Brad got me thinking about satellites this weekend and that got me to wondering how you, as scenario designers, like to define the path (altitude, direction, etc.) of a satellite.

 

A satellite orbit can be fairly well described with 6 items of data as defined and explained at http://www2.jpl.nasa.gov/basics/bsf5-1.html .

 

I look at that and say, that's great but as a scenario designer is doesn't help me, in most cases I just want to plot a certain number of points and speeds over the map area I'm concerned about. That leaves some unknowns to be taken care of (like when it should appear next at the start of the path).

 

Anyway, we're looking for ideas and I think the scenario designer's wishes may play a large role on this one.

Freek Schepers has written a couple of H3 scenarios using RORSat passes. Here are his notes from:

 

Atlantic Convoys

 

Space

 

Assumptions to work out the orbital mechanics.

 

- RORSAT moves south from 60N 20W, but earth rotates under it, so it moves to 30N 22.5W.

 

- It reappears at 60N 50W 02|03|00 Zulu (in two hours earth rotates 30 degrees)

 

- At 11|33|00 Zulu it reappears Northbound at 40N 12.5W when earth has turned nearly 180 degrees. since the last rotation of the satellite was not a full one (but 3/4) it arrives half an hour earlier and thus 7.5 degrees East of its arrival position at 70N (I know I will never be a math teacher!). It now moves to 70N 15W as again Earth rotates under it.

 

- Two hours later it reappears at 30N 42.5W moveing to 70N 45W.

 

- this happens each of the 7 days.

 

The Southbound and Northbound passes thus overlap and sweep an area of 880 nm in total. They must be passed with care|

 

When the satellite is Southbound, Enteprise must wait untill it has just passed, then move close to the detection limit of the Northbound next pass slightly further east 11.5 hours later. This works out at 360 nm at 31 knots.

 

The northbound radar detection cone has a diameter of 520nm, and must be passed in 24 hours, i.e minimum speed of 22 knots (but 26-29 is eeded as formation occasionally slows down).

 

RORSat

 

Space

 

Assumptions to work out the orbital mechanics.

 

- RORSAT moves south from 60N 20W, but earth rotates under it, so it moves to 30N 22.5W.

 

- It reappears at 60N 50W 02|03|00 Zulu (in two hours earth rotates 30 degrees)

 

- At 11|33|00 Zulu it reappears Northbound at 40N 12.5W when earth has turned nearly 180 degrees. since the last rotation of the satellite was not a full one (but 3/4) it arrives half an hour earlier and thus 7.5 degrees East of its arrival position at 70N (I know I will never be a math teacher!). It now moves to

 

70N 15W as again Earth rotates under it.

 

- Two hours later it reappears at 30N 42.5W moveing to 70N 45W.

 

- this happens each of the 7 days.

 

The Southbound and Northbound passes thus overlap and sweep an area of 880 nm in total. They must be passed with care|

 

When the satellite is Southbound, Enteprise must wait untill it has just passed, then move close to the detection limit of the Northbound next pass slightly further east 11.5 hours later. This works out at 360 nm at 31 knots.

 

Therefore AO Supply must be detached before starting out, it does not have enough speed.

 

The northbound radar detection cone has a diameter of 520nm, and must be passed in 24 hours, i.e minimum speed of 22 knots (but 26-29 is eeded as formation occasionally slows down).

 

I don't quite understand them, but anyone with a copy of H3 can open up the scenarios and see how he's arranged the satellite passes.