I’m in the final stages of US Launch Vehicles Projects #06, with a special focus on launch vehicles for the Solar Power Satellite program. Included there is a plan view of the initial NASA SPS, with Manhattan island for a scale reference. Why Manhattan? Because the SPS satellites were approximately the size of Manhattan, and thus Manhattan was used in schematics and art of the time to illustrate the scale of the program. But… who actually thinks in terms of Manhattan island as a unit of distance measure? Tell me that “such-and-such is the size of Manhattan,” it’ll mean nothing to me, as I’m sure it means nothing to the vast majority of people.
So… since this issue will arise again in future projects I’m working on, what alternatives to Manhattan are there to serve as scale references for structures twenty kilometers long?