Category How to Find the Apollo Landing Sites

Waxing, waning, first quarter, gibbous Moon, half Moon, full Moon, third quarter, waning Moon – the vocabulary for the different phases of the Moon can be and is daunting and confusing. Since sighting and observing the Apollo landing sites is dependent on the phase of the Moon for best views, it is best to review and clarify the various terms.

1. The Crescent Moon can be seen in the first 5 days after the New Moon. The line that differentiates the sunlit Moon and the dark shadowed Moon is known as the terminator (the reader can insert their own sci fi movie joke here). The crescent moon also represents the waxing phase of the Moon, with waxing describing the gradual illumination towards the full Moon. During the waxing phase of the Moon, the terminator begins on the eastern edge of the Moon and on subsequent days proceeds westward. The crescent Moon is a very attractive phase of the Moon, with deep shadows from the mountains and within craters. Look for the peaks of lunar mountains being illuminated while the lower elevations are still enshrouded in darkness. However, this early phase is of little interest to the observer seeking to discover the Apollo landing sites, since none are illuminated by sunlight at this time.

2. The next 3 days, days 6, 7, and 8, are the half Moon phase. This term is clearly named as half of the Moon being illuminated by sunlight. Confusingly, this phase can also be referred to as the first quarter. The lunar cycle proceeds from new Moon, first quarter, full Moon, last Quarter, and back to new Moon. The Moon is still waxing towards full. This is when the first opportunity is provided to view the Apollo landing sites. The earliest Apollo site to be clearly visible is the Apollo 17 on day 6, although sometimes Day 5 provides a glimpse. By Day 8, all Apollo landing sites with the exception of Apollo 12 can be seen during this half Moon phase.

3. Days 9 through 11 represents the gibbous Moon, which for all intents and pur­poses means more than half but less than full. The Moon is still waxing towards a full Moon. By now all the Apollo sites are visible to the earthbound observer. For amateur astronomers, the lead up to the full Moon is the best observing period since the terminator (the line separating sunlight lit and dark) provides shadows that can provide a 3D effect in lunar observations.

4. The Full Moon on days 12-16 are obviously days for locating the Apollo sites, although the full Moon can appear very bright. The brightness of the Moon will not damage the viewer’s eyesight (never look at the Sun unless properly equipped.), although some personal comfort benefits can be gained from using neutral density filters or polarizing filters to calm down the brightness of the moonlight. Because of the lack of shadows, the Moon tends to look a little flat from the direct reflection of sunlight and the lack of shadows.

5. The last 2 weeks of the lunar phases represent the Waning Moon, as the Moon passes through from Full, to waning gibbous, to half or Last Quarter Moon, to waning crescent. After the Full Moon, the terminator moves towards the western limb of the Moon. Like the waxing Moon, the waning Moon can afford very pleasing views cause of increasing amounts of dark shadows from the mountains and in the craters. Although the Apollo landing sites are observable during the waning Moon, but disappear in reverse order of their appearance during the wax­ing phase. The waning phases appear between midnight, gradually towards dawn, when most of us are asleep. Those readers with insomnia are invited to enjoy the still and quiet of these early a. m. hours and enjoy lunar observing.

Dates: 26 July – 7 August, 1971

Crew: Commander Dave Scott CM Pilot Al Worden LM Pilot James Irwin

Command Module: Endeavor Lunar Module: Falcon

Accomplishments: Longest Lunar Stay 66 hours 54 minutes, Landing in the Apennine Mountains

J. L. Chen, How to Find the Apollo Landing Sites,

The Patrick Moore Practical Astronomy Series, DOI 10.1007/978-3-319-06456-7_7, © Springer International Publishing Switzerland 2014

Apollo 15 was the first of the final three Apollo missions, and the first of the “J” missions. NASA had its funding cut by the Nixon Administration, with Apollo 18 and subsequent missions terminated. In light of the budget cuts, NASA planners placed a greater emphasis on scientific activities for the J missions, and maximized the scientific opportunities of the final three missions.

The J missions were designed to extend the lunar stay for longer periods, con­duct lunar exploration over a greater area, and were equipped with a larger array of scientific instruments than on the Apollo 11, 12, and 14 missions. Both the CSM and the LM included major renovations to make room for additional scien­tific experiments. The installation of a scientific instrument module in one of the service module bays was included for scientific investigations from lunar orbit. The LM received modifications to accommodate a longer stay on the lunar sur­face and carry a greater payload. The major innovation of the J mission series was the introduction and use of the Lunar Roving Vehicle, or LRV. The landing site chosen for Apollo 15 was at the foot of the Appenine Mountains, and next to Hadley Rille.

As with all Apollo missions, Apollo 15 was not without technical problems that potentially could have scrubbed the mission.

Following the launch, during the initial docking of the CSM with the LM and extraction from the S-IVB third stage, the “SPS Thrust” light on the Entry Monitor System of the control panel came on. The Service Propulsion System (SPS) was the rocket engine of the CSM and the SPS Thrust light was used to indicate that the valves in the engine were open and that the rocket should be firing, something that was not occurring. Just in case, the crew opened the circuit breakers that controlled the valves to prevent them from being opened by a short circuit and initiating the engine to fire.

After some period of troubleshooting, it was determined that there was a short circuit in the “Delta-V Thrust” switch. This switch opened the valves in the SPS. Having discovered that the technical problem was in the switch meant that the engine itself was fine, but new procedures would have to be used when operating the engine to stop accidental ignition.

One of the reasons for the success of the Apollo program was the redundancy of critical systems. In the case of the SPS, there were two independent valve systems for the engine, and with the proper reconfiguration of the valves and switches, any problems could be worked around. Similar redundancies of systems and system reconfigurations enabled successful missions, as seen for instance in the Apollo 12 SCE-to-Aux event. But redundancy has its downside. In a very counter-intuitive concept that is familiar to many logistical engineers, redundancy actually lowers system reliability while increasing the system availability. What? In brief, avail­ability is a measure of the percent of time the equipment is in an operable state, while reliability is a measure of how long the item performs its intended function. A dual redundant system implies two identical systems performing the same function, thus doubling the number of component parts. A failure on one side of the system results in the activation of the redundant system, thus assuring the continued function. With twice the number of parts to assure continued function, the chance of part failure increases and reliability actually decreases. But the redundancy increases the availability of the function.

The Apollo 15 landing site is a bit of a challenge to spot visually an is shown in Figs. 7.3, 7.4 and 7.5. It is located on the eastern edge of Mare Imbrium, or the Sea of Rains, just south of the “channel” opening to the Sea of Serenity. The landing site is just east of the Julienne Crater and north of the Mons Hadley in the region known as the Mons Hadley Delta. Visually, the telescopic view of this landing site is impressive when compared to the previous three missions because of the tight landing area selected by NASA. Apollo 11, 12, and 14 landed in relatively open terrain, whereas the Apollo 15 site required precision in landing in a restricted area.

Apollo 15, 16, and 17 represented the J missions, which expanded the capabili­ties for doing science on and near the Moon. NASA planned three 7-hour-long EVAs for Apollo 15, with extensive use of the lunar rover, significantly extending the distance the LM astronauts Dave Scott and Jim Irwin could travel over the lunar surface. Additionally, the restriction on landing near the equator was lifted. A new suite of science experiments was also carried in the service module, giving the CM pilot Al Worden the additional activity of mapping the Moon from orbit.

The landing site chosen for Apollo 15 was on the eastern margin of the Imbrium Basin in the region known as Palus Putredinis. There were two main objectives for this landing site: (1) the rim of the Imbrium Basin could be sampled along the Appenine Mountains, and (2) this site provided an opportunity to explore Hadley Rille, which scientists felt was formed by volcanic processes. Researchers expected that material from Hadley Rille would provide samples from deeper in the lunar crust than was sampled in the Fra Mauro Formation by Apollo 14.

The Lunar Laser Ranging Retroreflector (LRRR) left by NASA at the Apollo 15 site served as a plot point in a popular television show. An episode of the CBS television sitcom “The Big Bang Theory” featured the television show’s characters measuring the distance to the Moon using the Apollo 11 LRRR and a ground based laser. In the series third season, episode 23 called The Lunar Excitation, the “Big Bang Theory” cast is on the roof of their apartment building with a laser, tele­scopes, electronics, and computers to accomplish the distance measuring experiment.

As a precaution, NASA designed the Apollo 15 mission to limit the total radius of the Lunar Rover to 3 miles from the LM. This was done just in case the LRV failed to function (NASA doesn’t build equipment that breaks down! Equipment has a failure or fails to function.), the astronauts would be within walking distance back to the Falcon.

A few years ago, the Lunar Rover was an auction item on eBay as an April Fool’s Day joke, with the auction winner required to pick up the item after winning. The LRV was listed as having very low mileage and driven very little for the past two or three decades. Tires in great shape. A little dusty, but a good car wash would make it look like new. A real collector’s car. No rust and mint condition. No UPS, FedEx, or Parcel Post delivery was available.

The Lunar Rover is still on the Moon, so the auction winner has not made arrangements for pickup yet.

In addition to their studies on the lunar surface, the Apollo 15 crew performed intensive studies of the Moon from lunar orbit. In addition to photography per­formed with hand-held cameras in the Command Module, a series of experiments were carried in the Scientific Instrument Module on the Service Module. The same suite of SIM bay instruments was also flown on Apollo 16.

• The metric and panoramic cameras provided systematic photography of the lunar surface. Apollo 15, 16, and 17 carried a set of cameras in the SIM bay.

These cameras were used to obtain high-resolution photographs of the lunar surface, for use both in studying the geology of the surface and for producing detailed topographic maps of the surface.

• The Laser Altimeter measured the heights of lunar surface features. The laser altimeter used a pulse from a laser aimed at the lunar surface. The reflection of the pulse from the surface was then detected with a small telescope. The length of time the pulse took to travel from the spacecraft to the Moon and back translated to the height of the spacecraft above the surface of the Moon. Measure­ments were made roughly every 30 km across the Moon’s surface. These mea­surements are sufficiently accurate to distinguish height variations of 10 m between adjacent measurement points. Apollo 15 performed these measurements for a total of 4 1/2 orbits.

• The S-Band Transponder Experiment measured regional variations in the Moon’s gravitational acceleration. This experiment was identical to that carried on Apollo 14.

• The X-ray Fluorescence Spectrometer Experiment and the Gamma ray Spectrometer Experiment measured the composition of the lunar surface. The X-ray Fluorescence Spectrometer detected the ratio of aluminum to silicon and magnesium to silicon in the soil, while the gamma ray spectrometer detected the presence of iron, thorium, and titanium. The X-ray Fluorescence Spectrometer Experiment was limited to the sunlit side of the Moon since it relied on the fluo­rescence of aluminum, magnesium, and silicon in the presence of X-rays from the Sun. It measured the mare regions, such as the Sea of Serenity and the Sea of Tranquility, and found low abundances of aluminum and high abundances of magnesium. Over the lunar highlands, an opposite pattern of high aluminum abundances and low magnesium abundances were measured. The Gamma ray Spectrometer Experiment had no limitation and could function in both light and dark regions of the Moon. It found high iron abundances over all mare regions and lower abundances elsewhere. Thorium and titanium abundances were also highest over mare regions, but these two elements were not evenly distributed across the maria.

• The Alpha Particle Spectrometer Experiment measured radon emission from the lunar surface. It was flown on both Apollo 15 and 16. The Alpha Particle Spectrometer measured the alpha particles emitted by the surface, specifically by radon-222 and polonium-210 by detecting particles of energies of 4.7-9.1 MeV. When Uranium-238 undergoes radioactive decay, radon-222 and eventually polonium-210 are among the series of lighter isotopes that result. Rn-222 gas has a radioactive half-life of 3.8 days, which is long enough to allow some of it to diffuse through the lunar regolith and enter the lunar atmosphere. A later step in the same decay results in Po-210. Both Rn-222 and Po-210 undergo radioactive decay by releasing alpha particles (the equivalent of a Helium-4 nucleus). The experiment worked by detecting the alpha particles released when these isotopes decayed radioactively. Both Rn-222 and Po-210 were successfully detected in lunar orbit. Apollo 15 detected higher levels of Rn-222 around the Aristarchus

crater area. Higher levels of Po-210 were observed between Sea of Crisis (Mare Crisium) and the crater Van de Graaf on the Moon’s far side.

• The Orbital Mass Spectrometer Experiment (OMSE) measured the composition of the lunar atmosphere. The OMSE was deployed from the SIM on a 7.3-m boom. Most of the gases detected by the OMSE were associated with the Apollo spacecraft itself. However, Neon-20 was detected. Believed to be from external sources, it was about one-third of that expected to be found at the Moon due to capture of gases from the solar wind.

• The Bistatic Radar Experiment measured the scattering of radar waves from the lunar surface. This experiment was identical to that carried on Apollo 14.

• The PFS-1 Subsatellite was a small satellite released into lunar orbit from the SIM bay. The PFS-1 main objectives were to study the plasma, particle, and magnetic field environment of the Moon and map the lunar gravity field. The subsatellite was designed to measure plasma and energetic particle intensities, vector magnetic fields, and facilitate tracking of the satellite velocity to high precision. A basic requirement was that the satellite acquire fields and particle data everywhere on the orbit around the Moon. The Moon’s roughly circular orbit about the Earth at approximately 250,000 miles carried the subsatellite into both interplanetary space and various regions of the Earth’s magnetosphere. The PFS-1 orbited the Moon and remained operational from August, 1971 until January 1973.

• In later years, through a study of many lunar orbiting satellites, scientists came to discover that most low lunar orbits are unstable. Fortunately, the Apollo 15 subsatellite had been placed, unknown to mission planners at the time, very near to one of only four Lunar stable orbital slots known as frozen orbits, where a Lunar satellite may remain indefinitely.

Apollo 15 was the last mission in which a contingency sample was collected. Seven samples taken within 12 m west of the LM Falcon, and were collected to ensure that some lunar material would be returned for study on Earth in the event that an emergency required the rapid, unplanned end to the EVA.

I n addition to their geologic studies, the Apollo 15 crew performed several experiments on the lunar surface. The results of some of these experiments were either radioed to Earth by the crew or returned to Earth for laboratory analysis. The Soil Mechanics Investigation studied the properties of the lunar soil.

Our old friend, the Solar Wind Composition Experiment collected samples of the solar wind for analysis on Earth. Again, the foil used to collect the ions from the solar wind. The sampling foil was collected at the end of EVA-3, stored in the LM for its eventual return to Earth for analysis.

Other experiments were deployed by the crew and then monitored from Earth by radio telemetry after the crew departed.

The Apollo 15 ALSEP included some experiments that were part of previous missions, plus some new investigations were added. Each experiment was con­nected by a cable to the ALSEP central station, which provides radio communica­tion to Earth and electrical power from a radioisotope thermal generator. Some of these experiments continued to return data until September 1977, when the entire ALSEP network was turned off due to lack of funding for the ground support team.

• Added to the network from Apollo 12 and 14, Apollo 15 ALSEP added another PSE that detected lunar quakes, and provided information about the internal structure of the Moon. This experiment was identical to that carried on Apollo 14.

• The Heat Flow Experiment measured the amount of heat coming out of the Moon. This experiment was identical to that carried on Apollo 14.

• The Lunar Surface Magnetometer measured the strength of the Moon’s magnetic field. On Apollo 12, 15, and 16, the Lunar Surface Magnetometer was included in the ALSEP experiment package.

• The Laser Ranging Retroreflector measured very precisely the distance between the Earth and Moon. This experiment was identical to that carried on Apollo 14.

• The Cold Cathode Gauge measured the abundance of gases in the lunar atmo­sphere. This experiment was identical to that carried on Apollo 14.

• The Suprathermal Ion Detector Experiment studied the lunar ionosphere. This experiment was identical to that carried on Apollo 14, studying the lunar iono­sphere by measuring the various properties of positive ions in the Lunar environ­ment, collecting data on the plasma interaction between solar wind and the Moon, and measuring the electrical potential of the Lunar surface.

• The Solar Wind Spectrometer measured the composition of the solar wind, by continually sampling the solar wind to measure the effects of the Earth’s mag­netic field on the constitution of the solar wind. This experiment was identical to that carried on Apollo 12 and 14.

• The Lunar Dust Detector studied the effects of lunar dust on the operation of the experiment package.

And, as in Apollo 14, the Apollo 15 crew also performed the following

experiments:

• The Window meteoroid Experiment studied impacts on the windows of the Apollo 15 Command Module to obtain information about the size distribution of very small micrometeorites. This experiment was identical to that carried on Apollo 14.

• The Light Flashes Experiment studied light flashes seen by the crew that are related to charged particles in space. This experiment was identical to that car­ried on Apollo 14.

After returning to the LM at the end of EVA-3, Dave Scott famously performed a scientific demonstration for the television audience, using a feather and hammer to demonstrate Galileo’s theory that all objects, regardless of mass, in a given grav­ity field fall at the same rate, in the absence of aerodynamic drag. Scott dropped a hammer and a feather at the same time and the television audience on Earth were able to see both objects land on the lunar surface at the same time. The demonstra­tion worked on the Moon, since there was no drag on the feather due to the negli­gible lunar atmosphere.

During their second lunar EVA, Irwin and Scott retrieved a lunar rock sample that has become known as the Genesis Rock. Apollo 15 sample #15415 became the most famous lunar rock returned by any Apollo mission.

The early excitement of the sample, enhanced by the media dubbing it as the Genesis Rock, was a piece of the Moon’s primordial crust. Chemical analysis of the Genesis Rock has shown it is an anorthosite, composed mostly of anorthite. The dating of the rock was only 4.1 ± 0.1 billion years old, which is younger than the Moon itself. The rock was formed after the Moon’s crust had solidified. Dating of pyroxenes from other anorthosite samples gave a samarium neodymium age of crystallization of 4.46 billion years, with the solar system forming approximately 100 million years earlier.

Although not quite the Genesis Rock as the name implies, the sample is an extremely old rock and was a significant find by the Apollo 15 astronauts. It is cur­rently stored at the Lunar Sample Laboratory Facility at the Johnson Space Center, and is available for study by scientists.

As with all Apollo flights, not all phases of the mission went as planned. Whereas the launch of Apollo 15 was relatively uneventful, one of the parachutes failed to open during the landing. Apollo capsules were designed to land safely with only two parachutes, with the third parachute being redundant in case of failure. With two good parachutes, Apollo 15 landed with a slightly higher velocity of 24 mph, instead of the more gentle 19 mph if all three parachutes had deployed. The post mission analysis of the failure, as reported in the NASA Aeronautics book Coming Home, revealed the parachute lines had been damaged by the fuel from the Reaction Control System, or RCS. The raw fuel from the RCS was vented prior to landing in a depletion firing, and this firing caused a failure in the parachute riser and lines. The failure was regarded as a 1-in-17,000 chance of reoccurring.

Upon landing, Scott, Worden, and Irwin were the first lunar landing crew who were not subjected to quarantine, since the results of the previous missions clearly showed the lifelessness of the lunar environment. The LM Falcon, after returning Scott and Irwin to Endeavor, was jettisoned and impacted the Moon on August 3, 1971 at 26.36° N and 0.25° E. The Saturn S-IVB third stage impacted the Moon on an earlier date of July 29, 1971 at latitude 1.51° S and longitude 11.81° W. Both the Falcon and the S-IVB impacts were recorded by the PSE network which now included the PSE at the newly deployed Apollo 15 ALSEP at Hadley Rille and the Apennine Mountains.

Funding for scientific space exploration often is met with resistance by politicians and the general public. In a parallel example, the development and building of the International Station has been shared among several spacefaring nations with great success. A mission to Mars offers the opportunity for the development of new industries and new jobs to the benefit of all.

There is an enormous cost associated with space exploration. Traditionally, government-funded agencies such as NASA and the European Space Agency (ESA) have used monies obtained through tax dollars to pay for the expense of space. In many cases, such as the Department of Defense Global Positioning System, commonly known as GPS or SatNav, there are benefits that can be derived by the everyday man. Weather services are reliant on meteorological photo tracking of weather fronts and storms. The Apollo Program was funded using public funds, with the impetus of the Cold War driving the effort.

New funding sources may be needed to finance the herculean effort of a mission to Mars. Cost estimates for a Mars effort range from a paltry $6 billion to an enor­mous estimate of $500 billion.

An innovative and precedent making approach may need to be explored. In 2009, a science fiction television show called Defying Gravity offered a commercial solution to raising funds. In an episode called “Fear”, an in-space promotional event using the astronauts was scheduled, with the proceeds funding experiments conducted during the mission. Selling advertising space, naming rights, and com­mercials is an unexplored avenue for paying the expenses of space exploration, such as a Mars mission. Just imagine if this had been done during the Apollo era. The Saturn V could have been launched displaying the name brand of a leading soda, with the astronauts eating and endorsing freeze dried foods on camera during broadcasts to American television networks. General Motors, the developer of the lunar rover, could have taken better advantage of their participation in the Apollo program. One wonders if funding had been obtained in this fashion, would Apollo 18 have been a lunar landing instead of an orbiting handshake?

It is important to be familiar with the type of major features of the Moon prior to search­ing for the Apollo landing sites. In 1651, a Jesuit astronomer named Giovanni Battista Riccioli created and published a system of nomenclature still in use today. Originally written in Latin, many of the lunar names have been Anglicized. For the comfort of the readers, Seas, Ocean, Bay, and other English nomenclature will henceforth be used in this book, except in one case. Mare Cognitum will be used in its Latin form, because it translates to “the sea that has become known”, which is extraordinarily awkward.

• Mare or Sea – The near side of the Moon is characterized by large, dark, seem­ingly smooth areas that early astronomer Riccioli called Mare, or Sea (with the plural Marias or Seas). From the Apollo missions, scientists now know that what looked like water to early astronomers is comprised of vast fields of basalt lava flows. In keeping with the water-based nomenclature for the Moon, Riccioli named one oceanus (ocean), and several dark areas as lacus (lake), palus (marsh) and sinus (bay). The ocean, lake, marsh and bay have the same nature and characteristics, but differ in size.

• Major craters – The Moon is obviously pockmarked with craters, the majority being impact craters left from meteors over the eons. Two of the larger craters are named for the pioneering astronomers Tycho Brache and Copernicus. The meteor impacts that created these landmark craters spread lunar debris across the near face of the Moon, and influenced NASA planners in their selection of Apollo landing sites, as will be seen in the Apollo mission chapters of this book.

• Highlands and Mountain Ranges – The highlands and mountain ranges of the Moon provide the brightest images of the Moon. Some mountain ranges, such as the Apennines and the Alps are actually parts of the crater rim surrounding the Sea of Rains. Other peaks are part of mountain ranges that project above the surface as part of fluid dynamics resulting from the liquefaction of surface rock following a meteor impact. Apollo landing sites in the highlands gathered scien­tific data, rock and soil samples from these regions to provide a comparison with the basin material, as detailed in the Apollo mission chapters of this book.

Dates: 16-27 April, 1972

Crew: Commander John Young CM Pilot Tom Mattingly LM Pilot Charlie Duke

Command Module: Casper Lunar Module: Orion

Accomplishments: Landing in the highlands of the Descarte Region.

J. L. Chen, How to Find the Apollo Landing Sites,

The Patrick Moore Practical Astronomy Series, DOI 10.1007/978-3-319-06456-7_8, © Springer International Publishing Switzerland 2014

The primary objectives of the penultimate Apollo mission were as follows:

• to perform geologic surveys and sampling of materials and surface features in

the area of the Hadley-Appennius region

• to deploy and activate surface experiments included in a new ALSEP suite

• to evaluate the capability of the Apollo equipment to operate extended lunar

surface stay time

• to conduct inflight experiments and photographic tasks from lunar orbit, includ­ing new photographic surveys and orbital spectrometric data collection

Apollo 16 marked Ken Mattingly’s opportunity to finally fly as CM pilot on a Moon mission. Mattingly (who looks nothing like the Actor Gary Sinise from the movie Apollo 13) had originally been assigned to the prime crew of Apollo 13, but was exposed to the measles through Charlie Duke, a member of the back-up crew for Apollo 13, who contracted the illness from one of his children. Mattingly never contracted the measles, but was nevertheless removed from the crew and replaced by his backup, Jack Swigert, 3 days before the launch. Duke had never flown in space, and both rookie astronauts Mattingly and he were teamed on Apollo 16 with space veteran John Young. Young had previously flown on Gemini 3, Gemini 10, and Apollo 10, and had Space Shuttle STS-1 and STS-9 in his future.

Although not officially announced, the original backup crew consisted of Fred Haise as mission commander, William Pogue as CM pilot, and Gerald Carr as LM pilot, and would have been the prime crew for Apollo 19 under the normal crew rotation scheme. However, after the cancellations of Apollo 18 and 19 in September 1970 due to budget cuts, this crew would not rotate to a lunar mission as planned. With Haise still assigned as backup commander, Stu Roosa and Ed Mitchell were recycled to serve as members of the backup crew after returning from Apollo 14, while Pogue and Carr were re-assigned to the NASA’s first space station Skylab program as part of the Skylab 4 crew.

As a historical note, there was an Apollo 18 mission, but it was not a mission to the Moon. The Apollo portion of the Apollo-Soyuz Test Project (ASTP), the first joint U. S.-Russian space mission, was officially known as Apollo 18. The ASTP was primarily a political space mission which demonstrated detente between the two great nations, by rendezvousing an Apollo space craft with a Soyuz in Earth orbit. This mission marked the final spaceflight for the Apollo command module. Apollo 18 ASTP also was the first and only spaceflight for Deke Slayton, the last of the Mercury 7 astronauts. Slayton was selected to pilot the second U. S. manned orbital spaceflight (eventually flown by Scott Carpenter), but was grounded in 1962 by a heart murmur. He served as NASA’s director of flight crew operations from November 1963 until March 1972, and was responsible for crew assignments at NASA for the Gemini and Apollo programs. Later, he was granted medical clear­ance to fly, and was assigned as the docking module pilot of Apollo 18, becoming the oldest person at the time to fly in space at age 51.

Up to this point of the Apollo Program, three Apollo Moon landings were in mare regions and the fourth was in ejecta from the Imbrium impact. The objective of the Apollo 16 landing site was to land in the lunar highlands.

There is no easy way to describe in words how to find the Apollo 16 landing site, because of all the Apollo missions, this is the most challenging to spot visually through a telescope. The observer must first spot Sinus Asperitatis, or the Bay of Roughness, just south of the Sea of Tranquility. At the southern end of the Bay of Roughness is a large double crater called Theophilus and Cyrillus. Move westward to spot the Descarte crater, and then slightly north to identify the Apollo 16 site.

The Descartes region west of Mare Nectaris and Alphonsus crater was the main alternative considered for the Apollo 16 mission. Scientists believed prior to Apollo 16, that the Descartes and Cayley Formations were of volcanic origin. The objective for the astronauts was to sample the Descartes Formation and the Cayley Formation. There was observational evidence, gathered from telescope and orbital images, that both formations were volcanic in origin, although formed of magmas that were more viscous than mare lavas. Samples obtained by Apollo 16 have since been analyzed and are actually breccias produced by impacts rather than volcanic activ­ity. From the density of impact craters, the Cayley Formation was thought to be comparable in age to the Imbrium impact. These pre-mission geologic studies sug­gested that these two formations covered about 11 % of the lunar nearside, making them important for the overall understanding of the Moon’s history. Also, the large distance between the Descartes site and previous landing sites was helpful for the network of geophysical instruments created by the Apollo 12 through 16 missions.

The Alphonsus crater site was considered as an Apollo 16 landing site so as to gather samples from the crater fill itself, possible pre-Imbrium material from the crater wall, and possible young volcanics at some so-called dark halo craters on the floor of Alphonsus. However, some geologists felt that the Alphonsus site had been contaminated by ejecta from the Imbrium Basin impact. The Apollo 16 landing site was selected in June 1971, before the Apollo 14 samples had yet been completely analyzed and the Apollo 15 mission had not yet flown. It was considered possible that the objective of obtaining samples of old highland material (older than the Imbrium impact) might have been met with some of the Apollo 14 or 15 samples.

Therefore, the Descartes landing site was chosen for Apollo 16. The precision of this Moon landing is clearly shown in Fig. 8.6.

Once in lunar orbit, Ken Mattingly was scheduled to perform an engine bum to position Casper for a rescue in the event of an aborted landing. Meanwhile, the LM astronauts Young and Duke powered up the lander and separated from the Command Module. However, during tests of the control systems for the Command Service Module’s steerable rocket engine, an error light lit, indicating a malfunction in the backup system. Mission rules dictated that, at this point, the two spacecraft rendezvous in case it was decided that the crew would have to use the LM engines to get back to Earth, a la Apollo 13. However, after 6 hours of tests and analysis, Mission Control decided that the engine problem could be worked around and that the landing could proceed. The lunar landing was delayed, but not scrubbed.

The Apollo 16 crew performed several experiments on the lunar surface. The results of some of these experiments were either radioed to Earth by the crew or returned to Earth for laboratory analysis.

• The Soil Mechanics Investigation studied the properties of the lunar soil.

• The Solar Wind Composition Experiment collected samples of the solar wind for analysis on Earth. In addition to the aluminum foil used in previous Apollo mis­sions, Apollo 16 included a platinum sheet. This foil was exposed to the Sun for 45 hours. The foil was then returned to Earth for laboratory analysis.

• The Lunar Portable Magnetometer measured the strength of the Moon’s mag­netic field at different locations in the vicinity of the landing site. This experi­ment was identical to the device carried on Apollo 14.

• The Far/Ultraviolet Camera/Spectrograph took pictures and spectra of astronom­ical objects in ultraviolet light, and marked the first time a telescope was used from the Moon. Unique to Apollo 16, it used a 3-in. telescope to obtain images and spectra at wavelengths between 500 and 1,600 A. The telescope consisted of a tripod-mounted, 3-in. Schmidt camera with a cesium iodide cathode and film cartridge. For reference, visible light corresponds to wavelengths of 4,000­7,000 A. Emission at these wavelengths comes primarily from very hot stars of spectral classes O, B, and A, with surface temperatures of 10,000° to 50,000°K. For comparison, the temperature at the visible surface of the Sun is about 5,800°K or 11,000 ° F. Stars as faint as magnitude 11, or 100 times fainter than can be seen with the human eye, were recorded. Results were recorded on a film car­tridge and returned to Earth for analysis. A total of 178 frames of film were obtained. The telescope was periodically reoriented by the astronauts in order to study various parts of the sky. Among the objects studied were the Earth’s upper atmosphere and aurora, various nebulae and star clusters, and the satellite galaxy of the Milky Way galaxy known as the Large Magellanic Cloud.

• The Cosmic Ray Detector measured very high energy cosmic rays from the Sun and other parts of our galaxy. The detector was physically attached to one of the legs of LM Orion, but the deployment proved to be problematic. The detector was to be deployed by pulling a lanyard on the unit. The deployment lanyard broke. It was only partially deployed due to incorrectly installed screws which interfered with the travel of the plates. This degraded portions of the experiment. By the beginning of EVA-2, the temperature labels indicated that the detector was nearing overheating. The detector was removed from the LM and was placed on one of the foot pads so that it faced away from the Sun. A layer of lunar dust on the equipment contributed to the overheating. The experiment was redesigned for the Apollo 17 mission.

The Apollo 16 crew deployed another ALSEP, with experiments now familiar to

the reader:

• The Passive Seismic Experiment detected lunar tremors and provided informa­tion about the internal structure of the Moon. The deployed Apollo 16 PSE gathered seismic data as part of the network that included the ALSEP PSEs’ from Apollo 12, 14, and 15.

• The Active Seismic Experiment provided information about the structure of the upper 100 m of the lunar regolith. On Apollo 16, three of four mortar shells were used to lob explosive charges to distances of up to 900 m from the ALSEP. The fourth mortar shell went unused when a calibration error was detected. The mor­tars were activated by radio after the astronauts had returned to CM Casper. Hexanitrostilbene was the main explosive fill in the seismic source generating mortar ammunition canisters used as part of the experiment due to its high heat resistance and high insensitivity to impact. The astronauts were also equipped with an astronaut-activated “Thumper” device, which was designed to detonate individually 22 smaller charges, to create a small shocks in the lunar surface. The Apollo 16 crew fired off 19 of the 22 Thumper charges.

• The Heat Flow Experiment attempted to measure the amount of heat coming out of the Moon. Unfortunately, the HFE was damaged when John Young inadver­tently caught his foot on the cable that connected the experiment to the Central Station, and pulled the cable out of its connector at the Central Station. Although the damage was repairable, Mission Control ultimately decided that the repair time would adversely impact the completion of other lunar surface tasks. Apollo astronauts on all the missions complained about the presence of the many inter­connecting ALSEP cables and the problems of tripping over, stepping on, or snagging a cable was a real issue. So to the surprise of no one, the HFE experi­ment was terminated.

• The Lunar Surface Magnetometer measured the strength of the Moon’s mag­netic field. The magnetometers from Apollo 12, 15, and 16 showed large varia­tions in the magnetic field of the Moon. These variations indicate the presence of strong localized sources in the crust for the Moon’s magnetic field, a conclu­sion that is also consistent with observations from lunar orbit measurements gained from unmanned lunar probes such as Explorer 35. The Earth’s magnetic field is generated by the flow of fluids in the core and has a global dipole geom­etry, as seen in a simple handheld compass. The ALSEP results show no evi­dence of a global encompassing dipole field on the Moon.

The navigation system on the lunar rover failed during the return drive from EVA-2 and, since their outbound lunar rover tracks are out of sight to the east, John Young used horizon features as a guide. The fact that he was aimed directly at the LM is a testament to his landmark recognition skill.

In addition to their studies on the lunar surface, the Apollo 16 crew performed intensive studies of the Moon from lunar orbit. In addition to photography per­formed with hand-held cameras in the Command Module, a series of experiments were carried in the Scientific Instrument Module on the Service Module. The same suite of SIM bay instruments was also flown on the predecessor mission Apollo 15.

• The Metric and Panometric cameras provided systematic photography of the lunar surface.

• The Laser Altimeter measured the heights of lunar surface features

• The S-Band Transponder Experiment measured regional variations in the Moon’s gravitational acceleration.

• The X-Ray Fluorescence Spectrometer Experiment measured the composition of the lunar surface.

• The Gamma Ray Spectrometer Experiment measured the composition of the lunar surface.

• The Alpha Particle Spectrometer Experiment measured radon emission from the lunar surface.

• The Orbital Mass Spectrometer Experiment measured the composition of the lunar atmosphere. The results of this experiment proved to be as inconclusive as the identical experiment from the Apollo 15 mission.

• The Bistatic Radar Experiment measured the scattering of radar waves from the lunar surface.

• The Subsatellite measured regional variations in the Moon’s gravitational accel­eration and magnetic field and the distribution of charged particles around the Moon. The Apollo 16 subsatellite PFS-2 was a small satellite released into lunar orbit from the Service Module. Its principle objective was to measure charged particles and magnetic fields all around the Moon as the Moon orbited Earth, similar to its sister Apollo 15 deployed spacecraft PFS-1. PFS-1 and PFS-2 were deployed in similar elliptical orbits, ranging from 55 to 76 miles above the Moon. However, the orbit of PFS-2 rapidly changed shape and distance from the Moon. Within 2-1/2 weeks of deployment, the subsatellite’s orbit was scrapping over the lunar surface of 6 miles at perigee. The orbit kept changing to the point where PFS-2 perigee was 30 miles. The orbital instability continued, and the subsatellite’s orbit degraded again. On May 29, 1972, PFS-2 crashed into the lunar surface, lasting only 35 days and 425 orbits. In later years, through a study of many lunar orbiting satellites, scientists came to discover that most low lunar orbits (LLO) are unstable. Unlike its predecessor PFS-1, PFS-2 had been unlucky and was placed into one of the most unstable of orbits, with an orbital inclination of 11°, far from the four frozen lunar orbits discovered only later at 27°, 50°, 76°, and 86° inclination.

Upon the return of the crew to the CM Casper, the ascent stage of Orion was sent to the surface of the Moon to provide seismic data. The ascent stage of Lunar Module Orion separated on 24 April 1972, but a loss of attitude control rendered it out of control. It orbited the Moon for about a year. The Orion impact site on the Moon is unknown.

With the precedent established with the Apollo 13, 14, and 15 S-IVB third stages, the Apollo 16 Saturn third stage was intentionally impacted onto the Moon at longitude 1.3° North and latitude 23.8° West. This event provided data to the PSE network created by Apollo 12, 14, 15 and 16 using a known size and mass.

The lunar samples returned by Apollo 16 brought the biggest scientific surprise of the entire Apollo program. During mission planning, scientists believed the Descartes region to be volcanic plains of comparable age to the Imbrium impact basin. The Apollo 16 crew collected 731 individual rock and soil samples, including a deep drill core that included material over 6 feet below the Moon’s surface, for a record total of 208 pounds.

The samples turned out not to be of volcanic nature. Almost every rock collected on Apollo 16 was a breccia. Breccias are rocks that are composed of fragments of older rocks. Rather than being volcanic in nature, the lunar rocks returned by Apollo 16 showed the Descartes region to be composed of breccia created by mete­orite impacts. Meteor impacts broke many rocks up into small fragments, and sometimes fused small rock fragments into new breccia rocks. Continual meteorite bombardment of the lunar surface resulted in breccias forming larger breccias.

Apollo 16 geological findings changed the nature of scientific thought over the formation of the lunar crust. The previously held belief of a lunar crust formed by volcanic lava flows was dispelled, and replaced by a more complex concept of some magma flows caused by meteor impacts, followed by layers of meteorite impacts that formed the Moon’s crust. The meteorite impact source of the Descartes breccia is still under debate, whether the breccias were from the Imbrium impact or in combination with earlier meteorite impacts remains to be discovered.

The process of returning and decommissioning CM Casper was not without incident. Following the landing, the aircraft carrier USS Ticonderoga delivered the CM Casper to the North Island Naval Air Station, near San Diego, California, on May 5, 1972. Three days later, ground service equipment being used to empty the residual toxic reaction control system fuel in the Command Module tanks exploded in a Naval Air Station hangar. This is the same type of residual fuel and reaction control system that, when vented during landing, caused the Apollo 15 parachute failure. Forty-six people were sent to the hospital suffering from toxic fumes inha­lation. A technician suffered the most serious injury when a ground service equip­ment cart overturned on him and fractured his kneecap. Physical damage included a hole in the hangar roof 250 feet above the hanger floor, 40 windows in the hangar were shattered, and the CM Casper suffered a 3-in. gash.

LM Casper now resides at the U. S. Space and Rocket Center, Huntsville, AL.

As recently as 2006, the Apollo 16 mission was in the news, as an 11 year old boy discovered a piece of debris following Hurricane Ernesto off the coast of Bath, North Carolina. The yard wide flat sheet of metal had a very faded Apollo 16 mis­sion insignia on it. NASA confirmed the object to be a remnant of the first stage of the Saturn V that launched Apollo 16 towards the Moon. As a reward for returning the historic remnant to NASA, the young man was treated to a tour of the Kennedy Space Center, and was provided with a prime seat to witness the launch of the final mission of the Space Shuttle program STS-135, launched on July 11, 2011.

As seen in the Apollo Program, there were malfunctions, software glitches, mechanical and electronic failures, and accidents that occurred on every mission. Apollo 11 had its 1201 and 1202 overflow problems. Apollo 12 had the lightning strike during launch that led to the SCE to Aux activation. The near catastrophic oxygen tank explosion that cost the Apollo 13 crew the lunar landing and nearly cost them their lives. The faulty abort switch on Apollo 14 nearly ruined the lunar landing. Apollo 15 experienced a failed parachute during its return to Earth. There were broken lunar rover fenders on two missions. And the list goes on, many not publicly reported by NASA.

The Apollo spacecraft, the Saturn V, and Mission Control were extremely com­plex machines, built from hundreds of thousands of individual parts, and with computers both onboard and at Mission Control containing thousands of lines of software code.

One of the reasons for the success of the Apollo program was the redundancy of critical systems. During Apollo 15, there was a short circuit in the “Delta-V Thrust” switch. This switch opened the valves in the SPS. The short circuit of this switch meant that the engine itself was fine, but new procedures would have to be used when operating the engine to stop accidental ignition. In the case of the SPS, there were two independent valve systems for the engine, and with the proper reconfigu­ration of the valves and switches, any problems could be worked around. Similar redundancies of systems and system reconfigurations enabled successful missions, as seen for instance in the Apollo 12 SCE-to-Aux event.

But redundancy has its downside. As stated in the Apollo 15 chapter, redundancy actually lowers system reliability while increasing the system availability. To reiter­ate, availability is a measure of the percent of time the equipment is in an operable state, while reliability is a measure of how long the item performs its intended function. A dual redundant system implies two identical systems performing the same function, thus doubling the number of component parts. A failure on one side of the system results in the activation of the redundant system, thus assuring the continued function. With twice the number of parts to assure continued function, the chance of part failure increases and reliability actually decreases. At the same time, the redundancy increases the availability of the function.

A Mars mission with a duration of months or years will stretch the limits of tech­nological durability. Lessons of long term reliability and maintainability are now being learned on the International Space Station. Inherent in the design of both the ISS and a future Mars spacecraft is not only reliability and system maintainability, but also repairability. In the language of logistics engineers, a Mars mission will require an extraordinary set of mean-time-between-failures (MTBF), mean-time-to-repair (MTTR), and functional and service availability requirements that will be historic.

During the writing of this book, a pump on one of the ISS’s two external cooling loops shut down after hitting a temperature limit. The external cooling loops are systems that circulate ammonia outside the space station to keep equipment cool.

Two loops of circulating ammonia cool equipment on the station. The problem started with a malfunction of a valve inside the pump, located on one of the ISS exterior trusses. ISS flight controllers shut down the malfunctioning cooling loop, with the remaining loop provides sufficient for regulating the temperature of critical equipment, and there was no immediate danger to the six crew members aboard at the time. Astronauts aboard the ISS executed three spacewalks, each lasting 6.5 hours, to replace a malfunctioning pump.

An extended mission to Mars will necessitate an ability for the astronauts to repair any malfunctions aboard the Mars spacecraft. But unlike the ISS, which periodically receives supplies of consumables and spare parts, the Mars spaceship will have to carry a supply of repair items for any emergency.

Apollo 13 gave NASA the experience of reconfiguring a damaged spacecraft in times of emergency. A Mars mission will not have the luxury of a quick return to Earth, as Apollo 13 had. A major failure could occur at the mission’s furthest point, necessitating a return to Earth in terms of months. A Mars bound mission will require extraordinary logistical planning, while challenging the aerospace engi­neers to design a spacecraft with reliability, redundancy, and flexibility in configu­ration that allows for survivability in case of malfunctions.

For the Mars spacecraft to carry a warehouse of space parts for its journey would be a waste of resources, storage space, and added fuel costs. It is con­ceivable that a Mars mission could fabricate at least some of its spare parts and tools on the fly by using additive manufacturing, more commonly known as 3-D printer technology. This concept is reminiscent of the replicator technology proposed by the television series and movie franchise Star Trek. NASA has announced that it intends to send a 3-D printer to the International Space Station in 2014. NASA says that astronauts living aboard the ISS would use the 3-D printer to make spare parts and tools in zero gravity. Once the printer arrives at the ISS, it will mark the first time a 3-D printer has been used in space. 3-D printers typically use a polymer material, but there are 3-D printers able to use titanium and nickel-chromium materials to build stronger compo­nents. The 3-D printer technology will have to be modified to use raw materials in a form other than the powders used on Earth. Typical 3-D printers on Earth utilize polymer powders to form plastic 3-D objects, but in a weightless envi­ronment, powders of any kind will impact the onboard environment. Contamination of the breathable air and migration of any powder material into the electronics and mechanical systems onboard the ISS or a Mars bound space­craft could have disastrous results.

The lunar crust is a three layer cake affair, with an upper regolith, lower regolith, and then the mantle layer. The upper regolith extends from 3 feet to 60 feet in depth, and is the result of millions of years of constant bombardment of meteorites and geologic stress from heating and cooling. The lower regolith extends to a depth of 12 miles, and is made up of basalt rocks. Below the two layers of regolith is the mantle, consisting of less rigid material that is low in iron content. Scientists have postulated from the available data gathered from Apollo and unmanned lunar mis­sions that the core of the Moon is small and iron-rich.

There are three major types of features that dominate the surface of the Moon: impact craters, marias (or seas), and highlands. Most familiar are the many craters, caused by the eons of meteorite impacts on the surface. The wide, dark seas are composed of iron and titanium rich volcanic rock known as basalts. And the high­lands are made up of various types of silicate type rocks.

Unique to the Moon’s geology in the highlands, and not found on Earth, is the presence of a type of rock called KREEP. This acronym is formed from potassium (chemical symbol K), rare-earth elements (REE), and phosphorus (chemical sym­bol P). First discovered from the samples brought back by Apollo 12, KREEP is made up of normally incompatible elements, and represents part of the evidence for the formation of the Moon. The leading theory for the Moon’s formation is that it was formed from the remains of an ancient impact between the Earth and a Mars­sized proto-planetary body.

The Apollo missions provided detailed knowledge of the nature of the lunar soil and rocks, and evidence for the impact theory of the lunar genesis.

Crew: Commander Gene Ceman CM Pilot Ron Evans LM Pilot Dr. Harrison Schmidt

Command Module America Lunar Module Challenger

Accomplishments: Last Moon landing. Longest lunar stay of 74 hours and 59.5 minutes. Returned 243 pounds of lunar samples.

The Apollo 17 landing in the Taurus-Littrow Valley was the last Apollo mission, with Apollo 18, 19, and 20 terminated due to budget cuts. As of this writing, Apollo 17 proved to be the last time man set foot on the Moon. Apollo 17 was the final J-type mission, distinguished from the previous G – and H-series missions by expanded and improved hardware, a larger instrumentation package, and extended exploration and sampling range using the Lunar Roving Vehicle, or LRV. The pri­mary objectives of Apollo 17 were threefold:

• Conduct geological observations and collect samples of the Taurus-Littrow region for data of the specific area. The Apollo 17 mission collected Taurus – Littrow information for comparison with geologic data from the previous Apollo mission regions. This objective was aided with the extended range provided by the LRV. The LRV carried onboard two experiments, the Lunar Traverse Gravimeter (LTG) and the Surface Electrical Properties (SEP) experiment.

• Deploy and activate a new version of the Apollo Lunar Surface Experiments Package, or ALSEP, that included five experiments not previously deployed by the earlier Apollo missions. The ALSEP included a heat flow experiment; lunar seismic profiling experiment (LSPE); lunar surface gravimeter (LSG); lunar atmospheric composition experiment (LACE); and lunar ejecta and meteorites (LEAM).

• Conduct lunar orbiting experiments from Apollo 17’s Service Module, including a lunar sounder, infrared scanning radiometer, and far-ultraviolet spectrometer.

Apollo 17 was the first and only Apollo mission that included a scientist as part of the crew. Geologist Jack Schmitt served as the LM pilot, with veteran Astronaut Gene Cernan serving as the Apollo 17 Commander and flying the LM. Both Gene Cernan and CM pilot Ron Evans received extensive training in geology and lunar science, with Ron Evans concentrating on visual recognition and observation of geological features from long distance.

The original crew assignment was Gene Cernan, Ron Evans, and Joe Engle, a former X-15 pilot credited with 16 X-15 flights. Three of Engle’s X-15 flights exceeded the altitude of 50 miles which earned him astronaut wings prior to his joining Apollo. The normal NASA practice was to have the backup crew of a mis­sion be the primary crew three missions later. Cernan, Evans, and Engle served as the backup crew for Apollo 14, and as such were the primary crew for Apollo 17. Jack Schmitt was originally scheduled for Apollo 18 as the LM pilot. With the cancellation of Apollo 18, 19, and 20, there was pressure to include a scientist on Apollo 17. Thus, Schmitt replaced Engle as the LM pilot for Apollo 17. Prior to the Apollo 17 mission, Jack Schmitt’s claim to fame was cleaning up a transmission verbal faux pas of Astronaut Tom Stafford on Apollo 10 by rephrasing Stafford’s description of a crater as “bigger than Schmitt!”.

Joe Engle would never fly to the Moon, but he did fly as commander on Space Shuttle STS-2 with Shuttle pilot and future NASA Administrator Richard Truly, and as mission commander of STS-51-1. Engle is the only astronaut to fly both the X-15 and the Space Shuttle winged spacecraft into space, and to control and land the Space Shuttle manually.

The LM Challenger landed within 200 m from the planned landing coordinates. Three EVA’s were conducted, with the first EVA tasks including: the deployment of the ALSEP, deployment of the first set of geophones and explosive charges as part of the LSPE, and conducting a cosmic ray experiment using the Cosmic Ray Detector (CRD). During the second EVA, Astronauts Cernan and Schmitt used the LRV to collect core samples, dig trenches, and traverse from Nansen Crater, Lara Crater and various points along the way. These stops were made along the way to collect data from the Lunar Traverse Gravimeter (LTG) and the Surface Electrical Properties (SEP) experiment, and deploy additional LSPE geophones and explosive charges. The third EVA, additional sampling stops and traverse gravimeter mea­surements were made. Additional geophones and explosive charges for the LSPE were deployed, and the EVA ended with the retrieval of the neutron flux probe from the deep drill core hole. Each EVA lasted over 7 hours.

The Taurus-Littrow Valley is fairly easy to identify with a telescope. The site is at the southeastern rim of the Sea of Serenity and intersects the Sea of Tranquility.

The landing site selected for Apollo 17 was in the Taurus-Littrow Valley on the southeastern rim of Sea of Serenity. Obtaining samples that would determine how this region of the Moon formed particularly interested lunar scientists in this landing site. The two primary objectives were obtaining samples of highland material that were older than the Imbrium impact and investigating the possibility of young, explosive volcanism in this region. Taurus-Littrow was one of several sites consid­ered, along with the Tycho crater, Copernicus crater, and the Tsiolkovsky crater on the far side of the Moon. The Tycho crater was considered too dangerous because of the roughness of the terrain. Copernicus crater was a low priority site. A far side mission to Tsiolkovsky crater created significant communications problems, with the necessity of placing a constellation of expensive communication relay satellites in orbit around the Moon to provide continuous communications with Mission Control and the command module. The Taurus-Littrow site was selected with the anticipa­tion of sampling ancient highland material and young volcanic material in the same landing site. The Taurus-Littrow site also provided the sampling of Tycho ejecta, and geologists suspected some of the craters in the area could be volcanic vents.

As an observer increases magnification, under steady seeing, the landing area can be seen to have both lighter or darker material. The geologists referred to this mate­rial as light mantle and dark mantle material, stemming from suspected lava flows.

The chosen landing site is in an area between two geological massifs, or moun­tain masses, where observational evidence showed dark material from either land­slides or pyroclastic deposits. This dark mantle material is covered with small craters, which scientists at the time postulated either volcanic or meteoric in origin. The results of the Apollo 17 geological studies suggest that approximately 100 mil­lion years ago, lava seeped to the Moon surface and flooded and pooled to form the Taurus-Littrow area and Sea of Serenity. The lava flows apparently were accompa­nied by fire fountains, which formed both orange and dark-colored beads in the soil. Several samples of lunar soil from Taurus-Littrow contained orange glass beads, causing the samples to have an orange hue. Fire fountains also accounts for the dark glassy material collected at the Taurus-Littrow landing site.

Figure 9.6 is one of the LRO’s clearest photos of an Apollo landing, with the Challenger’s descent stage clearly visible. Since the Moon has no weather or envi­ronmental conditions that can inflict weathering on the soil, the tracks of the lunar rover and the footprints of the astronauts can be easily seen. Unfortunately, this cannot be seen with backyard telescopes. The LRO photographs are taken at an altitude of 50 miles above the lunar surface.

Also visible in this picture is a cluster of craters. It has been determined from the Apollo 17 mission, that much of the main crater cluster was the secondary impact result of the massive Tycho impact less than 95 million years ago. Most of these secondary impact craters were the result of eject spreading out downrange from the Tycho crater. The downrange pattern formed points directed at Tycho. The lighter colored material originated from landslides caused by the secondary ejecta from Tycho hitting the Taurus-Littrow massifs.

Apollo 17 LM Challenger Descent Stage

Fig. 9.7 A closer view from the LRO of the Challenger descent stage. Photo courtesy of NASA and Arizona State University

Apollo 17 ALSEP LROC NAC M168000580R

Fig. 9.8 LRO view of the Apollo 17 ALSEP with amazing detail of the Apollo 17 ALSEP setup. The Lunar Surface Gravimeter (LSG) and the Lunar Seismic Profiling Experiment (LSPE) and its four associated geophones can also be seen. Photo courtesy of NASA and Arizona State University

The Apollo 17 LRV carried onboard two experiments to obtain data during the lunar traverses. One experiment, the Lunar Traverse Gravimeter (LTG) measured the value of the Moon’s gravity around the Taurus-Littrow area. The LTG, by mea­suring the minute variations of gravity, provided data to determine the shape and depth of the bedrock. At each stop, the astronauts read the LTG readings over voice communications link to Mission Control. Twenty-six measurements were success­fully taken during the first, second and third traverses. This was fortunate, since the similar Lunar Surface Gravimeter (LSG) experiment, part of the ALSEP, failed to function due to a design error.

The other experiment, known as the Surface Electrical Properties (SEP) experi­ment looked for layering in Taurus-Littrow soil by transmitting radio waves into the Moon surface, using interferometry from the radio wave returns, and identifying the layers of the lunar soil. Readings were taken at each stop, with the SEP transmitter set up each time a distance away from the LRV, and the receiver mounted on the front of the LRV receiving the reflected radio signal.

An interesting and historically humorous footnote to the Apollo 17 mission was mankind’s first car accident and car repair on another world. Figure 9.12 shows the makeshift repair on the right rear fender of the lunar rover. Apparently during the first EVA, Gene Cernan brushed against the Lunar Rover, and a hammer in his spacesuit shin pocket caught the LRV’s right rear fender and knocked off half of it. As a result of the broken fender, the rover kicked up a dust plume while moving. The dark dust covered the astronauts, which absorbed the heat from the sunlight and could potentially cause overheating problems for Cernan and Schmitt. The abrasive moon dust also could cause scratching of the astronauts’ visors, and affect the operation of the various latches, hinges, and joints of the LRV. At the beginning of EVA 2, using the universal fix-all duct tape, Cernan was able to re-attach the fender piece after two tries. The taped on fender lasted for over four of the 7 hours EVA 2. However, the duct tape lost some of its stickiness because of the ubiquitous moon dust. For the rest of EVA 2, time was lost as the astronauts frequently used a moon dust brush to clean off the LRV, equipment and themselves. During the break between EVA’s, Cernan and Schmitt fashioned a makeshift fender out of four lami­nated maps and duct tape while inside the relatively cleaner LM. The tape worked better this time, and the new fender was attached by using clamps from the optical alignment telescope lamp. The makeshift fender lasted for the all of EVA 3.

Boulders of various sizes are scattered throughout the Taurus-Littrow valley. At the ALSEP area, deployed west of the Apollo 17 landing site, the boulders aver­aged about 4 m in size and were found to be more numerous than in other areas of the valley. Figure 9.13 illustrates the large rock where one of the LSPE geophones was placed.

The LSPE included explosive charges that were placed at distances away from the geophones, which when activated, sent shock waves through the lunar soil. A total of eight charges were deployed at distances of between 100 m and 3.5 km from the LSPE at the ALSEP site. The charges were detonated after the astronauts left the surface. The direct shock waves data from the geophones were compared with delayed waves from the detonations to determine the depth of the rock bed beneath the soil.

In light of the near-disaster of Apollo 13 due to an explosion, the safety of the LSPE explosive charges was a priority for the Apollo 17 mission. To assure safety from accidental or inadvertent detonation, the design of the explosive charges needed three safety rings pulled during deployment of the charge to enable three separate subsystems to activate simultaneously. One safety ring activated a timer

that after 90 hours allowed the explosive to be detonated. The second safety ring released the physical barrier that separated the detonator from the explosive charge. The third safety ring activated the battery that provided power to the receiver and firing circuitry for one minute. With the three rings pulled, three independent actions were needed to cause the explosion: the battery timer had to activate to allow power to the firing mechanisms, the sliding physical barrier that separated the detonator from the explosives had to slide into firing position, and a radio signal from NASA on Earth had to be sent to detonate. If the activation radio signal was not transmitted and received within the one minute time window, the device would move the sliding barrier back into the safe position. The explosives charges could not be activated until after 90 hours, well past the time for liftoff of the LM ascent module for its rendezvous with the command module.

The astronauts used a number of devices to take lunar surface samples. Figure 9.15 photo shows Jack Schmitt taking a drive tube sample. These 18-in. drive tubes were either pushed into or driven into the lunar surface to collect a short core sample. Two or three drive tubes could be joined together to create a longer, depth core sample. The depth of the core sample was often determined by the den­sity of the soil. Softer soil enabled the astronauts to physically sample greater depths, while hard dense soils limited the sample size.

The gnomon device was used to provide a physical scale and to color calibrate photos of lunar terrain and samples. One of the difficulties encountered during the Apollo missions was the underestimation of size and distances by the astronauts. The gnomon device provided a reference for determining physical scale. At one point, from his voice transcription at 140:58:51 and his journal notes of the Second EVA second traverse to Geology Station 2, Jack Schmitt used his own shadow as a ruler. His mission notes acknowledges that “everyone underestimates distance on the Moon”. He would call to mission control to check his shadow length from the television image uplinked from the LRV camera to give an estimate of scale. Even mission commander Cernan admitted misjudging distance on the Moon.

One of the discoveries made during Apollo 17 was uncovering orange soil dur­ing EVA 2. None of the previous Apollo missions ever uncovered this orange-hue soil. The orange soil was first identified by Jack Schmitt on the fourth stop of the second traverse. It pays to have a scientist on the mission!

A magnified view of the spheres and fragments in the “orange” soil which was brought back from the Taurus-Littrow landing site by the Apollo 17 crewmen may be seen In Fig. 9.17. Scientist-astronaut Harrison H. “Jack” Schmitt discovered the “orange” soil at Shorty Crater during the second Apollo 17 lunar surface extrave­hicular activity (EVA). The orange and dark glass beads provided clear evidence of volcanic fire fountains to geologists.

At the end of the third and final traverse, the 2-m long probe for the Lunar Neutron Probe Experiment (LNPE) was retrieved and deactivated at the end of the third EVA after 49 hours of exposure. The LNPE was designed to obtain data on neutron capture rates in the lunar regolith as a function of depth. The LNPE was an outgrowth from the analyses conducted of lunar samples returned from the Apollo 11 mission. In an effort by scientists to understand the processes that created the lunar soil, early studies indicated that neutron capture of certain isotopes of samar­ium and gadolinium were involved. The experiment was to gather data that would enable scientists to estimate the age of the lunar soil. The LNPE was deployed northwest of the lunar module in the hole from the deep drill core. Figure 9.18 shows the gold-colored Mylar transport bag and the treadle used for recovering the deep drill core.

The last view of the LM Challenger descent stage taken by the Apollo 17 remote video camera is shown in Fig. 9.19. A little known fact about the televised liftoff of Challenger from the Moon’s surface is that the television camera was manually controlled from Mission Control. The NASA controller manually panned the remote controlled camera 2 seconds ahead of the LM launch to compensate for the delay time of the transmission to the Moon. Millions of television viewers on Earth were treated to a live broadcast of the LM liftoff because of this carefully planned and executed action.

The television broadcasted launch of the LM Challenger culminated the evolu­tion of Apollo television cameras. The lunar-surface images provided by the cam­eras used on Apollo 15, 16, and 17 were of much higher quality than those used in the earlier Apollo missions. The Apollo television camera used on Apollo 11 was of poor quality, producing blobby low resolution black-and white images. The color cameras used during the Apollo 12 and 14 missions were too light sensitive, with the Apollo 12 astronauts burning out the video tube by pointing it at a reflected surface of the LM. Apollo 14 television images showed Astronauts Alan Shepard and Edgar Mitchell as white blobs most of the time. By the J-missions, a high quality color camera had been designed, implemented, and space and lunar qualified for use.

After the LM Challenger ascent stage rendezvoused with the CM America, the Challenger ascent stage was sent crashing into the Moon, with the ALSEP geo­phones left behind by Apollo 12, 14, 15, 16, and 17 recording the impact. NASA reported the ascent stage impacted the Moon at coordinates 19.96 N, 30.50E at 1:50 EST on 15 Dec 1972.

The spent Saturn IVB third stage for Apollo 17 impacted the lunar surface at 4.21S latitude, 12.31 W longitude at 3:32:42 pm EST on 10 Dec 1972.

As of this writing, Apollo 17 has proved to be the last time man has set foot on the Moon.

The longest Apollo lunar mission was Apollo 17, which lasted 12 days. The Apollo astronauts dined on freeze dried foods that were rehydrated with water to make their meals. The food was not spectacular as cuisine, but provided the necessary sustenance for the length of the mission.

Astronauts serving on the ISS, with periodic supply replenishment are aboard for months on end. Food technology for ISS personnel has been improved since the Apollo days. The ISS crews are treated to a wide variety of foods from several cuisines.

The major problem of a Mars mission is carrying enough food consumables to last the length of the mission. NASA has chefs planning and developing a cuisine that astronauts can eat that is varied, tasty, nutritious, and has a shelf life for the Mars expedition that may last years. But a spacecraft can carry only so much. In all likeli­hood, the Mars mission crew may have to use hydroponics to grow fresh vegetables such as lettuce, tomatoes, onions, garlic, peppers, cabbage and other foods in space.

Space food cannot be crumby (pun intended). Not only should it taste good and have good texture, it must keep the amount of crumbs to a minimum, since crumbs float, migrate, and contaminate equipment. Food currently chosen for space is selected for minimal crumbs, and ability to withstand mold and bacteria. In addition, under microgravity conditions, the astronaut’s sense of smell is dulled in space when the fluids in their bodies redistribute as a result of lowered gravity, causing nasal congestion. With smell as a major aspect of taste, and the stuffed up nose of an astronaut, space food tends to be more spicy. A variety of sauces like hot sauce, sweet and sour, sriracha hot sauce, barbecue sauce (Carolina-style? Kansas City – style? Texas-style?), and liquid salt solution (salt grains are like crumbs), can be provided for use to season and spice up most anything. The texture of food is a major aspect of Earthbound cuisine, with foods having a crisp texture, a crunchy texture, or a smooth and creamy texture. Achieving this wide range of food textures in space is difficult to achieve when food comes dehydrated in plastic pouches, and water is added to the pouches for rehydration, and the pouches are reheated as required.

The Moon is an easy and bright target for the beginning, casual, and serious back­yard observer. Even with the unaided eye, one can identify the major Seas as the large smooth grey areas. A good pair of 7 x 35 or 7 x 50 binoculars can resolve some of the major craters and large light and dark regions on the Moon’s surface. But it’s not until the observer starts using a telescope that the “OH WOW!” factor comes into play. “OH WOW” is the exclamation that issues from your mouth when you look through the eyepiece of the telescope at the Moon for the first time. Telescopes with apertures beginning at 60 mm and larger can produce very satisfying images of craters, mountain ranges, mares and lunar domes. And in the case of the subject of this book, a good telescope can help the reader to zoom-in on the Apollo landing sites and appreciate NASA’s great successes.

The reader needs to understand that, depending on the type of telescope being used, the orientation of the image may either be correct or mirrored. This can pose a problem when using Moon maps, or even the images presented in this book. The short-hand guidance is as follows: if the reader is using a Newtonian reflector, don’t worry. If using a refractor or other design, up will be up, down will be down, but left will be right, and right will be left. Don’t worry, you’ll get used to it.

Despite the sophistication and technology that is possessed by today’s backyard astronomer, the reader is reminded that although the Apollo landings sites can be identified, there is no hope to see the remaining Apollo relics left on the Moon. The smallest object that can be seen from an earthbound telescope is a crater the size of the Rose Bowl or Wembley Stadium. The largest Apollo object left on the Moon is the descent stage of the lunar lander, roughly the equivalent of two U-Haul trucks parked side-by-side.