"If it is possible to summarize the findings of the satellite program in any intelligible way, two statements may suffice: the studies revealed the extent of the earth's influence in space, and at the same time they showed just how little we understood of the environment of the earth." -- Vanguard, A History [NASA SP-4202], by Constance McLaughlin Green and Milton Lomask (quote appears in chapter 14)
[The oldest artificial satellite still in orbit was launched fifty years ago today. (The three satellites launched earlier have fallen.)]