Tech Level 8 Solar System

[Tom Kalbfus]

Using the same charts I used to map the Cyrannus System, I decided to map our own.

This is in the late 21st century or early 22nd century, this is a map of our Solar System out to Mars with movement plots of planets in 4-day increments out to 90 days. The point of this map is to track movement of spaceships between the planets and to find suitable locations for space colonies in orbit.

First we have Mercury,

Venus,

Earth,

Luna,

and Mars.
Spaceships use reaction drives, and fusion reactors to power them. Fusion reactors follow the standard rules, but reaction drives, have Jump fuel requirements per drive number. The drive numbers are the standard 1 through 6-G of acceleration, but the reaction drives can only maintain that acceleration for up to seven hours. The fusion power plants can power the ships systems for up to four weeks, using the power plant fuel. Spaceships typically accelerate until they reach cruising velocity, then they coast and then decelerate upon arrival. These maps are as yet unpopulated by space settlements, and right now I have only the close in orbits. I will draw some further out orbits, and then populate the orbits around these planets.
I am thinking of categorizing space colonies with lower case Roman Numerals, to distinguish them from World Sizes. Size categories will be based on spin diameter, as there is no other way to generate artificial gravity other than by acceleration.
Space colony sizes:
i = 880 ft.
ii = 1760 ft.
iii = 2640 ft.
iv = 3520 ft.
v = 4400 ft.
vi = 1 mile
vii = 2 miles
viii = 3 miles
ix = 4 miles
x = 5 miles
xi = 6 miles
xii = 7 miles
xiii = 8 miles
xiv = 9 miles
xv = 10 miles
xvi = 12 miles
xvii = 14 miles
xviii = 16 miles
xix = 18 miles
xx = 20 miles

 

[Tom Kalbfus]

Now we proceed to the Outer Solar System:

The most important moons are the Gallileans:

Io,

Europa,

Ganymede,

and Callisto.

 

[phavoc]

It's interesting to see laid out on a map, but for the most part, it's not used in a Traveller session. Even at TL8, with the tech you've postulated, a measly 1G contin.uous thrust open up the solar system like the sailing ships did the oceans. For a gaming session, with time taking days, or even a few weeks, orbital positions, especially for outer planets, is meaningless. They simply won't have travelled far enough to matter. And if you are traveling from say Earth to Saturn, even a journey of a few weeks won't require any real factoring in of Saturn's orbital change. Now in reverse it might, but only perhaps by a single degree of course change, and maybe a few extra hours of accel/decel.

System maps are nice to see relative distances, and at least at the time of departure, what your planned route is (which would be changing every week or month, depending on where you are going).

 

[Tom Kalbfus]

It's interesting to see laid out on a map, but for the most part, it's not used in a Traveller session. Even at TL8, with the tech you've postulated, a measly 1G contin.uous thrust open up the solar system like the sailing ships did the oceans. For a gaming session, with time taking days, or even a few weeks, orbital positions, especially for outer planets, is meaningless. They simply won't have travelled far enough to matter. And if you are traveling from say Earth to Saturn, even a journey of a few weeks won't require any real factoring in of Saturn's orbital change. Now in reverse it might, but only perhaps by a single degree of course change, and maybe a few extra hours of accel/decel.

System maps are nice to see relative distances, and at least at the time of departure, what your planned route is (which would be changing every week or month, depending on where you are going).

The main difference is the spaceships use reaction engines, the space usually allotted for jump fuel in a starship instead goes for reaction mass. The reaction engine takes the same power input as the standard reactionless thrusters of Traveller, except they also consume the allotted reaction mass equal to the jump fuel requirements of the jump drive with the same jump number as the maneuver drive, and since were using reaction engines, and since fusion releases only 1% of the energy as a matter/antimatter engine, the reaction engines only run for 7 hours on their entire jump fuel allotment of reaction mass. That means a 1-G reaction engine that accelerates for 3.5 hours can reach a top speed of 76.73 miles/sec using 10% of the hull volume in liquid hydrogen, using 60% of the hull volume in liquid hydrogen reaction mass, that same ship can reach a maximum speed of 460.36 miles/sec, (at that speed, it will take 56.115 hours to travel 1 astronomical unit) a higher acceleration will just get you to that speed faster, and since there is no artificial gravity, most people prefer to travel a 1-G acceleration. The fusion power plants run for 4 weeks on their allotted fusion fuel, here we'll assume its fuel is deuterium-tritium or helium-3, it doesn't matter much. A fuel processor allows such ships to skim gas giants, and separate out the deuterium from the ordinary hydrogen or the Helium-3 from helium-4 and hydrogen. Proton-proton fusion has yet to be achieved. Helium-3 can be found on all four gas giants, deuterium can be found on all four gas giants plus the oceans of Earth, ices on Mars, and in the clouds of Venus in the form of sulfuric acid. The Moon also has trace amounts of Helium-3 in its soil. You need a reaction engine thrust of 3 or greater to escape the atmosphere of Jupiter because of its gravity, for the other gas giants, a reaction engine thrust of 2 would suffice. I'm assuming a mature space colonization civilization, about 50 years after the first orbiting space colonies were built, so this might put us in the year 2100 AD or later. Lots of O'Neill colonies floating around, there are domed settlements on Mars, floating aerostat settlements high in Venus' atmosphere, and of course there are settlements on the Moon and Mercury. the asteroid belt, Jupiter and Saturn have colonies in orbit, and there are domed settlements on Titan, Callisto, Ganymede and other such places. I'd say some sort of limited artificial intelligence, up to Tech Level 15 is available. There are no grav vehicles, there are air vehicles that require an atmosphere in which to operate, there is something similar to an air/raft, but it hovers on ducted fans or jet engines, makes a lot more noise and it can't reach orbit, but otherwise its performance is similar to the grav vehicle of the same name, and it is similarly priced, it works in the atmosphere of Earth, high in Venus' atmosphere, and on Titan with suitable cold temperature adaptation, and requires at least a thin atmosphere in which to operate.

 

[Tenacious-Techhunter]

The more interesting uses of system maps arise from planetary positions having changed over the course of several months, and having a different inward trajectory puzzle than the last time you entered the system. It makes entering and leaving a system that much more dynamic, and worth spending some time considering your approach, if not also your jump vector.

 

[Tom Kalbfus]

The more interesting uses of system maps arise from planetary positions having changed over the course of several months, and having a different inward trajectory puzzle than the last time you entered the system. It makes entering and leaving a system that much more dynamic, and worth spending some time considering your approach, if not also your jump vector.

That is mostly the inner system, Jupiter and planets further out move very slowly, so that as far as the players are concerned they might as well have fixed positions, so I don't bother making tracking charts for those, and those of the inner planets I did only for 90 days or about the orbital period of the planet Mercury.

I wonder, what do you have to do to make the Solar System interesting? How much history do you need? In the 22nd century, most settlements are very young, there are a lot of young people in them, everything inside them is new, fresh structures, new buildings, a lot of it was built by robots, as there is no way these colonies could have been built otherwise.

The inside of a typical colony.

 

[Tenacious-Techhunter]

If you want to make the solar system interesting, make them do Hard Science Fiction control burns.

 

[Reynard]

If it's the 22nd century I could see there may be robots but your thread title is TL 8 solar system. Did I miss something in your posts? All drones I could find in 1e and 2e are at least TL 9. There would be no robots per se unless you have some sort of pre-programmed dumbots. Reaction engines should be extremely cost ineffective for such massive colonization projects and structures you illustrate unless you are mining and refining very locally. You might have robotic freighters that fire their engines briefly then coast for years to a target like we do with our probes today. Is it 22nd century because it took that long to colonize? I'm a little confused, are we talking TL 8?

 

[Tom Kalbfus]

If it's the 22nd century I could see there may be robots but your thread title is TL 8 solar system. Did I miss something in your posts? All drones I could find in 1e and 2e are at least TL 9. There would be no robots per se unless you have some sort of pre-programmed dumbots. Reaction engines should be extremely cost ineffective for such massive colonization projects and structures you illustrate unless you are mining and refining very locally. You might have robotic freighters that fire their engines briefly then coast for years to a target like we do with our probes today. Is it 22nd century because it took that long to colonize? I'm a little confused, are we talking TL 8?

The Jump Drive comes at tech level 9, and in the Traveller timeline it comes too soon! We don't know what technology is going to be available in the 22nd century, but we can guess. The least risky guess is to assume no new understandings of physics, and project some improvements on current technology and on what we know is possible, that means no Eureka moments where someone invents a jump drive in his garage, the speed of light remains the limit, no new understanding of how to turn on or turn off gravity fields at the flick of a switch. One can get technical and wonder how those fusion rockets shed all that heat, but we just hand wave it away and assume the future figures out something we hadn't thought of yet! No reactionless drives, everything is one sort or rocket or another. I assume fusion rockets can reach accelerations of 1 through 6-G and that they can be used for landing on planets, just to make things simpler. How? I don't know, if I did know I would patent it and build one!

We know artificial intelligence is possible because we exist. There is also the antimatter drive, it is extremely expensive, It is very compact however. Typically you have an arrangement of six antimatter drives in a ring, with six cables leading the crewed spaceship in the center. The antimatter engines contain all the antimatter they will ever use an then they are discarded when the fuel runs out, as the antimatter is much more expensive than the engine, it makes more sense to fuel disposable engines at the factory ad sell them fully fueled. The typical antimatter engine can operate at full thrust for a year before its antimatter fuel runs out. Only one thrust level is available 1-G.

Antimatter is produced around Mercury. Typically only governments or very large corporations can afford to use antimatter engines. Everyone else uses fusion.

 

[Tom Kalbfus]

Here are some more Outer Solar System Worlds starting with the Moons of Saturn.

Prometheus,

Rhea,

Titan,

and that mysterious moon Iapetus.

Continuing on with Uranus, we have two major moons we're concerned about,

Titania,

and Oberon.

And while Neptune has a bunch of moons, there really is only one major one,

And finally being the traditionalist I am,

I'll include Pluto, planet or not,

and I'll throw in Charon to keep it company.

Now we go back to Mercury, but at a greater distance.

The scale on this map is 5000 miles per square, and coincidentally, the ever popular 24-hour orbit is almost exactly 10,000 miles in radius around Mercury. This is a good spot to build space colonies, Rocks can be flung off the surface of Mercury using solar powered mass drivers to provide the materials to build them, Interestingly Mercury has more mass than the entire asteroid belt, though it is mostly metals like iron, the other stuff that life needs comes from elsewhere, though their is some at the poles.

 

[Reynard]

Tom, you're playing a far, far different game of Traveller than me.

 

[fusor]

Why on earth would anyone think that a bunch of pretty much identical graphs with a different sized circle in the middle is any use for anything at all? Would anyone honestly use these to plot ship movements on?

 

[Sigtrygg]

Yup, I have printed. the lot out.

They are a great play aid for a hard sci fi setting, one where orbital mechanics rather than the brute force of unlimited 'burn' 9g drives.

 

[Sigtrygg]

Tom, you're playing a far, far different game of Traveller than me.

I've been using circular graph paper (polar graph paper) for ship combat range bands for years, and I have been using a simple hex based system map - Tom's are much better and I am very rude for not thanking him for the work before now.

Thanks Tom.

 

[Tenacious-Techhunter]

Sigtrygg, I would argue that a logarithmic polar plot would be more useful, because you can more easily put all the planets on just the one chart. How much more difficult would you find it if the radii were logarithmic rather than linear?

 

[fusor]

They are a great play aid for a hard sci fi setting, one where orbital mechanics rather than the brute force of unlimited 'burn' 9g drives.

How does this have anything to do with orbital mechanics? These are just repetitive graphics that serve no purpose other than to say "this planet is this big", which can be succinctly summarised in a short sentence rather than a diagram. It adds absolutely nothing beyond that.

And the solar-system scale stuff is useless too. Plotting a few positions of planets over certain parts of their orbits doesn't tell you anything useful - you need to know the required deltaVs to plot out courses between planets, not just where a planet is in its orbit and when it's at that point. You want to know what the Least Energy (Hohmann Transfer) Orbit is and how to make that.

See e.g. http://solarsystem.nasa.gov/basics/bsf4-1.php for more info on how spaceflight between planets really works. Or even better, play Kerbal Space Program.

 

[Tom Kalbfus]

They are a great play aid for a hard sci fi setting, one where orbital mechanics rather than the brute force of unlimited 'burn' 9g drives.

How does this have anything to do with orbital mechanics? These are just repetitive graphics that serve no purpose other than to say "this planet is this big", which can be succinctly summarised in a short sentence rather than a diagram. It adds absolutely nothing beyond that.

And the solar-system scale stuff is useless too. Plotting a few positions of planets over certain parts of their orbits doesn't tell you anything useful - you need to know the required deltaVs to plot out courses between planets, not just where a planet is in its orbit and when it's at that point. You want to know what the Least Energy (Hohmann Transfer) Orbit is and how to make that.

See e.g. http://solarsystem.nasa.gov/basics/bsf4-1.php for more info on how spaceflight between planets really works. Or even better, play Kerbal Space Program.

And I suppose your players are very patient with you as you calculate the Hohmann Transfer orbit, and throw a bunch of numbers at them to tell them where their spaceship is going, how fast it is traveling and in what direction. Some people are visually oriented, they like to see a picture rather than have numbers thrown at them. As for a logarithmic scale, that only shows you the distance between one object and the center of the chart. If you want to know the distance between two spaceships, neither one of which is at the center, you can use the Pythagorean formula distance = ((x1-x2)^2 + (y1-y1)^2)^0.5. A hex grid makes it a little easier to count the hexes in 6 different directions, but the Pythagorean formula works in any direction at any angle. One can also make estimates by counting squares.

Anyway, you use Hohmann transfer orbits when your extremely limited in the amount of fuel to burn. I am assuming fusion technology. My ships have three components You have the fusion power plants, which are the same as in the standard game, you have the reaction thrusters, which you maneuver your ships with, unlike the standard maneuver drives, the reaction thrusters require reaction mass, this is not fuel, it is just matter the thrusters throw behind to push the ship forward, and to do this it need energy from the power plant. the standard jump fuel requirements are a good approximation for how much reaction mass is needed.

Now for a reaction drive that provides 1-G of thrust with the same letter power plant to provide energy input, a ship requires 10% of the hull volume to be set aside for liquid hydrogen reaction mass, and with this the ship can accelerate for 7 hours before running out of reaction mass. If a ship can accelerate for 7 hours at 1-G it doesn't need to make Hohmann transfer orbits, for game purposes, it can ignore gravity entirely, except for getting off of planets and landing on them. You basically have to match velocity with the planet, and then spend a number of minutes landing on it. The thrust your ship can provide has to be greater than the gravity on that world to take off from it again.

 

[Tom Kalbfus]

Here is Venus at the 5000 mile per square scale:

And here is a controversial idea of what could be put in that 24-hour orbit, and maybe kill two birds with one stone as well.

You wouldn't want to do this with Earth, but Venus needs the shade if it is to be properly terraformed some day. The shade takes the form of a ring shaped giant solar collector, Actually it is one giant solar power satellite that stretches all the way around the planet in a 24-hour orbit. A one point on the inside of this Solar Collector is a light source that shines down on Venus with Earth level illumination, the rest of the energy collected goes into antimatter production. The antimatter produced is anti-hydrogen, but that in turn is fed int a series of fusion reactors, the anti-hydrogen is fused into anti-helium, the anti-helium is fused into anti-carbon and so on until anti-mercury is produced. Anti-mercury would make an excellent starship fuel, it is very dense, 13.546 tons/meter^3, liquid hydrogen is 0.070 tons per cubic meter. A displacement ton can hold 1 ton of liquid hydrogen or 189.644 tons of liquid mercury. Mercury is also a liquid at room temperature, it can fit in a small space, which makes containing antimatter in mercury form that much easier, as there are fewer walls you have to prevent it from coming in contact with. This makes an antimatter reactor nice and compact although very heavy! When it gets used up you discard it!

 

[fusor]

And I suppose your players are very patient with you as you calculate the Hohmann Transfer orbit, and throw a bunch of numbers at them to tell them where their spaceship is going, how fast it is traveling and in what direction. Some people are visually oriented, they like to see a picture rather than have numbers thrown at them. As for a logarithmic scale, that only shows you the distance between one object and the center of the chart. If you want to know the distance between two spaceships, neither one of which is at the center, you can use the Pythagorean formula distance = ((x1-x2)^2 + (y1-y1)^2)^0.5. A hex grid makes it a little easier to count the hexes in 6 different directions, but the Pythagorean formula works in any direction at any angle. One can also make estimates by counting squares.

Anyway, you use Hohmann transfer orbits when your extremely limited in the amount of fuel to burn.

Right, so the usual Tom Kalbfus response of "I don't care, I'll post what I like anyway", gotcha. And obviously you *are* looking at "brute force 9g burns" and not hard scifi orbital mechanics. Well, I'm sure you'll continue to post a million more useless charts for a setting that nobody here asked for in the first place anyway.

 

[Tenacious-Techhunter]

And I suppose your players are very patient with you as you calculate the Hohmann Transfer orbit, and throw a bunch of numbers at them to tell them where their spaceship is going, how fast it is traveling and in what direction. Some people are visually oriented, they like to see a picture rather than have numbers thrown at them. As for a logarithmic scale, that only shows you the distance between one object and the center of the chart. If you want to know the distance between two spaceships, neither one of which is at the center, you can use the Pythagorean formula distance = ((x1-x2)^2 + (y1-y1)^2)^0.5. A hex grid makes it a little easier to count the hexes in 6 different directions, but the Pythagorean formula works in any direction at any angle. One can also make estimates by counting squares.

You may not be able to use the Pythagorean Formula with Polar Log Plots, but you can use the “Side-Angle-Side” formula to get the third side for the straight line distance (And since it’s a Polar Log Plot, the protractor is built in!):

c=√((a^2)+(b^2)-(2ab*cos(θ)))

Admittedly, that cosine is pretty unfriendly, but you can always overestimate by nudging it closer to 180 degrees.

Anyway, you use Hohmann transfer orbits when your extremely limited in the amount of fuel to burn. I am assuming fusion technology. My ships have three components You have the fusion power plants, which are the same as in the standard game, you have the reaction thrusters, which you maneuver your ships with, unlike the standard maneuver drives, the reaction thrusters require reaction mass, this is not fuel, it is just matter the thrusters throw behind to push the ship forward, and to do this it need energy from the power plant. the standard jump fuel requirements are a good approximation for how much reaction mass is needed.

The correct trajectory for constant thrust is a Brachistochrone Trajectory. A straight line would be an unnecessary waste of time; as would failing to take advantage of local bodies for a slingshot or two, where beneficial. And a Brachistochrone Trajectory is every bit as math intensive as a Hohmann Transfer orbit; fortunately, like Hohman Transfer orbits, and other orbits worthy of note, there are plenty of calculators available online. Anyone who thinks you need to do this stuff by hand anymore is ill-informed.