Rendezvous: stability hold or orientation hold?

[Jestersage]

Based on everyone's experience, durign rendezvous, IF I enabled SAS on the target, which one is easiest: stability hold, or one of the orientation hold? (eg prograde/retrograde)

[Superfluous J]

27 minutes ago, Jestersage said:

Based on everyone's experience, durign rendezvous, IF I enabled SAS on the target, which one is easiest: stability hold, or one of the orientation hold? (eg prograde/retrograde)

define "easiest"

I have found controlling from the docking port and locking hold to target to be helpful but only if you're coming in straight to begin with and don't have any lateral motion.

If you can't lock to target, I'd say just turn on SAS and do all the work from the docking craft, that you hopefully made as nimble as is necessary.

[Jestersage]

12 minutes ago, 5thHorseman said:

define "easiest"

I have found controlling from the docking port and locking hold to target to be helpful but only if you're coming in straight to begin with and don't have any lateral motion.

If you can't lock to target, I'd say just turn on SAS and do all the work from the docking craft, that you hopefully made as nimble as is necessary.

Well, the target (passive side) would be space station, while the active side is a spaceship/capsule/plane/shuttle. Now the spaceship will assume to operate in stability hold position, and use RCS to maneuveur.

Now, if you tell me that once I switch vessel view from the target to the active spacecraft, what SAS mode they operate doesn't matter, then I have my answer. (It's one of those based on the capability of the parts, select the right part for the build)

Edited July 7, 2019 by Jestersage

[Guest]

What I do is:

Go to the craft you are docking with and set it to target lock on your other craft’s docking port ^_~

Then go back to the docking craft:

Set SAS to target mode (as in orbital-surface-target) make sure you cancel out all relative motion and then just come in manual (stability hold) using RCS to move the prograde marker into the target market on the nav ball.

hope it helps!

Edited July 7, 2019 by Guest

[Jestersage]

3 minutes ago, Dale Christopher said:

What I do is:

Go to the craft you are docking with and set it to target lock on your other craft’s docking port ^_~

Then go back to the docking craft:

Set SAS to target mode (as in orbital/surface/target) make sure you have canceled out all relative motion and then proceed to move in with your docking craft. I just come in manual using RCS to move the prograde marker into the target market on the nav ball.

 hope it helps!

The thing is, it's one of those builds where I am trying to limit the technology available to the craft, so target lock is out for now (I know I can add the fly-by-wire hub if I really want to go that route)

[Guest]

Hmmm that’s ok. What I’d do is switch the tracking mode to “target” (I don’t think you need target lock in SAS for target tracking mode on the nav ball. And come in in stability hold keeping the prograde marker in the target marker. Then when you are close, orient the other craft with reaction wheels to face its port at your docking craft and stability hold that orientation. and then move in with your docking craft using tiny RCS tweaks 

Edited July 7, 2019 by Guest

[Superfluous J]

25 minutes ago, Jestersage said:

Now, if you tell me that once I switch vessel view from the target to the active spacecraft, what SAS mode they operate doesn't matter, then I have my answer.

When you switch away from your station to the approaching craft, the station will still hold its active sas mode. If you told it to aim at the target it will continue to do so. You can test this by wiggling your craft back and forth and observing that the docking port on the station follows it.

15 minutes ago, Jestersage said:

The thing is, it's one of those builds where I am trying to limit the technology available to the craft, so target lock is out for now

Then really your only choice is to turn SAS on and then do all the work with the approaching ship.

Well there is one other choice. Set the target port to hold one of the two normal directions, and tell your approaching ship to do the same with the other direction. Those two points on the navball are unique in that they do not wander over time like the -grade and radial points, so once you get that heading on your ports, they will be guaranteed to be aimed perfectly at each other. Then you can do the actual translations with RCS.

[bewing]

If your target is a space station, you have no choice but to use stability hold for that one. You don't want space stations to try to do any maneuvering.

If the docking port that you are aiming for is not on the CoM of your space station (and it's often not), then using almost any SAS targeting mode is out, because there is a bug. SAS will not target the correct point, and will make your life infinitely harder. The only exception is if you have your station's docking port aligned exactly North/South. In that one case, using Normal hold can be beneficial.

So, playing games with SAS modes is only useful with small stations or vessels with their docking ports aligned with their CoM. Otherwise, your only choice is Stability mode. Prograde/retrograde does absolutely nothing for you in any navball mode -- especially since they will deactivate when your speed goes below 1 m/s.

[Jestersage]

9 minutes ago, bewing said:

Prograde/retrograde does absolutely nothing for you in any navball mode -- especially since they will deactivate when your speed goes below 1 m/s.

I was originally thinking of just Prograde/Retrograde in terms of the Orbit... of course, by the time when they do drift out of the orbit's prograde/retro grade, there are other problem.

[Superfluous J]

1 hour ago, bewing said:

If the docking port that you are aiming for is not on the CoM of your space station (and it's often not), then using almost any SAS targeting mode is out, because there is a bug. SAS will not target the correct point, and will make your life infinitely harder.

People keep saying this but it's not happening to me. I just docked a ship to a station, neither docking port was REMOTELY close to the COM of either, and I was switching back and forth between them multiple times making sure the ports were each targeting the other (manually, I don't have the SAS option) and both of them targeted the other craft's correct docking port just fine.