What significant achievement is Alan Shepard known for?

Alan Shepard is primarily recognized for being the first American in space. This achievement occurred during the Mercury-Redstone 3 mission, which took place on May 5, 1961. Shepard's flight lasted about 15 minutes and reached a maximum altitude of approximately 116 miles. This milestone not only made Shepard a pivotal figure in the United States' space program but also marked a significant moment in the context of the Space Race with the Soviet Union. His successful suborbital flight helped pave the way for future manned space missions and showcased the capabilities of American space exploration during a time when the nation was focused on catching up to Soviet advances in space technology.

The other options, while significant in their own right, are not related to Shepard's achievements. The first artificial satellite was launched by the Soviet Union, not Shepard, and the V-2 rocket project was led by Wernher von Braun. The title "Father of Modern Aeronautics" is associated with various pioneers in aviation but does not specifically belong to Shepard, who is recognized for his contributions to human spaceflight specifically.