Monday, April 12, 2021

Space Combat - System Scale and Space Combat Scale

What I want: 

  1. Space Combat where there is order enough to grasp the most key Conditions. More specifically. 

    1. The Conditions are Defined and Loaded with Context. Example
      1. Vectors - Moving and "Stationary" 
      2. Delta-V Budget ΔVB vs ΔV
      3. I'd have to map the ΔVB of each Stationary Vector.  
        1. I need to make a Spreadsheet formula of Escape Velocity and Break it down to more. Thankfully Donjon's System Generator has Gravity, Mass (in Earths), and Radius.
        2. I need a way to quickly Transfer and Clean up Data from Donjon's System Generator, Nearby Space map, and other Such resources. 
      4. Tables of STUFF to encounter. 
      5. Distances and Ranges
      6. Logical Relationships / Dependencies - (Towards, Away, Following, Evading, Shadowing). LR = Attention and Resources spent. 
    2. There is a checklist that helps manages the details. 
    3. Benchmarks: 
      1. Regular Freighters - the regular Traffic and their ΔVB  and Shipping Tonnage periods.
      2. Regular Patrol - the Light Warships that Regularly Patrol or Guard these, as well as the system Defenses. 
      3. Free Traders - the difference between Free Traders and Freighters is that the Freighters are Assets, their contracts guarantee they will operate and make money. It is the WEALTH of the system that determines their GRADE (
  2. Players can Consider Actions and See the Limitations of their Adversaries as well as their Own Situations and Take Risks Accordingly. 
    1. In Hard Scifi Space Combat - Every Encounter has been Wargames/Preplanned and there are RISKS, phase gates, that depending on what happens modifies the odds of an outcome. 
    2. For example - merchants balance  ΔVB with profitability and pirates balance  ΔVB with profitability - the ability to Capture the vessel and the Equilibrium of Strategies. 
or a spherically symmetric, massive body such as a star, or planet, the escape velocity for that body, at a given distance, is calculated by the formula[3]

where G is the universal gravitational constant (G ≈ 6.67×10−11 m3·kg−1·s−2), M the mass of the body to be escaped from, and r the distance from the center of mass of the body to the object.[nb 2] The relationship is independent of the mass of the object escaping the massive body. Conversely, a body that falls under the force of gravitational attraction of mass M, from infinity, starting with zero velocity, will strike the massive object with a velocity equal to its escape velocity given by the same formula.

When given an initial speed V greater than the escape speed {\displaystyle v_{e},} the object will asymptotically approach the hyperbolic excess speed {\displaystyle v_{\infty },} satisfying the equation:[4]

In these equations atmospheric friction (air drag) is not taken into account.

Learning Escape Velocity Taught me:

  1. That Orbits, which require less Escape Velocity, eventually get pulled back to the Planet. 
  2. Seeing #1 in action Taught me how Rocket Stages Work and how I can break up ΔVB with Mass Drivers, Airship Platforms, Inertia Tethers etc.. How the 11km/s can be achieved in segments of 2-3km/s with InfraStructure. I wish I had a media artists to help me explain these concepts visually. 
  3. That this was Essential in Making a ΔVB Map of a System. And started me in Imagining how I will use to diagram a System. 
  4. That after learning the Travel Time Formula and How it Works - how to get Time, Distance, ΔV, ΔVBudget, we learn Escape Velocity to make sense of it all. THEN we learn the simple algebra of Impulse, Thrust, Propulsion: Intake of Wet mass to Accel and ΔV.  Then the Geometry of Ship Building. 

System Scale Map in Roll20.

  1. Default 25px x 70 px for Width and Height. 
  2. Background: Black
  3. Grid Scale: 1 hex 
  4. Hex (H)
  5. Cell With 0.3 px x 70px = 21 px


  1. Systems Like our Solar System are HUGE, so huge that if I scale it to include Pluto or its Heliosphere (44 Astronomical Units) - with AU per hex, Mercury, Venus and EARTH are in the SUN Hex!!! 
  2. Anything that happens in the AU scale happens in the AU/ ΔV (Delta V) of the Moving Vectors. 


  1. Scale on the Fly. DONT set the hex distance just yet. It takes about 2 minutes to Recalculate the SCALE and change the hex distance values. have a method for a GM to quickly Adjust the distances. 
  2.  Vectors and Orbits using the MAP tools in Roll20 can easily be adjusted, number of Hexes can be used to determine Orbits and Distances and Current positions. 

Delta-V Budget 

Delta-v from / to (km/s)LEO-KenLEO-EqGEOEML-1EML-2EML-4/5LLOMoonC3=0
Low Earth orbit (LEO-Ken)4.244.333.773.433.974.045.933.22
Low Earth orbit (LEO-Eq)4.243.903.773.433.994.045.933.22
Geostationary orbit (GEO)2.061.631.381.471.712.053.921.30
Lagrangian point 1 (EML-1)0.770.771.380.140.330.642.520.14
Lagrangian point 2 (EML-2)0.330.331.470.140.340.642.520.14
Lagrangian point 4/5 (EML-4/5)0.840.981.710.330.340.982.580.43
Low lunar orbit (LLO)0.900.902.050.640.650.981.871.40
Moon surface2.742.743.922.522.532.581.872.80
Earth escape velocity (C3=0)001.300.140.140.431.402.80 


Star Data
TypeF7 V Yellow-white Main Sequence
Radius8.78 x 105 km   (1.26 x sol)
Mass3.09 x 1030 kg   (1.56 x sol)
Temperature6300 K
Luminosity8.65 x 1026 W   (2.26 x sol)
TypeRock Planet (Escape Velocity 11,185.98 m/s
Orbital Radius6.41 x 107 km   (0.43 AU)
Period1.96 x 103 hours   (0.22 earth years)
Radius7698.77 km   (1.21 x earth)
Gravity11.72 m/s2   (1.20 x earth)
SpecialHeavy radiation, heavy volcanism
TypeRock Planet (Escape Velocity 10,914.76 m/s)
Orbital Radius1.27 x 108 km   (0.85 AU)
Period5.50 x 103 hours   (0.63 earth years)
Radius10158.97 km   (1.59 x earth)
Gravity16.36 m/s2   (1.67 x earth)
TypeTerrestrial World (Escape Velocity 11,185.98 m/s)
Orbital Radius1.84 x 108 km   (1.23 AU)
Period9.54 x 103 hours   (1.09 earth years)
PhysicsLarge iron/silicate
Radius9073.08 km   (1.42 x earth)
Gravity13.85 m/s2   (1.42 x earth)
Hydrosphere0 % water, 3 % ice
AtmosphereDense corrosive
SpecialLarge moon, planetary rings
TypeRock Planet (Escape Velocity 12,138.56 m/s)

Orbital Radius3.36 x 108 km   (2.25 AU)
Period2.36 x 104 hours   (2.70 earth years)
Radius8023.96 km   (1.26 x earth)
Gravity10.47 m/s2   (1.07 x earth)


No comments: