Tranquility Base

• 1. Site Selection And Landing

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  For more than two years, NASA planners considered a collection of 30 potential sites for the first crewed landing. High-resolution photographs taken by the Lunar Orbiter spacecraft helped narrow this list to five sites located near the lunar equator. These locations ranged between 45 degrees east and west, and 5 degrees north and south of the center of the Moon's facing side. They were numbered 1 to 5, going from east to west. Site number 2, centered at 0.674 degrees north latitude and 23.473 degrees east longitude, was the Sea of Tranquility site ultimately chosen. Since a precision landing was not expected on the first mission, the target area was an ellipse measuring 5 kilometers east and west by 4 kilometers north and south. On the actual landing day, a combination of thrust from residual pressure in the docking tunnel that connected the Lunar Module with the command module Columbia in orbit, and an imperfect understanding of the Moon's uneven gravitational field, resulted in navigation errors. These errors pushed the powered descent initiation point about 2 kilometers downrange, and thus the computer-targeted landing spot about 4 kilometers downrange west of the planned target. The automated targeting system was taking Eagle toward what Armstrong described as a football-field sized crater filled with big boulders and rocks. He avoided this hazard by assuming manual control and flying a bit farther downrange. The landing remained within the original target ellipse.

• 2. The Eagle Has Landed

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  On the 20th of July 1969, Apollo 11 crewmembers Neil Armstrong and Buzz Aldrin landed their Apollo Lunar Module Eagle at approximately 20:17:40 UTC. Armstrong exited the spacecraft six hours and 39 minutes after touchdown, followed 19 minutes later by Aldrin. Armstrong announced the name of the site at 20:17:58 UTC, approximately 18 seconds after his and Aldrin's successful landing. He stated Houston, Tranquility Base here. The Eagle has landed. During training, Armstrong and Aldrin had exclusively used the callsign Eagle in simulated ground conversations, both before and after landing. They decided on using Tranquility Base just before the flight, telling only Capsule Communicator Charles Duke before the mission so Duke would not be taken by surprise. The name has become a permanent designation for the site. Although the name was designated by the Apollo astronauts, the International Astronomical Union officially recognizes the designation Tranquility Base. It is listed on lunar maps as Statio Tranquillitatis, conforming to the standard use of Latin for lunar place names.

• 3. Artifacts And Scientific Legacy

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  About 100 artificial objects, as well as footprints left by Armstrong and Aldrin, remain at Tranquility Base. Armstrong commented that during the launch of Eagles ascent stage he could see Kapton and other parts on the LM staging scattering all around the area for great distances. The descent stage of the Lunar Module remains at the original point of landing. According to Aldrin with apparent confirmation from later Lunar Reconnaissance Orbiter photos, the US flag planted at the site during their moonwalk was blown over by the ascent rocket exhaust but remains on the surface of the Moon. A laser reflector was placed at the site to allow precise ongoing measurements of the distance to the Moon from Earth. A solar-powered seismometer was also left to measure moonquakes, but this stopped functioning after 21 days. A disc containing the Apollo 11 goodwill messages was left at the site. Various gear that was no longer needed for the return phase of the mission including Aldrins boots was left behind to lighten the craft for return to lunar orbit. They spent two hours and 31 minutes examining and photographing the lunar surface while collecting dirt and rock samples for return to Earth.

• 4. Legal Status And Protection Efforts

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  The U.S. states of California and New Mexico have listed it on their heritage registers since their laws require only that listed sites have some association with the state. Texas has not granted similar status to the site despite the location of Mission Control in Houston as its historic preservation laws limit such designations to properties located within the state. The U.S. National Park Service has declined to grant it National Historic Landmark status to avoid violating the Outer Space Treaty's prohibition on any nation claiming sovereignty over any extraterrestrial body. It has not been proposed as a World Heritage Site since the United Nations Educational Scientific and Cultural Organization limits nations to submitting sites within their own borders. Interest in according the site some formal protection grew in the early 21st century with the announcement of the Google Lunar X Prize for private corporations to successfully build spacecraft and reach the Moon. A $1 million bonus was offered for any competitor that visited a historic site on the Moon. One team led by Astrobotic Technology announced it would attempt to land a craft at Tranquility Base although it canceled those plans. The ensuing controversy led NASA to request that any other missions to the Moon keep a distance of at least 300 meters from the site. In 2020, the One Small Step to Protect Human Heritage in Space Act was enacted protecting Tranquility Base and other Apollo landing sites from damage from US-licensed space activity.

• 5. Cultural Impact And Depictions

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  Tranquility Base has been depicted in many books films and television shows such as in the 1996 novel The Tranquillity Alternative by Allen Steele. The 1998 mini-series From the Earth to the Moon also featured the location. The 2015 series The Astronaut Wives Club included references to the base while the 2018 film First Man portrayed events surrounding the mission. Tranquility Base is referenced in Boat on the River by the American Rock band Styx from their 1979 album Cornerstone with lyrics stating all roads lead to Tranquility Base. Indie rock band Arctic Monkeys released an album titled Tranquility Base Hotel & Casino in 2018 which used the location as the setting for a fictional hotel and casino. These cultural works reflect how the physical site became a symbol of human achievement and exploration beyond Earth.