how do i launch into a chase orbit?

[endl]

using mechjeb say i want to be "8 hours" or 120' behind/ahead of my target in identical orbit?

Edited October 22, 2014 by Vanamonde

[Vanamonde]

This request for support for a mod has been moved to Mod Support.

[HafCoJoe]

I don't think mechjeb can bring you to a specific time ahead of or behind an object. If you want to have a precise distance from something in orbit, I suggest you look into the mod "Hyperedit". Yeah its a cheaty mod that hacks your orbit but hey I'd count it the same as autopilot in terms of reaching orbit. I used mechjeb when I first started KSP and BOY does it teach you! Hyperedit I didn't use when I started but it is quite handy when I'm filming. I hope this helps!

[Capt. Hunt]

Well, much the same as launching into a rendezvous with a target, you could do it by timing your launch, but you'd have to get it pretty precise to come up with an exact distance.

[endl]

yea mech jeb isnt set up for delays that big it only takes delays in seconds, i was hoping for some kind of procedure i could follow in the maneuver planner. this one website suggested using K engineer to check phase angle and adjust it with resonate orbit then correct with a circularize burn i had gotten lucky and landed at 118 by eyeballing it so i tried for a 2' correction i follow the steps and wound up at 116 instead of 120, maybe he had gotten the procedure in reverse i dont know but either way i had to take it down because im still trying to get the right rocket/battery performance.

if anyone is wondering this is so i can set up ideal orbits for remote tech, im also going for a gps constellation and this would speed things along nicely since i need to launch 12 satellites in order to have proper coverage,

@mod this wasnt a feature request this was a general gameplay question so moving this was unnecessary, i just happen to not want to do it manually for all i know there might be some mod tools out there that can facilitate this.

Edited October 23, 2014 by endl

[tomf]

It is about a year since I used mechjeb but it used to have an option in the launch autopilot where you could put in the pahse angle that you needed to launch at in order to get a perfect rendevous. It would calculate that angle for you if you let it do a test launch. If you want to be 8 hours behind you could work out the angle made by your orbit in 8 hours and add that to the phase angle.

[rosenkranz]

You're looking for MJ's resonant orbit in the maneuver planner.

Launch your first sat into whatever orbit you're going for. I use a semi-synchronous orbits at 55 deg inclined.

Use MJ to launch into the plane of its orbit and get to 100x100. Then use the planner to do a holman transfer to it for rendezvous. Match velocity with it. You don't have to be real close, if you're within 10km you're golden.

Then use the planner to set a resonant orbit. Set it at 5/6. Do this and your orbit period will drop to 2h30m. Now, every orbit, you'll advance your phase angle to the first sat by 60 deg (1/6 of a full 360). So after two orbits you'll be exactly 120 deg ahead of the first sat. So as you hit Ap the second time circularize your orbit and get it to as close to the original orbital period as you can.

MJ's utilities can throttle to a specific percentage of max thrust. I set it to .1% and I can get to within .05 seconds of nominal on the period which should keep them in position for years.

If you're putting up more than 3 then adjust the resonant frequency as required. So 6 sats would still be 5/6 just circularize after the first orbit instead of the second. If putting up 8, or 9, then use 7/8 and 8/9 as required. You get the idea. I used 5/6 for 3 because 2/3 brought the Pe pretty low and required to much dV.

In my example I put up 3 inclined orbits, 120 deg apart with 3 sats in each orbit separated by 120 deg in those orbits for a total of 9 sats.

For the other orbits get to the launch pad (assuming you have no flags or anything to mark where KSC is in the map view). Then go to the tracking center. Wait until the KSC is right under the first orbit. Note the time. 120 deg on Kerbin would be 2 hours. Wait 2 hours and go to the launch pad and go for gold. If putting up 6 orbits then only wait one hour.

Hope this helps.