Astronaut Buzz Aldrin, lunar module pilot, walks on the surface of the Moon during the Apollo 11 exravehicular activity (EVA). Fellow astronaut (and photographer) Neil Armstrong, as well as the lunar module, Eagle, are visible in the reflection in Aldrin's helmet.

Photograph by Neil Armstrong, courtesy NASA
  • On July 20, 1969, American astronauts Neil Armstrong and Buzz Aldrin became the first humans to walk on the Moon. (The third member of the Apollo 11 crew, Michael Collins, piloted the orbiting spacecraft.) Armstrong stepped off the lunar landing module Eagle and,uttered the famous phrase “That’s one small step for man, one giant leap for mankind.”

    From more than 386,242 kilometers (240,000 miles) away, millions of people tuned into the radio and watched a live television broadcast. Armstrong and Aldrin spent 21 hours and 36 minutes exploring the Moon before safely returning to the command vehicle and Earth.

    NASA sent several additional Apollo missions to the Moon. Each mission studied different features of the Moon such as the Fra Mauro crater and the Taurus-Littrow highlands. These missions were interested in the physical and geographical aspects of the Moon, including soil properties, magnetic fields, and solar wind characteristics.

  • Term Part of Speech Definition Encyclopedic Entry
    aspect Noun

    view or interpretation.

    astronaut Noun

    person who takes part in space flights.

    crater Noun

    bowl-shaped depression formed by a volcanic eruption or impact of a meteorite.

    Encyclopedic Entry: crater
    highlands Plural Noun

    plateau or elevated region of land.

    lunar Adjective

    having to do with Earth's moon or the moons of other planets.

    magnetic field Noun

    area around and affected by a magnet or charged particle.

    Moon Noun

    Earth's only natural satellite.

    orbit Verb

    to move in a circular pattern around a more massive object.

    Encyclopedic Entry: orbit
    pilot Noun

    person who steers a ship or aircraft.

    soil Noun

    top layer of the Earth's surface where plants can grow.

    solar wind Noun

    flow of charged particles, mainly protons and electrons, from the sun to the edge of the solar system.

    spacecraft Noun

    vehicle designed for travel outside Earth's atmosphere.