On the third EVA, Cernan and Schmitt drove to Van Serg crater where they collected house-sized rock, took gravimeter readings, deployed more experiments, but ran out of both water and oxygen and had to retreat back to LM.
Once inside, they relaxed. However, upon closer inspection they saw that the amount of sunlit land on Earth was gradually diminishing.
Apollo 17 – Mission Overview
Apollo 17’s successful launch took place on December 10, 1972 when its Command and Service Module (CSM), named Challenger, separated from its Lunar Module (LM), named Challenger, to enter lunar orbit. For two hours afterward, during which in-flight experiments were carried out and preparations made to land. Once ready to land at Taurus-Littrow valley region chosen due to geologic interest as well as proximity to possible young volcanic areas – they inserted Challenger’s Lunar Module there.
As soon as they landed, astronauts set up the Apollo Lunar Surface Experiments Package (ALSEP). This included the Heat Flow Experiment to measure thermal convection on the Moon; a Lunar Surface Gravimeter to monitor changes to lunar gravity fields; mass spectrometer to analyze what makes up its atmosphere; and Lunar Ejecta and Meteorites Experiment which tracked meteoroids striking the lunar surface with size and velocity measurements. All instruments of the ALSEP were arrayed around a central station which provided power as well as communications with Earth.
An important achievement of Apollo 17 was Harrison Schmitt’s historic spacewalk – the inaugural scientist-astronaut spacewalk ever performed by any person! On this 7.5 hour, 16 minute trip, Tracy’s Rock was discovered – it is the oldest rock ever collected by the Apollo program and features some of its youngest volcanic materials.
Once back at their LRVs, the crew drove the rover back to Station 1 near Steno crater. While driving along they observed orange soil which may have been caused by new volcanic activity; similar deposits were spotted by Apollo 15 Command Module Pilot Al Worden near dark halo craters in Alphonsus Lava Field during his expeditions.
After spending 32 minutes at Steno, Cernan and Schmitt returned to their LM and deployed the ALSEP surface electrical properties experiment, before climbing back aboard and performing EVA close-out tasks. They spent 22 hours over three EVAs driving 19 miles (30.5 km), collecting 108 kilograms (238 pounds). Furthermore, they observed lunar craters, studied the Sculptured Hills region, as well as measured lava flows.
Apollo 17 – Landing
Apollo 17’s launch was delayed one day due to an unknown technical problem with its command module, but ultimately entered lunar orbit on December 10. Astronauts Eugene Cernan and Harrison Schmitt prepared for exploration, using their Lunar Roving Vehicle (LRV) after disengaging from the command module to deploy scientific instruments including seismic experiments started on prior Apollo missions as well as scientific experiment packages with explosives for seismic investigations begun previously on previous missions.
The LRV’s primary duties were to collect samples and take photographs of lunar terrain, as well as to utilize an infrared imaging spectrometer and far-ultraviolet imaging spectrometer, respectively, to detect lunar surface temperatures and analyze chemical samples taken from various samples on its mission.
As they drove, the astronauts observed the varying shades of the Moon’s dusty landscape. One area, Shorty Crater, caught their eye; at first glance it appeared to be a volcanic vent due to the dark haloed material present; however upon closer examination they realized it was in fact just an impact crater rather than its source; nonetheless they were thrilled by this unexpected discovery! geologists were overjoyed about this unexpected finding!
As soon as they arrived at Station 4, it was time to prepare some lunch. Following a swift repast, they returned to the LM and prepared for another extravehicular activity (EVA).
After successfully performing their braking maneuver, the astronauts deployed an ALSEP seismometer near the rover’s parking spot before driving south towards Steno-Apollo or “Steno” crater and excavating 14 kilograms or 31 pounds of lunar rock to be placed into their experimental package along with two explosive charges to conclude seismic experiments initiated on previous Apollo missions.
On the second moonwalk, astronauts made use of tools aboard their Lunar Roving Vehicle including hammers and shovels for traversing across its desolate surface. Cernan was particularly proud to install his gnomon onto the surface which now sits as part of an exhibit at Washington D.C.’s Smithsonian Institution.
After 22 hours and 4 minutes, the scientists returned to the LM. This EVA became the longest in history, surpassing Armstrong and Aldrin’s 21 hour and 39 minute expedition at Tranquility Base.
Apollo 17 – Lunar Surface Experiments Package
ALSEP was an array of experiments intended to collect geological information on the Moon. It consisted of a central station that relayed commands, received and transmitted data, as well as providing two-way communications to enable astronauts to read out experiments via voice link back home on Earth. All other instruments were placed around it and powered by its 25 kilogram solar array.
ALSEP experiment packages were kept on a second subpallet along with tools and carrybar. Once unloaded from storage, these were to be carried at least 90 metres from LM and could take up to 120 minutes for deployment, power up, and activation. They consisted of a central station connected by flat ribbon cable to four individual probes each equipped with its own electronics box for controlling operation of instruments – each probe connected directly with central station via 15m cable.
ALSEP employed a passive seismic network to assess variations in lunar surface acceleration caused by lunar meteorite impacts and Earth’s tides on the Moon, and to compare with information obtained through stereo photography of the landing site to establish topography and subsurface structures of this area. Furthermore, eight small explosive charges were deployed during each EVA by LSPE to collect structural data of surface layers of Moon surface layer.
ALSEP also included a dust detector, which measured samples of lunar regolith located below its surface for signs of micrometeorites and their subsequent impacts, and debris left by their impacts. According to data gathered by this dust detector, large portions of lunar soil appear fragmented, suggesting it has been bombarded for some time now.
A fourth and final element of ALSEP was an active seismometer, used to detect lunar seismic events over a larger area than was possible with passive seismic networks like those employed during Apollo 14 and 15 missions. Consisting of four geophones placed along each corner of a 90-meter equilateral triangle, this active seismometer measured vertical components more accurately than passive networks used on earlier missions.
Apollo 17 – Moonwalk
Apollo 17 marked a final journey to the Moon, and its landing on December 11, 1972 marked its sixth and last successful lunar surface landing of the Apollo program. Additionally, it produced numerous scientific findings, as well as iconic photos of Earth from space.
Apollo 17 featured Eugene Cernan as commander, Lunar Module Pilot Harrison Schmitt and Command Module Pilot Ron Evans as astronauts. Over their 75 hours on the Moon, they conducted three periods of extravehicular activity (EVA), totalling more than 22 hours outside their lunar module dubbed Challenger.
Cernan and Schmitt had both previously flown in lunar orbit during previous missions; however, during EVAs during this mission they made history by walking on the Moon for the very first time! Their excitement stemmed from all the scientific tasks they planned on accomplishing while there.
Cernan and Schmitt completed various science tasks during their first EVA, lasting 7 hours and 37 minutes, such as surveying the area around their lunar module, collecting samples in nearby locations, collecting 243 pounds of lunar rocks, driving their Lunar Roving Vehicle (LRV), an electrically powered wheeled vehicle used by astronauts to explore lunar surface terrain.
The Apollo program’s second EVA, lasting 8 hours and 33 minutes, was the longest by both duration and distance traversed. On this EVA, astronauts completed various science tasks during which they examined geologic formations such as crater rims and lava tubes as well as used a hammer to repair damage sustained to their rover fender during this EVA.
The third and final EVA was an eight-hour-and-39-minute trek, making it the longest of them all by distance traveled. Here, astronauts used a telescopic pole to examine distant geologic formations nearer to home as well as photograph craters called Van Serg, thought by some experts to have been formed due to volcanic activity.