### Post by dpidz0r on Oct 28, 2016 4:41:52 GMT

The easiest way to do this I've found so far:

1) Spend 25-50m/s to burn away from the asteroid in any direction

2) Extend your orbit so the apoapsis is about a day out

3) Use your green vector to manipulate the apoapsis to be as close to the orbital node as possible (for most efficient plane change)

4) Start your next trajectory change about an hour before the orbital node. You should be able to make your plane and periapsis match the station in a single burn.

5) Run the sim until you've completed the trajectory change (be careful because the burn can last a long time past the node)

6) You should be near apoapse ~16-24 hours away from periapse. Fiddle with your orbit until you get an approximate intercept with the station. Your tangential velocity will work counter intuitively: Burn retrograde to "catch up" to the station, prograde to let it get ahead. Use the green slider to help line it up if your periapse gets too high or too low.

7) After the burn is complete, drop a fleet of ~5 missiles. These will have a low chance of hitting but they'll be good practice.

8a) With your ship, pick a point several minutes before periapse and plan a retrograde burn. You should be able to expend several km/s of deltaV. Just make sure that your periapse stays even with the stations orbit. If it starts to go nuts your burn is too long (though remember that you can adjust it again at apoapse).

8b) With your missiles, set the station as reference and tweak the orbit until you've got a real intercept. Note the engagement velocity (probably something on the order of 4km/s).

9) Run the sim until your missiles are several minutes out, zoom the camera in, set station as reference, and plan a high deltaV burn away from the station (you'll be using red and green sliders, and occasionally blue). The goal is to reduce the closing velocity by as much as possible. You should be able to drop about 2km/sec off it.

10) run the engagement, if you miss it's fine. You've got enough time and missiles for quite a few more waves.

11) your ship should be completing its retrograde burn. Run the sim until you're near apoapse (should be ~5-8 hours away) and begin fiddling with the trajectory again until you have another periapse encounter near the station. Drop missiles as per last time.

12) Tweak missile trajectory as per last time. Now that your orbit is a lot less energetic, you'll have a slower encounter velocity

13) You should be able to easily get a sub 1km/sec intercept this time with your last minute burn. You can also start your burn from a lot closer in since your closing velocity will be slower. I can easily get sub 1km/sec encounters at this point.

Random notes:

- Steps 2/3 should take on the order of 3-4km/s of deltaV

- Step 4 should take another 3-4km/s of deltaV

- For the second half of the mission, your ship should have a highly elliptical orbit. Station encounters should always happen at periapse.

- If your last minute missile slowdown is impacting the planet, start the burn later. And notice how it extends the time until your intercept happens? That often extends the intercept far enough away that you need to plot a second or even third burn to avoid a planetary impact.

- Think of your orbit as having a fixed amount of energy being constantly shuffled between kinetic and potential. Adding the two up will always equal the same constant at any point in your orbit. At periapse you've traded all of your potential energy for velocity, and at apoapse you've traded all of your velocity for potential energy. The greater the energy differential between you and the station, the greater the intercept velocities will be at periapse. Every time you lower your apoapse, you decrease the energy differential therefore making your missile intercepts slower. This comes at the cost of having less opportunities to make periapse encounters with the station.

edit: here's a quick playthrough off my twitch stream: www.youtube.com/watch?v=iczQS2olvXM

1) Spend 25-50m/s to burn away from the asteroid in any direction

2) Extend your orbit so the apoapsis is about a day out

3) Use your green vector to manipulate the apoapsis to be as close to the orbital node as possible (for most efficient plane change)

4) Start your next trajectory change about an hour before the orbital node. You should be able to make your plane and periapsis match the station in a single burn.

5) Run the sim until you've completed the trajectory change (be careful because the burn can last a long time past the node)

6) You should be near apoapse ~16-24 hours away from periapse. Fiddle with your orbit until you get an approximate intercept with the station. Your tangential velocity will work counter intuitively: Burn retrograde to "catch up" to the station, prograde to let it get ahead. Use the green slider to help line it up if your periapse gets too high or too low.

7) After the burn is complete, drop a fleet of ~5 missiles. These will have a low chance of hitting but they'll be good practice.

8a) With your ship, pick a point several minutes before periapse and plan a retrograde burn. You should be able to expend several km/s of deltaV. Just make sure that your periapse stays even with the stations orbit. If it starts to go nuts your burn is too long (though remember that you can adjust it again at apoapse).

8b) With your missiles, set the station as reference and tweak the orbit until you've got a real intercept. Note the engagement velocity (probably something on the order of 4km/s).

9) Run the sim until your missiles are several minutes out, zoom the camera in, set station as reference, and plan a high deltaV burn away from the station (you'll be using red and green sliders, and occasionally blue). The goal is to reduce the closing velocity by as much as possible. You should be able to drop about 2km/sec off it.

10) run the engagement, if you miss it's fine. You've got enough time and missiles for quite a few more waves.

11) your ship should be completing its retrograde burn. Run the sim until you're near apoapse (should be ~5-8 hours away) and begin fiddling with the trajectory again until you have another periapse encounter near the station. Drop missiles as per last time.

12) Tweak missile trajectory as per last time. Now that your orbit is a lot less energetic, you'll have a slower encounter velocity

13) You should be able to easily get a sub 1km/sec intercept this time with your last minute burn. You can also start your burn from a lot closer in since your closing velocity will be slower. I can easily get sub 1km/sec encounters at this point.

Random notes:

- Steps 2/3 should take on the order of 3-4km/s of deltaV

- Step 4 should take another 3-4km/s of deltaV

- For the second half of the mission, your ship should have a highly elliptical orbit. Station encounters should always happen at periapse.

- If your last minute missile slowdown is impacting the planet, start the burn later. And notice how it extends the time until your intercept happens? That often extends the intercept far enough away that you need to plot a second or even third burn to avoid a planetary impact.

- Think of your orbit as having a fixed amount of energy being constantly shuffled between kinetic and potential. Adding the two up will always equal the same constant at any point in your orbit. At periapse you've traded all of your potential energy for velocity, and at apoapse you've traded all of your velocity for potential energy. The greater the energy differential between you and the station, the greater the intercept velocities will be at periapse. Every time you lower your apoapse, you decrease the energy differential therefore making your missile intercepts slower. This comes at the cost of having less opportunities to make periapse encounters with the station.

edit: here's a quick playthrough off my twitch stream: www.youtube.com/watch?v=iczQS2olvXM