Wow...I just read the post 2 and 3 and it keeps me reading and reading...but I should do some work today :-( Thanks for the wiki link and the links to all the posts, however I am a little dissappointed you butterflied out Ms Tereshkova and kept only Yuri As regards as the Sammit, what a bizzarre idea to take photo from a 1.5 tonne satellite a low polar orbit and return them in a small re-entry capsule a few days after launch!! Was it really the plan? If we think of today technology it was bizzare I have then a question a little scientific. Sorry I am a bit ignorant on this topic and from what you write you seem really prepared on all the technical aspects of rockets! The point is on the density of the atmosphere. Was it not estimated from the rate of change of the period of the satellite, like Explorer I, Explorer IV, Vanguard I and Vanguard II? I read something like that, but you mentioned a frequency shift in your post. What did you mean? And you forgot to say one important thing: the Vanguard-1 established beyond every doubts the geologists' suspicion that Earth is pear shaped Good work...I am enjoing it a lot!