Inbound System Comms

[MasterGwydion]

I'd have to go pull the PDF to verify, but from what I recall it's more than just emergence. It will track the ship from the time it arrives till it leaves (only reappearing on sensors 3years later 1 parsec away). So any object in a system would show up on the sensors, moving or not, starship or not. Just mass.

It specifies jump emergence and jump entry as being detectable. It does not say that you can detect that ship at any other time while using the range group for jump detection.

 

[swordtart]

I'd have to go pull the PDF to verify, but from what I recall it's more than just emergence. It will track the ship from the time it arrives till it leaves (only reappearing on sensors 3years later 1 parsec away). So any object in a system would show up on the sensors, moving or not, starship or not. Just mass.

I am not sure what "it" you are referring to. I an basing this on jump signature (HG2022 p28).

 

[Fluffy Bunny Feet]

Gavity Detection Suites have enough range and are passive and can detect things as small as comets automatically at 3,000,000,000,000km. That is trillion with a T. You are still going to have the lightspeed delay though.

About 31% of a year or 2780 hours if you prefer or 103.333 days.

 

[MasterGwydion]

I am not sure what "it" you are referring to. I an basing this on jump signature (HG2022 p28).

This is page 28. I am confused.

 

[hopsnbaer]

The heat from your ship is almost impossible to hide in space. The rules say anything over 50,000 Kilometers could be a ship or junk. That's where sensor scans come in. I have been spit balling adding the range modifiers to the difficulty. I would be interested to hear if other folks are doing something similar. There si a pretty detailed argument here - https://www.projectrho.com/public_html/rocket/spacewardetect.php

High Guard page 26, also has from 300,000 to 5,000,000 Kilometers the difficulty for sensor scans goes to 14+

 

[swordtart]

This is page 28. I am confused.
View attachment 6310

Ooops, typo p26 sidebar on System Defence and Sensors.

Can you cite a reference to the gravity sensor chart you posted as it seems to be in a book I don't own.

 

[OriginalCaruso]

Round trip RADAR return time for 1 nautical mile is 12.35 microseconds: https://en.wikipedia.org/wiki/Radar_mile

Radiated power requirements square to double the range within atmosphere, I don’t have the physics for vacuum.

Antenna rotation speed is also a factor, antenna have a beam width, typically a fraction of a degree. And beam focus spreads at distance reducing the power density for any given point in space. Typically, the slower an antenna rotates, the longer the range. For a 100 mile range RADAR, the antenna will complete one full rotation every 4 seconds. For a 270 mile range the antenna will rotate every 15 seconds.

Sweeping frequency provides elevation information resulting in height determination.

Doppler effect occurs for moving targets which shift the returned frequency and can be used for velocity calculations.

Passive detection will also rely upon some of these considerations.

Detection is one part of the equation. Signal processing, event detection and operator action are other parts of the equation.

Naturally the above is not the complete picture, there are other factors given we are playing a future-state game. Despite not wanting the physics to get in the way, in the words of Scottie: “We cannae change the laws of physics, Jim” and the speed of light will always be a limiting factor

 

[rinku]

In practice, the gravity detectors are only really useful for observing stuff inside a system, or stellar objects.

Gravity waves do travel at light speed, so while you may be able to detect a jump made a parsec away, it will be one made several years ago.

Even an in-system jump is only going to be detectable after the gravity wave, as well as its transponder and any other EM emissions have reached the observer.

 

[swordtart]

In practice, the gravity detectors are only really useful for observing stuff inside a system, or stellar objects.

Gravity waves do travel at light speed, so while you may be able to detect a jump made a parsec away, it will be one made several years ago.

Even an in-system jump is only going to be detectable after the gravity wave, as well as its transponder and any other EM emissions have reached the observer.

So far the limited words I have seen regarding gravity sensors indicate that you can detect a jump event at up to 1 parsec. I can detect a noxious smell in a room. It does not mean I can immediately identify the source of the smell or precisely where it emanates. To do that I need to triangulate (by moving the sensor or having multiple sensors linked together). That still takes time and if the source of the smell is moving (or not stable) I may never nail it down. I have been trying to track the source of a damp patch in my dining room for months.

"Sir, the Tarsus system just lit up like a Christmas tree."
"Hmm, so we are looking at a number of ships that emerged from jump space, 3.2 years ago (give or take a few weeks). Let's get Naval Intelligence on the comm, I am sure it will be their top priority!"

 

[rinku]

Exactly. It will be far more important in-system, with multiple observation points.

If a jump is detected 1 light hour away, much more of an immediate issue.

 

[swordtart]

But is it like RADAR or like a Geiger counter?

"Sir, a ship has just jumped in."
"Where?"
"Within the system."
"Can you tell me more precisely?"
"Yes sir, it is definitely within the operating range of the system, subject to current astronomical phenomena and other operational parameters."
"When did it arrive?"
"Sometime between the sensor picking it up and it actually arriving sir."
"Can you at least tell me how close it is."
"Sir... These ships are small... these one are FAR AWAY..."
"I hate this job!"

 

[OriginalCaruso]

I refer to RADAR because that's what I know in the real world, and the physics translate to space games in general

The Geiger counter analog is useful - the source is somewhere "out there" and the detector could be directionally sensitive. However, nothing moves faster than the speed of light therefore your conversation snippet has the ring of truth too

What this thread points to is that complexity can be either hand-waived away or embraced in varying degrees of depth and in accordance with the rules which themselves could be revised. The point of the thread was to add colour to ship ingress and egress from systems, and provide referees with options

 

[MasterGwydion]

Ooops, typo p26 sidebar on System Defence and Sensors.

Can you cite a reference to the gravity sensor chart you posted as it seems to be in a book I don't own.

 

[MasterGwydion]

In practice, the gravity detectors are only really useful for observing stuff inside a system, or stellar objects.

Gravity waves do travel at light speed, so while you may be able to detect a jump made a parsec away, it will be one made several years ago.

Even an in-system jump is only going to be detectable after the gravity wave, as well as its transponder and any other EM emissions have reached the observer.

In practice it is how you initially detect hidden bases. Seeing historical jump traffic where there is no reason to have any traffic, in-system or in nearby systems.

 

[Fluffy Bunny Feet]

So my ship jumps to 100 diameters of an Earth type planet. The jump emits some form of "radiation" that can be detected a parsec away. How much does that affect the planet or nearby spaceships/stations? Sounds like it should be pretty devastating.

 

[OriginalCaruso]

Earth diameter is just under 8000 miles therefore 100 diameters is 800,000 miles, around 3x the distance to the moon.

Around1% of the distance to Mars which is 55M miles at closest approach

 

[swordtart]

So my ship jumps to 100 diameters of an Earth type planet. The jump emits some form of "radiation" that can be detected a parsec away. How much does that affect the planet or nearby spaceships/stations? Sounds like it should be pretty devastating.

Could be like a neutrino and pass through entirely unnoticed.

 

[Fluffy Bunny Feet]

Blow up every neutrino detector in the system.

 

[swordtart]

Blow up every neutrino detector in the system.

Or maybe it is like the Sun which is visible many many parsecs away but does not in fact destroy the Earth that is not so very far away.

 

[MarcusIII]

You don't have to store it as it is processed in real time. That's just a note if you wanted to store it. And YES, you could buy NAS of that amount back then.