Solved How do you ACTUALLY DOCK? (not rendezvous)

[SPQRALAN]

I watch many tutorials on how to dock and I can get a pretty good approach and rendezvous, but whenever I start to actually dock, I just miss my target by 50 meters. Maybe answering these questions could help me. Thanks.

1) What direction should I burn in?
2) How powerful must my throttle be to propel myself towards target(% of Broadsword LF engine)?
3) When should I start translating/propelling myself towards target?
4) When I try to rotate with RCS, I always over-rotate or under-rotate, so I miss the target.
5) Occasionally, I get to meet the target spacecraft and crash into it, how do I prevent that?

Thank you for helping me and I hope I could dock.

 

[Roosterbooster]

Normally go full percent and do quick burns and get close, then use RCS, lots of RCS sometimes.

 

[Roosterbooster]

Normally go full percent and do quick burns and get close, then use RCS, lots of RCS sometimes.

Then the docking is simple.

 

[Jez 10]

I watch many tutorials on how to dock and I can get a pretty good approach and rendezvous, but whenever I start to actually dock, I just miss my target by 50 meters. Maybe answering these questions could help me. Thanks.

1) What direction should I burn in?
2) How powerful must my throttle be to propel myself towards target(% of Broadsword LF engine)?
3) When should I start translating/propelling myself towards target?
4) When I try to rotate with RCS, I always over-rotate or under-rotate, so I miss the target.
5) Occasionally, I get to meet the target spacecraft and crash into it, how do I prevent that?

Thank you for helping me and I hope I could dock. View attachment 20099 View attachment 20100

Check the velocities.

 

[Altaïr]

Welcome to the forum SPQRALAN

If you manage to get a rendez-vous, you've done the hardest. Something useful to know is that your relative speed at the encounter will depend on the orbits of your two ships: the closer they are, the smoother will be the encounter.

Now when you get sight on your target, the first thing to do is to cancel your relative speed, so that the 2 ships seems practically motionless with respect to eachother.
The RCS can be enough for that if the encounter is very smooth, otherwise you'll have to do most of the job with your main engine. There is no standard appropriated throttle for that, as the acceleration also depends on the mass of your ship, but it's better to make small corrections: short bursts with significant throttle. Then make the last adjustments with the RCS.

Now they are close to each other, and they don't move anymore. You just have to drive your ship to the target with the RCS. No need to hurry, take your time to do it, and it should be fine.

 

[Lt. Snakestrike]

I watch many tutorials on how to dock and I can get a pretty good approach and rendezvous, but whenever I start to actually dock, I just miss my target by 50 meters. Maybe answering these questions could help me. Thanks.

1) What direction should I burn in?
2) How powerful must my throttle be to propel myself towards target(% of Broadsword LF engine)?
3) When should I start translating/propelling myself towards target?
4) When I try to rotate with RCS, I always over-rotate or under-rotate, so I miss the target.
5) Occasionally, I get to meet the target spacecraft and crash into it, how do I prevent that?

Thank you for helping me and I hope I could dock. View attachment 20099 View attachment 20100

Yeah, basically what Altaïr said...
You've got an encounter, yes, but once you get close you need to slow your spcaecraft down to match the velocity of the other. From there you just use RCS to finish the manuever.

 

[SPQRALAN]

Welcome to the forum SPQRALAN

If you manage to get a rendez-vous, you've done the hardest. Something useful to know is that your relative speed at the encounter will depend on the orbits of your two ships: the closer they are, the smoother will be the encounter.

Now when you get sight on your target, the first thing to do is to cancel your relative speed, so that the 2 ships seems practically motionless with respect to eachother.
The RCS can be enough for that if the encounter is very smooth, otherwise you'll have to do most of the job with your main engine. There is no standard appropriated throttle for that, as the acceleration also depends on the mass of your ship, but it's better to make small corrections: short bursts with significant throttle. Then make the last adjustments with the RCS.

Now they are close to each other, and they don't move anymore. You just have to drive your ship to the target with the RCS. No need to hurry, take your time to do it, and it should be fine.

Thank you. Just to make sure, I burn retrograde to reduce relative velocity right? Do I burn at an angle or tangent to trajectory?

 

[Altaïr]

Thank you. Just to make sure, I burn retrograde to reduce relative velocity right? Do I burn at an angle or tangent to trajectory?

Not necessarily retrograde. If your target is faster than you, you'll have to burn prograde to catch up with it. Actually the direction of your burn depends on your situation, you can even have to burn sidewards.

At that moment, you shouldn't reason in terms of orbital movement, just focus on the other ship's movement.
For example, if it moves from left to right, then you should burn towards the right. The purpose is that your ship's speed is the same than your target's speed in the end, so that they don't move anymore with respect to eachother.

 

[Horus Lupercal]

 

[SPQRALAN]

Thank you everyone for your help and support. I am finally able to dock. Now I just need a little more practice and I'll be on my way to making a space station.

 

[Roosterbooster]

Thank you everyone for your help and support. I am finally able to dock. Now I just need a little more practice and I'll be on my way to making a space station. View attachment 20426

Good luck!

 

[TtTOtW]

Good job guys

 

[Roger Jolly]

Just to note:
The ease of docking is entirely dependent on the quality of approach...
When an object is inside another’s orbit on this side and outside the other orbit over the other side is when your target seems to do loopty loops in the rocket view

Keep one arc of the orbits matched with the opposite side as close as reasonable for the trailing object to catch the lead, wider is fine if it’s a long run to catch but close the orbital gap to a couple km when they are about 10 degrees apart...
Only then when there is about 2 orbits before approach, use rcs to adjust the closest approach to about 200 meters
Then docking should be easy with only rcs if you go to the rocket view early and take it slow, zoom out and use the time warp to check the subtle drift and adjust accordingly

 

[SPQRALAN]

Just to note:
The ease of docking is entirely dependent on the quality of approach...
When an object is inside another’s orbit on this side and outside the other orbit over the other side is when your target seems to do loopty loops in the rocket view

Keep one arc of the orbits matched with the opposite side as close as reasonable for the trailing object to catch the lead, wider is fine if it’s a long run to catch but close the orbital gap to a couple km when they are about 10 degrees apart...
Only then when there is about 2 orbits before approach, use rcs to adjust the closest approach to about 200 meters
Then docking should be easy with only rcs if you go to the rocket view early and take it slow, zoom out and use the time warp to check the subtle drift and adjust accordingly

I can dock successfully and efficiently but thanks anyways. This might be useful for other people who want to know how to dock in the future. But I do have a follow-up question. Is it more efficient to dock in LEO then propel the whole space station to a High Earth Orbit or to dock in the high earth orbit?

 

[TtTOtW]

Docking in an orbit below 200km is risky if you're not an expert. You dock, and the next thing you know your station is heading for terra firma at an unstoppable rate. With experience you'll consistently dock safely at even 1km above the Karman Line. Don't try it just yet... First get acquainted with dock shock and master its avoidance before approaching lower docking orbits.

 

[Altaïr]

I can dock successfully and efficiently but thanks anyways. This might be useful for other people who want to know how to dock in the future. But I do have a follow-up question. Is it more efficient to dock in LEO then propel the whole space station to a High Earth Orbit or to dock in the high earth orbit?

That doesn't really change things.
If you want to dock in HEO you'll have to propell the station onto it first. You just do things in a different order, but the energy spent will be the same in both cases.

 

[Roger Jolly]

200km!?!

Real Earth scale?
I started with 100km as a LEO target and drawn back to 50-60, think I lost one craft ever in a wreckless pursuit

Where you dock doesn’t matter, but getting the target escape window as low possible is max efficiency to leave a SOI, so staying low generally best

 

[TtTOtW]

Be

200km!?!

Real Earth scale?
I started with 100km as a LEO target and drawn back to 50-60, think I lost one craft ever in a wreckless pursuit

Where you dock doesn’t matter, but getting the target escape window as low possible is max efficiency to leave a SOI, so staying low generally best

Beginners are not as well rounded in docking procedures. They need the safe zone.

 

[SPQRALAN]

Docking in an orbit below 200km is risky if you're not an expert. You dock, and the next thing you know your station is heading for terra firma at an unstoppable rate. With experience you'll consistently dock safely at even 1km above the Karman Line. Don't try it just yet... First get acquainted with dock shock and master its avoidance before approaching lower docking orbits.

Um... actually my first docking attempt was done on 80km. I built my space station at 70 km altitude. I want to build a space station at 29,363km altitude so I'm worried that I don't have enough fuel to dock that high.