Why does target tracking option come and go?

[THX1138]

Why does target tracking SAS option come and go like in this video: https://youtu.be/KT0d6fb1FSo

(the fuel line is just another KSP bug - I can't explain it)

[Gaarst]

Yes, it's a bug or a feature (not sure) and there has already been a similar thread about it, a few days ago, here, though no solution has been found

And about the fuel line, it sometimes happens when using symmetry with fuel lines, I already had that, but it's no big deal.

Edited May 8, 2015 by Gaarst

[adinfinitum]

I haven't gotten any pilots to where they're experienced enough to use target tracking, but could it be because your relative velocity is too low? I know that when I'm landing and using retrograde hold, as soon as my velocity gets below a certain point it automatically switches to heading hold. The game does this so that the ship isn't trying to flip itself around as the markers flip around. I suspect it might be something similar

Edit: Looks like I was probably wrong

[amorymeltzer]

That's intentional. The 1.0 update introduced new behavior for SAS which automatically puts it in hold when your movement or the target is likely to change rapidly. The perfect example of this is when landing on the Mun or Minmus. You'd have your SAS set to retrograde, but if you accidentally overshot by 0.1 m/s your rocket would flip over to point down, then back up again as gravity caught you. Same for when you land and aren't moving - weird things happen there.

Because your relative speed to your target is almost 0 it's flipping off, but you appear to be hugging the line between on and off. If you get it up to 0.3 or something I bet it'll stop. Honestly, I'm surprised you even had the option - I didn't think it'd give it to you at 0.1 m/s. Maybe because the ships are large?

[THX1138]

I haven't gotten any pilots to where they're experienced enough to use target tracking, but could it be because your relative velocity is too low? I know that when I'm landing and using retrograde hold, as soon as my velocity gets below a certain point it automatically switches to heading hold. The game does this so that the ship isn't trying to flip itself around as the markers flip around. I suspect it might be something similar

Edit: Looks like I was probably wrong

The direction that the target is in isn't changing though, so it doesn't make sense like it might for determining where prograde/retrograde are. That said, when the velocity is higher, the marker stays on. Because of that, I think maybe Squad accidentally applied the afforementioned feature to the target tracking as well.

[adinfinitum]

I thought about it a little more, and do you think its distance based instead of velocity based for target tracking? Since prograde/retrograde flipping happens at low velocity, and the situation where target marker flipping is when you're close up, it'd make sense to do it that way.

[THX1138]

I thought about it a little more, and do you think its distance based instead of velocity based for target tracking? Since prograde/retrograde flipping happens at low velocity, and the situation where target marker flipping is when you're close up, it'd make sense to do it that way.

It could be but in that case two changes would improve the situation:

1. a message should pop up in the usual yellow font saying that the automatic tracking is being disabled and

2. hysteresis in the algorithm should stop the flickering on/off when at the threshold

[adinfinitum]

Those sound like good changes to me, hopefully they make it in the game sometime.

[Lorunification]

Hey Everyone,

Because your relative speed to your target is almost 0 it's flipping off, ...

That is wrong. Relative velocity to your target describes the change in position relative to your target. So a rel. velocity of 0 means that you are not moving at all resulting in the exact opposit of "flipping off". For prograde, retrograde as well as the maneuver marker that is true, for target and anti-target, however, it is not.

I thought about it a little more, and do you think its distance based ...

I can also confirm that it is not distance related. As soon as you start moving faster than ~0.1 m/s the target marker becomes active, independent from the distance to your target.

I assume it is just a bug since the deactivation of the target marker makes no sense at all. While it is reasonable to deactivate pro- and retrograde when the velocity is ~0 m/s since the vectors tend to "flipp off", as amorymelzer already mentioned, the target as well as anti-target vectors are perfectly stable at low relative velocities.

Edited May 8, 2015 by Lorunification