Forty years ago men from Earth made history on the moon. On July 20, 1969, Apollo 11 astronauts Neil Armstrong and Buzz Aldrin became Earth's first human emissaries to set foot on the lunar surface while crewmate Michael Collins orbited high above. In this retrospective for SPACE.com, Armstrong - the first human to walk on another world - recalls the heady year at the peak of the Space Race between the U.S. and Soviet Union that led to the first manned moon landing:

From a historic perspective, this is a particularly significant time in the annals of space exploration.

The first artificial earth satellite was launched just over a half century ago marking the beginning of the Space Age in 1957. Yuri Gagarin became the first human to orbit the Earth four years later.  

Forty years ago, the Soviet Union and the United States were locked in an epic battle to be pre-eminent in space and the first to send humans to the moon.

In October of 1968, the Americans launched their first Apollo spacecraft with humans aboard. Later that same month, the Soviets launched Soyuz 3 which rendezvoused with Soyuz 2. In December, the second Apollo crew (Apollo 8) became the first humans escape the Earth's gravity and the first to circle the moon.

In January of 1969, Soyuz 4 launched and was followed by Soyuz 5 the following day. After docking, two crewmen from Soyuz 5 exited their craft and transferred outside to the other craft, Soyuz 4. They returned to Earth in Soyuz 4.

Two months later, Apollo 9 launched with two spacecraft, the normal Apollo Command Module and the new lunar landing craft, the Lunar Module. It was the first checkout flight of the ungainly machine in Earth orbit.

The lunar module flew again in May on Apollo 10, this time to the moon in a full dress rehearsal except for the descent and landing. Those two flights completed the flight test requisites mandatory prior to an attempt to achieve the Apollo goal.

On July 20, Apollo 11's crew piloted their Lunar Module to the first successful landing on the surface of the moon. In October, Soyuz 6, 7, and 8, with seven cosmonauts aboard, flew simultaneously and in November, Apollo 12 made the second of the six successful landings on the moon.

The flights of 40 years ago were among the most exciting in the history of spaceflight. We can expect a number of retrospective articles and television broadcasts to focus on this anniversary year. I look forward to remembering that memorable time.

--  Neil Armstrong

• Video: The Meaning of Apollo
  Neil Armstrong and other Apollo astronauts reflect on the project with thoughts personal and profound, on risk, fame, and what's next for the moon.

• SPECIAL REPORT: The Moon: Then, Now, Next
  Forty years after astronauts first set foot on the moon, SPACE.com examines what we¹ve done since and whether America has the right stuff to get back to the moon by 2020 and reach beyond. For exclusive interviews and analysis, visit SPACE.com daily through July 20, the anniversary of the historic landing.