TransX Encounter: how to know if i'll be captured prograde or retrograde

[Lele81]

Hi all,
I have understood quite well how to use TransX to manage a deep space flight, I can go to the Moon, to Mars, to Jupiter with no problems...except one:

yesterday I went to Jupiter for the first time, but when I reached to stabilize my orbit around the planet...I discovered to be rotating retrograde respect to the jupiter axes rotation wise (and to it's satellites revolution around the planet).
The transfer have been made in a classical Hohmann manner, infact my ship and jupiter were rotating around the Sun in the same direction.

How do I see in TransX if I'm going to be captured pro or retro grade??? and how to change it?

My Encounter schema showed ( at about half trip distance):
Inclination: 3.8
LAN: 175

When I get closer, the encouter image changes, showing a more zoomed planet, and suddenly my Encounter shows instead (without any burn made):
Inclination: 176
LAN: -13


Does it have something to do with my retro-capture? can someone explain me?

Many thanks!!

 

[Evil_Onyx]

Simple method is to arrange to arrive behind or ahead of the planet depending on if you are coming in from above or below. If you are going from Earth to Jupiter (Arriving from below) to go prograde around Jupiter upon arrival you need to aim to arrive late to Jupiter, but the down side of this is your capture burn will be slightly higher as you end up arriving with a slight gravity assist (Slingshot).

 

[asbjos]

When I get closer, the encouter image changes, showing a more zoomed planet, and suddenly my Encounter shows instead (without any burn made):
Inclination: 176
LAN: -13

That's the problem. TransX (or any other trajectory planner) isn't perfect in predicting the trajectory. You made a good burn, but in the cruise phase your orbit got influenced by the gravitational forces from the other planets in the Solar System (plus radiation pressure if you have it enabled), pushing on your orbit ever so slightly so that you arrived at Jupiter in a different place than expected.

Therefore you have to do some mid-course corrections. While you cruise to Jupiter, you should keep an eye on the Encounter screen and make a couple of deep space manoeuvres to fine-tune you trajectory.

 

[PhantomCruiser]

I must admit I use IMFD more than TransX, but I've used both at the same time.

The reason being just what you've described, to avoid this I use the Map mode from IMFD, I can tweak my planetary approach to arrive in front of, or behind the planet as I make my turnover for an orbital insertion burn.

 

[Lele81]

Many thanks for your help,

so, from your answeres I understood that my capture rotating wise depends on my cruise trajectory, it is depending from my arrival (behind or ahead); and I understood that I maybe need some more course correction manouvres while I'm very near to the planet.

The only thing to understand is now, how can I see if I'm approaching from behind or ahead? In Encounter TransX can I see this? I didn't know how...or if I should look to another MFD (in particular I didn't understand how the MAP MFD can help me in this).

 

[PhantomCruiser]

IMFD has a mode in which you can see your course as it lays out in front of you. It's a map of the road you are on. NOT the Map MFD that is stock with Orbiter (you are right, that wouldn't do you a whole heck of a lot of good).

Get IMFD, take a look at it. IMFD + TransX = Really cool.

 

[statickid]

The way I do it in trans x is plan from the start to "hit" the target body.

Then half or three quarters of the way there make a very small burn with an engine nozzle that faces 90 degrees attitude. In a typical Earth /Moon flight, this nudges your trajectory "to the left" if you're looking out the cockpit window. The effect is that your path goes on the leading side of the moon instead of the trailing side off the moon. Getting closer, 90-95% there (which is still pretty far away) make final adjustments such as raising/lowering capture altitude and adjusting inclination. It can get confusing at first but being deliberate and methodical helps me more than anything. Also take advantage of the ecliptic projection, since its always "top-down".

 

[Lele81]

Thanks to you both, tomorrow (now I can't) I'll try your suggestions!!! And I also will try IMFD, I'll let you know!

Thank you:thumbup:!!