Archive for the Rules Category

Sensor types part 1

Posted in Intercept, Rules, Science on September 20, 2018 by Anders Backman

Planet LOS in Star Wars

Space combat takes place at incredible ranges, tens of thousands of kilometers, and unlike in the movies, you won’t see anything through your window; a nuclear detonation for sure, fission or fusion thrusters as pinpoints of light maybe, the plume of a missile just before it hits you, the blinding flash from a laser hitting your ship, but aside from that nothing…

All ships carry sensors to see things around them and this is especially true of warships. All ships will have optical sensors seeing in visual and infrared wavelengths and most will also have radar. More exotic sensors such as neutrino or gravity sensors may be carried by larger or more specialized vessels.

Visual, infrared and radar sensors are mounted on the surface of the hull and can only be used when unfolded and extended, popped out as it is called in the game. Neutrino and mass sensors sees right through the hull so they can be used whether popped out or not. This make them especially suitable for military purposes as they can be used while still protected by the ships armor.

Visual

Visual scans are done with optical telescopes collecting light from visible wavelengths.

Light sources can be light from the sun reflected from the hull. How much depends on the strength of the sunlight, the area of the reflecting hull and how reflective the hull material is.

Light can also be directly emitted by a ships thrust, either the intense light from fission or fusion rocket plumes or the much fainter glow from impulse thrusters or floaters (that magic sci-fi blue glow).

The Inverse square law

The light falls off in strength as it spreads from its source, in both dimensions, if range doubles the intensity goes down as 1/2 times 1/2 or 1/4.

Infrared

Popular media usually depict space as cold but in reality the problem is the opposite, getting rid of heat is hard part and the only viable long term way of doing it is by radiating it away. Every object radiates heat, how much depends on its temperature.

Ships have optical sensors that can either look in visual wavelengths or in infrared to detect objects as they radiate heat to cool. Ships radiate enormous amounts of heat when using fission or fusion thrusters, less infrared is radiated from the power plant when running, ships also radiate a faint heat from the temperature of the hull itself.

The infrared light falls off the same way as visual light, by the square of the distance. A given ship is typically easier to detect visually than by infrared, at least when the ship is in sunlight or if the ship has a running power plant. If the ship is using fission or fusion thrusters it’s about as easy regardless of using infrared or visual scanning. What to use really depends on what you think you are trying to find, tricky.

Plotting board

Radar

Everyone is familiar with radar works; you send out radio bursts that bounce off the target and get detected as it comes back.

One problem with radar is that it falls off much faster than visual or infrared does. Radar, although invented during World War II didn’t detect the planet Venus until 1961 yet it can easily be seen by the naked eye. Doesn’t radar waves fall off by the inverse square as visual and infrared does?

Of course they do. The problem is they fall off by the inverse square both going there and coming back again, 1/r^2 going there x 1/r^2 coming back again or, 1/r^4. If this sound weird and hard to grasp think about the following analogy:

You walk at night in a forest with a flashlight in your hand. The flashlight is a powerful maglite showing you the trees out to about 30 meters.

The flashlights range depends on the power of the flashlight but also the quality and focus of the lights parabolic mirror. The light falls off going out, bounces off trees and falls off coming back again, back to your eyes, your detectors, just like a radar.

Let’s say you decide to try your car lights instead. They must be a hundred times more powerful right? And now you can see trees out to about a hundred meters, three times farther or so. Three to the fourth power (3^4) is about a hundred (81) so that terrible range fall off of radar affects flashlights and headlights the same way.

t2kdetector-640x200

Two men in a rubber raft inspect the wall of photodetectors
of the partly filled Super-Kamiokande neutrino detector (Ars Technica)

Neutrino

Neutrinos are these strange subatomic ghost particles created in fission and fusion reactions. These particles really fleeting, reacting to next to nothing. Build a wall one lightyear thick and half of them still get through. How can one ever hope to detect them with something smaller than a solar system, smaller than a planet even, small enough to fit on a ship?

What you do is you amass an enormous amount of atoms, in the hope that one neutrino might interact with one of them and then surround the mass with super sensitive detectors hoping to catch that one interaction somehow. The first detectors used thousands of cubic meters of water or chlorine as the mass and after waiting a long time they got the first signal from the sun. Imagine that, it took this enormous tank lined with super sensitive detectors sitting for months to detect a single neutrino coming from this enormous fusion reactor we call the sun.

Neutrino detectors in Intercept appear at TL-11 and assumes that some breakthrough has appeared, some resonance to exploit or some other way to make the neutrino detectors much smaller and much more sensitive, still bulky but practical. Neutrinos created in fission or fusion thrusters and fission or fusion power plants are what these detectors see. As the neutrinos leave their source they spread out, just as the visible photons for the visual scans and the infrared photons for the IR scans so the fall off is the same.

Neutrino sensors can only detect fission and fusion thrusters and fission and fusion power plants. On the other hand when they can see targets on planets or right through planets as if they aren’t there at all. In fact, a ship in the planetary shadow scanning towards the sun will be affected by Sunglare as if the planet wasn’t there at all.

Gravity with Thrust

Mass

Detecting a nearby mass seems easy. Just measure its gravitational pull on you. Not so easy. Imagine you were locked inside a small box either being a hundred km above earth and falling towards it (let’s ignore air drag completely) or being a light year away in the depth of space.

How can you detect which is case it is? How can you detect how far away earth is and in what direction? In both cases the box and you would be at rest with each other, either falling freely towards earth or just drifting in interstellar space. You could peek out of the box but that would be cheating. There is one difference that you can actually measure, being near earth means you closest point, say your toe, would be pulled towards earth a tiny amount more than your furthest point, say your nose, the difference between these pulls could be measured as a very weak force and this force would grow weaker the farther away from earth you go, a light year away in deep space and you’d measure nothing at all.

This force is called the tidal force and pulls apart parts of objects in a gravity field. The ocean water closest to the moon gets pulled towards the moon relative the water on the other side causing two bulges that move as the earth rotates. Yes that is why there are two tides each 24 hours.

Tidal force falls off as 1/r^3, double the range and the tidal force is 1/2 x 1/2 x 1/2 or 1/8 the strength. This limits the range of mass sensors but on the other hand they can see right through planets and because of the 1/r^3 falloff can scan towards the sun.

Mass sensors detect the mass of a ship directly but usually they detect the much stronger emissions from the gravitic Impulse or Floaters and also any working floorfields. This means that older low tech ships lacking floorfields and relying on fusion or fission for thrust are actually the hardest to detect.

Well, that is all for now. The next article will deal with the practical use of these sensors in Intercept. How to use them effectively and how to avoid being detected by them. Keep the solar wind to yer backside folks!

Intercept rulebook update

Posted in Intercept, Rules on July 6, 2018 by Anders Backman

Elite Dangerous_20180701172211

I have updated the rulebook with some minor changes mostly for readability. There is also a step by step example on how to achieve stable orbits added, on page 21. As always you get the rulebook, ship designs, map templates to print, ship data cards etc here, and as always it is free of charge.

Landed or docked

Posted in Intercept, Rules on July 2, 2018 by Mr Backman

Landed on planet with atmosphere

Space is empty and very hard to hide in as your ship will stick out like a beacon against all that black. Sure, getting far enough away from any sun, painting your ship the blackest of black and not using any  thrust might make you harder to see against the black but what about infrared? Sure, you can turn off your powerplant and distribute the remaining heat radiating from your ship more evenly via stealth tech, and of course not using any rocket thrust but that black space around you is only 3 degrees Kelvin, so what to do?

The best way to avoid detecting is staying away from space altogether. Dock with something big, land on an asteroid or a planet, preferably with a thick atmosphere, or hide hovering inside the swirling clouds of a gas-giant. These rule will teach you how to scan for landed or docked targets, scan while being landed or docked and finally how to perform combat between landed ships and space, in both directions. The updated Intercept rulebook including these rules can be downloaded here.

A landed or docked ship is either in the Sunside illuminated by the sun or the Darkside hidden in the shadows, both sides have their pros and cons.

Scan for landed

Landed LOS

Sunside The planet or asteroid will block half your view so you cannot see anything farther from the sun – but on the other hand those farther from the sun cannot see you either. You are lit up by the sun by so is your surroundings. If the planet has any kind of atmosphere you cannot see out at all using Visual or IR sensors, Neutrino and Mass sensors completely ignore planets and asteroids. If there’s no atmosphere you can scan using Visual or IR into any square equal to or closer to the sun than you, if there is an atmosphere you cannot scan at all (neutrino and mass scans can always scan of course). Being in the Sunside also means having to worry about staring into the sun, make sure that your Scan doesn’t touch the Sunglare column as your opponent will happily remind you.

Darkside The planet or asteroid will block half your view so you cannot see anything equal or closer to the sun – those equal or closer to the sun cannot see you either of course. You are in the shadows cast by whatever it is you are docked to or landed on, good for you. At night the atmosphere is dark so you can actually scan using Visual or IR sensors. Your surroundings will be heated from the sun so your ships infrared emissions will be harder to pick up. As usual Neutrino and Mass ignore the planet, asteroid or docked ship and can scan as if nothing was there.

Scanning for landed or docked targets

When scanning for docked or landed targets you must tell your opponent that you wish to do so and what side you scan, Sunside or Darkside as you cannot do both with the same scan. Scanning for docked or landed makes your Sense task harder, how much harder depends on what you scan but the Sense roll will always be harder so don’t scan for landed or docked willy-nilly.

Reveal your Scan as usual, strength, size etc, tell the opponent that you want to scan for docked and landed too, tell if you Scan for Sunside or Darkside. Opponents ask you the usual questions:

  • Does the Scan touch Sunglare? Works as normal, subtract Sun factor from your Scan strength the Scan touches the Sunglare column, but not if your ship is in planet or asteroid shadow.
  • Does the Scan touch Suncolumn or Shadowcolumn? Works as normal. If it touches Suncolumn you must say if you are in the shadow column or not, and if it touches Shadowcolumn you must say if you are in the Suncolumn or not, if it touches both you must say if you are in either.
  • Is part of your Scan blocked by the planet? Works as normal. Note however that you can only scan squares for Sunside of they are equal to or closer to the sun than you and you can only scan Squares for Darkside if they are farther from the sun than you.

Then roll a Sense task, use the highest target number for all applicable targets within the Scan. If both a planet and an asteroid are inside the scan you must roll 9+ if you wish to look for landed on both but you only need to roll 8+ if you only search the asteroid.

  • Sense 6+ If scanning normally for ships in space
  • Sense 7+ If scanning for docked ships
  • Sense 8+ If scanning for ships landed on asteroids
  • Sense 9+ If scanning for ships landed on planets
  • Sense 10+ If scanning for ships hovering in gas giant atmospheres

Ships in space (ie not docked or landed) reveal Contact info if the Signal is 0+ as usual, landed or docked ships however, never reveal Contact info, either you saw nothing or you get a Tracked result.

Landed or docked Signatures

Landed side These effects only apply to the ship landed or docked.

Landed side

Atmospheres These effects apply when scanning from the planet as well as to the planet, both directions reduce the Signatures. Note also that ships landed in the Sunside of a planet with atmosphere cannot scan Visual or IR at all, radar, neutrino and mass work fine.

Landed atmosphere

Aerobrake signatures An aerobraking ship will shine brightly in both visual and infrared, the more so the faster it goes and harder it brakes, if you don’t believe me check out the video.

Aerobrake glow

Aerobrake signature

Scanning when landed or docked

Docked or landed ships are Sunside if unrolled and Darkside if rolled, if the ship you are docked to roll your ship become rolled too. Sunside can only see squares that are equal to or closer to the Sun, Darkside ships can only see squares that are farther from the sun. This mean that if the enemy cannot see you then you cannot see them either.

When the target ask Is part of your Scan blocked by the planet? You must tell him which squares that are blocked and this pretty much guarantee that he will know that you are landed and what side. To counter this avoid when Sunside and thus unrolled only scan squares that are equal or closer to the sun and when Darkside and thus rolled only scan squares that are farther from the sun. This means that you should avoid scanning boxes of the same row as you are in or only do smaller 1×1, 2×2 or 3×3 square scans.

If the planet you are landed on has an atmosphere, including when hovering in a gas giant atmosphere) the atmosphere absorption modifier is applied to your scan strength before revealing it to your opponent. That is all there is to scanning from landed or docked.

Combat between landed and space

So, one can scan for landed or docked and one can also scan when landed or docked, this inevitably lead to combat between landed / docked and those in space. Ships can only be attacked if they are tracked of course, which even simpler for docked or landed targets as they never reveal Contact info, it’s tracked or nothing.

Docked ships have the same status of thrusting or drifting as the ship docked to, landed on asteroids, planets or hovering in gas giant atmospheres are all treated as drifting. All other effects of being landed depends on the atmosphere of the planet.

Beam weapons suffer PEN and DAM reductions and negative hit DMs from the atmosphere, worse the thicker the atmosphere is and particle accelerators double these modifiers making them nearly useless in all bit the thinnest of atmospheres.

Beams through atmosphere

Missile weapons must have airframes to be used in an atmosphere at all. They have a max speed when entering or leaving an atmosphere and when entering the atmosphere their speed is reduced before determining PEN, DAM and hit DMs.

Missiles through atmosphere

Yes, these rules may rarely come up in scenario play but whenever the subject arise it’s good to have it answered. It will however crop up all the time in roleplaying situations.

Players “Can I see the smugglers ship on the runway from orbit?”

Referee Checks what signature the ship would have using these rules “Yes.”

Players “Can we shoot it?”

Referee Sighs “Eh, I guess” (watching his complicated scheme go up in smoke ‘land in jungle nearby – sneak into the smuggler ship and steal it – weird cross between a tiger an crocodile enter the cargo bay – fight ensue – smugglers alarmed – another fight – ref get to test new cover system’).

Sensors, Scans, Signature and Signal

Posted in Intercept, Rules on May 17, 2016 by Mr Backman

Planetary shadowWe don’t experience the world directly. Our senses react to certain physical phenomenon and our brains interpret the data and paints us a picture that feels both real and coherent, the world is a fantasy of our creation. The sensors of your ship is just one more redirection from the universe and your mind.

3 worked Scan examples

The rulebook tell us how a Scan is performed. The scanner adds his sensors Sensitivity to the Scan size modifier to get a Scan strength. The Scan strength together with type of sensor, position and size is presented to the opponent. The opponent then, ask three questions and the answers determine if the Scan strength should be reduced or if there are areas of the Scan that cannot be seen by the scanner and should therefore be ignored.

If the opponent has target(s) inside the legit area he will add the relevant Signature(s) to the Scan strength and if the result, the Signal, is 0+ he must tell the scanner each relevant Signal that was 0+. The Scanner finally decides whether to perform a Sensor task and that task will give him an Indication, a Contact or the much coveted Tracked result. Read pages 6-7 for the basics and page 18 for planets and page 22 for asteroids and there respective effects on scans. End  of story, right? Below follow three scan examples, with pictures and all, enjoy.

Scan 1

The player A, the scanner, decides to try a 1×1 box towards the sun to see if the sneaky player B is maybe approaching from the sun. The ship is where number 1 is located and the green area is the Scan. The ship has a +2 Sensitivity Visual/IR sensor, and the modifier for a 1×1 box is -1 so Scan strength is +1.

Scan 1

Scan 1 – Visual 1×1 box, strength +1 in B3

Player A “I will do a Visual Scan, 1×1 box,  with a strength of +1, in B4”

Player B “Does the Scan touch your ships Sunglare column?”

Player B starts asking the three questions, this one is from page 6 in the rulebook, the other two are from page 18. The Sunglare question must always be asked, even if there are no planets or asteroids on the map.

Player A “Yes, my Scan touches my Sunglare goddamit!”

Player B “Does your Scan touch a blocked sun or shadow column?”

This question need only be asked if the map has planets or asteroids on it.

Player A “No, and you can clearly see that I don’t, but I know, you have to ask”

As the Scan didn’t touch the sun or shadow columns of the planet this question is not strictly needed but it can be good practice to ask all three questions regardless. The Sun column is the three squares wide light grey column above the planet and the Shadow column is the three squares wide darker grey column below the planet. Large planets have three squares wide Sun and Shadow columns, small planets and asteroids have one square wide, planets have columns infinitely long while asteroids have columns limited in length, see page 18 and 22 for details.

Player B “Finally, does the planet block parts of your Scan?”

Player A “Eh, wait a minute, checking…, ah nope”

The Scan is neither from nor to the planets gravity-well so player A can can swiftly answer this with a resolute ‘no’ but sometimes taking longer to check can fool the opponent into believing you are somewhere else.

Scan 1b

Scan 1 – Sunglare always affect none or the whole Scan, never parts

The one square wide column extending up from the scanners ship, not including the square of the ship itself, in grey, is its Sunglare column. Any Scan touching the Sunglare column will have its Strength reduced by the Sun factor (from now on called simply Sun). The Sun factor is normally 6 so in this case the Scan strength goes from +1 to -5.

If player B has any ships inside the B4 box he must now add the Scan strength of -5 to all his ship’s or missile’s Visual signatures, always Visual(Hull) and Visual(Thrust) too but only if thrusting. If the Signal (the Scan strength plus Signature) is 0+ he must tell player A that he got an Indication at least, and tell him the actual Signal(s). Player A may now rolls a Sensor task to determine if the Signal was high enough to also give him a Contact or the coveted Tracked result.

Player A have hopefully learned that Scans containing your scanning ships Sunglare column are stupid, the space combat equivalent of staring straight into the sun.

Scan 2

Player A now has his ship in position 2 and is about to declare his second Scan. This time he tries a larger 3×3 box one well away from his Sunglare. Note that parts of the Scan is outside of the map, which is perfectly fine as long as the center is still inside. Ships and missiles outside of the map are lost but Scans partly outside are simply a bit wasteful.

Scan 2

Scan 2 – A Visual 3×3 boxes Scan with Strength -1 in E1

Player A “This time I do a Visual Scan, 3×3 boxes, with a strength of +1, in E1”

Player B “Does the Scan touch your ships Sunglare column? You do know that parts of your Scan is off the map right?”

Player A “Yes I know and no, this time my Scan does not touch the Sunglare column of my ship”

The grey one square column stretching up above position 2 is the ship’s new position and we can clearly see that the new Scan doesn’t touch it, no Sunglare reduction this time.

Player B “Does your Scan touch a blocked sun or shadow column?”

Player B can clearly see that the planet’s Sun column is touched by the Scan but even if it didn’t it might be a good idea to ask this question, just to get into the habit.

Player A “Yes,the Scan touches the Sun column, but no, my ship is not in the Shadow column”

If the Scan touches the Sun or Shadow column the scanner must tell his opponent whether his scanning ship is in the opposite column or not. Whenever a Scan has the potential of having areas blocked they will also tell the target something about the scanners location.

Player B “Does the planet block parts of your Scan?”

Only omit this question if there is no planet on the map. If the Scan is from within he gravity well of a planet or if th Scan touches the gravity well of a planet, parts may be blocked. Planets have 8 sectors around them, near sectors inside the gravity well and far sectors extending infinitely far out. Pictures on page 18 show you the sectors of small and large planets. If your Scan doesn’t touch any blocked sectors you must still tell your opponents this, that nothing of the Scan is blocked.

Scans from a Near sector blocks the opposite near and far sectors.

Scan from Far sector blocks opposite near sector only.

Player A “Yes, my Scan is blocked in the planet’s North-East near and far sectors”

If player B has any ships or missiles in the North-East near or far sectors they should be ignored, any targets in the boxes D1 and D2 are still valid of course. Player B also now knows that player A has his scanning ship inside the South-West near sector. This is why the order of Scans are important, players take turns scanning first or last using the A/B turn order rule as explained on page 2 of the rulebook.

Scan 2b

Scan 2 – Parts of the Scan blocked by the North-East near and far sectors.

Scan 3

Turn 3 has player A’s ship just outside of the gravity well of the planet, and well inside the planets Shadow column. Being inside the Shadow column not only block scanned targets in the Sun column it also reduces the Visual(Hull) Signature. Normally, in sunlight, the Visual(Hull) uses the number written +Sun but when the ship is inside the Shadow column the Sun factor is 0 making the ship much harder to detect.

This time player A decides to Scan near the planet, thinking player B is maybe lurking there, inside the gravity well. A 3×3 Visual with a Scan strength of -1, centered in E5, as shown by the grey area.

Scan 3

Scan 3 – Visual 3×3 boxes, strength -1 in E5

Player A “OK, another Visual Scan, 3×3 boxes, with a strength of +1, this time in E5”

Player A once again ask the only question one must always ask, the one about scanning the Sunglare. If you look at the figure it might look like the S´can really is touching the shops Sunglare, it is – but – if a ship is in the Shadow column they are unaffected by Sunglare! Go outside in the middle of the night, stare straight down – do you feel blinded by the sun? No, didn’t think so, the Earth was in the way, you were technically in Earth’s Shadow column and thus unaffected by Sunglare, and if´you were away from streetlights and such, I bet your body was harder to see too.

Ships in the Shadow column are unaffected by Sunglare

Player B “Does the Scan touch your ships Sunglare column?”

Player A “No”

Player A doesn’t have to tell player B that the reason Sunglare isn’t in effect is because he is in the Shadow column. Don’t reveal what you don’t have to.

Player B “Does your Scan touch a blocked sun or shadow column?”

As the Scan touches both the Sun column and the Shadow column of the planet player A must reveal if he is any of them or outside both.

Player A “Sigh, my ship is in the Shadow column, the Sun column is blocked”

Player B “Aha! That explains why Sunglare didn’t affect you. I think I know where you are now!”

Player B “Does the planet block parts of your Scan?”

Player A “Yeah, my Scan is blocked in the North near sector, and the Sun column too as you already know”

Boxes D4 and D5 have small parts that are not blocked but most are, but still, big chunks of the SCan are still valid, don’t be afraid to do Scans including the planet, trick players tend to stay close to the planet thinking they’ll be blocked but as you can see that is far from the truth.

Scan 3b

Scan 3 – Sun column and North near sector are blocked, shown in red here.

Page 16 to 22 of the rulebook covers everything you need to  know about planets and asteroids, not only how they affect Scans but how you land on them, how their gravity affect your movement, how you can use their atmosphere for aerobrake maneuvers, and even how your Scans and Signatres are affected by being landed on a planet or asteroid.

Smugglers do it in the shadows – faded text on a dead captains T-shirt.