July 20th marks the 50th Anniversary of the successful Apollo 11 lunar landing. Born as an outgrowth of the Cold War competition between the United States and the Soviet Union, the Apollo program sent twenty-four astronauts to the moon. Twelve of them set foot on the moon. The first two were Neil Armstrong and nineteen minutes after his first step Buzz Aldrin. Ten additional men walked on the moon. The last two were Apollo 17 astronauts Harrison Schmitt and Eugene Cernan in December 1972. As the last to enter the lunar module, Cernan was the last human to leave footprints on the moon.
Moon Birth
Earth’s moon is the fifth largest satellite in the solar system. Rocks brought back by Apollo astronauts support the theory that the moon was formed ~4.5 billion years ago. While there are competing theories, the most popular is the Theia impact theory. The Moon forms from debris after Theia, a Mars-sized object crashes into the young Earth.
Relationship with Earth
The moon’s orbit is synchronous with the Earth’s rotation. Because of this, viewers from Earth always see the same side of the moon. The Moon’s average distance from the Earth is 238,856 miles (384,402 km). Retroreflectors placed by Apollo 11, 14, and 15 as well as two Soviet Lunokhod missions allow accurate measurements of the distance to within 1 millimeter.
The gravitational interaction between the Moon and the Earth slows the rotation of the Earth. The effect is small, but in one hundred years our day will be two milliseconds longer. Additionally, this transfer of the Earth’s rotational momentum to the Moon increases the Moon’s speed. As the Moon gets faster, it moves further away from the Earth. Currently it recedes approximately 1.5 inches (~3.8 cm) per year.
Apollo Program Facts
- At 316 feet (96 m) the Saturn V rocket that carried the Apollo missions was taller than the Statue of Liberty and The Tower Clock (Big Ben) in London.
- Apollo cost $25.4 Billion in then dollars or ~$120 in today’s dollars.
- All Apollo landing sites have been found and photographed by various lunar orbiters. All US flags except the one left by Apollo 11 remain standing. It was knocked down by the blast when the crew lifted off.
- Black & Decker’s Dust Buster portable vacuum shares code with a drill the company designed for NASA.
- William Anders picture of the Earth rising over the Moon (known as Earthrise) was taken on the Apollo 8 mission.
- More than 400,000 people (34,000 NASA employees and 375,000 contractors) worked on the Apollo program.
- The spacesuits worn by the astronauts on the Moon were designed by the industrial division of Playtex.
- NASA required astronauts from the first three missions to land on the moon to remain in quarantine for three weeks after splashdown.
- During lift off Apollo 12 was struck by lightning – twice. The crew used an auxiliary system to continue their mission.
- On 27 January 1967, Virgil I “Gus” Grissom, Edward H. White II, and Roger B. Chafee die in a fire during a launch rehearsal test.
This week’s map (courtesy of Westminster College)
The near side of the moon with major features and Apollo landing sites labeled.
For those interested more than the Apollo landings, here’s a lower resolution map (Wikipedia Commons).
As always thanks for reading.
Armen
Note to pay the bills: The moon is a central feature in many of the stories in the Warder series – in fact a full moon is on every cover. Interested in a James Bond-like thriller in a fantasy setting? Check out a summary of the series here or find links to purchase books here.