Archive for September, 2018

Sensors part 2

Posted in Intercept, Rules on September 25, 2018 by Anders Backman

Sensor_Operator

Stars, hide your fires; Let not light see my black and deep desires – William Shakespeare, Macbeth

We’re deep in space. Corner of no and where. You take extra care. ‘Cause we’re very much alone out here – Captain Malcolm, Firefly

In art and dream may you proceed with abandon. In life may you proceed with balance and stealth – Patti Smith

Intercept have four sensor types and five types of scans (Optical sensors can scan using Visual or IR). Each scan type in Intercept (Visual, IR, Radar, Neutrino and Mass) have their own strengths and weaknesses. To get a basic a basic understanding of how the different types actually work you should read Sensors part 1.

Scan modifiers

 

Visual

Location

Stay in the shadow columns of planets and asteroids or stay directly north of your target forcing him to scan with Sunglare. Have planets block the enemy scans of you if you know their location.

In shadow columns the Sun factor is 0 instead of the typical +6 but if your enemy is clever he will scan specifically in the shadow column using IR so, if approaching via the shadow column take your time and drift in with power off.

Approaching from the sun is another way of avoiding detection. Forcing your opponent to scan with Sunglare reduces his scan with the Sunfactor, typically by 6.

Self
Avoid thrusting unless absolutely necessary, drift instead.

Don’t thrust, specially if you have fission or fusion thrusters with their huge signatures, but even impulse or floater drives normally give off the same signature as your hull in sunshine.

Planet and asteroid sun and shadow columns

IR

Location
Approach from the sun and force the opponent to scan with Sunglare. Use fission or fusion thrusters as little as possible. Have planets block the enemy scans of you if you know their location.

Just as for Visual scans approaching from the sun will force your opponent to scan with Sunglare and IR scans too subtract Sunfactor from the scan, typically 6. This is your only option, the shadow column won’t help your IR signature at all.

Self
Turn off the powerplant using Silent running. Use fission or fusion thrusters as little as possible.

Silent running reduce every signature of yours except Visual. Your ship would only have IR(Hull) for IR, typically with the same low strength as your hull in shadows. Don’t use fusion and fission thrusters except when absolutely necessary, impulse and floaters are fine but you need to have the powerplant running to use them of course. Keep in mind that if your powerplant is off you need to power it up using your repair crew which on larger vessels can take a turn.

Sunglare

Radar

Location
Have the planet block radar scans. Keep distance to the enemy.

Radar is rarely used except when the enemy knows they are detected. Try to keep distance to your enemy as radar falls off much faster than other sensors by range. Radar is unaffected by Sunglare so coming from the sun won’t help you.

Self
Pop in to reduce signature. Works on any ship except Open frame ships.

Popping in will reduce the radar signature of your ship by 6 on all ships except open frame hulls whose signatures are unaffected by popping in. Note that if you pop in you can no longer scan (except with neutrino or mass sensor), you will also lose any tracks you have (once again except if you track using neutrino mass sensors) and finally you will lose any launched missiles, drifting decoys remain however.

Cloud chamber.png

Neutrino

Location
Stay north of the enemy forcing him to scan with Sunglare. Neutrino sensors are always subject to Sunglare, even when in planetary shadow.

Coming from the sun forces your opponent to scan with Sunglare. Sunglare reduces the scan by Sunfactor, typically subtracting 6 from the Scan. As neutrinos can travel straight through a planet Sunglare affects scans even when a planet would normally block (sun column, shadow column questions are ignored for neutrino scans).

Self
Turn off your powerplant using Silent running. This works with both fission and fusion reactors. Use fission and fusion thrusters as little as possible.

Neutrinos are only given off in detectable quantities from fission or fusion reactors and fission or fusion thrusters. So, turn off your powerplant using silent running and don’t use your fission and fusion thrusters. With these off your ship has no Neutrino signature at all and thus no chance of detection from neutrino scans whatsoever.

Elite Dangerous_20180624213851

Mass

Location
Stay away from known mass sensors, their falloff is as bad as radar so range alone might save you. Coming from the sun has no effect on mass scans, they ignore Sunglare.

Mass sensors fall off much faster than regular sensors because they rely on tidal force rather than gravity directly. Try to stay away from known mass sensors is about all you can do.

Self
Don’t use Impulse, Grav or Floater thrusters needlessly, fission and fusion thrusters work fine. Turn off floor field when drifting.

Thrusting using Impulse or Floater give off huge signatures, on par with fission or fusion thrusters for Visual and IR scans. Use them only when you absolutely must. Fission or fusion thrusters are actually fine and won’t show up on mass scans. When you are not thrusting your strongest signature comes from your floor field, turn it off when drifting. Your ship have a mass signature like a ship in sunshine when the floorfield is on and like a ship in shadow when the floorfield is off.

That’s all folks, stay cold, dark and inert.

Sensors 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!