Herbert William Mullin was an American serial killer born on April 18, 1947 who operated in Santa Cruz, CA. 
Mullin was serving life in prison for 13 murders which he says he committed to prevent further natural disasters.  Mullin died of natural causes on August 18, 2022.

4" x 6 1/2" Space Shuttle STS-121/Discovery card amd envelope on which Mullin has sent his friend Thanksgiving wishes. 
The card has a handwritten message and is hand signed in full, Herbert William Mullin. 
The front of the Space Shuttle envelope has the same message and is hand signed, H.W. Mullin.
 
This is a one off Mullin piece and the only one like it we've seen!