50
Fifty years after Sputnik launched! Let's see; I was 10 years old then, and already reading science fiction and non-fiction books about astronomy and rockets. Still have some of them on the shelf behind me, in fact. I remember seeing Sputnik a couple of times; I think that was one of the occasions where Dad hauled us all out on the patio to look. I remember the beep.
I was one of the beneficiaries of the space race -- the US reacted to Sputnik by sharply raising the priority of science and math education. Junior high and high school were fun! Well, except for PE and history, of course, and finding out just how lousy I was at learning languages.
Fifty years ago. Wow!
(E.t.a.: excellent picture at APOD, by the way.)