TLI Plots

[JayUtah]

It is a graph of height above the geomagnetic plane versus distance from Earth.  It is simply a data plot[...].  I hope that makes sense to you.

It does, but I admit it's a noodle-baker when you first see it.  The depiction of Earth and the different radiation belts as visual representations rather than abstract forms probably doesn't help.  It's like the geodetic altitude plots of re-entry that appear to show the spacecraft climbing when in fact the geodetic altitude increases artificially due to the (unrepresented) curvature of the Earth.

Some of the reference-frame diagrams I'd seen before in guidance and control displays suddenly "clicked" when a mathematician introduced me to non-uniform rational parametric functions.  When you can vary the denominator of the ratio according to the independent parameter, you realize there is additional information you need to consider before you can visualize the real-world geometric representation from the almost-but-not-quite representational display.

Thanks for clarifying this.

[Bob B.]

It does, but I admit it's a noodle-baker when you first see it.

I realized back when I originally wrote the article that that diagram was likely to cause confusion.  I tried to explain it in the article but apparently my explanation is lacking.  This isn't the first time it has been called into question (Kiwi said something about it a few years ago).  I'll consider making some edits to the text that might help clear up some of the confusion.

It's like the geodetic altitude plots of re-entry that appear to show the spacecraft climbing when in fact the geodetic altitude increases artificially due to the (unrepresented) curvature of the Earth.

I know what you mean.  It doesn't help when people talk about "skipping off the atmosphere (like a stone off water)".  Nothing skips off the atmosphere, the spacecraft simply passes through the atmosphere and exits on the other side.