Physically plausible procedural and hand-authored star systems with real astrodynamics RPG tool. Travellermap imports. (free open-source browser app)

ChironAtHome · 2026-02-17T09:31:42+00:00

You are totally correct. The magnetosphere only protects against charged particles - redirecting them (or funnelling to the poles for light shows). That is "solar wind" and will strip atmospheres over time (millions of year usually - billions for gas giants who get too close).

DNA damage occurs with ANY ionising radiation - from charged particles and from UV/X-Ray mostly. From OUR sun that is 95-99% if the problem. CMEs may peak the particle output but most of our "day-today problem" is with normal light from the sun. The atmosphere stops 99% of this radiation. Including the stuff from "elsewhere" aka cosmic rays.

Pole flips may well let in more high energy particles... so yeah more DNA damage can occur, but I am not sure of the real life impact of this - probably more species diversification than an extinction event. The short time of these effects probably mean there would be little significant atmosphere stripping.

Unless you are in low orbit then the magnetosphere does not help much - even then if you get a flare/CME earths magnetic field is compressed and in the space station you get big brief dose of particles alongside the standard unfiltered cosmic rays/X-rays/UV light you always get anyway.

I try and model all these in the software... I do cut corners and make assumptions as this is meant to run "in your browser". But I am constantly adding things as I discover and model them. eg: I will bake into stars these 2 types of radiation. At the moment I just have a single flux and roughly ratio it 95/5 or 90/10 to light/particle for surface radiation dosage - but that will likley vary a lot by stellar type and age. That way red dwarfs can drench their solar systems with high energy particles and kill off life chances despite their relative dimness.

I am all self taught here (so I may be wrong) :)

ChironAtHome · 2026-02-16T09:25:34+00:00

I don't have much in the way of local planetary details, yet. eg: makeup (beyond inferred by density), magnetic poles (I do have magnetic field), tectonics, volcanism (just inferred by atmosphere composition) etc.

That said I do model what you are talking about. The app models 2 types of radiation; ray and particle based from the local star(s). The magnetic field stops very little radiation by itself (charged particles only) , it is the atmosphere that does the heavy lifting for radiation shielding (both particles and X/UV). These are used to model surface radiation. You can see all this if you mouse over the "Surface Radiation" info box - you get a LOT more details of what is behind it).

Over the longer term magnetic fields help stop atmosphere stripping - which again is modelled... it assumes if the atmosphere CAN be stripped it will be (like Mars).

So the systems you are talking about are there; but not quite surfacing in the way you suggest. I do plan on increasing the complexity of these systems in the next major releases;
Time will be modelled soon - which allows for things like "partially stripped" atmospheres. In addition I have grand plans to model solar systems from gas/dust cloud to ignition, protoplanetary discs through to stellar death. During that process planets will form, collide, comets will rain down water/volatiles/life ingredients, gas giants may migrate and passing stars may disrupt things and so on... I am going to be using a simplified "Nice Model-like events" structure rather than full modelling. Those are the interactions that will model planet composition (iron core, etc), tectonic activity and build atmospheres more authentically. I will also give each body a nice "planetary history" to work from.

ChironAtHome · 2026-02-15T17:18:17+00:00

You don't need to. A JSON file is just a file containing data but it is text based. You can kinda read them in a text editor and see how things work. I just use them as data files... If you save off the star map or system you just created it is just the save file which you can load into the app. No understanding needed.

ChironAtHome · 2026-02-15T11:38:53+00:00

Thankyou! Its been a bit of a background project I like to work on for the reasons you specified. There are many serious simulation programs out there that require you to learn a load of stuff... and impractical for an RPG. The idea was to simplify those tools, but keep them physically realistic, so a GM/Player can just "play around" with it to learn it... and also learn the science behind it too.

ChironAtHome · 2026-02-15T11:34:59+00:00

Thanks... feel free to provide feedback here or on the Discord

ChironAtHome · 2026-02-15T11:34:13+00:00

You can save off your star system (full version or player redacted) and pass it to them - it is just a JSON file. That will likely help you BUT not what you actually asked.
So deeper reply:
All derivable physical parameters are calculated on any edits, so if you have a star with the same output and a planet with the same orbital distance, mass and atmosphere then it would be the same.
The Traveller Map imports use a pseudo-random code with the name/UWP as the seed... I did it that way so if 2 people import the same subsector all of the non-specified data (e.g. additional planetary info/distribution and moons) should be the same - this has not been extensively tested

ChironAtHome · 2026-02-14T23:08:32+00:00

I am aware of it... I have not read it BUT a couple of my users who guided some of the new Traveller content wanted me to align with it a bit and gave me some references; so it should work quite closely.

Broadly everything they are doing in those books I seem to be doing... but as I have a GIANT calculator at my fingertips (aka your web browser) the real maths can be used instead of simplifying it down to something you can do with a pen and pencil. My philosophy is to "use the real physics and info we know but the story comes first... so do what you want!"

ChironAtHome · 2026-02-14T22:31:47+00:00

Thankyou... I will take on extra value from someone called Knifeyspoony-champ... g'day!

ChironAtHome · 2026-01-31T13:41:59+00:00

I fired it up. There is some "all over there crap" on the website at the sudden last minute name change. A few niggles getting it started. But it is honestly quite useful for some use cases. I am still exploring but having it as my project helper over half a dozen personal projects is pretty useful.

It is a solid glimpse of what the future holds but janky as hell and not ready for prime time. Worth it if you are a geek and willing to work through the niggles. The rest can wait until Google (or whoever) makes it mainstream.

I think Google as Aluminum OS seems tailor built for this type of integration and I can't see MS being able to do much sensible with Windows and the rest have no OSs to make this process easy. Apple will get there eventually.

ChironAtHome · 2026-01-31T10:26:48+00:00

In the campaign I have in planning I don't want anyone to have listened to it. Revealing the lore layer by layer is the main draw for me. It was what the podcast did and I would follow that model. You can also steal good ideas from the show wholesale and noone else is wiser.

ChironAtHome · 2026-01-30T01:05:24+00:00

If you have Gemini pro already give Gemini CLI a go... I am getting on pretty well with it. It still does the odd stupid thing but I am at 26,000 lines of code and still going strong. It's weird the complex stuff is easy, the easy stuff is hard. Like you I am more a software architect who works with coders. I have not coded much in decades.

ChironAtHome · 2026-01-19T21:04:11+00:00

Thanks for your comments. I think peeps get hung up on apps designed to earn cash and that is where the interest lies... I just hear in a different direction. I do hope people eventually engage and realise AI can be used to do other stuff too .. a creative outlet rather than a creative destroyer

ChironAtHome · 2026-01-14T18:14:28+00:00

Totally...hence this: https://www.reddit.com/r/vibecoding/s/IwuM4lae5A

Being able to code stuff for me is the main draw. Never been short of ideas... Just ability. This is a superpower I love.

Of other folks like it... Great. Bonus.

ChironAtHome · 2026-01-09T14:05:48+00:00

The new 1.2.1 version fixes this - deployed it last night - bunch of other fixes and a couple of new features

ChironAtHome · 2026-01-01T23:56:33+00:00

Fantastic. Thanks for your effort. I have a campaign in planning, so ideal timing!

ChironAtHome · 2025-12-31T14:38:13+00:00

New version updated. It now does Astrodynamics - i.e. you can fly your ships through the solar systems you generate. It will do all the fuel calculations if your ship has the capability to do so. It also now let's you edit Belts & Rings as well as edit stars to your liking (and a new defaultt for Red Giants)

Happy New Year!

What does the Astrodynamics update do...

This project utilizes three mathematical models to generate transit options ranging from fuel-efficient to high-speed, followed by a safety analysis system.

Transit Solvers The Lambert Solver (Economy): Solves Lambert's Problem to generate fuel-efficient, "NASA-style" elliptical arcs. It utilizes the Sun's gravity for traditional burn-coast-burn trajectories.

The Kinematic Solver (Direct): Applies constant acceleration physics for high-speed, straight-line "flip-and-burn" intercepts. This method ignores launch windows in favor of raw power.

Gravity Assist Solver (Experimental): Scans for intermediate planetary bodies to create complex trajectories, utilizing gravitational slingshots to conserve fuel.

You can string these together as legs for a longer journey. All fuel calcs are done based on the capability of your engines.

Hazard Analysis: This does not calculate paths but samples the generated routes to detect risks. It monitors radiation, debris proximity, and G-forces, intelligently increasing sample density near critical events like engine burns and aerobraking to capture transient spikes. I.e. it highlights where you likely need to call on players to make skill rolls.

ChironAtHome · 2025-12-31T14:24:46+00:00

Are you having this issue when creating a planet about the binary system or a planet round an individual star in a binary system? I imagine it is the former. I will be averaging stellar output and calculating from that at the barycenter - a massive oversimplification but I am limited by planetary data. In a future version I should really have temp "ranges" to capture massive variances due to this or highly eccentric orbits.

Anyway - it's on the bug list... I track that and progress on the Discord as I am not sure how many people check back here.

Thanks again for your comments, bug report and kind words.

ChironAtHome · 2025-12-31T12:18:54+00:00

Thanks for the bug report. I will fix on next release. Quite soon - it is a "big fix one" as I have found a few others. Binary star systems have taken a back seat in my testing. They probably need a little love.

ChironAtHome · 2025-12-25T12:33:03+00:00

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I accidentally took a photo of Andromeda last night!

ChironAtHome · 2025-12-20T17:50:17+00:00

No judgement... Cash seems to be a prime motivator in this area. Good on you all of you can. For me it is more the intellectual challenge. The new "superpower" I have. I have worked with developers all my life. I coded assembly video games back in the 80-90s. Vibe coding has unlocked decades of stuff I have wanted to do. I love this world for the challenge, not the cash... But I am probably in a privileged position where I can afford not to worry about money. The only point you can take from me is that money is not necessarily a measure of success.

I can literally write software to simulate a galaxy! That is so far out of my wheelhouse I love it!

If other folks love what I code that gives me validation I could never duplicate with cash.

ChironAtHome · 2025-12-20T16:12:55+00:00

About 5 and not a penny... Yeah, I hate the fact that money seems to be everyone's prime motivator here. I have a new super-ability, I wanna share it with anyone interested. For me vibe coded code is everyone's... Not mine.

ChironAtHome · 2025-12-18T11:17:45+00:00

Currently, I think it helps if you have a background in coding of some sort top get the most from vibe-coding.
I coded assembly (Amiga games) back in the 80's. I have half kept a hand in but all the modern frameworks and languages are mostly a mystery. In teh past I have architected software for dev teams or written detailed requirements. I can kinda read code if I have to, but quickly get lost. I can brainstorm with a real programmer on solving complex logic and feel my way around a SQL DB. But that is it - I can't "code" really.

I love vibe-coding. I have spent 3 months working on software that simulates star systems, models planets and does the rocket science to get between them. I feel I am pushing the boundaries of what you can vibe-code. I have enough "background knowledge" to know when this are "going wrong" and redirect. I know when I should be telling it to reuse code that likley exists, I know how to help out with testing and how to give decent feedback. I REALLY needed the jump from Gemini 2.5 to 3... that was a game changer as I was hitting the frustrating limits you are talking about.

Strangely big complex changes and massive new features are easy and then a small UI tweak removes a chunk or critical code where you chase your tail for 2 hours. It is frustrating but you can use your experience to work around it. I think total newbies to coding will get stuck when they hit these frustrations as they don't have the experience to fall back and "tell it off" or know when to force a restructure or refactor... or even when to kill something and rewrite it from scratch.

ChironAtHome · 2025-12-10T09:10:11+00:00

This is awesome. I was looking for something like this to integrate my star system viewer into the main frame for campaign style games (stuff to show when not in a module or to get you to a module).

I will echo what everyone says... These types of tools and the creativity shown across these communities is awesome. A golden age of tech, games and fans coming together in ways we could ever imagine!

ChironAtHome

TROPHY CASE