As Neil Armstrong and Buzz Aldrin’s Apollo 11 rocketed away, an eager crowd watched it lift off at Cape Kennedy. Following four hours of restful flight time, their astronauts started their first lunar excursion mission.
Apollo 11 was the inaugural lunar landing mission, fulfilling President John F. Kennedy’s 1961 goal and opening up five additional landing missions that greatly increased our knowledge of its geologic history. Armstrong made history by setting foot on its surface at 9:56 PM on 21 July 1969; saying to himself “That’s one small step for a man, one giant leap for mankind!”
Two hours later, Aldrin joined him. They spent just over two hours collecting rock and soil samples while conducting various experiments – such as installing a seismometer to record moonquakes and meteor impact after they had returned home, using laser retroreflectors to accurately measure distance between Earth and Moon by timing laser beam travel times, as well as collecting samples of lunar solar wind for study purposes.
Armstrong and Aldrin then embarked upon their voyage, reaching the Sea of Tranquility at 2:28 AM on 22 July–about one half hour ahead of schedule.
The Apollo 11 landing was the result of years of complex engineering and scientific planning and design. Although they experienced no major difficulties on the ground, they did need to overcome several computer alarms not present during simulations of their landing sequence. Armstrong took semi-manual control to steer his LM away from an area of boulders that turned out to be debris from West crater; otherwise the computer would have guided them there instead.
Apollo 14, the eighth and final US Apollo program crewed mission, was launched on February 5, 1971. This mission marked the first exploration of Fra Mauro Highlands – planned as Apollo 13’s destination – as it marked an H mission, designed for landings lasting two days each with two EVAs or moonwalks planned. Joe H. Engle was Lunar Module Pilot while Ronald E. Evans served as Command Module Pilot.
After conducting an initial check of Eagle, Armstrong and Aldrin launched their single moonwalk on February 6. When they first set foot onto the lunar surface – about 100 feet from where their LM would land – Armstrong famously said, ‘That’s one small step for man; one giant leap for mankind.”
They deployed seismometers and seismographic experiments designed to measure vibrations caused by tectonic activity on the Moon; performed passive seismic experiment monitoring gravitational environment changes; installed first lunar surface ALSEP central station antenna; photographed their surroundings; placed an American flag and plaque; collected rock samples as well as soil samples; took photographs and collected samples of rock.
Shepard and Mitchell attempted to ascend Cone Crater at the edge of Fra Mauro Highlands during their second EVA. Unfortunately, however, they ran into difficulty with navigation due to rough terrain that caused them to continually lose their way and turn back towards Mission Control’s Lunar Module (LM). Concerned that oxygen supplies might run low quickly, Mission Control quickly called them back. NASA engineers came up with an innovative solution: telling the flight computer that an abort sequence had already been initiated so any additional abort signals would simply be ignored by flight computer.
Apollo 15 marked NASA’s inaugural “J” mission series – scientifically ambitious expeditions designed to allow astronauts greater surface mobility than previous missions had allowed for. The crew consisted of Commander David Scott, Lunar Module Pilot James Irwin and Command Module Pilot Alfred Worden.
Launched on 20 July, the crew traveled quickly towards lunar orbit, arriving there the following day. On arrival they unloaded from their lander and explored Hadley-Apennine region including Hadley Rille – a canyon formed by lava flows – via three extravehicular activities (EVAs). Furthermore, astronauts conducted engineering evaluations on new equipment as well as conducting lunar orbital experiments.
On their second EVA, the astronauts traveled to Hadley Delta’s rim – known as “Elbow crater”. As the sun shone brightly overhead, casting plenty of shadows across the surface area. On this EVA, two lunar surface scientific experiments were activated while one failed prematurely; unfortunately they had to cancel one because it malfunctioned too soon.
On their return from their third EVA, astronauts were dismayed to see that the LM had not been completely recovered from its landing position. They noticed an off-scale temperature reading on its surface as well as discovering that its umbilical cable wasn’t connected properly – however re-plugging its connector fixed it quickly so astronauts could resume work immediately.
At the start of their final descent to the Sea of Tranquility, one of their parachute failed to open properly; nevertheless, they managed to land safely using both remaining parachutes and retro-fires – receiving greetings from President and Mrs. Nixon as well as receiving a framed flag worn by Irwin during EVAs.
Apollo 16 was NASA’s third and final lunar landing mission, launched from Earth on April 16, 1972 by a Saturn V rocket. It featured astronauts Commander John Young, Lunar Module Pilot Charles Duke and Command Module Pilot Ken Mattingly aboard its spacecraft; its goal was to conduct more science on the Moon than previous missions by conducting extensive lunar surface operations and an extended stay inside its lunar module (LM).
At 102 hours and 45 minutes into their flight, Eagle separated from Columbia and entered Site 2 in the Sea of Tranquility on the Moon’s surface. Following a quick check-out of Eagle’s systems, Armstrong took his first steps upon the moon with this gesture of humanity: he declared: “That’s one small step for man; one giant leap for mankind!”
On their single EVA (extravehicular activity), Armstrong and Aldrin conducted several scientific experiments, such as seismometers to monitor Moonquakes and a laser retroreflector that enabled precise measurements between Earth and Moon distance. They also took photos, placed an American flag in the soil, placed commemorative plaques, collected rock samples for returning back home as well as small amounts of water samples to bring back with them to Earth.
On their second trip out from the LM, astronauts took advantage of young lunar mare features surrounded by heavily cratered older regions to conduct geology traverses. An error in their lunar module computer caused an accidental drive into West Crater boulder field; Young used semi-manual control to avoid both boulders and an adjacent smaller crater (later named Little West) while conserving fuel.
After two and a half hours on the Moonwalk, Armstrong and Aldrin returned to the LM. Reentered their cockpit and, assisted by Mattingly, recovered several film cassettes from outside of the Service Module.
Apollo 17 was the sixth and final lunar mission in the Apollo program, landing on December 7th 1972 near Taurus-Littrow valley in Taurus-Littrow valley. Meanwhile, Command Module Pilot Ronald Evans prepared landing site preparation and conducted experiments from his spacecraft’s cabin during orbit around the Moon.
On EVA 1, astronaut Schmitt completed three Hasselblad panoramas at an ALSEP site located 195 meters from LM, as well as installing Heat Flow and Thermal Emission Array (HEAT) instruments and conducting Solar Wind Composition experiments. He also deployed HEAT.
At another ALSEP site, Schmitt and HEAT conducted experiments to gather data on lunar environment. In particular, they deployed eight seismic experiments (Set) and measured their effects with a traverse gravimeter (TGR).
At one of their sites, astronauts used explosive charges to create an artificial crater for Earth observation video footage and also conducted terrain surveys and deployed the Lunar Ranging Retroreflector as navigation control devices.
After completing their tasks and returning to the LM, the astronauts opted against taking their scheduled four-hour rest period due to excitement over having accomplished so much for their country.
The crew remained aboard the LM for over 21 hours before beginning their return journey back to Columbia. While on lunar orbit, they circled it 75 times. Evans performed two EVAs: an hour and six minute spacewalk to retrieve film cassettes from mapping cameras mounted outside, as well as performing an additional EVA to gather geologic data.