The launch of Explorer 1 on Jan. 31 in 1958 marked the United States' first foray into off-planet research. The small satellite lifted off atop a Juno 1 rocket and operated in orbit for 100 days to study cosmic rays in a region that was later known as the Van Allen radiation belt. It took 12 years, however, for the spacecraft to ultimately reenter the Earth's atmosphere and be destroyed.
Beat by the Soviet Union but not out of the Space Race, NASA bounced back on May 5, 1961 when Mercury astronaut Alan Shepard launched into space atop a Redstone rocket to become the first American spaceflyer. But unlike the Soviet Union's orbital success of cosmonaut Yuri Gagarin, Shepard's flight lasted just 15 minutes in a suborbital hop.
NASA's "Grand Tour" of the outer solar system launched the Voyager 1 and 2 probes in 1977 on a 12-year flight to the gas giants Jupiter, Saturn, Uranus, Neptune and their moons. The spacecraft returned stunning images and data of the outer planets and carried golden records bearing the images, greetings and sounds of Earth to the stars in case alien life forms should find them.
On December 21, 1968 Apollo 8 launched on a stunning first manned trip around the moon. It was the first crewed spacecraft to leave low Earth orbit and the first to reach the Moon, orbit it, and return, all while beaming home the first photos of Earth as seen from the moon.
On July 20, 1969, after the Apollo 1 tragedy and series of successful tests in Earth and lunar orbit, Apollo 11 astronauts Neil Armstrong and Buzz Aldrin guided their Eagle lander to Tranquility Base on the surface of the moon while crewmate Michael Collins circled above inside the command module Columbia. The landing marked success for the U.S. over the then-Soviet Union what has since been billed as the Space Race.