Virgil Ivan "Gus" Grissom (April 3, 1926 – January 27, 1967) was an American astronaut, and one of the original Mercury Seven selected by the National Aeronautics and Space Administration (NASA) for Project Mercury, a program to train and launch astronauts into outer space. Grissom went on to be a Project Gemini and Apollo program astronaut for NASA. As a member of the NASA Astronaut Corps, Grissom was the second American to fly in space in 1961. He was also the second American to fly in space twice, preceded only by Joe Walker with his sub-orbital X-15 flights.

Grissom was a World War II and Korean War veteran, mechanical engineer, and United States Air Force test pilot. He was a recipient of the Distinguished Flying Cross, the Air Medal with an oak leaf cluster, two NASA Distinguished Service Medals, and, posthumously, the Congressional Space Medal of Honor.

As commander of AS-204 (Apollo 1), Grissom died with astronauts Ed White and Roger B. Chaffee on January 27, 1967, during a pre-launch test for the Apollo 1 mission at Cape Kennedy, Florida.

Virgil Ivan Grissom was born in the small town of Mitchell, Indiana, on April 3, 1926, to Dennis David Grissom, a signalman for the Baltimore and Ohio Railroad, and Cecile King Grissom, a homemaker. Virgil was the family's second child; his older sister, Lena, died a year prior to Gus' birth. He was followed by three younger siblings: a sister, Wilma, and two brothers, Norman and Lowell. Grissom started school at Riley grade school. His interest in flying began during that time, building model airplanes. He received his nickname when his friend was reading his name on a scorecard upside down and misread "Griss" as "Gus".

As a youth, Grissom attended the local Church of Christ, where he remained a lifelong member. He joined the local Boy Scout Troop and earned the rank of Star Scout. Grissom credited the Scouts for his love of hunting and fishing. He was the leader of the honor guard in his troop. His first jobs were delivering newspapers for The Indianapolis Star in the morning and the Bedford Times in the evening. In the summer he picked fruit in area orchards and worked at a dry-goods store. He also worked at a local meat market, a service station, and a clothing store in Mitchell.

Grissom started attending Mitchell High School in 1940. He wanted to play varsity basketball but he was too short. His father encouraged him to find sports he was more suited for, and he joined the swimming team. Although he excelled at mathematics, Grissom was an average high school student in other subjects. He graduated from high school in 1944.

In addition, Grissom occasionally spent time at a local airport in Bedford, Indiana, where he first became interested in aviation. A local attorney who owned a small plane would take him on flights and taught him the basics of flying.

World War II began while Grissom was still in high school, but he was eager to join the armed services upon graduation. Grissom enlisted as an aviation cadet in the U.S. Army Air Forces during his senior year in high school, and completed an entrance exam in November 1943. Grissom was inducted into the U.S. Army Air Forces on August 8, 1944, at Fort Benjamin Harrison, Indiana. He was sent to Sheppard Field in Wichita Falls, Texas, for five weeks of basic flight training, and was later stationed at Brooks Field in San Antonio, Texas. In January 1945 Grissom was assigned to Boca Raton Army Airfield in Florida. Although he was interested in becoming a pilot, most of Grissom's time before his discharge in 1945 was spent as a clerk.