Rare and historically significant baseball signed in blue ink by four of the legendary seven Mercury astronauts: Gus Grissom, Alan Shepard, Scott Carpenter, and Wally Schirra. The Official National League (Giles) ball has been signed by Grissom and Shepard together on a side panel, while the signatures of Carpenter and Schirra appear individually on opposite side panels. The date of the signing, "July 7, 1963/Houston, Texas," is written in blue ink on the sweet spot. All the signatures are uniform in grade, averaging 8/10. The signature of Gus Grissom is the scarcest of the four because he died tragically in the cabin fire of Apollo 1 in 1967. While only speculation, this ball was most likely signed when the four appeared at a Colt 45's game at Colts Stadium in Houston, Texas. (Research indicates that the Colts hosted the Milwaukee Braves on July 7, 1963.) The "Mercury Seven" as they were named, were America's first astronauts and helped pioneer the space program, which culminated in a manned moon landing in 1969. Excellent to Mint condition overall. Full LOA from PSA.