Is it possible to see our horizontal velocity x y with respect to a target?

[Ermanphrodite]

All in the title

[Blueberry Muffins!]

Yes. You can build pretty much any instrument and instrument readout you want. I made a dune buggy feedback device to rate progress getting away from the start point, showing radial velocity and a running weighted sum. It means getting in kinda deep with the vizzy docs, this kind of use is definitely intended.

[mreed2]

Yes, if you use Vizzy. This is covered (among many other topics) in my guide:
https://steamcommunity.com/sharedfiles/filedetails/?id=2944674093
If you are asking "Is there an option that I can toggle in the game to display the horizontal and vertical components of my relative velocity without writing custom code" then the answer is "No." The best you can do is display the combined relative velocity by toggling the navball into "Target" mode.

[Ermanphrodite]

Yes thanks, I'd like to design an auto lander to avoid spending too much on career mods; I'm going to learn a lot of things, I like it a lot!

[mreed2]

If you are attempting to create automatic stage recovery (mimicking Falcon 9 or Starship), note that Vizzy code ceases to execute in crafts further than 5 km from the craft you are controlling. This is a side effect of the craft despawning when it gets goes outside this "physics bubble."

Thus, outside the physics bubble all crafts are treated as point masses on purely ballistic trajectories, uneffected by the atmosphere nor with any engines. KSP 1 and 2 both work the same way. This limit can be increased in the settings menu, but 10 km isn't significantly better than 5 km for stage recovery.

Therefore, to do stage recovery it is necessary to put the rocket on a trajectory where it will not reach apoapsis before the 1st stage lands (despite the fact that the engine will shut down as soon as it gets too far away), switch control (using the "[" and "]" keys) to the discarded first stage, then remain in control of that stage until it is safely landed. Finally, switch control to the 2nd stage (via the map view) and perform the final burn to enter orbit. No Vizzy operator exists to automatically switch control of the active craft, so a fair degree of manual interaction is required for this to work properly.

While all of this is feasible (and there are many rockets that you can download that implement this), it requires significant compromises in trajectory design and engine selection, which both increases cost (in career mode) and reduces payload to orbit. Thus, stage recovery isn't especially effective at reducing launch costs in career mode. That doesn't mean it isn't fun to do so, of course... 😀

Kitten Space Agency (KSA) is supposed to eliminate this problem, but it isn't released today and likely won't be for many months to come.

The above only applies to stage recovery -- if you are attempting to recover the final stage of the rocket then there is no issue. Also, if you are attempting to make a precision landing on (say) Luna there is no issue either. In both cases the difference is that you are only attempting to control one craft at a time.

As a much more minor point, if you are attempting stage recovery you will need to add a second control pod with the required Vizzy code to perform the landing that is part of the first stage. Vizzy code attached to the command pod that is attached to the second stage (and is heading to orbit) will be unable to control the first stage after staging occurs. Keep in mind that the code on this "first stage command pod" is going to start executing while the rocket is on the pad, so the fiest thing you will need to do is setup the code to wait until stage separation has occurred before trying to do anything.

[Ermanphrodite]

yes I know it requires to change ships in the meantime but it's not really a problem if I send the 2nd floor as at 200k height, I'll have time to control the landing.

By the way, I have already developed a lander with a friend; It adapts its thrust according to speed and mass, which allows me to land where I want safely but inaccurately, hence the need for the precision guidance system.

All this with a horizontal velocity correction that allows you to land or land vertically and without moving horizontally. It's beautiful to see. All I have to do now is the precision guidance module, correct my horizontal velocity with respect to the target and land; It seems feasible to me but complicated to interpret all the data, I'll succeed.

I have to make sure that it adapts to every rocket, and target and the planet that I would give it. XD