For those of you that read these “state of the Frontier” posts, you probably realize that my plans got turned all upside down this month. The plan was to focus on Ghost Ship Osiris and the Death at Rosegard adventures with maybe some other items in the background. Well, the background jumped to foreground and then the month was over.
I had intended to work on the Ghost Ship Osiris adventure but for the most part that didn’t happen. I did get some initial sketches done of the Pursale ship. But I’m not completely happy with them and they definitely need some work.
Death at Rosegard didn’t even get touched. I honestly don’t think I even thought about it this month. I have now added it to my list of draft posts, however, and so it will be bugging me to get it finished now when I look at active projects.
What did come to the forefront was the beginning of the “Create a Star System” series. Triggered by a couple of posts I made on the timeline project, that series got stuck in my brain and seriously worked on. This month we got the details on creating the system data and actually drawing the map (including a video of the drawing process). The drawing of the map didn’t take as long as I expected but it took me a lot longer to actually do the write-up in the posts than I was anticipating.
I also posted a short bit on my new starship construction system covering hull types, armor, and sensors systems. Those are the last of the pieces of the system that differ significantly from the standard starship components in the core Star Frontiers Knight Hawks rules. I’ve been thinking about the system and realize I need a little bit more work on the engines so there is one more post on that before I can pull it all together.
Behind the scenes, the timeline project continues unabated. I also started working on pulling the next issue of the Frontier Explorer together, more on a management side, but things are progressing.
So what’s in store for this month? We’ll start the month off with the now usual timeline post. I have entries for half the days this month (up through the 12th and a few random days after that) plus about half of April as well. So at some point in the next week or so I’ll be sitting down to flesh out the rest of the events happening over the next 30-60 days in the Frontier. We’re still a bit away from the massive Sathar fleets showing up in the Frontier but the activity is starting to heat up.
Now that I missed it last month, I plan on getting the sathar inhabited cave system finished and out this month. It really just needs some work cleaning up the map so I really don’t have an excuse.
After that, I intend to finish up the “Building a Star System” series with the Fochrik system’s calendar. That will wrap up that series for now.
I’m not sure what the 4th post of the month will be. Most likely it will be the last little bit about the engines in the new starship construction system. I’ll be working on the Pursale ship but I don’t know that I’ll have anything ready to go on that before the month is out unless I do a post just about the sketches and general design. Or it could be that something else grabs my interest and I run with that. We’ll see where it falls out.
The other thing I’ll be working on behind the scenes are the Frontier Explorer and another fanzine. There will be a big push on my part this month to get the next issue of the Frontier Explorer ready since we plan on releasing it in April. Keep your eyes on the magazine’s website for more details as they come out. We have all the articles we need, we just need to finish polishing our new layout. I’ve also been asked to head up another fanzine, this one more focused on general OSR topics and probably more fantasy focused. It’s in its infant stages but I have a big team and plan on leveraging my Frontier Explorer experience to put them to work and minimize what I need to do. More director than front-line worker bee. There will be more information on that in the coming months as well.
I think that’s it for now. I had a good month and am looking forward to a busy but exciting March. See you all around the Frontier.
Okay, in my last post on this topic, we generated all of the data needed to draw out a system map for the Fochrik star system. If you haven’t read the previous entry, you might want to but it’s not necessary. The next step is to take that data and turn it into the actual image. This post will cover that process. Let’s dive right in.
First a quick summary of the data for the system that we generated last time. While we won’t need all of this for the map, but it’s good to have it all summarized in one place. For generating the system map, we’re only going to need the orbital distance and the planet’s radius.
Orbital Distance (AU)
Orbital Period (hrs)
When drawing the map, we want the distances to be all on the same scale. However, we cannot use a simple linear scale in most cases as that would put all the inner planets right on top of each other if we want to see the outer planets on the same image. You can see this in the following diagram that has a linear distance scale.
As you can see, those inner planets are bunched up pretty close together while the outer planets have huge gaps. We want to spread out the inner planets while compressing the outer ones but still have the relative scale be correct. To do that we need to shift from a linear scale to a logarithmic one.
To get on a log scale, we are just going to take the base 10 logarithm (the ‘log’ key on your calculator) of each of the orbital distances and use that value to draw the distances. First I’ll present the numbers and then another simple drawing.
Orbital Distance (AU)
Orbital Distance (log(AU))
We can’t quite use the log(AU) values as the smaller numbers generate negative values (I’m not going to do a math lecture here. If you’re interested in why, you can check out this Wikipedia article). So we need to scale those numbers somehow. The scaled distance value in the table above was calculated by taking the log(AU) distances, adding 0.75 and then multiplying by 500. We’ll use these values to create the plot.
As you can see, the range of values is greatly compressed which allows things to be a bit more evenly spaced. The only issue with this scale is that zero (i.e. the position of the star) has a value of negative infinity so we’ll have to pick some arbitrary distance to separate them. However, since we’re just trying to show the relative position of the planets, that’s not too big of a problem. Here’s the simple plot we get:
This scale compresses the outer planets a bit but helps us spread out the inner planets which are the ones we’re more interested in anyway.
Drawing the Map
With the numbers above, we have all the information we need to create the map. The last thing to decide is if we are going do make a horizontal map (oriented like the diagrams above or the map in the Clarion Calendar post) or a vertical one (like in the Duergan’s Star post). For this map, I’m going to make a horizontal map simply because all of the “along the way” image will fit better into the post than a vertical one will. However, the process applies just as well to a vertical map, you just have to rotate everything 90 degrees.
I’ll be building the map in Inkscape, my vector drawing program of choice and it will be a simple black and white drawing so it shouldn’t be too complicated.
Here’s a video I made of the map building process if you want to watch it in real time, It’s about 53 and a half minutes long and completely unedited so you can see all my mistakes and fumbling around. If you don’t want to watch the video, I’ve described all the steps below.
Laying the ground work
To start, we want to set up the basic image and some guides for us to work with. I’ve decided to make the image 1200×400 pixels in size so I create a blank document of that size to work with. I also turn on a rectangular grid to help with position items. This grid will get turned on and off as needed during the drawing process.
I’m going to use the logarithmic distance scale for my planet spacing so I then import that image into my document and position it accordingly.
Finally, I draw a guide line down the middle of the image so I know where the center line is. After this initial setup, the image looks like:
I’ve shifted the imported image just slightly so that it’s 10 pixels to the right of where it was in the original. I wanted a little more space between the star and the first planet. Since I’ll be measuring the scaled distances from the left edge of the image, this means I’ll have to add 30 pixels to the values in the table above for the final radii of the orbits.
All of the above was done on the initial default layer. I then create three more layers: one for the orbits, one for the objects (star and planets), and a third for the labels. I like to work in lots of layers as it makes it easy to turn bits and pieces on and off and add in effects if needed.
The star and the orbits
The next step is to draw in the star itself and then start adding arcs for the orbits. The symbol for Fochrik is created using the star and polygon tool in the star setting with corners set to 30 and spoke ratio set to 0.8. This is drawn on the object layer.
Next I hide the objects layer and move to the orbits layer. Here I use the circle tool to draw in the first orbit. Clicking on the point where the center guide meets the edge of the image I then drag out the circle holding down the shift and the control keys until it reaches out to the position of the guide line for the planet T1.
Holding the control key down makes the circle drawn have integer ratios between the x and y directions allowing you get a proportional circle. Holding down the shift key makes your initial click point the center of the circle instead of the upper left corner of the box enclosing the circle. Once I have the circle drawn to approximately the correct size, I use the spinner boxes for Rx and Ry (the x and y radii) to set the exact radii (44 px in this case). The fill of the circle is set to transparent, the stoke is set to black with a thickness of 2 pixels.
Inkscape allows you to draw off the edge of the image so we drew a whole circle for this first orbit. Since we will be copying and scaling this up, we don’t want our circles going way off to the left. We can turn the full circle into an arc by grabbing the small circular mark on the drawn circle (it’s at the 3 o’clock position) and moving it clockwise to break the circle. I move it down to just past the 6 o’clock position. Then I go back and grab the other small circle node at 3 o’clock and move it up to just before the 12 o’clock position. This gives us a half circle which is all we need.
Now it’s just a matter of duplicating that arc and setting the correct radii for each one. As we move out we’ll want to adjust the size of the arc so it’s not sticking up well above or below the edge of the image just to make things a little cleaner on our drawing canvas.
We can duplicate a selected object by pressing Control-D. Then we just go up and set the Rx and Ry values based on the scaled distance values in the table above (remembering to add 30 to each one). You have to remember to have the circle tool selected while you do this or you can’t set the radii.
Once that is done, we have an image that looks something like this:
Notice how the arcs are going high. They will be cut off when we export the final image. They were originally also going low as well but they have been adjusted (at a later step) and I didn’t export an image while I was drawing them.
You might also notice that the arc for the planet T2 is not lined up with it’s guide line. That is because as I was drawing it, I noticed a discrepancy between where the guide line was and where the arc was drawn based on the scaled distance values. I originally though there was an error in the scaled distance but it turns out I just drew my guide sketch wrong. It’s always good to double check your work.
Drawing the planets
We’ve got our orbits, now we need to draw the planets. This will be done on the planet layer so we switch to that layer now.
Like the orbits, we want the planets to all be on the same scale. This obviously can’t be the same scale as the orbits or we wouldn’t be able to see them since they’d just be dots on the page. To pick the initial scale, I just let the radius of the circle we’re going to draw be equal to the radius of of the planet (in km) listed in the table divided by 2000. I computed each of these values and wrote them down on a piece of scratch paper to have them handy.
Depending on how you have Inkscape set up, when you draw in the first circle, you’ll notice that you just get an arc instead of a full circle. That was my case as I have Inkscape set to remember the last setting for the tool and use that instead of resetting to the default. I find that more useful. But we need to reset the tool to draw circles. This is done by finding the Start and End boxes (up by the Rx and Ry boxes) and setting them to 0 and 360 respectively. Now we’re drawing circles again. Also you’ll want to set the fill to white instead of transparent.
I then just move to an arbitrary point on each planet’s orbit, draw a small circle and then set Rx and Ry to be the values determined for that planet. It doesn’t matter exactly where you draw them as we’ll go back and properly position them once they are all drawn.
When you start doing this, you’ll quickly notice that the scale we’ve picked is simply too small for the small terrestrial planets. In the case of a few of them, you can’t even see the disk as it is smaller than thickness of the line we drew for the orbit. To solve this we simply double the radii of these planets. However, that would make the giant and Jovian planets too big if we doubled them as well. So we’re just going to have to have different scales. The terrestrial and ice dwarf planets will be to scale with each other as will the giant and Jovian planets but the smaller planets will be twice as big as they would be if they were to scale with the larger planets.
The last step of drawing the planets is to place them at an appropriate position on their orbit circle. There are two requirements here. One is that the disk of the planet should be centered on the orbit line. The other is that for planets with close orbits, they are spread out across the image so that when we add labels there won’t be any overlap. To make this easier you should turn off the grid that we set up at the beginning so the software isn’t trying to snap your circles to positions you don’t want.
Once that is done, we have an image that looks something like this:
You’ll notice that even doubling the scale, some of those planets are pretty tiny. In fact, you might not even be able to see ice dwarf 2 unless you click on the image above to get the full sized one. But that’s okay.
The next step is to label everything. There are a few things we want to put in our labels. The most obvious is the name of the planet. I still haven’t come up with official names for the planets but that doesn’t matter for the purposes of demonstrating the mapping technique. The other thing we need to do is add the scale for the system map. Finally we’ll add a label for the system. I’ll be using the Copperplate Gothic Bold font for my lettering.
Let’s start with the scale. If you watched the video, you’ll know that I actually did this way back at the beginning of the process. Since it was already there in the imported image, all I had to do was trace it. Once it was drawn in and had the numbers, I put the “Distance (AU)” label on and then moved everything down as close to the bottom of the image as I wanted it.
The labels on the the scale are drawn with a height of 16px for the numbers and 20px for the label. What you choose is arbitrary and it should be picked to match the size of the drawing. You don’t want it too small but you don’t want it too large either.
However, at this point, I didn’t like the orbit lines crossing over the scale and I went back and adjusted them so that they stopped just before touching it. If you look closely in the previous image, you’ll see another guide line that sits just above the scale that all the orbit lines touch. I drew this line in and then, using the circle tool, adjusted the end of the arc of each orbit line to just touch that line, which is why they don’t extend below the image.
Turning off the layer with the guides and the scale image gives us the following at this point. I’ve also now only exported the actual drawing so everything is trimmed appropriately.
Next we label the planets. For each planet I’m going to put the name in using a 20px high font and then centered under the name, put its orbital distance in a 10px high font. Again still using Copperplate Gothic Bold. I had originally intended to just type both and then change the font size of the distance but found that I couldn’t adjust the vertical spacing like I wanted to. So instead I created two text objects, one for each line, used the alignment tools to get them lined up, and then grouped the label for each planet into a single object so I can move it around easier later.
It doesn’t really matter exactly where you put the labels to begin with as you’ll be moving them around once they are done and you have their exact sizes. Just go through and add them for each planet. Then, once they are in the drawing, move and position them so that you like the placement. This may also involve moving the position of the planet’s disk on the orbit line to get a spacing you want.
Typically for the smaller planets, I like to place label so the center of name is aligned with the center of the disk. For the large planets, I tend to set it to the lower left or right corner depending on the exact positioning. I just do this by eye. You want to avoid having the text run over the orbit lines as much as you can but in some cases it’s unavoidable. Just place the names where it looks good to you. On a vertical map, I’ll often try to center the name of the planet under the planet’s disk.
Now we have to deal with the text that is overlapping the orbit lines. This often makes the text hard to read so we need to mask out the orbit lines under the text. Your text layer should be positioned above the orbit layer. If it isn’t you’ll need to move it up in the layer stack. What we’ll do is draw some white rectangles to hide the orbit line below the text. I like to set their opacity to about 75-80% so the orbit lines slightly peek through but you can make them fully opaque if you prefer. Drawing the rectangles can either be done on a new mask layer that is placed directly under the labels layer or in the labels layer itself.
In this image I drew the rectangles directly into the labels layer. Using the rectangle tool I just drew in a small rectangle over the orbit lines in each location there was overlap between the text and the lines. You’ll want to make the rectangle extend just a bit below and above the text. Exactly how much depends on how much space you want between the lines and the text and is a matter of taste. As you draw the rectangles, they are placed above the text so you need to send them to the bottom of the z-order for the layer so they are behind the text instead.
If you draw on a new mask layer, then you don’t have to worry about moving the z-order of the boxes as they will all be between the orbit lines and the text. You also don’t have to worry about the opacity on the individual boxes but can adjust the opacity of the entire layer all at once. This is typically how I do the masks but for some reason didn’t on this particular drawing. Probably due to the fact that I was recording and it slipped my mind.
We are almost done. At this point our image looks like this:
The only thing left to add is the label for the system, a border, and a white background.
We’ll put the label in the upper left. We want this to be large so we’ll use a 32px high font. We’ll also need to add a mask as it will be overlapping the orbit lines. I considered simply adjusting the orbit lines to end below the label but decided to leave them in and mask them off.
The border and background I did with a single object. You may not have noticed, but all of the images so far have had a transparent background with just the objects drawn on it. This can cause some issues depending on how the image is rendered so we want to add a solid white background.
To do this I make a new background layer that sits at the very bottom of the layer stack. On this layer I draw a single large rectangle that stretches corner to corner across the entire image. I set the fill to white and the stroke to black with a 6px thickness. Due to the way Inkscape draws the stroke, half of that will be off the final image giving a 3px border. If you want it thicker or thinner, simply adjust the stroke width.
And now we’re done. Here’s the final image:
If you’d like to look at or play with the original SVG file of this map, they you can grab it here:
For this demo, I didn’t do anything special with the planets themselves. If you wanted to, you could add in cloud bands or rings on the giant planets to give them a little bit of character. Especially if they have features called out in their descriptions. I didn’t have any special descriptors so I left them as simple circles but that could be added in later.
The FTL Horizon
If I was doing this map for FrontierSpace, the other thing I would add in is a dashed arc at the position of the FTL Horizon, which in that game is the distance you need to be from the star in order to engage your Nova Drive to travel between the star systems. That would be an important bit of information for the map to include.
I also didn’t add in an asteroid belt in this system. If I did then I would determine the distances for the inner and outer boundaries of the belt and draw orbit circles on the guide layer at those distances. Then on the object layer I’d go in by hand and draw in all the asteroids. I work on a 2-in-1 laptop that has a stylus so I can actually flip my laptop into tablet mode and draw the asteroids with my stylus right on the screen. I find this much easier and faster than trying to do it with the mouse but it can be done that way (and I’ve done it that way in the past). There’s a bit more to it than that so I might do a mini article on drawing in asteroid belts.
And that’s everything. I think the map turned out pretty well. I was actually surprised it only took a little less than an hour to draw it out once I had all the data. All told I probably spent about 2-2.5 hours creating the data and making the drawing. It would have taken a bit longer if I had had an asteroid belt to include or added details to the planets but that gives you an idea of the effort involved. It actually took me longer to do these two blog posts (5-6 hours total) than it took to actually do the work.
I still have one more post on the calendar system to do and that will come in March. I’d like to hear your comments, questions, or any suggestions you have about the process. What wasn’t clear? What would you like more information on? Did you try this yourself? If you did, share your results. Let me know below.
This is a continuation of the excerpts from the starship construction system. I had originally planned to have the how to draw a star system map post ready for today but I didn’t quite finish it. So I’m posting this one in its place and will have that one up next week.
This article will be about the various type of hulls that you can make you ship out of and the effects they have on the hull points and mass of the ship. In the new system I expand on the basic hull from the original rules to four different types that have different characteristics and costs.
While not related, I’m also including the section on the radar and energy sensors as that is another deviation from the standard system
There are four different hull types. Each type has a mass
and cost associated with it depending on the hull type selected. Different
hulls provide different amount of hull points for a given ship size.
Hull Point Multiplier
35 cr * total volume
0.15 tons * total volume
50 cr * total volume
0.25 tons * total volume
100 cr * total volume
0.50 tons * total volume
200 cr * total volume
0.40 tons * total volume
Light Hull – This
is a light duty hull. It costs and
weighs less than a standard hull but only provides sixty percent of the hull
points of a standard hull.
Standard Hull –
This is the standard type of ship hull and provides the standard number of hull
points. This is the typical hull used on
most civilian vessels
Armored Hull –
This is the highest grade hull available to civilians. It is twice as massive and twice as expensive
as a standard hull and provides a forty percent increase in hull points over a
Military Hull – Combining specialized materials and designs, the military grade hull is not available for civilian ships. It is more expensive than even the armored hull although it doesn’t contain as much mass and provides double the number of hull points of a standard hull.
Example: Obar Enterprises is designing a new mid-sized freighter that has 100 cargo units of space. After selecting all the ship’s, the total volume of the ship is 18,453.2 cubic meters. Selecting a standard hull gives a cost of 18,453.2 x 50 = 922,660 credits and a mass of 18,453.2 x 0.25 = 4613.3 tons. This hull would have the standard number of hull points.
If the cost or mass were a concern, they could go with a light hull, which would have a cost of only 18,453.2 x 35 = 645,862 cr (saving nearly 300,000 cr) and have a mass of only 18,453.2 x 0.15 = 2767.98 tons saving nearly 2000 tons. However, this hull would have a hull point multiplier of 0.6 or only 60% of the standard hull points.
Sometimes even the strongest hull just isn’t enough and you
want to add more armor to the ship. Once you have your base hull, you can add
additional layers of protection to the ship as desired. This will greatly
increase the cost and mass of your ship but won’t affect the volume.
You can add armor on to the ship to increase its hull points by up to 25% in 1% increments. The cost of additional armor is 8 cr. per cubic meter of volume per percentage increase. Thus to get a 5% HP increase it would cost you 40 cr. per cubic meter of the ship, nearly doubling the cost of a standard hull. The armor adds an additional 0.016 tons of mass per cubic meter of volume per percentage increase. Thus that 5% increase above would also add 0.08 tons per cubic meter of the volume of the ship.
The armor modifier for calculating the ships final hull points is just 1+(armor bonus/100). So if my armor bonus is 20% the modifier is 1+(20/100) = 1.2. This will be multiplied by the ship’s base hull points to determine the actual number of hull points the ship has.
Long Range Detectors
Radar systems are combination active/passive systems. In active mode they send out pulses of radio
waves and detect the reflected pulses.
In passive mode, they scan space for emissions from other ships. The range of the radar system depends on its
rating. The higher the rating the more
distant an object it can detect due to stronger emitters and more sensitive
receivers. It takes a lot of power and
large transmitters to get returns from objects in the larger areas covered by
the higher rated systems. The listed
range is the range for the active system.
In passive mode, the ranges are at least 10 times larger but can only
detect targets that are radiating at radio frequencies.
Cost: 10,000 cr x Multiplier, mass: 15 tons x Multiplier,
volume: 5 cu m x multiplier (7 cu m if aerodynamically streamlined)
These are broad spectrum radiation detectors that look at
multiple wavelengths to detect radiation from ship systems. They scan radio, optical, infrared, x-ray,
and microwave wavelengths and have gamma-ray detectors to look for signatures
from ships’ engines and power plants.
These are completely passive systems and like radar come in different
ratings that have increased sensitivity.
The ranges listed are for detecting shielded, ship-sized energy sources
against the cosmic background. If an
object is putting out energy emissions that are stronger than typical radiation
leaked from ship systems, the detection range could be much larger. For example, even a type 1 energy sensor
suite will still be able to detect the system’s star at ranges of billions of
kilometers. Exact details are left up to
Cost: 200,000 cr x Multiplier, mass: 50 tons x Multiplier,
volume: 20 cu m x multiplier
That’s it for the hull types, armor, and long range detectors. It’s a fairly simple change but allows for a wide range of ships with various characteristics and costs. Obviously the heavier hulls, armor, and larger sensors are going to require bigger, more expensive engines or suffer a performance penalty but sometimes you just need more hull points or a larger sensor range.
Share your thoughts, suggestions, and questions in the comment section below.
In a couple of my timeline posts at the end of last week, I mentioned an annual competition on Hum in the Fochrik system, the homeworld of the Humma race in Star Frontiers. The tweets were as follows:
FY60.032 – Contestants, spectators, and reporters gather on Hum (Fochrik) for the annual Humma Jump Competition. Speculation is high that the current record in the standing long jump event of 38.272 meters will be surpassed this year. #SFTimeline
FY60.034 – After two days of competition, Zonuul Usu of Larg (Fochrik) wins the Humma Jump Competition jumping 38.275m, beating the previous species record by 3 millimeters. Two others beat the previous record in the final round of competition but lost to Zonuul. #SFTimeline
This immediately got me thinking about how the Hum calendar interacts with the Galactic Standard calendar of the Frontier and if the Rim had a different standard calendar.
Since in my Clarion calendar system post, I mentioned that I would probably do more calendar systems for other planets and in my last State of the Frontier post I said I would write about creating a system map, I thought I’d roll all of these thoughts and ideas into a series of “how to” posts as I flesh out the Fochrik system.
I’m planning on dividing this into three parts. In this first article, I’ll be talking about generating the astrophysical description of the system. We’ll go over what we know from published material, adding a bit to that, refining the details, and trying to generate a stable star system.
In the next post, I’ll actually walk you through the process of creating a system map for Fochrik like I did for the Duergan’s Star system.
In the third post, I’ll generate a calendar for the Fochrick system. I don’t know yet if all three planets will have a unique calendar or if Larg and Forge will base their calendar off of Hum’s. We’ll see when we get there. I’m not planning to address a standard Rim calendar at this time as I need to look over the other Rim systems first. That may be a future post.
Anyway, let’s get started.
What We Know
Let’s start with what we know from published materials, both original with TSR and material from the fan magazines. There isn’t much, but let’s assemble what we have.
The Rim was introduced in TSR’s Zebulon’s Guide to Frontier Space, vol 1 as the area of space that the three new races introduced came from. It was specifically left vague in the supplement. Whether they intended to flesh it out more in later volumes that never were published we’ll never know. On page 50, in the “Planets of the Frontier” table we have the following entry for Fochrik:
For this series of posts, we’re interested in the stellar spectral type (F9), the number of known planets (three in this case) and their rotational period (the Day column which is given in hours). Also, the number of moons might be used in making the system map and we should probably consider them in making the calendars as well. The other information is not needed for this endeavor.
Beyond that, there is little said about the system in Zeb’s Guide. The worlds of the Frontier have little blurbs with interesting facts about each of them but there is nothing on any of the Rim worlds. We’re basically left with a blank slate.
In a Star Frontiersman article (issue 15), entitled Humma Hop Back, TheWebtroll talked about the race but gave no information on the star system. Tom Verrault did a little bit of work on the Humma in issue 13 of the Frontier Explorer were he fleshed out their racial description some more but again nothing was really mentioned about their star system. However in another article in that same issue, where he adds detail to the boon’sheh, a fan created race from the early Star Frontiersman issues, he places them with the humma in the Fochrik system with the humma forcibly relocating the boon’sheh to Larg from their mutual homeworld of Hum. But that’s all we have.
In the end, we just have the table entry for the system to work with. Which tells us we have three habitable planets, some moons, and their approximate rotation periods. We get to create everything else so let’s dive in.
We start with the star. It is given a spectral type of F9. That makes it a little more massive and brighter than the sun but not by much. I like to use the table on this page for my starting point of stellar masses and radii as it has broken the data down in to details for each spectral classification. Plus the author has gone through, and based on the spectral energy distribution, given you the RGB colors for the star. I’m a little leery of the radius data on that page but we won’t be using that in this analysis.
From that page we get a mass of the F9 star for 1.1 solar masses. Looking at the adjacent spectral types, F9 and G0, they have listed masses of 1.2 and 1.1 respectively so that gives us a range to work with and tells us that the F9 star is probably a bit heavier than 1.1 solar masses but within rounding errors. Plus there is scatter based on other factors as well so we have some room to wiggle about. Let’s do some quick calculations.
The mass of the sun is 1.989 × 1030 kg. so we have a range of 1.1 to 1.2 times that to work with or from 2.1879 × 1030 to 2.3868 × 1030 kg. Like I did for White Light, I want a few more decimal places so I’m going to roll some dice for the digits. I’ll keep the 2 before the decimal place, roll a d4 for the first digit, and then d10s for everything else. That will possibly let me go slightly outside the range but that’s fine. Here’s what we get:
So we end up with a stellar mass of 2.21766549 × 1030 kg which probably has more decimal places than we need but that’s fine.
Size of the Habitable Zone
The next thing we need to know is the range of the habitable zone for an F9 star. We’ve got to squeeze three planets into that area. We don’t need to be exact, but we want some reference. For this Wikipedia has a good article on the habitable zone that you can read to determine the various factors that go into determining it. There is also a really great picture (reproduced here) that almost gives us what we need.
The only real problem with this image is that the x-axis is in relative flux on the planet rather than distance. But I can work with that to get values for Fochrik.
We start by getting the percentages for the edges of the habitable zones. This is done by drawing a line across at the temperature of Fochrik (6140 K) and then drawing lines down from those to the x axis like this (the blue lines)
This gives us a range of 178% to 34% for the optimistic habitable zone and a range of 115% to 36% for the conservative one. Now we just need to turn those into distances.
The amount of starlight on the planet is dependent on three things. The first is the temperature of the star (which we’re taking to be 6140K. We could figure it out exactly based on the mass but that is a close enough approximation). The second is the radius of the star. These two give us the total luminosity of the star, L, which is proportional to R2T4. The final bit, which we are trying to solve for, is the distance from the star. The amount of starlight received at a planet, F (flux), is proportional to the luminosity of the star divided by the distance squared, i.e. F~L/D2.
Combining those gives us that the amount of starlight at a planet, F, is proportional to R2T4 / D2. or D ~ sqrt(R2T4 / F). If we work in ratios to the solar temperature, solar radius, measure distances in AU (the distance from the earth to the sun), and enter fluxes as multiples of the flux at the earth (i.e. flux at earth =1, 200% = 2, 50% = 0.5, etc), everything works out.
For this exercise, we’re going to assume the radius of the star is the same as the sun. In reality, it’s probably a little bit larger but we’re not going to worry about that. So we can drop the R2 term. The ratio of the temperatures is just 6140/5780 = 1.062283737. That raised to the 4th power is 1.273392. Plugging in those number gives the following distances for the four flux percentages:
178% = 0.8458 AU (inner edge of optimistic habitable zone)
115% = 1.0523 AU (inner edge of conservative habitable zone)
36% = 1.8807 AU (outer edge of conservative habitable zone)
34% = 1.9353 AU (outer edge of optimistic habitable zone)
Those numbers seem about right. The star is brighter and hotter than the Sun so it makes sense that the habitable zone is a little further out than in the solar system.
Placing the Planets
Now that we know where the habitable zone is, we need to place the planets and add other details to the system. We start with the three known planets, Forge, Hum, and Larg.
The Habitable Worlds
Each of these planets is habitable, with fairly large populations. As such, they need to be at least somewhere within the habitable zone. Also, since they are relatively low gravity worlds, around 1g, they should probably be close to or in the conservative habitable zone as the optimistic one is more for “super earths” which these are not.
Forge is the innermost world of the three and the name itself implies that it’s a hot world. I’m going to place it just inside the conservative zone. It’s livable, but its a bit on the warm side. We’ll place it at 1.08 AU from Fochrik.
Hum is the humma homeworld. As such we’d expect it to have a relatively nice, comfortable climate. If we go back to the flux calculation from above and find the distance for 100% we get a distance of 1.13 AU. That’s a little too close to the 1.08 AU I picked for Forge so I’m going to move it out just a bit further than that and place it at 1.23 AU. It will be a bit cooler than Earth receiving only 84% the amount of starlight.
Finally, we have Larg. This has the smallest population, medium instead of heavy, so I’m taking that to mean that it probably has a less hospitable climate (in addition to the higher gravity). Plus, if we’re using the fan material from the Frontier Explorer, it’s where the humma deported the boon’sheh to. We’ll place this one out towards the outer edge of the conservative habitable zone at 1.61 AU.
Now that our habitable planets have been placed we need to fill the rest of the system. There are a number of ways you could do this. I have a really old program called StarGen that makes solar systems around F, G, & K type stars based on habitability ideas presented in a paper by the Rand corporation. It works pretty well but doesn’t take into account modern information as that paper is from the 60’s or 70’s if I remember correctly.
You could also use the star system creation system presented in the FrontierSpace Referee’s handbook. It’s a good system as well. However, for this system I’m just going to be arbitrary. I’ll roll some dice for distances but beyond that, I’m just going to pick what I want in the system.
The Inner Worlds
Let’s start close. What is inside the habitable planets? I’m going to place two small worlds in there. They are small, hot, and airless. They probably have mineable mineral resources but they are not very hospitable. We’ll place these worlds at .19 AU and 0.52 AU from Fochrick. To get those distances I simply rolled 4d10 and 9d10 respectively and divided the number by 100 to get the AU.
The Outer Worlds
Next let’s move out from the inner system and see what’s out in the outer reaches. We’re going to add in 6 more worlds outside the habitable zone. For now, I’m not planning on having an asteroid belt but that may change when we do some sanity checks below. We’re going to add the following planets to the system:
The truth is, it probably doesn’t matter how you generate the planets, their types and masses, and their distances. As long as you don’t repeat the same patterns over and over. The universe is vast and as modern exoplanet discoveries have shown, you can get all kinds of crazy systems. As a general rule, I allow anything to happen. Once. The more off the wall the idea is, the less likely I am to allow it to enter the setting twice but anything is possible once.
Jovian – 4.66 AU
Jovian – 10.59 AU
Ice dwarf – 16.58 AU
Ice giant – 18.13 AU
Ice dwarf – 20.53 AU
Ice giant – 26.01 AU
In each of these cases, to get the distance I created a number between 1 and 6.99 by rolling a d6 and two d10s. The d6 was the integer bit and the two d10s were the decimal bit. I then added that number on to the orbital distance of the previous planet. Like I said, this was going to be pretty arbitrary. Let’s keep going.
Now that the planets are all placed, we want to compute their orbital periods to know how long the length of their orbit is. While we don’t need this to create the map of the system. We want to do some sanity checks since the planetary placements were fairly arbitrary.
Orbital periods are given by Newton’s form of Kepler’s Third Law of Planetary motion, namely:
which I described in the Clarion Calendar post but P is the orbital period, a is the distance from the star, G is the gravitational constant, and M1 and M2 are the mass of the star and planet respectively. Since M1 >> M2, we’ll ignore M2 in our calculations.
You could do this by hand, or use a spreadsheet, or use an on-line calculator. I’m going to use this handy website that allows you to enter the values in a number of different units and does the math for you. I’m just going to leave the mass of the planet at 1 earth mass in the calculation. If I was going for full detail, I’d figure out the mass of each of the planets but this is really just an approximate sanity check. For example, if I set the mass of the first Jovian planet to 100 earth masses, it would lengthen the orbital period by only 10 hours, so it’s not something I’m going to worry about here.
Plugging in the values for the planetary orbital distance and the mass of the star we get the following data:
Orbital Distance (AU)
Orbital Period (hours)
I should really come up with names for the other planets but since this is the humma homeworld, the names should tie into their history and culture and I haven’t really thought too much about that yet. I’ll leave naming for a future post or as an exercise for the reader.
Mainly here I’m just looking to see that we don’t have any resonant periods with the two Jovian planets. With orbital periods in ratios such as 2:1, 3:2, & 3:1 we would have potential stability issues. My only concern is with the second jovian and the first ice dwarf. They are in a nearly 2:1 orbital resonance but that might actually be okay and why that planet is where it is. So I’m going to leave it alone. If I really wanted to check system stability, I’d generate the masses, starting positions and velocities, and then enter all of that into a simple n-body computer simulation and run it for a million years or so of simulated time to make sure nothing went crazy but I think this will be fine.
Okay, while this isn’t strictly necessary to draw the system map, we might as well figure out how big each of the planets are (and their surface gravity. When I do the system map, I like to have both the distances to scale and the sizes of the planets to scale so if I want to do that, I need the sizes.
The equation we’ll be using for this is
where g is the acceleration due to gravity (m/s2), M is the mass of the planet (kg), r is the radius of the planet (m), and G is just the gravitational constant (6.67408 × 10-11 m3 kg-1 s-2). Additionally we’ll want an equation relating the mass of the planet to its density which is just the volume of the sphere times the density or
where ρ is the density (kg/m3). While we could do this just with the mass, I like to make sure the physics work out for the type of planet so I like the densities to make sense and prefer to include it in the calculations. Combining those two equations gives us an equation that relates the gravity, the radius, and the density:
This is what we’ll be using to get the data we need.
As part of this we’ll need densities for the planets. We’ll just be picking those from reasonable ranges which are the following (in g/cm3):
Terrestrial (rocky) Planets – 3.5 – 5.7
Ice Dwarfs – 1.8 – 2.5
Ice Giants – 1.2 – 1.8
Jovians – 0.6 – 1.4+
To get it into the units we need (kg/m3 ) we just multiply by 1000. The Jovian planets may not have an upper density limit because once you get to be the size of Jupiter, adding more mass doesn’t change the radius much, it just increases the densities. Brown Dwarfs, which are 10-80 times Jupiter’s mass are still all about the same size.
We’ll use these density ranges to pick densities for the individual planets in the sections below.
The Habitable Planets
First up are the three habitable planets that we know the gravity on. In this case we need to rearrange the last equation to solve for r giving us:
A Note on Gravity
For Star Frontiers, I’ve adopted the conventions that 1g = 10 m/s2 rather than 9.8 m/s2 as on Earth. It makes all the math in the end easier and there isn’t much difference. I figure that if you have all the races coming from different worlds, it would make sense that they standardized on a round number instead of some arbitrary fraction.
All that’s left is to pick a density or each of the planets and start computing. Well, almost. I also want one more decimal place for the actual gravity of the planet. To get that I’ll roll d8-4 x 0.01 and add that to listed gravity to give me some variation that would round to the listed value.
The table below is what we ended up with. Interestingly, all the gravity adjustments I rolled were positive. I also selected the planets with the higher gravity to be a little more dense but modulated that somewhat due to the fact that planets that form closer to the star would have higher density as well. Thus the densities of these three planets are pretty close together.
Hum turns out to be almost exactly the same size and mass as Venus, just a little further out in the system so it’s not as hot. Forge is smaller still by about 10% in radius and 75% in mass while Larg is about 13% larger in radius than the earth and almost 50% more massive.
Now lets due the rest of the planets in the system. In this case we have to pick two of the three values: radius, density (or mass), and surface gravity. I’m going to select the radius and density for each of these planets and then compute the mass and surface gravity. Surface gravity doesn’t exactly make sense for the giant planets (jovians and ice giants) but it is the gravity present if you were stopped at that radius at it’s upper atmosphere. Here’s the table:
J1 is almost two times the mass of Jupiter while IG2 is a little smaller than Pluto. If you want to compare them exactly this Planetary Fact Sheet page gives the data for all the planets in the solar system.
Wrapping up for now
And that’s it for this entry. We have the number of planets in the system, mass data on the star, and orbital and size data on the planets. I’m fairly confident that we don’t have to worry about system stability issues (of course since I didn’t do a rigorous check, this will be the one time it doesn’t work 🙂 ).
In the next post, we’ll create a system map for Fochrik and walk through the process of doing so. If you have any questions or comments, let me know below.
Here’s the next installment of the timeline. This section include the events that will be considered the first battles of the Second Sathar War, namely the Battles of Volkos and Zebulon between ground and spaces forces of the UPF and the sathar at Volturnus in the Zebulon system.
After posting the last installment, I was asked if it would be possible to provide references to the sources I’m using to create the entries. I realized that would be a good idea so I’ve started adding reference notes to all the entries that come from other sources other than me just making them up for the timeline. I also wrote a short introduction to the timeline that explains the references that I’ve reproduced below.
I’ve gone back an annotated all the previous entries in the downloadable timeline document and where a reference occurs in the blog post, I’ve included the key for those references at the end of the post.
The following timeline represents the events of the Second
Sathar War as I designed them to act as a backdrop to various campaigns I am
running. I have a different timeline
that runs the PCs though all the game modules in an appropriate order to
progress their skill level but that is not this one. This is somewhat of a more fiction-oriented
timeline rather than on specifically designed to run PCs through.
One major aspect of this time line is that I’m using the
Knight Hawks rules for interstellar travel, namely that it effectively takes 9
day to make an interstellar jump between systems (ignoring astrogation
calculation times). I also make the
assumption that if you’re not stopping in a system, you only have to spend as
much time in that system as the astrogation calculations take as you stay near
jump speed during your transit. If you
assume 1 day per light year per the original Alpha Dawn rules, it would change
the timing of many of these events, possibly significantly.
If you’re familiar with the timeline in the Zebulon’s Guide
to Frontier Space, you’ll quickly notice that I don’t follow that much at
all. I pull some of the names and ideas
but the timing and actual events follow my own muse. Additionally, regardless of the source of the
events, the exact dates are all of my creation.
In the events that follow, I’ve tried to annotate the source
for names, dates, and events if they come from any of the material originally
published by TSR. Although I’m not going
to annotate the system, planet, and common megacorp names as I assume those are
common knowledge. I will also try to
annotate any material coming from the Star Frontiersman and Frontier Explorer
Fanzines. If you notice that I missed
anything, let me know so I can fix it.
Annotations that appear at the end of an entry refer to the entire entry. If it appears in the middle, it applies just to the name that the annotation follows. Each time an annotation first appears, there will be a footnote describing it. I’ve also added an Appendix listing all the annotation codes. If no particular annotation is associated with an entry you may assume I made the entry up out of whole cloth or extrapolated it from other events specifically for this timeline.
As always, the data presented in this blog post cover only the new dates but the downloadable document at the end is cumulative over all the timeline posts up to this point.
Subspace signal received at Laco from unknown location in Sathar space. Images appear in the great pyramid showing a similar complex on a warm, swampy world with a large number of sathar and a bipedal insect race (Zuraqqor) working around the complex.
Despite efforts to keep the images contained,
news and clips of the images race across the Frontier on the subspace
network. Scientists, politicians, and
the general populous speculate as to the cause and meaning.
new group, calling themselves the Anti-Satharian League (ZG), stage
demonstrations on the major population centers of the Frontier and at the
Council of Worlds, broadcasting excerpts from the Laco pyramid images and
demanding increased military buildup for Spacefleet.
Completing its time in the
Cassidine system, SF Nova departs Triad for the Dramune system to spend some
time cooling rising tensions between Inner and Outer Reach.
A CDC scout ship, the Twilight Moon, returns from charting a jump route to the Rhianna system. Due to preliminary geological findings, CDC decides to keep the route a secret and establish a mining outpost on the planet Alcazzar. (SF4)
Most businesses across the Frontier close a day
early in anticipation of the big Founding Day celebrations tomorrow, allowing
citizens and organizations some extra time to prepare.
– UPF Founding Day celebrations occur on most planets across the Frontier to celebrate 6 decades of peace. However, there is a subtle undercurrent of concern due to the recent events on Laco.
– The first new sathar ship that will be committed to the coming conflict, a destroyer, emerges from Sathar Starship Construction Center (SSCC) #2, located in the as of yet unexplored (and unnamed) Liberty system.
– In wake of the Founding Day celebrations, the Frontier Peace Organization hold a rally outside the Council of Worlds headquarters demanding a reduction in Spacefleet and Landfleet operations. Some small altercations occur with members of the Anti-Satharian League.
– Observance Day on Clarion (White Light) commemorates all who have fallen defending the system through history. This year it also continues the UPF Founding Day celebration on the planet for an extra day.
PG Virgo, together with the Pale militia (a frigate and 3 assault scouts),
depart for the Zebulon system. Streel additionally sends a frigate, 4
corvettes, and 3 assault scouts to assist.
Council of Worlds reconvenes for its 60th
session. Initial topics of debate include events on Laco and Zebulon and
their implications for the future of the Frontier.
breaks out between Frontier Peace Organization and Anti-Satharian League
supporters outside the Council of Worlds headquarters. Local police have to resort to doze and
tangler grenades and stun weapons to break up the fighting. Over 4 dozen beings detained.
Sathar SSCC#4, near Fromeltar and Klaeok,
completes construction of a light cruiser and 4 fighters.
SF Nova arrives in the Dramune System. It will remain in system for 15 days as a
show of force to help quell rising tensions between Inner and Outer Reach
Laco artifacts taken from the PGC
chartered freighter, KSS Dawn’s Glow, anonymously arrive at the Triad
Institute of Technology (TriTech) and are delivered to their originally
intended recipients. (NCW)
The Sathar cleansing fleet arrives in the Zebulon system and begins decelerating towards Volturnus. (SF2)
The UPF fleet arrives in the
Zebulon system and begins decelerating toward Volturnus and the sathar fleet.
A small freighter, the KKSS Trader’s Gambit, misjumps travelling from K’aken-Kar to K’tsa-Kar and ends up in the Sundown system. Damaged engines force the crew to look for a planet to land on to effect repairs. (SF3)
– Battle of Volkos – Sathar ground troops advance on the ruins of the Eorna city of Volkos. A rag-tag army, composed of members of Volturnus’s native races and lead by members of the TSES Second Volturnus Expedition, manage to hold off the invaders. (SF2)
– Battle of Zebulon – UPF forces engage the Sathar fleet around Volturnus. Although the UPF forces are mostly smaller vessels, the sathar are driven off with only a frigate, 2 destroyers, and a heavy cruiser surviving. UPF losses were 1 UPF LC and AS, 1 Streel Corvette, and 1 militia AS (SF2)
of defeat at Zebulon reaches sathar space.
Clan infighting begins around debate of invasion and who should lead
assault. This will continue for
several months. At the same time all
the clans begin building up their military.
– News of victory over sathar forces in the Zebulon system announced across the Frontier to mixed reaction. Performance of the Assault Scout in its first major engagement with sathar forces is deemed a success.
– Pale militia and Spacefleet given priority at the Pale and Gran Quivera starship construction centers to replace vessels lost in the battle at Zebulon.
– The KKSS Trader’s Gambit sets down on the planet Starmist in the Sundown system. (SF3)
– Having effected repairs from the battle with the sathar, the Pale militia and Streel ships depart Volturnus (Zebulon) to return to Pale (Truane’s Star) while the UPF forces remain on patrol.
– The Anti-Satharian League stages demonstrations on Pale, Gran Quivera, Triad, and Clarion demanding increased militarization and growth of Spacefleet
– The navigator and second master of the KKSS Trader’s Gambit, Maximillian Malligigg, makes contact with an intelligent race, the Heliopes, on the planet Starmist (Sundown). (SF3)
(SFKH0) Valentine Leotus, crown princess of Clarion (White Light), celebrates
her 32nd birthday (18.5 earth years)
A listening station in the Kazak system in the
Rim detect faint signals of sathar ships in the outer system. Flight vessels are dispatched to
completed, the KKSS Trader’s Gambit leaves Starmist to attempt to return to
charted Frontier space. (SF3)
The Flight vessels in Kazak arrive at the
location of the sathar signals but find nothing more than a faint indication
that ships had passed through the area days before. Two ships are left on station while the
rest return to base.
begins in earnest on Alcazzar, delaying the start of CDC operations on the
planet. The corporation hopes that this delay will throw off any competitor’s
interest in the mineral rich system. (SF4)
SF Nova departs the Dramune system
for the Fromeltar system
– The KKSS Trader’s Gambit successfully jumps back to the K’tsa-Kar system.
– The Pale militia arrives back home from the Zebulon system.
Scouting through the Zebulon system, a UPF
frigate and assault scout find an ancient vessel in a distant solar orbit.
Investigation reveals it to contain a cache of cryogenically stored Eorna
eggs. If still viable, the eggs will secure the survival of that species.
from the Pale militia are dispatched to testify at the Council of Worlds regarding
events on Volturnus.