Polar orbit rendezvous and docking.

[strider3]

Equatorial orbit docking is fairly simple, when the target ship has side mounted docking ports. You set the target ship in a "Normal" or Anti-normal" position...and the thing stays that way pretty much forever, even after you go back to another ship. As you approach this target ship the only thing you might have to do is rotate it so a clear docking port is facing your approaching vessel (to make life even easier). Polar orbits, at least AFAICT, are way harder. There doesn't seem to be a way to have the target ship maintain any kind of orientation as there is in an equatorial orbit? So far I've had to constantly re-orient the target ship to my approaching vessel, as I approach it, for a smooth dock.

Am I missing something or is this one of those "it is what it is" moments?

[Pecan]

(Anti-)Normal is relative to the orbit, so should work exactly the same whatever inclination the orbit has.  You are rather missing a trick if you're orienting the ship so the docking ports are still pro- or retro-grade.  Something (like an incoming docking ship) that is trailing in orbit will still be trailing on the other side of the planet but since the vehicles are not rotating it will have gone from pointing towards the target vehicle to pointing exactly the other way.  Similarly, the target docking port would then be facing away from the docking vessel.  Instead, the usual plan is to have the docking ports aligned in the normal/anti-normal direction so there is no need to keep rotating vehicles or flying around the target.

 

[VoidSquid]

Regardless if polar, equatorial or other orbit, when I get close to my target, I switch to the target vessel, turn it if required so the docking port points to my other vessel, then turn SAS on to "hold". Switching back to the other vessel, I just do the docking.

Have you tried out this mod? A wonderful visual aid for docking, makes the whole process totally painless:

 

Edited October 26, 2019 by VoidSquid

[bewing]

Normal/Antinormal in orbit mode on your navball should always be 90 degrees from the plane of your orbit. So if you lock your target craft's SAS to that, its orientation should remain stationary. And if your craft is locked to the opposite, then you should have a matching pair. If you have two craft within physics range of each other, the previous one that you controlled remembers its SAS setting, until you return to it again.

[strider3]

I was not aware that the SAS setting would "stick" when switching to a different craft. I always assumed that when I left a vessel, it reverted to "SAS only" at that time.

Edited October 26, 2019 by strider3

[strider3]

4 hours ago, VoidSquid said:

Regardless if polar, equatorial or other orbit, when I get close to my target, I switch to the target vessel, turn it if required so the docking port points to my other vessel, then turn SAS on to "hold". Switching back to the other vessel, I just do the docking.

Have you tried out this mod? A wonderful visual aid for docking, makes the whole process totally painless:

 

I have tried it but I could never quite figure out what it was telling me to do to correct my alignment.

 

4 hours ago, Pecan said:

(Anti-)Normal is relative to the orbit, so should work exactly the same whatever inclination the orbit has.  You are rather missing a trick if you're orienting the ship so the docking ports are still pro- or retro-grade.  Something (like an incoming docking ship) that is trailing in orbit will still be trailing on the other side of the planet but since the vehicles are not rotating it will have gone from pointing towards the target vehicle to pointing exactly the other way.  Similarly, the target docking port would then be facing away from the docking vessel.  Instead, the usual plan is to have the docking ports aligned in the normal/anti-normal direction so there is no need to keep rotating vehicles or flying around the target.

 

I do get that part, I don't bother rotating the target ship, to align the target's docking port with the incoming one, until I'm within 1,000m, usually less. Covering that small a distance I find very little rotation of the target docking port to correct for. The incoming ship is under my control so any movement is being corrected by me as I approach.

[bewing]

47 minutes ago, strider3 said:

I was not aware that the SAS setting would "stick" when switching to a different craft. I always assumed that when I left a vessel, it reverted to "SAS only" at that time.

You'll see when you start using "target" alignment during docking. You can set both vessels' targets as the docking ports on the other vessel, then set SAS to "target" on both. Both ships will constantly readjust until they are docked -- and you can easily see them doing it when viewing from outside the craft. If you don't turn off RCS, then you can watch the RCS bursts on both craft completely wreck the whole docking process.

[Superfluous J]

2 hours ago, strider3 said:

I was not aware that the SAS setting would "stick" when switching to a different craft. I always assumed that when I left a vessel, it reverted to "SAS only" at that time.

That may be because it used to. I don't recall when it changed, just that I was happily surprised to discover it had.

[VoidSquid]

5 hours ago, strider3 said:

I have tried it but I could never quite figure out what it was telling me to do to correct my alignment.

Here's a review about it incl. how to use it:

 

Edited October 27, 2019 by VoidSquid

[Pecan]

Is Navball Docking Port Alignment Indicator still going anywhere?  Just a single new indicator on the navball instead of a whole popup window, it was great.

[pincushionman]

16 hours ago, strider3 said:

I was not aware that the SAS setting would "stick" when switching to a different craft. I always assumed that when I left a vessel, it reverted to "SAS only" at that time.

Since normal/antinormal doesn’t change throughout an orbit, once the vessel gets done pointing the behavior is exactly the same as SAS hold.

[Scarecrow]

No matter the orbit, I've never bothered with normal, anti-normal but just concentrate on orienting the docking craft correctly before translating as necessary to complete the dock.

Unless you are taking an absolute age to complete your docking, the fact that the two craft will be in an almost identical orbit at the point of docking, you shouldn't see any relative movement in orientation between the two during the docking process.

[Pecan]

2 hours ago, Scarecrow said:

Unless you are taking an absolute age to complete your docking

I know what you mean and sort of agree but for beginners, in low orbit?

Low Kerbin orbit has a period of roughly 30 mins, so 15 mins to go from completely aligned to pointing in totally opposite directions, assuming pro/retro-grade approach.  Yes 15 mins is 'an absolute age' once you've got used to docking but I'm not sure it is for a lot of people.  Worse, it's only half that, 7.5 mins from aligned to 90 degrees away from each other.  2.5 mins is enough for a 30-degree shift and I wouldn't count that as very long at all.

Of course, once you've "got it" you can easily and automatically compensate for that rotation but it is significant and it only gets worse where you have a shorter orbital period.  The principle of (anti-)normal alignment is helpful in such situations, just to have one fewer thing to worry about.

[strider3]

21 hours ago, bewing said:

 If you don't turn off RCS, then you can watch the RCS bursts on both craft completely wreck the whole docking process.

LOL, been there, done that. What's worse is if you come in a bit too hot and bounce off...RCS will completely destroy any alignment you had while trying to maintain target.

21 hours ago, bewing said:

You'll see when you start using "target" alignment during docking. You can set both vessels' targets as the docking ports on the other vessel, then set SAS to "target" on both. Both ships will constantly readjust until they are docked -- and you can easily see them doing it when viewing from outside the craft. If you don't turn off RCS, then you can watch the RCS bursts on both craft completely wreck the whole docking process.

But, I assume I will have to set the target ships docking port as the "control from here" so that the actual docking port is trying to align with my incoming vessel?

3 hours ago, Pecan said:

I know what you mean and sort of agree but for beginners, in low orbit?

Low Kerbin orbit has a period of roughly 30 mins, so 15 mins to go from completely aligned to pointing in totally opposite directions, assuming pro/retro-grade approach.  Yes 15 mins is 'an absolute age' once you've got used to docking but I'm not sure it is for a lot of people.  Worse, it's only half that, 7.5 mins from aligned to 90 degrees away from each other.  2.5 mins is enough for a 30-degree shift and I wouldn't count that as very long at all.

Of course, once you've "got it" you can easily and automatically compensate for that rotation but it is significant and it only gets worse where you have a shorter orbital period.  The principle of (anti-)normal alignment is helpful in such situations, just to have one fewer thing to worry about.

I'm a little bit better than that, gang...LOL. Usually 2 - 3 minutes, including alignment.

[Superfluous J]

20 minutes ago, strider3 said:

But, I assume I will have to set the target ships docking port as the "control from here" so that the actual docking port is trying to align with my incoming vessel?

IMO you should anyway and I always do, but no, this will work fine so long as your docking port and whatever you're controlling from are in line with each other (as usually they are if your port is on top of your command pod). Forward is the same way for both of them and if the target is offline for one, it's offline for both.

[Pecan]

2 hours ago, strider3 said:

I'm a little bit better than that, gang...LOL. Usually 2 - 3 minutes, including alignment.

Good for you, if true!  Time yourself next time and sometimes 3 minutes is really 5 ... or 6.
Equally likely that you do dock in 2 or 3, it's just that docking usually takes a relatively greater amount of concentration than everything else and time has a way of slipping passed ...

[NavyFish]

@strider3  This video has a better tutorial. The one linked by @VoidSquid is pretty inaccurate (though more entertaining :))

 

 

Edited November 30, 2019 by NavyFish
forum blerp

[strider3]

Very nice, NavyFish...thanks for that!

[Starhawk]

On 10/27/2019 at 4:58 AM, Pecan said:

Is Navball Docking Port Alignment Indicator still going anywhere?  Just a single new indicator on the navball instead of a whole popup window, it was great.

Yes.

Happy landings!