An Apollo 17 flown Robbins medal is valued in excess of $20,000 at Heritage Auctions.
The lot will lead a November 6 auction of space memorabilia in Dallas.
It comes from the personal collection of mission commander Gene Cernan.
Heritage comments: "This 35mm sterling silver medal was one of only eighty flown aboard Apollo 17, December 7-19, 1972, with crewmembers Gene Cernan, Ron Evans, and Harrison Schmitt.
"A total of 300 were minted to commemorate this sixth and final lunar landing of the NASA program…
"This is the rarest of all Apollo silver Robbins. Being from the flight commander's collection makes it even more desirable."
Apollo 17 was the last manned mission to the Moon and is of special importance to collectors.
Robbins medals in particular are highly sought after, with one specimen selling for $58,546 in 2012.
Others regularly hit sums around the $50,000 mark.
A pair of Apollo 9 flown scissors and A7l Pocket Assembly is expected to make more than $18,750.
The lot belonged to the mission's Lunar module pilot Rusty Schweickart.
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