A handwritten letter from astronaut Gus Grissom to his mother will be offered at RR Auction.
The lot dates to October 7, 1961 and offers a fascinating insight into the internal politics of the US space program.
At the time it was written Grissom had just found out that he would not be the first American to orbit the Earth aboard Mercury 6 - with the honour instead bestowed on colleague John Glenn.
It reads, in part: "The flight crew for the orbital mission has been picked and I'm not on it. Neither Al nor I get one of the first two orbital shots. Glenn gets the first one and Deke Slayton gets the second one.
"Anyway I know you'll be relieved that you don't have to go through another launch. Of course I've been feeling pretty low for the past few days.
"All of us are mad because Glenn was picked. But we expressed our views prior to the selection so there isn't much we can do about it but support the flight and the program. Of course no one is to know a selection has been made, so keep it under your hat."
Grissom was one of the three astronauts to die in the Apollo 1 tragedy in 1967.
Memorabilia associated with him, and particularly from his time at NASA, is extremely rare.
The lot is expected to sell for $8,000-10,000 ahead of the March 9 close date.
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