Question Returning Earth from the Moon

[HarvesteR]

Hello

i was wondering what would be the best way to put myself in an earth-bound trajectory departing from lunar orbit

i think the proper place to make a burn would be on the opposide side of the moon, so my orbit would extend towards earth... but i can't really find out when i'm in the correct spot...

here's what i've been doing...
i launch from brighton beach into lunar orbit, then align my orbit to earth... then i figured that i could see when i'm on the far side if i put the orbit MFD to reference earth, with the moon as target... i figured that when i reached the apoapsis of the "earth" orbit, i would be at the far side...

then i burned... but the orbit didn't extend as i intended and i ended up lost in space as i ran out of fuel.... plus i don't know how to set my MFDs so i can properly see what i'm doing...

i know the seat-of-the-pants way of doing it is burning when the earth rises on the lunar horizon... but i think that method takes way too long to get into a stable earth orbit and uses way too much fuel

does anyone know of a more 'professional' way to make the return burn??

Cheers

 

[n72.75]

IMFD

 

[Master of Blades]

Haven't been on Orbiter for quite a while... But planetary approach with IMFD would be the easiest... If I remember correctly

 

[stjimmy225]

point the nose at the earth and floor it till orbit mfd is basically a straight line towards the earth, not the most efficient method but results are more exciting.

 

[pandadude]

http://www.eharm.net/shop/freeware/orbiter/tutorials/orbiter_instrument/return.html

A very basic idea, but it works. If you want to do things more accurately, IMFD is probably the way to go.

 

[ar81]

IMFD settings

Source: Your craft
REF: Earth
Target: ISS or any object orbiting Earth

 

[Matt Decker]

I just blast off right from Brighton Beach and point at Earth. Then about a day later when I'm out of the SOI of the Moon make a course correction.

IMFD would probally be more professional.

 

[Sherrif of Nottingham]

Ugh, you posted right before me!

Ar81: why don't you write the quick starts?

That post right there just showed me how to use IMFD!

And Matt, I do it your way when I return to earth, I place my Prograde (+) close to the edge of the earth, then wait.

 

[ar81]

Ugh, you posted right before me!
Ar81: why don't you write the quick starts?

Writing a checklist on hwo to perform every single trip from/to different planets would take forever.

[ame="http://www.orbithangar.com/searchid.php?ID=3403"]Tutorial: Concepts for Interplanetary MFD 4.2.1[/ame]
shows the principles to plan trips at the very end of the tutorial.
That way you can think and plan every kind of trip you want.

 

[Nickmick95]

Come On! Stop Promoting your tutorials! :sos:

 

[ar81]

Come On! Stop Promoting your tutorials! :sos:

I made those tutorials so I dont have to post the same answer multiple times.

 

[n122vu]

I made those tutorials so I dont have to post the same answer multiple times.

Keep promoting them!

I'm finding them very helpful...thanks and keep up the good work! :speakcool:

 

[Sherrif of Nottingham]

I meant that IMFD was hard to understand...

I thought:
Source: Brighton Beach
REF: Moon
Target: Earth

I'm a noob...

 

[Zatnikitelman]

Um, I hate to revive this topic, but I can't get back from the Moon to Earth. I tried setting Src to my ship, Ref Earth, and Target Mir, but it spat out an invalid source error. I'm using IMFD 5.1k if that helps. I've tried just about all source/reference/target combinations you can think of to no avail. Whenever I didn't get an error message, I didn't have a burn vector to follow.

 

[Goth]

The return was very simple to me.
I hover from the pad, put the DG to 90° than, when at the right altitude, start main engines to reach a stable orbit. Then, I simply wait that Earth is visible at the horizon and I fire main engines pro-grade. One minute burn or more and you are going home. No IMFD or Transfer MFD, only Align MFD and Orbit MFD.

 

[astrosammy]

IMFD Source Moon, Ref Earth, Target Mir worked good for me.

 

[mauzer]

I always use the INTERPLANETARY MFD it has the map of our solar system,you can plan your way even to the sun...and the is an option there for orbiting a moon or a planet.

 

[Major Tom]

When returning from the Moon or Mars, do you orbit earth first? With the DGIV reentry angle do you use to prevent skipping off the atmosphere.

 

[Gorn]

When returning from the Moon or Mars, do you orbit earth first? With the DGIV reentry angle do you use to prevent skipping off the atmosphere.

Personally, I always go through LEO as an intermediate stage, unless I'm so woefully short of fuel that I must aerobrake; that's happened a couple of times. That way, whether I'm coming back from ISS or Neptune, the actual reentry is the same, makes things that much simpler.

Don't know about the DGIV specifically, but I imagine the same logic would apply there.

Danny

 

[Tommy]

I just posted a tutorial at Orbit Hanger (it's called Home Direct) that shows how to use IMFD to plan a course from the moon to Earth. It covers setting the Planet Approach program, using Surface Launch program to take off on the right heading, and Base Approach to set up a direct re-entry. Changing Base Approach's mode from reentry to orbit will allow you to enter LEO before reentry, set the "number" option to the number of FULL orbits you plan to complete before reentry so that the Earth's rotation is calculated correctly to sync with your base. You can use BaseSync MFD for more accuracy once in LEO, but IMFD's Base Approach program gets it close enough that you can use a little bank during reentry to end up on target for a dead stick landing using AerobrakeMFD.

Burn time for TEI is about 32 seconds.

Tommy