SlabGizor117

Is there a way to use mechjeb, or another mod, to set a certain orbit?

Recommended Posts

I want to set up a relay network but it's so tedious and annoying and I want the accuracy of an autopilot mod to do it for me so it doesn't fall out of sync.  Can I use mechjeb?  If so, how?  Otherwise, is there another mod that will do that?

Share this post


Link to post
Share on other sites

Mechjeb will help.  It won't get perfection, but you can get away without having perfection in most cases.  Here's a good writeup of techniques:

 

Share this post


Link to post
Share on other sites
6 minutes ago, DStaal said:

Mechjeb will help.  It won't get perfection, but you can get away without having perfection in most cases.  Here's a good writeup of techniques:

 

Well I know about setting things in formation by halving the orbital period and stuff like that but I wanted MechJeb to be able to do it down to the meter which it can't.  I'm tempted to just use Hyperedit..

Share this post


Link to post
Share on other sites

You could always get it close and then hyperedit (or manually edit the save file) it into perfection. I wouldn't call that cheating personally. I recommend not hyperediting the active vessel, since with physics running on the vessel it won't stay perfect, but unloaded vessels should remain virtually perfectly placed as long as you never load them. Even if you do, the changes to the orbit would be minor, but over a large time they'd get messed up.

Share this post


Link to post
Share on other sites

v1.2.2 has Set Orbit build in on the cheat menu (RightAlt+F12 or RightShift+F12 on Linux).  No mods needed.

Share this post


Link to post
Share on other sites
Posted (edited)

I actually just finished a mod that does exactly this.  Get to within 1% of your target orbit and click the button in the Tracking Station to get to exactly the orbital period you want. (The ship will consume the tiny amount of fuel it takes to get there.) I was planning to post it in Add-On Releases later today (after I get home and get a screenshot or two) but you could go grab it now from GitHub: https://github.com/swilbur/StationKeeping

Edited by HenryBlatbugIII

Share this post


Link to post
Share on other sites

Even with cheats I don't think you can set things to the same orbit with a specific phase difference, can you?

In hyperedit you can do a rendezvous with a lag time, I wonder if that still works if the time is like 1/3 of an orbital period?

Share this post


Link to post
Share on other sites
Posted (edited)

You can use mechjeb to circularize at a particular height, so long as that height is between your current apoapsis and periapsis. Once the satellites are in the right orbit, you can fine tune by thrust-limiting your engine down to 0.5 percent and watching the orbital period time in MJ like a hawk. I'm generally able to match orbital periods within 1 or 2 hundredths of a second this way.

One more thing - if you have a relay mothership, make sure that the docking port or decoupler is facing normal or antinormal when the satellite casts off. If the decoupler is facing prograde or retrograde, it will affect your orbital velocity enough to mess things up just enough to make things drift out of position over the long term.

Edited by Norcalplanner
Dang autocorrect

Share this post


Link to post
Share on other sites
21 hours ago, HenryBlatbugIII said:

I actually just finished a mod that does exactly this.  Get to within 1% of your target orbit and click the button in the Tracking Station to get to exactly the orbital period you want. (The ship will consume the tiny amount of fuel it takes to get there.) I was planning to post it in Add-On Releases later today (after I get home and get a screenshot or two) but you could go grab it now from GitHub: https://github.com/swilbur/StationKeeping

And I've posted it:

 

Share this post


Link to post
Share on other sites

Mechjeb can set your altitute once in orbit easily, the Accent Guidence can lauch you to any height of the body your orbiting, it can time your launches for Rondevous's, and it has built in Rondevous and Node autopilots. If you can get past all 20 of the UI's, you can do damn near anything

Share this post


Link to post
Share on other sites
7 hours ago, DarknessHasLost said:

Mechjeb can set your altitute once in orbit easily, the Accent Guidence can lauch you to any height of the body your orbiting, it can time your launches for Rondevous's, and it has built in Rondevous and Node autopilots. If you can get past all 20 of the UI's, you can do damn near anything

But it's not accurate enough to get within the meter of the orbit of your other com-net sats, especially if you aren't rendezvousing with them.  It's close, but it's just not precise enough.  I've done it using MechJeb to get close and then using RCS to fine-tune, but even then the limits of the KSP simulation will bite you eventually, unless you never visit those sats again.

Share this post


Link to post
Share on other sites
7 hours ago, DStaal said:

But it's not accurate enough to get within the meter of the orbit of your other com-net sats, especially if you aren't rendezvousing with them.  It's close, but it's just not precise enough.  I've done it using MechJeb to get close and then using RCS to fine-tune, but even then the limits of the KSP simulation will bite you eventually, unless you never visit those sats again.

there is an Altitiuted adjustment and circularizing functions with the Manuver planner

Share this post


Link to post
Share on other sites
2 hours ago, DarknessHasLost said:

there is an Altitiuted adjustment and circularizing functions with the Manuver planner

Yep.  I use them all the time.

They usually get me within a couple of kilometers of my desired orbit.  Close enough for a space station, not for a com-sat.

Share this post


Link to post
Share on other sites
On 4/2/2017 at 10:56 AM, DStaal said:

Yep.  I use them all the time.

They usually get me within a couple of kilometers of my desired orbit.  Close enough for a space station, not for a com-sat.

if you want stable com sats, make a couple dozen in LKO, then make a few HKO's to act as the Long range relays, Makes it easier to maintain signal once you leave Kerbins orbit

Share this post


Link to post
Share on other sites
1 hour ago, DarknessHasLost said:

if you want stable com sats, make a couple dozen in LKO, then make a few HKO's to act as the Long range relays, Makes it easier to maintain signal once you leave Kerbins orbit

Which is basically what the post I linked to in the second post in this thread says.

Just be aware that MechJeb is *not* accurate enough on it's own to do what the OP was requesting. 

Share this post


Link to post
Share on other sites
42 minutes ago, DStaal said:

Just be aware that MechJeb is *not* accurate enough on it's own to do what the OP was requesting. 

It is accurate enough. You just must not expect it to do a 500+ m/s burn with a "large" TWR with perfect precision. Adjustment needs small engines and small burn. Like IRL.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now