Help identifying silver bar. 8c united states in space

[brianbye]

Found this silver bar on ebay. I tried for days to find another just so that I could identify what it was and what it is worth. I have found many similar envelopes but none with the silver bar. I also could not find the silver bar anywhere even without the envelope. I probably overpaid but I think its cool so I took a chance. Anyhow, here are the pics. Any help is appreciated.

Source:

Source:

 

[pi]

What is the weight and purity?

 

[brianbye]

The envelope weighs 1.45 oz and the purity is .999

 

[bull_bear]

Might have come from this collection
http://forums.silverstackers.com/message-612210.html#p612210

 

[clear]

Nice - don't sell it, 8 cents, 1971, and to da moon.

 

[nicwinner]

i had one, similar but without envelope. sold last year

and it's not belong to the medal collection Bull_bear mentioned.

 

[brianbye]

I dont plan on selling it. I just wish I knew officially what set it is.. Maybe how many were produced, and an approximate value..

 

[brianbye]

Anyone else have any information on this bar?