#mare tranquillitatis

Concept art of Apollo 11 landing on the lunar surface.

"TRW Incorporated's artist concept depicting the Apollo 11 Lunar Module (LM) descending to the surface of the moon. Inside the LM will be astronauts Neil A. Armstrong, commander, and Edwin E. Aldrin Jr., lunar module pilot. Astronaut Michael Collins, command module pilot, will remain with the Command and Service Modules (CSM) in lunar orbit. TRW's LM descent engine will brake Apollo 11's descent to the lunar surface. The throttle-able rocket engine will be fired continuously the last 10 miles of the journey to the moon, slowing the LM to a speed of two miles per hour at touchdown. TRW Incorporated designed and built the unique engine at Redondo Beach, California under subcontract to the Grumman Aircraft Engineering Corporation, Bethpage, New York, the LM prime."

Date: July 1969

A hole in the moon This image, taken by the LROC instrument in orbit of Earth’s moon, shows a gigantic cave in Mare Tranquillitatis (The Sea of Tranquility). Based on the position of the sun and the spacecraft at the time this photo was taken and the length of the shadow on the bottom, scientists estimated the bottom of the cave was about 100 meters below the upper surface.

Here are some facts about the Sea of Tranquility, the chosen landing site for our first walk on the Moon:

Mare Tranquillitatis (Sea of Tranquility)

00.67408° N latitude, 23.47297° E longitude

Named in 1651 by astronomers Francesco Grimaldi and Giovanni Battista Riccioli, the Sea of Tranquility is a large lunar basin thought to have been formed 3850—3800 million years ago during the formation of the Inner Solar System (ca., Late Heavy Bombardment). Basalts in the area date back to 3800—3200 million years ago.

For the first lunar landing, the Sea of Tranquility was chosen due to its relatively smooth and level area. However, a last minute change in the original landing site was made due to the amount of craters present. The lunar module Eagle, piloted by Neil Armstrong, landed some four miles away from the pre-planned site.

But Apollo 11 was not the first to visit this area of the Moon. On February 20, 1965, the Ranger 8 spacecraft was deliberately crashed into the surface after successfully transmitting over 7,000 photographs of the Moon in the final 23 minutes of its mission.

Surveyor 5 also landed in Mare Tranquillitatis on September 11, 1967, after transmitting 19,118 images of the Moon, and was the fifth lunar lander of the unmanned Surveyor program.

Humanity's first steps beyond Earth were taken here on July 20, 1969 at 8:18 PM UTC (4:18 PM EDT). While astronaut Michael Collins orbited above, Neil Armstrong and Buzz Aldrin set up experiments and collected 49 pounds of lunar rocks and soil — the first extraterrestrial samples returned to Earth.

“The boundary between Mare Serenitatis and Mare Tranquillitatis”

L' Ametlla del Vallès, Barcelona, Spain, 6 December 2017