[amsat-bb] satellite orbiatl prediction through obersvation

I. have been reading up on the history of the Kettering group and I am particularly curious about one thing: how did they determine the orbit of the satellite strictly from observation. Can anyone help me with this?

I can see how you could pick up the period of the satellite from observation, but am stumped as to how the rest of it is worked out...

Thanks and VY 73 de W1ICW