Where can I do accurate manoeuvres on a Halo Ornit

[EwTE_H]

I have put a satellite into the halo orbit around Kerbin-Mun L1, but it will never stay there for more than 15 days. The minimum thrust of the engine is about 0.5 Newton, which is very large for my 300 kg satellite. Therefore, the manoeuvre time is always 0.0 seconds, and it is difficult for me to cut it off at the right time. So I want to ask which point on such an orbit is the least sensitive. (It seems that pictures can't be successfully loaded on my browser, so please use texts to describe such a point.)

Thank you. (Hope there are no grammatical errors)

[Hotel26]

Someone will give you a more erudite answer shortly, but Lagrange points are a result of N-body forces, i.e. the action of more than one other heavy body (in this case Kerbin and the Mun).

Meanwhile, KSP does not simulate N-body physics, instead using a simplification called "patched conics"^[1].  This basically means you are either under the influence of Kerbin, or of the Mun, (or something else if outside that system), but not both.

There are no L1 points in KSP.

[1] the patched conic term refers to the idea that the "sphere of influence" of the Mun punches a hole through the sphere of influence of Kerbin.  And the Kerbin system punches its own hole through that of Kerbol.  This is how KSP determines which sphere of influence you are in -- and only that one, at any one time.

You might go look for an appropriate mod -- maybe Principia.  I'm no expert here, though.

(And apologies if you've already found it or are using it!  If that's the case, also investigate R-click on your engines and reducing the Thrust Limiter: it will go down as low as 0.5%.)

Welcome to the forum. 

Edited May 25, 2022 by Hotel26

[EwTE_H]

27 minutes ago, Hotel26 said:

Someone will give you a more erudite answer shortly, but Lagrange points are a result of N-body forces, i.e. the action of more than one other heavy body (in this case Kerbin and the Mun).

Meanwhile, KSP does not simulate N-body physics, instead using a simplification called "patched conics"^[1].  This basically means you are either under the influence of Kerbin, or of the Mun, (or something else if outside that system), but not both.

There are no L1 points in KSP.

[1] the patched conic term refers to the idea that the "sphere of influence" of the Mun punches a hole through the sphere of influence of Kerbin.  And the Kerbin system punches its own hole through that of Kerbol.  This is how KSP determines which sphere of influence you are in -- and only that one, at any one time.

You might go look for an appropriate mod -- maybe Principia.  I'm no expert here, though.

(And apologies if you've already found it or are using it!  If that's the case, also investigate R-click on your engines and reducing the Thrust Limiter: it will go down as low as 0.5%.)

Welcome to the forum. 

Well, I do use Principia, and the thrust limiter is already reduced to 0.5%. The engine is Ant by the way.

[Hotel26]

5 minutes ago, EwTE_H said:

Well, I do use Principia, and the thrust limiter is already reduced to 0.5%. The engine is Ant by the way.

Very good.  So I have a question for you: what were you hoping to achieve/see?

15d is not bad.  You know you have to do station-keeping, right?

Edited May 25, 2022 by Hotel26

[swjr-swis]

23 minutes ago, EwTE_H said:

the thrust limiter is already reduced to 0.5%

The thrust limiter is an artificial limitation imposed by the game editor, forcing fixed 0.5 steps. Nothing stops you from manually editing the craft file (or if you've already launched it, the save file) and lowering that limiter to say, 0.01%. Search for 'thrustPercentage = 0.5', since that's the value you have on it now.

That should at least give you more time to react for the cut off. Not sure if it will help to show the maneuver time though - at some point the values become so small the in-game code simply shows zero regardless.

 

For future reference, if you wish more accurate thrust for small probes, try using monoprop and either one of the small RCS thrusters - 0.1 Thruster power, 20x smaller than the Ant.

Edited May 25, 2022 by swjr-swis
forgot image

[Hotel26]

Excellent idea.

 

Edited May 25, 2022 by Hotel26

[swjr-swis]

Oh and a belated welcome to the forum.

 

Edited May 25, 2022 by swjr-swis
thanks @Hotel26 for reminding me of my manners

[Lt_Duckweed]

If you tie thrust limit to a axis group, and then turn on fine adjustment mode with caps lock, you can get very very fine grained control, allowing you to use a very very small thrust limit.

[EwTE_H]

On 5/25/2022 at 5:39 PM, swjr-swis said:

Nothing stops you from manually editing the craft file (or if you've already launched it, the save file) and lowering that limiter to say, 0.01%. 

This directs me to America! With this, as well as Better Time Warp, now my satellite won't fall off within plotting limit. Thank you very much!

[Kryxal]

Do note that L1, L2 and L3 are unstable.  Only L4 and L5 are stable.