SEA OF TRANQUILITY

Sea of Tranquility Location Description

Mare Tranquillitatis, Latin for the Sea of Tranquility, is one of 23 Maria formations on the Moon. These types of formations appear as dark areas on the lunar surface when viewed from Earth. Ancient astronomers believed these dark areas were large bodies of water and named them Mare, from the Latin word Maria, which means Seas. These Lunar Maria were actually created by ancient lava flows which occurred on the Lunar surface between 3.8 to 3.2 billion years ago while the Moon was undergoing a period of major volcanic activity. The Sea of Tranquility was a large impact basin that filled with lava during this volcanic period. The lava in this Sea encompasses an area of approximately 700 to 950 Km (435 to 590 miles) in diameter and has an average depth of 1 kilometer (3,281 feet) thick.

The volcanic material in this basin consists mostly of basalt. Basalt is a common form of volcanic rock found on Earth as well as the Moon. Basalt is a Silicate mineral formed when lava flows are pushed to the surface and cool rapidly. This type of rock is characterized by its dark color and lack of crystallization. The Tranquillitatis basin was filled with this type of lava when its mantle partially melted more than 3 billion years ago. It is believed that major impacts thinned the crust in this basin, causing the mantle to either rise because of the reduced pressure pushing down on it, or allowing the molten lava below to be pushed towards the surface and upwards through the mantle, due to the reduced surface material holding it down.

The Sea of Tranquility is best know as the location where man first set foot on the moon when the Apollo 11 Lunar Module, named the “Eagle”, touched down at “Tranquility Base” on July 20, 1969, with astronauts Neil Armstrong and Edwin “Buzz” Aldrin aboard. Astronaut Michael Collins remained in orbit around the moon aboard the Command Module, named “Columbia”. A few glitches in the Lunar Modules computer caused them to overshoot their intended landing site, and necessitated that pilot Neil Armstrong take semiautomatic control of the descent in order to keep them from landing in West crater and the surrounding area which was filled with large boulders. This first moon landing was filled with anxiety as the Lunar Module began running low on fuel, and several computer alarms diverted the crews attention. When the Eagle had finally landed, there was only an estimated 25 seconds of fuel remaining for the descent stage engine. Approximately 7 hours after landing on the lunar surface, Armstrong and Aldrin became the first men to walk on the moon. The Apollo 11 Lunar Module remained on the moon for a total of 21 hours and 38 minutes, and the astronaut’s moon walk lasted only 2 hours and 31 minutes, during which time they covered an area smaller than the size of a soccer field. As a result of this successful mission, three craters in the area were officially named after the crew of Apollo 11; crater Sabine B was renamed Aldrin Crater, Sabine D was renamed Collins Crater and Sabine E was renamed Armstrong Crater.

Two unmanned mission sites, Surveyor 5 and Ranger 8, are also near the Apollo 11 landing site. The Surveyor 5 spacecraft is approximately 25 km north-northwest of the Apollo 11 landing site, and the impact crater formed by Ranger 8 is 69 km northeast of the landing site.