Flight Question Encounter planet with correct LAN

[Vanguard]

So here's the scoop... As an example, I want head from Earth to the moon, and arrive there with the correct inclination and LAN so that my orbit passes directly over Brighton Beach (negating the need for a plane change upon arrival).

I can't seem to find an MFD that provides my expected geocentric longitude. Brighton beach sits at 33.4375W, 41.125N. So I assume my inclination needs to be at least 41.125. As for the LAN, I know that (at 41.125 inclination) I want it to be at 80.88W (moon coords) using some basic trig. Prob is, every MFD I know provides the LAN in the ecliptical frame from the vernal equinox. How can I predict where my LAN will be in the geocentric frame upon my arrival?

I was hoping to at least eyeball it with mapMFD but my path is not drawn until I'm too close. I want to have it right from my TLI burn (although I realize an MCC will be required for "final adjustments").

Ideas?
Vanguard

 

[Tommy]

IMFD's base approach can do this. Also, if you use IMFD for the transfer burn, you can specify a landing site in IMFD's main configuration page. This will adjust the transfer course plotted to minimise or often eliminate the base approach burn.

 

[Arkalius]

The only way to choose a specific LAN and inclination is to control the precise arrival time of day at the planet. This is easier when you are far away so it needs to be planned in advance.

I'm sure there are MFDs that can help with this.

 

[Vanguard]

Thanks Tommy. I'm not really a huge fan of IMFD to be honest... mostly for this reason. I'm sure it can get me there, I guess "I'm" trying to get there Clicking TGT, typing "moon" and hitting the AB button has never really brought me any feelings of success. I suppose once I fully understand and accomplish what I'm trying to do, then I don't mind using IMFD to take care of what I already know so I don't waste time. It's extremely powerful and full credits to the author, but using it from the get go removes the learning curve for me...

I'm trying to plan and visualize what I need to do (or at least what I think I need to do), and use something like transX to create the path and then execute it and see if I got it right. Perhaps what I need is a formula for "Longitude(moon) @ MJD x = Longitude(ecliptic)". Couldn't find one, hence I was fishing for an MFD that displayed it.

Broken down, exactly what are the steps involved in order to calculate what I'm trying to do, mathimatically?

 

[tofitouf]

Thanks Tommy. I'm not really a huge fan of IMFD to be honest... mostly for this reason. I'm sure it can get me there, I guess "I'm" trying to get there Clicking TGT, typing "moon" and hitting the AB button has never really brought me any feelings of success. I suppose once I fully understand and accomplish what I'm trying to do, then I don't mind using IMFD to take care of what I already know so I don't waste time. It's extremely powerful and full credits to the author, but using it from the get go removes the learning curve for me...

I'm trying to plan and visualize what I need to do (or at least what I think I need to do), and use something like transX to create the path and then execute it and see if I got it right. Perhaps what I need is a formula for "Longitude(moon) @ MJD x = Longitude(ecliptic)". Couldn't find one, hence I was fishing for an MFD that displayed it.

Broken down, exactly what are the steps involved in order to calculate what I'm trying to do, mathimatically?

I don't like IMFD neither.... I never really understood what's going on inside. I prefer transX but the interface is not good enough. And like you I need to understand everything. that's why I begun my map3D devs. To see and understand what is gooing on. A next release of the map will do what you want graphically. you will see the planned position of planet and vessel at any time, and what would happen if I change my trajectory at a certain time. A little bit like transX but more intuitively.

 

[agentgonzo]

There is something in TransX that will do this. I don't know whether it will show it from the launch stage when you're on Earth, but if you use the encounter view whilst flying and select a base in MapMFD, it will show you your off-plane distance of your target orbit. Minimise this value to pass directly over the base.

 

[flytandem]

Yes I use TransX to set up the TLI burn to be very close to passing over the Brighton Beach site on arrival's 1st orbit . Usually a small MCC is needed part way there to get it right, but not always. You arrive and do an orbit insert, and then pass over the base something like 2/3rds orbit after the insert. There are actually 2 solutions for all this because you could go either way around the moon. And for that matter there are infinite solutions becase you can increase the TLI deltaV to arrive sooner if you like.

When setting up the TLI you also will need to first bring up Map MFD and ref moon, target brighton beach. Then on the stage showing your arrival at the moon, graph projection should be focus, so as you start tweaking the TLI variables (mostly date, and prograde, with a tiny bit of plane change if needed) you can see the location of brighton beach graphically and you want to get it pointed out to the edge of the moon circumference.

A fun task I often do before going to bed at night is a real time launch of the deltaglider and TLI with about 7000 m/s dvthat gets me to the moon in about 11 hours. Then leave it in real time and do the rest of the flight with morning coffee in hand. It's fun to plan, not only an arrival in plane with passing over brighton beach, but also to be timed to have the orbit insert at exactly a specific time that fits into my day's schedule.

 

[Vanguard]

I tried using the encounter display of transX which is exactly what started this whole thing You must admit it's a little difficult to visualize that dotted yellow line representing brighton beach to intercept your planned orbit. As tofitouf said, it just needs to be represented slightly different to get a better focus on what's at hand. Can't wait for that map3D. I checked it out, nice so far. I'll try changing the encounter MFD with the focus projection to see if I can get a better visual. I suppose if I fix my Inc to 41.12 degrees, then lowering the encounter distance will tell me I've got it right, I just won't be able to picture it. I wish mapMFD was able to show your path across the surface based on my arrival. Since it's not spinning too quickly, even showing my path from further away would be better than nothing. By simple lowering the encounter distance, I can't tell if I'm over it based on my ascending or descenting, on my first pass, or second.