Six Apollo lunar landing missions explored various geologic terrains on the near side of the Moon. This collection of images shows each site explored along with footprints left by astronauts between landing sites.
Apollo 14 conducted research at Fra Mauro Crater for evidence of impact melt breccias and rock ages from Imbrium Basin. This mission included two EVAs and ALSEP experiments.
Apollo 11
Neil Armstrong and Buzz Aldrin left footprints etched into lunar soil at the Sea of Tranquillity (Mare Tranquillitatis), where they set foot on 21 July 1969. For two and a half hours at this location, Apollo 11 astronauts conducted science and engineering experiments, displayed an American flag, read an inscription plaque, photographed their surroundings, spoke to President Richard Nixon via telephone call, took photographs for President Nixon, collected rock samples and soil samples and conducted scientific observations at this spot.
Apollo missions to the Moon returned with nearly 400 kilograms of lunar samples that have since formed the backbone of most current Solar System research. Furthermore, various Apollo landing sites provide areas on which spacecraft orbiting above can calibrate instruments for use on orbit and test analytical techniques against samples returned by Apollo missions.
Each Apollo site was carefully selected to explore a particular geologic terrain. While on the surface, astronauts collected everything from mare basalts and ancient highland rocks to impact-shattered breccias.
Given their limited time on the Moon, selecting an ideal landing site was no simple matter for astronauts. Many factors must be considered when making their selection – including how easily a lander could reach its target destination.
As such, a large area along the Moon’s equator was identified as being suitable for landing missions.
NASA selected a site near the boundary between Mare Crisium and Mare Fecundiatis for their second lunar landing, at a site situated between Mare Crisium and Mare Fecundiatis. This location enabled their astronauts to achieve their mission goals efficiently, including deployment of experiments which measured temperature changes on the lunar surface as well as thermal flows in lunar regolith. They could also collect rocks from Crater Gassendi and explore Humorum basin from this spot.
Apollo 15
Astronauts Dave Scott and Jim Irwin from Apollo 15 collected over 115.3 kilograms (253 pounds). Their landing site was in Taurus-Littrow region dominated by Littrow craters and Taurus Mountains – this hilly region incorporated two main geology objectives – collecting rocks from Apennine Mountains for analysis, as well as studying Hadley Rille, a volcanic channel nearby the landing site.
At Spur Crater on Mount Hadley Delta, the crew collected samples of anorthosite rock composed almost entirely of plagioclase mineral; scientists believe it was formed early in Moon history during an event known as magma ocean. Furthermore, they collected some pyroclastic glass which is an intriguing type of volcanic rock which forms quickly when lava cools rapidly; geologists can use pyroclastic glass samples to gain more information on conditions at which lava flowed onto and across its surface.
As well as collecting rock samples, the astronauts also took photos and deployed the first Lunar Surface Experiment Package (ALSEP). Furthermore, they visited an adjacent crater as well as NASA’s Surveyor III radar station which had just landed 20 April 1967.
For optimal viewing of Apollo 15 sites, the ideal time is one or two days either side of full Moon. Craters such as Descartes feature bright patches of material on its northern wall; surrounding lava fields can also be observed. Fra Mauro offers plenty of interesting craterlets such as Bonpland, Parry and Catherina located to its south and east as well as many smaller craterlets such as Silver Spur which is actually located along its edge; furthermore Bennett Hill lies directly north-northwest of crater Last as indicated on labeled images provided by ALSJ images.
Apollo 16
Apollo 16 was supposed to land on the near side of the Moon on March 17, but due to an issue with docking ring jettisoning it had to be postponed until April.
The astronauts focused their exploration on the Descartes region of the lunar highlands. Their goal was to ascertain whether these features, suspected through orbital observations and telescopic imagery, were volcanic in nature or not. Their chosen site offered the perfect chance for this investigation: at its edge lay Cayley Plains crater adjacent to Descartes Mountains offering ample opportunity for sampling both features simultaneously.
Geologists had anticipated that this region of lunar terrain would provide samples of ancient volcanic rock. Instead, astronauts discovered complex breccias–rock fragments fused together by impacts. This evidence indicated that mountains weren’t formed through volcanic action alone but rather glacial activity which had created depressions on its surface.
Young and Duke used their lunar module rover to travel north from where it landed on April 20, passing Survey Ridge before climbing a crater wall to Stone Mountain. There they discovered a variety of rocks and soil samples originating from South Ray Crater; additionally they collected footprints as evidenced by this photo taken by Young.
The Apollo astronauts returned 731 lbs of rocks and dirt from their landing sites back home. Additionally, they took many photographs – our collection provides a selection of them! Of course, to truly see Apollo hardware is to visit the Moon (we wish!) or at least view it from space via NASA’s Lunar Reconnaissance Orbiter which has taken some breathtaking shots showing not only spacecraft like Apollo but also tracks left by astronaut rovers on its surface.
Apollo 17
After three and a half years of space flight and five manned landings, Apollo 17 marked the sixth and last time humans set foot on the Moon. Commander Gene Cernan and Lunar Module Pilot Harrison Schmitt spent 22 hours outside their lunar module collecting rock samples at Taurus-Littrow Valley in Taurus-Littrow that revolutionized our understanding of our celestial neighbor.
At the conclusion of their mission, astronauts aimed to meet several scientific objectives during this final mission of the manned program. For instance, they wanted to collect both older highland rocks and younger volcanic materials – an effort crucial in dating the impact basins where these deposits originated.
Astronauts selected a location on the rugged highlands north of Fra Mauro Crater as the optimal place for this mission, in hopes that complex impact melt breccias in this area would reveal how old Serenitatis basin really was compared with Imbrium basin, thought to be relatively younger.
Other sites were considered, including Alphonso Crater and Gassendi and Copernicus Peak Central Peak Central Peak Central Peak Central Peak Gassendi Copernicus Copernicus Central Peak Copernicus Copernicus Copernicus; but in the end, scientists decided on a highland-volcanic site located south of Mare Serenitatis as their choice.
Astronauts also carried an Advanced Lunar Surface Experiments Package (ALSEP), although its effects did not have as large an effect in selecting landing sites as in earlier missions due to networked deployment of instruments by this ALSEP and heat flow experiment malfunction; regardless, all scientific goals of this mission were accomplished successfully.
Apollo 18
Harrison Schmitt and Gene Cernan led the final Apollo mission, landing at Taurus-Littrow valley near Mare Serenitatis (Serenity Sea). While close to Apollo 15’s landing area but further east across Posidonius crater’s distinctive oval shape, Taurus-Littrow valley provided them with the chance to sample both young rocks from the valley floor as well as older specimens in nearby craters.
Geological samples collected by astronauts would help scientists date and understand the impact of Humorum Basin, as well as give more information on Gassendi crater’s age. Two EVAs were carried out and collected 43 kilograms of samples in total.
Alternatively, had Apollo 18 been successful, it would have provided valuable insight into the Moon’s past history and promoted lunar science further – as well as reinvigorating public enthusiasm for NASA’s grand space adventures, leading to increased funding and possibly leading back towards Mars.
Alphonsus Crater Landing Zone offered several intriguing geological features despite being an uncertain landing site, according to modern datasets. Astronauts planned on exploring Copernicus’ central peak base; modern datasets suggest they might have discovered exotic rocks such as olivine and pink spinel anorthosite, both thought to originate in the Moon’s mantle. Furthermore, several dark-halo craters on its wall offered opportunities for sampling young volcanic material; but eventually decided these sites weren’t scientifically significant as other options available in order to land at Alphonsus crater.