6 1/2 x 3 5/8 in (16.5 x 9.2 cm)

Provenance and Authentication:
This collectible has undergone a rigorous forensic evaluation. The signatures were carefully analyzed across multiple criteria, including ink deposition, material aging characteristics, stylistic consistency, and historical alignment. The findings provide a sound basis for authenticity and historical context, and the piece is accompanied by comprehensive documentation supporting both its provenance and verification.

This signed First Day Cover (FDC) from the International Geophysical Year 1957-1958 is autographed by U.S. astronaut Gus Grissom. The FDC, which features a commemorative stamp and postmark from May 31, 1958, marks the beginning of the international scientific initiative to study Earth's physical properties, a significant event in the history of space exploration.

The signature of Gus Grissom is prominently displayed in black ink across the bottom of the envelope. This item is particularly valuable as it was signed by one of the original seven astronauts selected for NASA's Project Mercury. Gus Grissom became the second American to fly into space, further cementing his legacy as a key figure in the early years of the U.S. space program.

The International Geophysical Year, which took place from July 1957 to December 1958, was an important event that laid the groundwork for the space race. Gus Grissom's signature on this FDC not only connects to his personal achievements but also to this historic period in space exploration.

This signed First Day Cover offers a rare opportunity to own a piece of history that is directly tied to the early days of the U.S. space program and the pioneering astronauts who helped shape its legacy. Collectors of space exploration memorabilia highly value signed items from astronauts like Gus Grissom, particularly those that commemorate significant milestones like the International Geophysical Year.