Observation of First American in Space: Alan Shepard

May 5, 1961, Alan Shepard reached the air / space dividing line acknowledged by U.S. government, 50 miles / 80 km. The mission, known as Mercury-Redstone 3 (MR-3) or Freedom 7, was part of Project Mercury, the United States’ first human spaceflight program.

The internationally accepted altitude of 62 miles / 100 km is called the Kármán Line. Cosmonaut Yuri Gagarin became the first human in space 3 weeks previously, making one orbit of Earth.