How to get into perfect equatorial orbit?

[Corw]

In Kerbin orbit I can use Mun as a target for aligning and I use that a lot. I usually place my bases/landing sites at equators for ease of access (as the Apollo program did). But more often than not my orbits are eccentric and I don't see how I could easily and reliably align them. Eyballing is really something I do not like.

Is there a technique or mod I could use? Maybe there is a mod that allows you to place something like contract orbit that you could use as a reference for placing maneuver nodes?

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Thread summary

There are indeed tools/mods to give you information about your inclination and to help to adjust orbit, but none of them (or combination of them) tell you when exactly and how much. You can't just burn anywhere to change inclination (perform a plane shift). It has to be precisely on the intersection of your current and desired orbit, in our case on equator.

There is a possible workaround with Hyper Thread and positioning a satellite object at desired inclination and use that as target reference for the maneuver. I may investigate additional options, but this is satisfactory for now.

Edited September 15, 2015 by Corw

[Superfluous J]

There is a mod. Kerbal Engineer will tell you your current orbit, and I believe PreciseNode can tell you the inclination of the resultant orbit from a maneuver node. I wouldn't be surprised if Kerbal Engineer had that as well. I also wouldn't be surprised if MechJeb had a "Make my oribit equatorial" button

If you don't want to use mods, you could accept a "satellite in equatorial orbit around ..." contract and then set your AN and DN relative to that to 0. But then you'd have to either complete or cancel the contract

[Yasmy]

There are a number of mods which display basic orbital information. Kerbal Engineer Redux (KER) is a community favorite. Other people will happily chime in after me with other recommendations.

Edit: And of course, the 5th Horseman will chime in while I'm typing

[Corw]

I do use both KER and Precise Node. KER does tell me how much my orbit is eccentric, but I didn't figure out where to place the maneuver. Precise Node does not give the resulting inclination of the maneuver (I may be mistaken and/or blind).

[Superfluous J]

One problem is I never bother to do this. So, let me take a different tack...

Why do you want this? If your orbit is obviously not equatorial, it's obvious. If it's too close to tell the difference, why does it matter if it's not perfect?

One way you could do this with KER would be to have your latitude readout on the screen as you're orbiting. As soon as you pass 0 degrees, drop a maneuver node. Next orbit, when you reach that maneuver node, you'll know you're at the AN or DN and you can burn. It'll take several orbits to get closer and closer but it shouldn't be that bad, and you can leave that maneuver node there as a marker (though the AN/DN may move if you burn too far away from it).

Another idea is to install HyperEdit. Put a one-part ship on the launchpad, HyperEdit into an equatorial orbit around the planet in question, align your ship to that part so you know it's perfect, and then terminate the part. Or cut out the middle man and HyperEdit to just change your ship's tilt to 0.

Edited September 14, 2015 by 5thHorseman

[Corw]

I want it because simply sometimes I'm annoying pedantic person. At other times I'm just annoying

You know that feeling when you have the orbital lab in say, Minimus orbit. It is in perfectly round orbit with apoapsis that is dividable by 10 that you tuned to perfection with RCS puffs for ages (only 5 meters difference between Ap and Pe!). Yet again, you are not happy. The accomplishment is completely ruined. The damn orbit has 1 degree inclination...

That doesn't look right...

It is not always just equatorial orbit, but it is the most common case. I would like to plan ahead and see how much the correction maneuver will cost me in delta v etc... And I would like to do it in one burn, not incremental correction over several orbits.

Edited September 14, 2015 by Red Iron Crown
Easy with the language, please.

[RizzoTheRat]

If there's something else there in the correct angled orbit (eg a moon), target it and you'll get the ascending and descending nodes highlighted. Not sure if it will work the other way though (ie targeting a planet when you're orbiting a moon). As others have said KER will tell you the current inclination but you'd need to eyeball the burn to change it.

The simplest mod would be MechJeb which can set up a node to achieve a defined inclination, and then do the burn for you as well if you're so inclined.

[Warzouz]

Perfection is not always wonderful : If you orbit is too circular, AP and PE start jumping everywhere. It becomes very hard to add a manoeuver node. I aloways keep 2 to 5% between AP end PE.

[Brainlord Mesomorph]

Isn't this what the numbers on the NavBall are for?

If my Prograde is 90 or 270 (on that "ring")doesn't THAT mean my orbit is equatorial?

Edited September 14, 2015 by Brainlord Mesomorph

[Red Iron Crown]

Isn't this what the numbers on the NavBall are for?

If my Prograde is 90 or 270 doesn't THAT mean my orbit is equatorial?

No. Every non-polar orbit will point at 90 or 270 twice an orbit.

[The_Rocketeer]

No. Every non-polar orbit will point at 90 or 270 twice an orbit.

Being another pedant, even polar orbits will, it's just it flashes by really fast.

Edited September 14, 2015 by Red Iron Crown
Easy with the language.

[Red Iron Crown]

I don't really consider what I said pedantic, prograde pointing at 90 or 270 is not a good indicator of zero inclination. You are right though that a polar orbit will instantaneously point at those directions, too.

[Brainlord Mesomorph]

No. Every non-polar orbit will point at 90 or 270 twice an orbit.

ok well then just watching the NavBall for one full orbit making sure it stays in the 90/270 plane, then?

[Red Iron Crown]

ok well then just watching the NavBall for one full orbit making sure it stays in the 90/270 plane, then?

That works, as long as the navball is precise enough for the purpose (i.e. one degree won't make a difference). Probably enough for most purposes.

[sgt_flyer]

As KSC is on the equator, if you can stick to the 90° angle through the ascent (should be feasible with a correctly balanced rocket with a smooth G-turn) - you'll end up equatorial anyway

If you end up needing to correct afterwards a slight angle, target the mün (it's on a perfect equatorial orbit) place a manoeuver node on either the AN or DN node (which will give you your orbital angle - if it's displaying NaN, you're on the same inclination as the target), then fiddle with the controls to see in which direction the AN-DN reverse themselves. (The moment the reverse themselves around the orbit is the 0° inclination)

Orient your spacecraft to face the manoeuver node, then remove the node. Wait until just before the AN or DN node you previously placed to start your burn. As soon as you see the AN DN markers reverse, kill your throttle, and you can finetune with RCS

[Superfluous J]

You know that feeling when you have the orbital lab in say, Minimus orbit. It is in perfectly round orbit with apoapsis that is dividable by 10 that you tuned to perfection with RCS puffs for ages (only 5 meters difference between Ap and Pe!). Yet again, you are not happy. The accomplishment is completely ruined. The damn orbit has 1 degree inclination...

No, I don't. But I can understand it.

[Corw]

As KSC is on the equator, if you can stick to the 90° angle through the ascent (should be feasible with a correctly balanced rocket with a smooth G-turn) - you'll end up equatorial anyway

If you end up needing to correct afterwards a slight angle, target the mün (it's on a perfect equatorial orbit) place a manoeuver node on either the AN or DN node (which will give you your orbital angle - if it's displaying NaN, you're on the same inclination as the target), then fiddle with the controls to see in which direction the AN-DN reverse themselves. (The moment the reverse themselves around the orbit is the 0° inclination)

Orient your spacecraft to face the manoeuver node, then remove the node. Wait until just before the AN or DN node you previously placed to start your burn. As soon as you see the AN DN markers reverse, kill your throttle, and you can finetune with RCS

I don't have this problem when ascending from the body, problem occurs when I'm transferring to it then circularizing to anything but Kerbin. The HyperEdititing solution of positioning a navigational beacon sounds very reasonable and quick fix. I've never touched Hyper Edit before, but I'll try it out. Thanks for that idea, 5thHorseman.

Another thing I have in mind is making a plugin to insert a 0 value contract with desired orbit. That could be interesting and extendible.

[jiminator]

if you want to be absolutely orbital then use kerbal engineer redux, orbit tool. it list inclination. get it to 0. you can use a node, or if it is close you can just point at a node and use RCS, hit H or N, whatever makes the number smaller.

[Corw]

if you want to be absolutely orbital then use kerbal engineer redux, orbit tool. it list inclination. get it to 0. you can use a node, or if it is close you can just point at a node and use RCS, hit H or N, whatever makes the number smaller.

Hi. Thank you for your input but I don't think you've read the thread. Let me summarize. There are indeed tools/mods to give you information about your inclination and to help to adjust orbit, but none of them (or combination of them) tell you when exactly and how much. You can't just burn anywhere to change inclination (perform a plane shift). It has to be precisely on the intersection of your current and desired orbit, in our case on equator.

There is a possible workaround with Hyper Thread and positioning a satellite object at desired inclination and use that as target reference for the maneuver. I may investigate additional options, but this is satisfactory for now.

I consider thread answered and will change its status accordingly.

[vej]

HyperEdit seems like a weird overkill when you can just use MechJeb.

Open the Maneuver Planner, choose "change inclination" in the dropdown and set 0 as the new inclination. It lets you choose whether you want to do it at the equatorial AN or equatorial DN. I do virtually perfect equatorial 0º inclination orbits (and perfect 90º polar orbits) all the time and it takes me less than a minute to accomplish. MechJeb will create the maneuver node for you and can execute it itself if you want it to.

KSP really should have a way to see the equatorial AN / DN for the body you're orbiting in map mode, especially when creating maneuvers.

[Corw]

Sorry, I don't do MechJeb. Yes, I'm one of those people But it is good to know it actually has the option to create node, I'll have to look into that. Thank you.

Edited September 15, 2015 by Corw

[Champ]

There are indeed tools/mods to give you information about your inclination and to help to adjust orbit, but none of them (or combination of them) tell you when exactly and how much. You can't just burn anywhere to change inclination (perform a plane shift). It has to be precisely on the intersection of your current and desired orbit, in our case on equator.

KER tells you exactly when (time to local An/Dn). You have to configure it, as this information is not in the default display.

To know how much, just use manoeuvre nodes.

[Corw]

KER tells you exactly when (time to local An/Dn). You have to configure it, as this information is not in the default display.

To know how much, just use manoeuvre nodes.

Oh. I'll have to check that too. Thanks.

[Sacs]

I often use Kerbal Alarm Clock for this. With no target, setting an alarm for the next An/Dn sets it to the appropriate equatorial An/Dn for the body you're orbiting.

Or in career... rescue a Kerbal in low orbit, they're almost always perfectly inclined. Before the actual rescue I rename their piece of space junk to 'Inclination Zero' and use that for the target.

[Corw]

I often use Kerbal Alarm Clock for this. With no target, setting an alarm for the next An/Dn sets it to the appropriate equatorial An/Dn for the body you're orbiting.

Or in career... rescue a Kerbal in low orbit, they're almost always perfectly inclined. Before the actual rescue I rename their piece of space junk to 'Inclination Zero' and use that for the target.

That is a nice trick