible at ~39 million km, assuming that the ship is maintained at a temperature of 32 degrees F. (And no, you can't refrigerate the ship to avoid this problem; this requires power, which will create a highly visible hot spot on your ship). Temperature is a bitch in space. The background temperature of space is about 3 degrees K. The freezing temperature of water is 273 degrees K. So even powered down ships will be highly visible.

At the end of the day, Run Silent Run Deep-style battles in space require enough handwaves to sprain your wrist. I don't object to handwavium, but I prefer that it be clearly identified as such.

To quote an extensive usenet thread on the subject--"he who radiates is lost". And everything radiates in Real Space.

And another bummer. If you know the operating parameters of the ship's M-Drive, you can instantly tell how big it is by its heat signature and acceleration. Heat signature will tell you the thrust, acceleration will allow you to determine ship mass.

 

[tbeard1999]

Does anyone here understand that active use of sensors, pinging away is going to be detectable by the prey long before the hunter is getting anything back that they can use?

Apparently not. But you're correct; active sensors let everyone in the neighborhood know where you are. Note that this is the case with other forms of sensors as well. Active infrared night vision systems are disfavored by the military because the IR illuminator broadcasts your location to everyone with a passive IR system. Passive thermal sights are favored because (among other things) they do not give away your position.

But that's just cause I am annoying and read lots of sub stuff.

It's a darned shame that Real Space won't let us have analogs to submarine battles. Of course, the fun thing about sci-fi is that we can handwave inconvenient facts away. But we should admit that it's a handwave.

 

[Commander Truestar]

It's a darned shame that Real Space won't let us have analogs to submarine battles. Of course, the fun thing about sci-fi is that we can handwave inconvenient facts away. But we should admit that it's a handwave.

One option I have used to recreate the "submarine battle" experience is the use of unstable stars or gas giants flooding local space with UV rad, etc... While not going too deeply into the numbers, the GM can create a situation where ships can become lost in the backgroud. You can even add in sun spot storms to re-create the effect of thermal currents blocking out sensor read

This (and handwavioum if you prefer) can be used to enable, disable or color sensor data to the point you can create almost the feel of a sub-battle.

Sadly, there will never be the "sonar tech bent over his board listening intently for the faintest sign of screws or boiler/steam hiss" as space does not transmit sound. But that can be replaced with the reaction of the ship;s metal hull reacting to local radiation..heheh

Marc

 

[zonk]

Of course, the fun thing about sci-fi is that we can handwave inconvenient facts away. But we should admit that it's a handwave.

Yes of course we have to handwave. But we have to do so with so much of Traveller... or pretty much any SF rpg.

The only one that might be close is Transhuman Space and I find that such a depressing society that I won't play it.

 

[tbeard1999]

One option I have used to recreate the "submarine battle" experience is the use of unstable stars or gas giants flooding local space with UV rad, etc... While not going too deeply into the numbers, the GM can create a situation where ships can become lost in the backgroud. You can even add in sun spot storms to re-create the effect of thermal currents blocking out sensor read

I like the idea, but you'd have to have a lot of such systems to justify navies having dedicated craft to operate in that environment.

Even if you don't have a lot of such systems, you can have an ad-hoc submarine style action. Could be a heckuva good adventure. I'll probably steal this idea.

 

[tbeard1999]

Yes of course we have to handwave. But we have to do so with so much of Traveller... or pretty much any SF rpg.

The only one that might be close is Transhuman Space and I find that such a depressing society that I won't play it.

Agreed.

I should've been clearer -- I don't object to handwavium at all. (Of course, I do object to certain kinds of handwavium, primarily because of genre concerns). And I agree that handwavium is pretty much required in a classic SF setting. My purpose in making the observation is that factual debates are a waste of time in areas with significant amounts of handwavium. (For instance, it's silly to waste a lot of time arguing about Real Space detection if the referee has imposed handwavium rules to force the result he wants).

Therefore, the handwavium should be clearly identified IMHO.

 

[Rev Round]

1G (OTU G) = 10.m/s/s
1 hour = 3600.s
1G-Hour = 36000m/s/s = 36.km/s/s
C (OTU) = 300,000.km/s
1 G-Hour = 0.00012 C
a G-Day is 24 Ghours... or 0.00288 C (actually, less, as time dilation starts to be measurable. Or 0.288PSL

Not enough to seriously deter sensors. You'll get some NICE doppler shift....

keep in mind: Bat sonar routinely tracks objects up to Mach 0.07 or so 50MPH dragonflies can be tracked by bats.

Off thread somewhat but maybe of interest and or entertainment.

As a youngster i learned how to whistle between my teeth and raise the pitch beyond my young ears range of hearing. Many years later under a bright full moon on an island off the Thai coast i saw this big bat hunting the mosquitos and could occasionally feel the sound/sonar at the back of my neck. The beach dog would chase the moon shadow of the bat it being more apparent. It enjoyed the futile chase. And i thought..... yes. so i did. I gave it, the bat, the old whistle working the pitch up which to my older ears went out of my range much sooner. I did that for a while noticing the slight change in bat behaviour which brought a smile to my face when wooosh! the bat silently flew right up to my face scanned me and i felt like it knew the shape of my skull. All over in an instant and never forgotten.

Scanned at less than six inches! i had no time to be scared or even to reflexively duck. Awesome isn't the right word. Impressive is.


yes this true story is copyright by the way. lol