Editing LEO-lunar transfer

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[[Image:MoonScrshot.jpg|thumb|right|Moon in Orbiter]]
 
 
So you're in [[LEO|low Earth orbit]], in a gassed up [[Delta-glider]]. From here you want get to the [[Moon]] above. Here's how.
 
So you're in [[LEO|low Earth orbit]], in a gassed up [[Delta-glider]]. From here you want get to the [[Moon]] above. Here's how.
  
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Now comes the fun part. Bring up the '''transfer MFD''', either in the same screen, or the other one if you like. Target the moon as before. You'll see a circle representing the Moon's orbit, and text stating 'no intersect'. This is because your orbital path and the Moon's do not, in fact, intersect. Yet.
 
Now comes the fun part. Bring up the '''transfer MFD''', either in the same screen, or the other one if you like. Target the moon as before. You'll see a circle representing the Moon's orbit, and text stating 'no intersect'. This is because your orbital path and the Moon's do not, in fact, intersect. Yet.
  
First thing to do is hit the '''HTO''' button. Once you've done this, you press and hold the '''DV+''' button. This will cause a dashed oval to grow out of the point in the middle of the display. You want this dashed oval to just touch the circle of the moon's orbit. When it does, you'll get a whole bunch of new symbology. The yellow dashed line is where the moon will be when you get to the other end of the oval. The green dashed line is the point in your orbit where you should make your ejection burn (which will initiate the transfer), the solid yellow line is where the Moon is now in its orbit, and the grey line is where your proposed trajectory (the dashed oval) intersects with the Moon's orbit. What you should do is fiddle with the '''EJ+''' and '''EJ-''' buttons to position this grey line over the dashed yellow one. Once you've done this, wait until the solid green line (your position in your orbit) is either at or close to the dashed green line. Using the '''Prograde''' autopilot mode, make a long burn, watching the transfer screen. A solid green oval representing your actual current orbit will grow out from the center of the circle, and eventually match the dashed proposed orbit. When it does, kill your engines.
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First thing to do is hit the '''HTO''' button. Once you've done this, you press and hold the '''DV+''' button. This will cause a dashed oval to grow out of the point in the middle of the display. You want this dashed oval to just touch the circle of the moon's orbit. When it does, you'll get a whole bunch of new symbology. The yellow dashed line is where the moon will be when you get to the other end of the oval. The green dashed line is the point in your orbit where you should make your ejection burn (which will initiate the transfer), the solid yellow line is where the Moon is now in its orbit, and the grey line is where your proposet trajectory (the dashed oval) intersects with the Moon's orbit. What you should do is fiddle with the '''EJ+''' and '''EJ-''' buttons to position this grey line over the dashed yellow one. Once you've done this, wait until the solid green line (your position in your orbit) is either at or close to the dashed green line. Using the '''Prograde''' autopilot mode, make a long burn, watching the transfer screen. A solid green oval representing your actual current orbit will grow out from the center of the circle, and eventually match the dashed proposed orbit. When it does, kill your engines.
  
 
Congratulations, you're on your way to the Moon. '''So, a couple days later'''...
 
Congratulations, you're on your way to the Moon. '''So, a couple days later'''...
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You've arrived! The Moon is getting pretty big in the viewscreen. Really big. Too big in fact. Oh dear, we're about to impact the lunar surface at some 17,000 miles per hour. Now what?
 
You've arrived! The Moon is getting pretty big in the viewscreen. Really big. Too big in fact. Oh dear, we're about to impact the lunar surface at some 17,000 miles per hour. Now what?
  
Bring up the '''orbit''' display in one of your MFD's. Hit the '''ref''' (reference) button, and put in 'moon'. This brings up a display of your orbital path around the Moon. In your case, this probably looks like a straight green line (your path) intersecting the gray circle (the Moon). If so, switch the HUD to surface mode. Use the autopilot's '''prograde''' mode to point the engines. Fire all engines, and watch the '''orbit''' display. It should, ideally, turn into a hyperbola with a circle inside. You want to continue this burn until the green hyperbola is entirely outside the grey circle representing the Moon. Disaster averted!
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Bring up the '''orbit''' display in one of your MFD's. Hit the '''ref''' (reference) button, and put in 'moon'. This brings up a display of your orbital path around the Moon. In your case, this probably looks like a straight line. Switch the HUD to surface mode. By this point the Moon should be your primary gravity source, and it should be using it for reference. Bring your nose around so that it is level with the lunar surface (00 on the ladder bars). Fire all engines, and watch the '''orbit''' display. It should, ideally, turn into a parabola with a circle inside. You want to continue this burn until the green parabola is entirely outside the grey circle representing the moon. Disaster averted!
  
=== Entering the lunar orbit ===
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There is one final problem. Continuing on this path will cause our ship to slingshot around the moon and off into deep space somewhere. So the final operation in lunar orbit insertion is to wait until near the closest point in your lunar passage, and retrograde burn to circularize your orbit (by watching the '''orbit''' MFD). All circular? Congratulations, you're here! One thing I enjoy doing at this point is seeing how low I can continuously orbit the moon without touching. Actually landing at Brighton Beach is an entire tutorial in itself, and outside the scope of this writing.
  
There is one final problem. Continuing on this path will cause our ship to slingshot around the Moon and off into deep space somewhere. So the final operation in lunar orbit insertion is to slow down the spacecraft somewhere near the closest point to the Moon. Use the autopilot's '''retrograde''' mode. While watching the '''orbit''' MFD, wait until you reach the closest point and fire the engines. Your path will slowly turn into a smaller and smaller hyperbola until suddenly turning into an ellipse. If you continue the burn you can get the orbit to be close to a circle. All done? Congratulations, you're here!
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[[Category:Tutorials]][[Category:Transfer tutorials]]
 
 
=== What's next ===
 
* [[Landing on a surface base]]
 
* [[Docking with a space station]]
 
 
 
{{HasPrecis}}
 
 
 
[[Category: Articles]]
 
[[Category:Tutorials]]
 
[[Category:Transfer tutorials]]
 

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