Lunar and Planetary Institute






Apollo 11 Mission


Landing Site Overview

Astronaut Aldrin immediately began describing the the view from the window:

". . . it looks like a collection of just about every variety of shapes, angularities, and granularities, every variety of rock you could find . . . it looks as though they're going to have some interesting colors to them."

Landing Site Selection
The Apollo 11 landing site in Mare Tranquillitatis was one of three sites selected for the first lunar landing from a list of 30 sites originally under consideration. Final site choices were based on the following factors:

Smoothness:  Relatively few craters and boulders

Approach:  No large hills, high cliffs, or deep craters that could cause incorrect altitude signals to the lunar module landing radar

Propellant Requirements:  The least expenditure of spacecraft propellants

Recycle:  Effective launch preparation recycling if the Apollo Saturn V countdown is delayed

Free Return:  Within reach of the spacecraft launched on a free-return translunar trajectory

Slope:  Less than 2° slope in the approach path and landing site

Orbital Views of the Landing Site
   
Apollo 11 site: Earth-based telescopic view Apollo 11 site: Earth-based telescopic view
The arrow points to the landing site in the southern portion of Mare Tranquillitatis. The two large craters near the middle of the lower margin of the photograph are Theophilus and Cyrillus. The rim of Theophilus Crater truncates (cuts across) the rim of Cyrillus Crater, indicating that Theophilus is the younger crater. Ejecta from Theophilus may be present in the vicinity of the Apollo 11 landing site. Craters in the vicinity of the landing site include Moltke (the bright-rayed crater to the lower right of the arrow), Sabine (left of arrow) and Maskelyne (upper right of arrow). (Consolidated Lunar Atlas photograph E9. [Reference: Kuiper, G.P., E.A. Whitaker, R.G. Strom, J.W. Fountain, and S.M. Larson (1967).] Consolidated Lunar Atlas: Supplement Numbers 3 and 4 to the USAF Photographic Lunar Atlas. Lunar and Planetary Laboratory, Tucson, Arizona.)
   
Apollo 11 site: Oblique view Apollo 11 site: Oblique view
The bright rays of Moltke Crater (lower right of arrow) are quite prominent in this low-phase-angle photograph. The higher albedo of the highland material, relative to the dark mare regions, also is evident in this view. Due to the oblique viewing geometry of this photograph, the scale bar is most accurate near the bottom margin of the photograph. (NASA photograph AS16-1389[M].)
   
Apollo 11 site: Moderate-resolution vertical view Apollo 11 site: Moderate-resolution vertical view
This photograph was taken from the Lunar Module and it includes both the landing site (arrow) and the Command/Service Module (upper right of arrow). The sharp-rimmed crater at the lower margin is Moltke. The craters north and west of the landing site are secondary craters resulting from ejecta thrown out of Sabine Crater. (NASA photograph AS11-37-5447.)
   
Apollo 11 site: Enlargement of high-resolution view Apollo 11 site: High-resolution vertical view
The two groups of irregularly shaped craters north and west of the landing site are secondaries from Sabine Crater. This view was obtained by the unmanned Lunar Orbiter V spacecraft in 1967 prior to the Apollo missions to the Moon. The black and white film was automatically developed onboard the spacecraft and subsequently digitized for transmission to Earth. The regularly spaced vertical lines are the result of combining individually digitized 'framelets' to make a composite photograph. and the irregularly-shaped bright and dark spots are due to nonuniform film development. (NASA Lunar Orbiter photograph V-76-H3.).
   
Apollo 11 site: Enlargement of high-resolution view Apollo 11 site: Enlargement of high-resolution viewThe fresh 180-meter-diameter crater left of the center is West Crater. The landing site is about 60 meters west of 33-meter-diameter Little West Crater. Astronaut Neil Armstrong visited the rim of Little West Crater while astronaut Edwin Aldrin worked around the Lunar Module. (NASA Lunar Orbiter photograph V-76-H3.)
   
Apollo 11 approach view Apollo 11 site: Approach view
This oblique photograph was taken from the Apollo 11 Lunar Module looking west over Mare Tranquillitatis. The Apollo 11 landing site was to the right of center in this photograph, near the terminator (the transition from day to night). Although there are a number of craters, ridges, grooves, and volcanic channels visible here, the region overall is relatively smooth, which was a primary consideration in its selection as the landing site. In the right foreground, the crater Maskelyne is 23 kilometers in diameter. It is 210 kilometers from the center of Maskelyne to the Apollo 11 landing site. (NASA photograph AS11-37-5437.)

 

Zoom in on the Landing Site (115KB) in quick time format

Stereoscopic Views of the Landing Site

Stereoscopic Views of the Landing Site
Stereoscopic View of the Landing Site

Stereo Viewing
Red/Green (Anaglyph) Images
To view anaglyph stereo pairs you need red-green (or red-blue) stereo glasses. These glasses have a red lens over the left eye and green (or blue) lens over the right eye.

Black and White Images
To view side-by-side stereo pairs, use pocket stereo viewers (obtainable from local educational suppliers, bookstores, etc.).

Side-by-side stereo pairs can also be viewed with the unaided eye by focusing on each image separately and allowing the eyes to cross. If you wear glasses, it may be necessary to remove them and view the pairs from 6 to 10 inches away. These techniques may require some practice (the Apollo 15, 16 and 17 stereo pairs are good for this purpose). Another means of assisting this process is to place an index card upright between the two images, forcing each eye to see the different images. Only approximately 10% of the general public cannot view images stereoscopically.

The Apollo 11 landing site is located on the smooth volcanic plains of southwestern Mare Tranquillitatis. The landing site is marked by the small green cross. Comparison of this site with the subsequent landing sites for Apollo 14, 15, 16, and 17 dramatically illustrates why this site was chosen, namely for its lack of rugged relief. These views show an area 25 kilometers across from top to bottom, with north at the top. The vertical exaggeration is about 3. Apollo 10 photographs (AS10-31-4537 and AS10-31-4539.)

Surface Views of the Landing Site  
Panoramic Views Around the Landing Site  
   

North of the Apollo 11 Landing Site
This photograph was taken from a lunar module window and shows a boulder field to the north of the landing site. The boulders were ejected from West Crater, which is about 400 meters east of the landing site. During Apollo 11's lunar landing, Neil Armstrong had to manually fly the lunar module over West Crater and portions of the boulder field to locate a safe landing site. Most of the rocks collected on Apollo 11 are believed to be material that was ejected when West Crater formed about 100 million years ago. (Apollo 11 photograph AS11-37-5467.)

Apollo 11 image showing a boulder field to the north of the landing site.
   
East of the Apollo 11 Landing Site
Little West Crater is about 60 meters east of the Apollo 11 landing site. It was briefly examined by Neil Armstrong near the end of his moonwalk. The crater is 33 meters across and 4 meters deep, with many small boulders on its floor. This photograph was taken from the southwest rim of the crater. (Apollo 11 photograph AS11-40-5956.)
Little West Crater
   
South of the Apollo 11 Landing Site
The terrain near the Apollo 11 landing site is generally quite flat. This site was chosen to minimize risk on this first lunar landing. (Apollo 11 photograph AS11-40-5890.)
South of the Apollo 11 Landing Site
   
West of the Apollo 11 Landing Site
(Apollo 11 photograph AS11-40-5930.)
West of the Apollo 11 Landing Site

The Lunar Regolith

The lunar regolith, or "soil," consists of tiny rock fragments that have been broken up by the bombardment of meteorites on the lunar surface over the eons. Most regolith particles are the size of fine-grained silt or sand.However, there are also larger fragments, including pebble-sized objects and even some boulders. At the surface, the regolith is somewhat porous, but it becomes more densely packed as the depth below the surface increases.

One important objective of the Apollo 11 mission was to observe the properties of the regolith and assess how these properties affected the crew's ability to move about and to work on the lunar surface. This investigation was known as the Soil Mechanics Investigation, which on Apollo 11 consisted of verbal descriptions by the crew and close-up photographs of the regolith, including three-dimensional stereo photographs.

Image of footprint on the Moon "The surface is fine and powdery. I can kick it up loosely with my toe. It does adhere in fine layers like powdered charcoal to the sole and sides of my boots. I only go in a small fraction of an inch, maybe an eighth of an inch, but I can see the footprints of my boots and the treads in the fine sandy particles." - Neil Armstrong (Apollo 11 photograph AS11-40-5977.)
   
Image of the footpads on the lunar module's legs. The footpads on the lunar module's legs penetrated 2-8 centimeters into the regolith. This is about the amount of penetration that was predicted prior to the mission. The rod-shaped object protruding from beneath the footpad is a contact probe. These probes originally extended about 1.5 meters vertically below the footpads and were used to indicate when the lunar module was approaching the Moon's surface. This allowed the descent rocket engine to be turned off just prior to landing. (Apollo 11 photograph AS11-40-5925.)
   
Image of lunar module's descent engine. The exhaust gas from the lunar module's descent engine caused some scouring of dust on the surface during landing. On Apollo 11, a significant dust cloud was visible when the lunar module was still 30 meters above the surface. The scouring of the surface is visible in this photograph of the region below the descent engine, although the scouring did not form any sort of hole in the surface. (Apollo 11 photograph AS11-40-5921.)