The choice alternatives for the PopupMenu's was not known when starting from scratch. Therefore the errors. In the attached I have defined them as local variables with initial values.

Also the evaluation of the Manipulate's was continuously being triggered. So I added the TrackedSymbols option.

First Manipulate:

    {{maxht, 200, Style["Maximum Altitude", Medium]}, heightList, ControlType -> PopupMenu},
    (* Constant *)
    {{heightList, {200, 400, 600, 1000, 1500, 2000, 4000, 6000, 10000,15000, 20000,22236}},ControlType -> None},
    (* Option *)
    TrackedSymbols :> {maxht}
    (* End Manipulate *)
],

Second Manipulate:

     {{perUheight, 200, Style["Perigee Height", Medium]}, perHtList, ControlType -> PopupMenu},
     (* Constants *)
     {{eccentricityList, Range[.0, .95, .05]}, ControlType -> None},
     {{perHtList, {100, 200, 400, 600, 1000, 1500, 2000}}, ControlType -> None},
     (* Option *)
     TrackedSymbols :> {maxEcc, perUheight}
     (* End Manipulate *)
],

Attachments:

Space_Rule_CalcM...nb