OrbiterSim | FAQ |Acronyms | Add-ons | Screen Shots | Orbiter Tutorials
Return Flight to Earth from the Moon
Here is an easy method to get you home from the Moon. There is nothing elaborate about this one. The basic principle is to set a course
that will get you into the Earths sphere of influence. Then from there you let the Earth pull you in. This is actual quite easy since there is a wide margin of error that will still get you into Earths SOI.
Once you aligned your ship with the Earth open up two Orbit MFDs side by side. Set the one on the left with the Moon as the reference. This
will show you your ships current position as it orbits the around the Moon. With the Orbit MFD on the right side set the reference to the Earth and target the moon with the projection as ecliptic. You are now able
to view the Moons current position in its orbit around the Earth and your ships position around the Moon. To reach the Earth wait until the your vessel is on the far side of the moon. You will know when you are at
the far side when the radius vector of the ship ( Orbit MFD w/moon as reference ) is at the same position as the radius vector of the moon ( Orbit MFD w/earth as reference ) around the Earth. The radius vector
is that line that extends from the central ( reference ) body to the current position of the orbiting body. In this case when the position of your vessel matches the position of the Moon orbiting around the Earth
you are on the far side.
You would think if you orient your ship prograde and begin to burn from the far side you would go straight to earth by the Homann transfer
method. However I find waiting until the earth rises above the moons horizon works better. So when you see Earth rise you know it's time to go. Burn prograde until the ApD is just under 300M. This will easily get us
into the Earths SOI.
Sit back and coast for the next few days while we approach the Earth. In the Orbit MFD with the Earth as reference you can watch the Rad to count down
your approach to Earth. You will want to warp to 100x or even 1000x to speed things up. Watch the gravity reading at the bottom of the MFD. This will tell you when you leave the moons sphere of influence, SOI. When
the G indicator turns form brown to red the ship is then out of the Moons SOI and now under the suns SOI. We must wait until we are close enough to the Earth to be under its SOI. By bringing up the HUD in Orbit mode
it will display [ Earth ] in the upper left of the screen when you get close enough ( ~257M for Rad ). Once under the Earths SOI maneuver retrograde and burn until you have a Ped around 8M. The Earth will now pull you home.
This method requires no calculations on your part but be warned it will take twice as long to make the trip back to Earth this way. This
may seem like a very crude way of returning home but it could save your life if you didn't have the means to perform precise calculations. Also I feel it's nice to know if I pirated an old tin can of a ship, I could
make it home in her by the seat of my pants. For fun you can try making this trip without any MFDs open. In the DG using the HUD only make your burn after the Earth rises for one minute . Good luck
Apollo Lunar Landing Mission Tutorial