On July 20, 1969, Apollo 11’s Lunar Module successfully landed on the Moon. It was the culmination of so much work and carried the hopes and dreams of the entire nation. You’ve seen Neil Armstrong’s first steps on the Moon. You’ve heard his historic first words. But, did you know these other things about that mission?
In this article, we’ll talk about the Eagle almost running out of fuel, how long Armstrong and Buzz Aldrin spent on the moon and which of the experiments they planted is still working today.
1) The Eagle landed with less than a minute of fuel left
This Lunar Test Article 8 is what Apollo astronauts used to train for lunar descents.
Apollo 10 came within 8.4 nautical miles of the moon and served as a warmup act for the historic day Apollo 11 provided a few months later.
Those last eight miles proved to be a doozy. When Armstrong and Buzz Aldrin were descending to the lunar surface, Armstrong had to think fast as the Eagle overshot the original descent location by four miles due to their speed and a slight miscalculation. Armstrong had to avoid their new target, which was right in the middle of a crater, since they needed a level landing site and the crater was strewn with boulders.
Armstrong’s maneuvering put the Eagle in a solid landing position, but left him with precious little fuel to abort. The descent section of the Eagle only had a minute of fuel left when it touched down on the Moon.
Armstrong was a former naval aviator who was a test pilot for the precursor to NASA, the National Advisory Committee for Aeronautics. His quick thinking saved the mission.
2) Neil and Buzz spent less than a day on the Moon
Apollo 11 went a long way to stay for less than a day. Though later missions increased the duration of the astronaut’s stay on the Moon, Neil and Buzz were never set to stay long. The entire Apollo 11 mission took eight days, launching July 16 and splashing down in the Pacific Ocean July 24.
That didn’t leave much time for those historic first Moon walks. The Eagle touched down on the lunar surface at 20:17 GMT July 20 and lifted off again at 17:54 GMT July 21.
The two intrepid astronauts used up every second of that time, however, planting a close-up soil camera, the iconic American flag, a solar wind collector, a plaque commemorating the occasion, medallions honoring cosmonauts, a seismometer and collected rock samples. They even had time to talk to U.S. president Richard Nixon.
3) The Laser Ranging Retroreflector still works
The Laser Ranging Retroreflector at its new home on the Moon.
Basically, there are still laser beams being shot at the Moon and this piece of equipment still works 49 years later. The Laser Ranging Retroreflector experiment was deployed on Apollo 11, 14, and 15. It consists of a series of corner-cube reflectors, which are a special type of mirror with the property of always reflecting an incoming light beam back in the direction it came from.
Why are we still shooting lasers at the Moon? Besides the simple fact that we can, this neat bit of science helps us learn about the Moon every day.
These reflectors can be illuminated by laser beams aimed through large telescopes on Earth. The reflected laser beam is also observed with the telescope, providing a measurement of the round-trip distance between Earth and the Moon. This is the only Apollo experiment that is still returning data from the Moon.
That data includes an improved knowledge of the Moon’s orbit and the rate at which the Moon is receding from Earth (currently 3.8 centimeters per year) and of variations in the rotation of the Moon. These measurements have also improved our knowledge of changes of the Earth’s rotation rate and the precession of its spin axis and have been used to test Einstein’s theory of relativity.