Dunastationary comsat constellation

[QF9E]

The mission

Deploy a constellation of communications satellites around Duna. Each of these satellites must be in Dunastationary orbit, which means that their orbital periods must match the rotation of Duna. The constellation must consist of at least 3 satellites, but a bigger constellation is to be preferred. All satellites must be equally spaced around the planet to give optimum coverage. There's just one slight complication: Duna's moon Ike is also in Dunastationary orbit, so you'll have to make sure that your satellites are not disturbed by it.

 

Rules

• Autopilot mods such as MechJeb and kOS are not permitted
• Mods such as Principia that change how gravity works in the game are not permitted
• Most other mods are permitted. I limited myself to Transfer Window Planner, Better Time Warp and KER in my test runs but most other mods are fine as well. When in doubt, please ask
• There's no limit on the number of launches
• The entire constellation must be in contact with Kerbin at all times, regardless of Kerbin and Duna's relative positions, with one exception: connection does not need to be maintained while Kerbin is directly behind the Sun, as seen from Duna.
• Please provide evidence of all maneuvers, either as a photo album or as game footage video. Be sure to include at least one picture for each satellite in its final orbit, with orbital parameters visible
• To be able to gauge the quality of your constellation, please provide two pictures of the completed constellation, 1 directly after deployment of the final satellite, and a 2nd one at least one year later. During this time period no station-keeping maneuvers of any kind are permitted - you'll have to deploy your sats in rather precise orbits to keep the constellation intact and ensure no sats are disturbed by Ike

 

Scoring

Every satellite deployed gets you points, as follows:

• Inclination
  • > 1 degree: This satellite gets you 0 points, regardless of its other orbital parameters
  • 0.1 - 1 degree: 1 point
  • 0.01 - 0.1 degree: 2 points
  • < 0.01 degrees: 3 points
• Eccentricity
  • > 0.001: The satellite gets you 0 points regardless of other orbital parameters
  • 0.0001 - 0.001: 1 point
  • 0.00001 - 0.0001: 2 points
  • < 0.00001 (KER will show 0.00000): 3 points
• Orbital period
  • > 10 seconds off Duna's sidereal rotation period: This satellite earns you 0 points, regardless of other orbital parameters
  • 1 - 10 seconds off: 1 points
  • 0.1 - 1 seconds off: 2 points
  • < 0.1 seconds off: 3 points

If either of your pictures of the entire constellation is visually asymmetric, you will lose 20 points. I hesitate to make this specific, as numerically verifying that your sats are equally spaced is rather tedious, but by all means feel free to provide longitudes for all satellites to show that they are equally spaced around Duna.

If a satellite is disturbed by Ike during the required one year period of unguided operation, your constellation is disqualified from the challenge and does not get you any points. Your constellation must remain stable during that time.

 

Note 1: The sidereal rotation period of Duna is 3 days 0 hours 11 minutes 57.859 seconds, as given by the KSP wiki: https://wiki.kerbalspaceprogram.com/wiki/Duna

Note 2: To get precise readouts of these orbital elements, I recommend using KER. Its output tends to be more precise than KSP's stock orbital element window in the lower left corner of the screen. It is also capable of outputting additional orbital elements that can be of use to this challenge.

Edited September 19, 2020 by QF9E

[sturmhauke]

That's a nice octagon you have there. It's Duna Fight Club!

[vyznev]

I just felt I had to post the obligatory note that, due to Ike's presence, a constellation such as depicted in your image would not be stable under realistic gravity. At best, you could put three satellites at the Duna/Ike Lagrange points 3–5 to get a (nearly) equilateral triangle.

Still, nice challenge.

[QF9E]

1 hour ago, vyznev said:

I just felt I had to post the obligatory note that, due to Ike's presence, a constellation such as depicted in your image would not be stable under realistic gravity. At best, you could put three satellites at the Duna/Ike Lagrange points 3–5 to get a (nearly) equilateral triangle.

Still, nice challenge.

Good point. It's the reason I disallow Principia. But still, if you want, feel free to use it and make an equilateral triangle with the Lagrange points. Although I've never run Principia myself, does it support realistic Lagrange points?

[sturmhauke]

It does. Some of the planets and moons had to have their orbits adjusted though, for stability.