Mapping the Moon

Ordnance Survey celebrate the 50th anniversary of Apollo 11 by exploring the importance of moon mapping and creating our own

Buzz Aldrin on the moon with Neil Armstrong reflected in his visor

Despite it being one of the lesser documented components of the 1969 Apollo 11 mission, precise mapping was a key step in NASA’s preparation. 

Given the year this event took place, technology was limited in terms of mapping somewhere we had never been to before which was some 384,000km away. Understanding the lunar surface was logistically crucial in working out the safest landing site for Neil Armstrong and Edwin “Buzz” Aldrin.  

The landing site selection was an important step to achieving the goal of landing on the Moon before the end of the decade (a national goal set by President John F. Kennedy in 1961). 

So, how did NASA pick the landing site? 

Map of the Moon showing the five candidate landing sites chosen by the Apollo Site Selection Board in February 1968 (nasa.gov)

After two years of study, on 8 February, 1968 NASA’s Apollo Site Selection Board announced  five potential landing sites  for the first human lunar landing. These were chosen from a list of 30 3 by 5-mile candidate sites, all of which satisfied criteria that principally took the astronaut’s safety into account. All five sites for each mission were within the Apollo Zone of Interest, an area on the visible side of the Moon between 45 degrees East and West longitude and between 5 degrees North and South of the lunar equator. 

Close-up of the landing sites within the Apollo Zone of Interest (nasa.gov)

To select the five areas, NASA used high-resolution orbital photography and surface data returned by five Lunar Orbiters.

The following criteria was considered to determine the suitability of the candidate sites: 

  • Smoothness of the area: the sites should have relatively few craters.
  • Approach paths: there should be no large hills, tall cliffs or deep craters which could cause incorrect altitude signals to the landing radar. 
  • Propellant: the sites were selected to allow for the expenditure of the least amount of propellant.
  • Recycling during countdown: the sites were selected to allow for the recycling time of the Saturn 5 if the countdown were to be delayed.
  • Free-return: the sites must be within reach of the Apollo spacecraft in the free-return trajectory, that is a path that would allow a coast around the Moon and safe return to Earth without any engine firings should a problem arise on the way to the Moon.
  • Lighting: for optimum visibility during the landing approach, the Sun angle should be between 7 and 20 degrees behind the lunar module; for any given site, this results in a one-day launch window per month.
  • Slope: the general slope of the landing area must be less than 2 degrees.

On July 20, 1969, Armstrong and Aldrin became the first people to reach the moon when their Apollo 11 lunar lander Eagle touched down in the Sea of Tranquillity. The landing was about four miles downrange from the predicted touchdown point and occurred almost one-and-a-half minutes earlier than scheduled. It included a powered descent that ran 40 seconds longer than pre-flight planning due to translation manoeuvres to avoid a crater during the final phase of landing. Named by Aldrin and Armstrong, the landing site became known as Tranquillity Base. 

Statio Tranquillitatis (Tranquility Base) OS Moon Map

From launch to landing, the mission had taken 8 days, 3 hours, 18 minutes and 35 seconds.  

Before the Apollo programme ended in 1972, six missions and a dozen men had visited the moon. In 2019, as of the  50th anniversary of the Apollo 11 mission , 12 humans—all American and all men—have set foot on the moon. 

Following direction from President Trump on 26 March 2019 to land humans on the lunar surface again by 2024, NASA is planning their next mission to the moon with a spacecraft aptly named Artemis. By 2024, the first woman and next man will step foot where no human has ever been before; the Moon’s South Pole.  Find out more 

Historical moon mapping 

 The first published map of the Moon was made by the Belgian astronomer and cartographer  Michael Florent van Langren  in 1645. Thomas Harriot and Galileo Galilei both drew telescopic representations of the moon before this, but sadly these drawings remain unpublished. Langren was the first to assign names to many of the lunar features, however, few of these were accepted as they mostly corresponded to Catholic monarchs, scientists and artists. 

Map of the Moon, published by Michael van Langren in 1645 in his book Plenilunii lumina Austriaca Philippica

Famous amateur astronomer, Sir Patrick Moore, also produced a hand drawn map of the moon from his own observations using his homemade telescope at his home in Selsey, Sussex. These detailed pen and ink maps of the Moon's surface were used by NASA as part of their preparations for the moon landing. In 2007, Ordnance Survey (OS) printed 250 signed limited editions of the maps! 

Sir Patrick Moore's Outline Map of the Moon

OS mapping 

As we now have access to a range of images and 3D images of the Moon, the OS map of the Moon has been made using more modern-day techniques. If you’d like to find out more about the data and technicalities behind this design, then have a read of  our blog .

DEM to Hillshade

I mapped the lunar surface using a 60 metre per pixel digital elevation model or DEM which is a 3D image of the surface built using the terrains elevation data. This was supplied by  United States Geological Survey  (USGS) and was created by NASA's LOLA Team and JAXA's SELENE/Kaguya Team. I then converted this into a hillshade to give a more realistic view or impression of the moon's surface which I could control using the direction and height of a light source and vertical exaggeration of features.

The colour scheme for the lunar surface of our map was inspired by the winning Astronomy Photographer of the Year 2018 entry by Jordi Delpeix Borrell that I found on the  BBC website . Colour can seem so trivial at times, but as a cartographer I always aspire to represent map features as closely to their real-world equivalent as possible. Whilst I believe most of us would say the moon is grey and/or white, occasionally we are treated to a true-blue moon when the atmosphere is filled with dust or smoke particles. These particles scatter the red light and make the moon appear blue. It’s a wondrous sight and something I wanted to replicate in the map.

Extract from the OS Apollo 11 Landing Map OS Moon Map

The labels for the map came from the Planetary Nomenclature Gazetteer, which was supplied by NASA and the United States Geological Society (USGS). This includes the names of craters, lunar mares, bays, mountain ranges, ridges, valleys and trenches. 

I also decided to hide a couple of Easter eggs within the map. Both are linked to some information that is found in the maps legend. Happy hunting!

Ordnance Survey Apollo 11 Moon Map

This commemorative map is available to buy from the Ordnance Survey online shop and is available in a range of formats.

Grab yourself a piece of history!

Map of the Moon showing the five candidate landing sites chosen by the Apollo Site Selection Board in February 1968 (nasa.gov)

Close-up of the landing sites within the Apollo Zone of Interest (nasa.gov)

Statio Tranquillitatis (Tranquility Base) OS Moon Map

Map of the Moon, published by Michael van Langren in 1645 in his book Plenilunii lumina Austriaca Philippica

Sir Patrick Moore's Outline Map of the Moon

DEM to Hillshade

Extract from the OS Apollo 11 Landing Map OS Moon Map

Ordnance Survey Apollo 11 Moon Map