Category How to Find the Apollo Landing Sites

Excerpt from his speech delivered before a joint session of Congress May 25, 1961

First, I believe that this nation should commit itself to achieving the goal, before this decade is out, of landing a man on the Moon and returning him safely to the Earth. No single space project in this period will be more impressive to mankind, or more important for the long-range exploration of space; and none will be so dif­ficult or expensive to accomplish. We propose to accelerate the development of the appropriate lunar spacecraft. We propose to develop alternate liquid and solid fuel boosters, much larger than any now being developed, until certain which is supe­rior. We propose additional funds for other engine development and for unmanned explorations—explorations which are particularly important for one purpose which this nation will never overlook: the survival of the man who first makes this daring flight. But in a very real sense, it will not be one man going to the Moon—if we make this judgment affirmatively, it will be an entire nation. For all of us must work to put him there.

Second, an additional 23 million dollars, together with 7 million dollars already available, will accelerate development of the Rover nuclear rocket. This gives promise of some day providing a means for even more exciting and ambitious exploration of space, perhaps beyond the moon, perhaps to the very end of the solar system itself.

Third, an additional 50 million dollars will make the most of our present leadership, by accelerating the use of space satellites for worldwide communications.

Fourth, an additional 75 million dollars—of which 53 million dollars is for the Weather Bureau—will help give us at the earliest possible time a satellite system for worldwide weather observation.

Let it be clear—and this is a judgment which the Members of the Congress must finally make—let it be clear that I am asking the Congress and the country to accept a firm commitment to a new course of action, a course which will last for many years and carry very heavy costs: 531 million dollars in fiscal’62—an estimated 7 to 9 billion dollars additional over the next 5 years. If we are to go only half way, or reduce our sights in the face of difficulty, in my judgment it would be better not to go at all.

Now this is a choice which this country must make, and I am confident that under the leadership of the Space Committees of the Congress, and the Appropriating Committees, that you will consider the matter carefully.

It is a most important decision that we make as a nation. But all of you have lived through the last 4 years and have seen the significance of space and the adventures in space, and no one can predict with certainty what the ultimate meaning will be of mastery of space.

I believe we should go to the Moon. But I think every citizen of this country as well as the Members of the Congress should consider the matter carefully in mak­ing their judgment, to which we have given attention over many weeks and months, because it is a heavy burden, and there is no sense in agreeing or desiring that the United States take an affirmative position in outer space, unless we are prepared to do the work and bear the burdens to make it successful. If we are not, we should decide today and this year.

This decision demands a major national commitment of scientific and technical manpower, materiel and facilities, and the possibility of their diversion from other important activities where they are already thinly spread. It means a degree of dedi­cation, organization, and discipline which have not always characterized our research and development efforts. It means we cannot afford undue work stop­pages, inflated costs of material or talent, wasteful interagency rivalries, or a high turnover of key personnel.

New objectives and new money cannot solve these problems. They could in fact aggravate them further—unless every scientist, every engineer, every serviceman, every technician, contractor, and civil servant gives his personal pledge that this nation will move forward, with the full speed of freedom, in the exciting adventure of space.

Apollo 12

Apollo 12

Date: 14-24 November 1969

Crew: Commander – Pete Conrad

CM Pilot – Dick Gordon LM Pilot – Alan Bean

Command Module: Yankee Clipper Lunar Module: Intrepid

Accomplishments: Pinpoint landing within 535 feet of Surveyor 3, two extended Moonwalks, setup and initiated Geophysical Station and Lunar Nuclear Power Station.

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

The Patrick Moore Practical Astronomy Series, DOI 10.1007/978-3-319-06456-7_4, © Springer International Publishing Switzerland 2014

Apollo 12

Fig. 4.1 Apollo 12 Insignia. Courtesy of NASA

Early in Apollo program planning, NASA defined a sequence of missions:

• “A” missions were unmanned tests of the launch vehicles and the Command Module

• “B” missions were unmanned tests of the LM

• “C” missions (Apollo 7) were manned, Earth orbital tests of the Command Module

• “D” missions (Apollo 9) were LM/CSM tests in Earth orbit

• “E” missions (none were flown) were tests in high Earth orbit

• “F” missions (Apollo 10) were lunar orbit tests

• The “G” mission was the Apollo 11 landing.

• “H” missions (Apollo 12, 13, and 14) would be subsequent flights to other land­ing sites using the basic equipment

• “I” missions (none flown) would be lunar orbit-only science flights

• “J” missions would be the longer visits that LM design changes would make possible. Equipped with Lunar Roving Vehicles (LRV), the J-mission crews would be able to extend their range on the lunar surface and visit a variety of geologic features some distance away from the landing site, collect greater quantities of rock and soil samples, utilize a greater number of tools carried on the Rover, and LRV would serve as a mobile experiment platform. In general, the J-missions promised a significant increase in productivity. However, before the J-missions could be attempted, NASA had to demonstrate that crews could achieve pinpoint landings, work a full-day in the stiff suits and, if necessary, walk several kilometers back to the LM from a disabled Rover.

Apollo 12

Fig. 4.2 The Apollo 12 team. Courtesy of NASA

Apollo 12 represented the first of the H missions. The Apollo 12 mission was presented with a couple of challenges not faced by Apollo 11, one known prior to launch and one occurring during launch.

The particular challenge for the Apollo 12 mission was the achievement of a pinpoint landing. One of the significant discoveries prior to the Apollo landings was the existence of mass concentrations, or mascons, on the Moon. The lunar mascons were discovered by scientists at the NASA Jet Propulsion Laboratory (JPL) in 1968 from analyzing the orbital and navigational data from the NASA’s Lunar Orbiter spacecraft. The analysis established a correlation between very large positive gravity anomalies and depressed circular basins on the moon. Many of the Apollo experiments on the lunar surface tried to collect data to explain the gravity variations.

NASA had to establish a special team of scientists and engineers to explain why the Lunar Orbiter spacecraft being used to test the accuracy of the Apollo naviga­tion system were experiencing errors. The mission specification required an accu­racy of 200 meters, whereas the test results predicted a navigational position of 2,000 meters, ten times the allowed specification error. This meant that the pre­dicted landing areas were 100 times as large for reasons of safety, and posed a challenge to precise lunar landings. The principle cause for these lunar orbital errors was due to the strong gravitational perturbations of the mascons. NASA was able to compensate for the existence of the mascons in the Apollo navigation soft­ware, and this compensation was first applied to Apollo 12. The Apollo 12 landing was within 163 meters of the target, the Surveyor 3 spacecraft.

During the launch of Apollo 12, the spacecraft and Saturn V were twice struck by lightning, causing a momentary power crisis aboard Yankee Clipper that almost aborted the mission. Apollo 12 launched on schedule from Kennedy Space Center, during a rainstorm. 36.5 seconds after lift-off, friction from the vehicle passing through the rainstorm triggered lightning through the launch vehicle, through the Saturn’s ionized plume, and down to the ground. The protective circuits of the fuel cells in the Service Module (SM) took all three fuel cells offline because the lightning caused a surge that falsely indicated overloads. The cascading effect of the lightning strike also disabled much of the Command/Service Module (CSM) instrumentation. A second strike at 52 seconds after launch knocked out the attitude control. The telemetry stream at Mission Control was totally disrupted. However, the vehicle con­tinued to fly correctly; the strikes had not affected the Saturn V Instrument Unit.

The loss of all three fuel cells put the CSM entirely on batteries. Apollo 12 power systems were unable to maintain normal 28 V DC bus voltages into the heavy 75 amp launch loads. One of the AC inverters dropped offline. As a result, these power supply under volt conditions lit nearly every warning light on the con­trol panel and caused much of the instrumentation to malfunction.

Legendary NASA “steely-eyed missile man” John Aaron was the EECOM at Mission Control for the launch. Aaron remembered a similar telemetry failure pat­tern from an earlier test when a power supply malfunctioned in the CSM Signal Conditioning Equipment (SCE). The SCE converts raw signals from instrumenta­tion to standard voltages for the spacecraft instrument displays and telemetry encoders.

Aaron made a call to the Apollo 12 crew, “Try SCE to aux.” This switched the SCE to a backup power supply. The switch was fairly obscure and neither the Launch Flight Director Gerry Griffin, CAPCOM Gerry Carr, nor Commander Conrad immediately recognized it. Lunar Module Pilot ( and future Apollo artist) Alan Bean, flying in the right seat as the CSM systems engineer, remembered the SCE switch from a training incident a year earlier when the same failure had been simulated. Aaron’s and Bean’s quick recall saved the mission and prevented an abort. Bean put the fuel cells back on line, and with telemetry restored, the launch continued successfully. Once in earth orbit, the crew and Mission Control reviewed all systems and declared all systems go prior to trans-lunar injection. The lightning strikes had caused no serious permanent damage and the crew, with the onboard power systems restored, were able to continue the mission.

Apollo 12

Fig. 4.3 Apollo 12 and the Ocean of Storms. Courtesy of the author

Apollo 12

Fig. 4.4 First Zoom-in of Apollo 12 landing site. Courtesy of the author

Apollo 12

Fig. 4.5 Second Zoom-in of Apollo 12 and Surveyor 3 site. Courtesy of the author

The key to sighting the Apollo 12 landing site is first recognizing the great Copernicus crater. Copernicus is one of the most easily identifiable features on the Moon, located south of Mare Imbrium, or the Sea of Rains. Through a small tele­scope, one can make out the layered nature of Copernicus, and outward “rays” of light and dark material splashed by the impact of an object that created the crater eons ago. South of Copernicus and past a smaller crater known as Reinhold, is the small Ocean of Storms and the site of Apollo 12. NASA’s conservative approach to landing site selection resulted in another rather featureless landing zone that can be appreciated, but the actual site is difficult to pinpoint for the backyard observer. Apollo 12 landed near the Surveyor 3, near the edge of a small crater. However, the Surveyor 3 and the crater are beyond the resolution of most backyard telescopes.

As with Apollo 11, conservative safety considerations dominated the criteria for landing site selection for Apollo 12. The Ocean of Storms site was chosen because it had few craters and boulders, with less than 2° slope in the approach path and landing site. The site had no large hills, high cliffs, or deep craters that could reflect erroneous altitude radar returns to the lunar module landing radar. As with the Apollo 11 landing site, the Ocean of Storms presented a fairly featureless target area. NASA still wanted the least expenditure of spacecraft propellants, with crew and mission safety in mind.

These criteria dictated landing in a mare region near the equator. Mare regions in Ocean of Storms were given high priority because telescopic study suggested that these areas are younger and of a slightly different composition than the Apollo 11 landing site.

Since Apollo 11 overshot its planned target by 4 miles, the goal of Apollo 12 was to demonstrate a precision landing capability. Precise landings capability was vital to set the stage for more complex missions. Therefore, a landing near where Surveyor 3 landed was planned. This provided both a clear marker for determining the accuracy of the landing, and an opportunity to return parts of the Surveyor 3 that had failed to function 2 1/2 years earlier. Of scientific interest was sampling ejecta from the crater Copernicus, in an effort to establish the crater’s age. And, this land­ing site allowed the CM Yankee Clipper good orbital imaging of the Fra Mauro site that was the target of the ill-fated Apollo 13 mission, and was eventually achieved by the Apollo 14 mission.

Apollo 12

Fig. 4.6 LRO view of Apollo 12 Landing site in 2009. Photo courtesy of NASA and Arizona State University

 

Подпись: Apollo 12

Apollo 12

Fig. 4.7 LROviewidentifyingApollo 12. PhotocourtesyofNASAandArizonaStateUniversity

Apollo 12

Fig. 4.8 Closer LRO view of the Apollo 12 landing site, an easy neighborhood moon walk away to the Surveyor 3 landing site. Photo courtesy of NASA and Arizona State University

As previously mentioned, the difficulty of attempting such a precision landing was complicated by the existence of mass concentrations, or mascons, on the Moon. These mascons caused variations in local gravity on the Moon, variations that easily affected the navigation landing computer onboard the LM, as well as the lunar orbiting CM. These mascon regions were first discovered in 1968, and proved to be a problem for both the American Lunar Orbiter missions, and the Russian Luna missions. NASA’s Lunar Orbiter spacecraft was used to test the Apollo navi­gation algorithms, and produced errors ten times the specification requirement because of the lunar mascons. Instead of specification error of 200 meters, an error of 2,000 meters would result. An error of almost 1-1/4 mile was intolerable.

NASA had to develop a method to compensate for the mascon error, without actually knowing what a mascon was. The answer was using the Doppler effect to map and compensate for the mascon gravity variations. The Doppler shift of an orbiting LM, although variable, would be predictable. By comparing the predicted Doppler shift against actual Doppler shifts, it could be determined if the LM was off course and how far off course. The trick was how to input the correction infor­mation into the LM guidance computer, recognizing the state-of-the-art of the 1960s. The Apollo CM and LM computers were highly primitive by today’s stan­dards. It’s hard to believe that the computer technology of the 1960s limited the LM memory to 2,056 bytes (that’s right, kilobytes, not megabytes, not gigabytes). The technological slight-of-hand was used to fool the computer into thinking the land­ing site had moved instead of the LM being off-course! The result of this software finesse was the Apollo 12 landed within 163 m of the planned target, and an easy lunar stroll to the Surveyor 3 spacecraft.

Once on the Moon, a major task for the crew of Apollo 12 was the collection of lunar soil and rock samples. A major find of Apollo 12 was the discovery of the first KREEP samples. Unique to the Moon’s geology in the highlands, and not found on Earth, KREEP is a moon rock containing potassium (chemical symbol K), rare-earth elements (REE), and phosphorus (chemical symbol P). Containing potassium, phosphorus oxides, rubidium, and lanthanum, KREEP is made up of normally incompatible elements, and was first found in the Apollo 12 samples in agglutinate glasses and polymict breccias.

KREEP and other anorthosite samples represent 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 Mars-sized proto-planetary body about 4.5 billion years ago. This collision threw a large amount of material into orbit around the Earth that eventually became the Moon.

A large amount of energy was generated by this collision. Scientists have deduced that a large portion of the Moon would have liquified, initially creating a magma covered Moon. As the magma crystalized, minerals precipitated and sank to the bottom to form the lunar mantle.

As the Moon solidified, low density anorthosite material began to crystallize and float towards the surface, forming a solid crust. Elements that are usually incompat­ible then progressively concentrate into the magma. The magma that formed, sand­wiched between the crust and mantle, was rich in KREEP. The evidence for these processes came from the presence of the rocks rich in KREEP, and the highly anorthositic composition of the crust of the lunar highlands from samples from later Apollo missions.

Apollo 12

Fig. 4.9 LRO view of Apollo 12 ALSEP, clearly showing the experiments Astronauts Bean and Conrad deployed as part of the Geophysical Station. Photo courtesy of NASA and Arizona State University

The Apollo Lunar Surface Experiments Package, or ALSEP, aboard Apollo 12 and deployed by Astronauts Conrad and Bean at the Ocean of Storms was made up of a more extensive set of experiments than the EASEP of Apollo 11:

• The Passive Seismic Experiment (PSE) detected lunar seismic activities and provided information about the internal structure of the Moon. The Passive Seismic Experiment studied the propagation of seismic waves through the Moon and provided data about the Moon’s internal structure. The Apollo 11 seismometer returned data for just 3 weeks but provided a useful first look at lunar seismology. More advanced seismometers were deployed at the Apollo 12, 14, 15, and 16 landing sites and transmitted data to Earth until September 1977.

Each of the PSE’s measured all three components of ground displacement (up-down, north-south, and east-west). In 2011, based on 30 year old data from these four PSE sites, a new analysis confirmed the layering of the Moon’s core. This analysis, using a technique borrowed from one originally developed to analyze Earth’s earthquakes, concludes that the Moon’s core has a solid inner core surrounded by a molten outer core. Additionally, the analysis suggested that the iron-rich lunar inner core contains less than 6 % of the light elements of the Periodic Table. Most useful for this study utilized data from more than 6,000 deep moonquakes occurring about 435 miles below the Moon’s surface.

• The Lunar Surface Magnetometer (LSM) measured the strength of the Moon’s magnetic field. The magnetic field data included field strengths both from the Moon’s intrinsic magnetic field mixed with external magnetic fields of the Earth and Sun. These external fields varied in strength with time as the Moon moved through Earth’s magnetosphere as it orbited the Earth. By making measurements over several months, these time-varying fields were be separated from the Moon’s steady, intrinsic magnetic field. LSM experiments were part the ALSEP included in the Apollo 12, 15, and 16 missions.

• The Cold Cathode Gauge (CCG) measured the atmospheric pressure of the lunar atmosphere. On Apollo 12, the CCG instrumentation was a part of the Supra Ion Detector Experiment (SIDE). Unfortunately, the CCG failed after 14 hours. The strong magnetic field of the CCG caused interference with the SIDE, which resulted the experiment was packaged as a standalone implementation in later missions.

• The Suprathermal Ion Detector Experiment (SIDE) studied 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 (SWS), in addition to the SWCE, was identical to that included in the Apollo 11 EASEP, measured the composition of the solar wind. This experiment, unlike the SWCE, continually sampled the solar wind to measure the effects of the Earth’s magnetic field on the constitution of the solar wind. The results of this experiment showed that most of the Moon’s orbit, which is outside the Earth’s magnetic field, a proton density of 10-20 protons per cubic centimeter was detected. However, no protons were detected during the 5 days in which the Moon is in the tail of the Earth’s magnetic field. Clearly, the SWS demonstrated the shielding effect of the Earth’s magnetic field from the solar wind.

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

Apollo 12

Fig. 4.10 hoto of Astronaut Conrad and Surveyor 3. Courtesy of NASA

Pete Conrad Jr., Apollo 12 Commander, examined the unmanned Surveyor III spacecraft during the second moon walk as seen in Fig. 4.10. The “Intrepid” landed on the Moon’s Ocean of Storms less than 600 feet from Surveyor 3. The television camera and several other components were taken from Surveyor 3 and brought back to earth for scientific analysis. Surveyor 3 soft-landed on the Moon on 19 April, 1967.

Apollo 12

Fig. 4.11 Surveyor 3. Courtesy of NASA

Surveyor 3 was unintentionally the first spacecraft to liftoff from the Moon’s surface. In fact, it did this twice. Due to a problem with the Surveyor 3 landing radar, which did not shut off the vernier engines, kept them firing throughout the first touchdown, and continued until a second touchdown. The Lunar Module Intrepid landed 600 feet from Surveyor 3, as planned. Surveyor 3’s TV and telemetry systems were found to have been damaged by its unplanned landings and liftoffs.

Apollo 12

Fig. 4.12 Astronaut Alan Bean during experiment setup. Courtesy of NASA

Another element of Apollo 12 is the Radioactive Thermoelectric Generator. Astronaut Alan Bean can be seen in Fig. 4.12 unloading the nuclear fuel element for the RTG in the foreground. Bean is attempting to remove the fuel element from the cask using the Fuel Transfer Tool (FTT). On Apollo 12, the fuel element stuck in the cask because of thermal expansion (Bean could feel the heat through his suit). Conrad pounded the side of the cask with a hammer while Bean successfully worked it loose. He then inserted it into the RTG and discarded the FTT.

Apollo 12

Fig. 4.13 Apollo Lunar Surface Experiments Package (the ALSEP portable scientific lab). Courtesy of NASA

Apollo 12

Fig. 4.14 LM Pilot and future artist Alan Bean. Alan Bean has produced a number of paintings and published a book of his artwork depicting his and NASA’s moon experiences. A select number of his paintings actually contain moon dust mixed into the paints. Courtesy of NASA

From a public relations point-of-view, the only part of the mission that had gone really wrong was the failure of the color TV camera. The public had great expecta­tions for a spectacular television broadcast from the Moon. The Apollo 11 televi­sion camera produced low resolution, grainy, black-and-white video. This was the first color TV camera to be used on the Moon. Unfortunately, the development of the camera had experienced delays, and the contractor Westinghouse delivered the camera to NASA just days before the launch. As a workaround, Alan Bean trained with a mockup of the camera, which did not highlight the design limitations of the equipment. Initially, the TV camera was operational, but 42 minutes into telecasting the first EVA, astronaut Bean accidentally pointed the camera at the Sun while preparing to mount it on the tripod. The Sun’s extreme brightness burned out the vidicon imaging tube, rendering the camera inoperable. When the camera was returned to Earth, it was shipped to Westinghouse for post-mission analysis. Westinghouse engineers were able to get an image on the section of the tube that wasn’t damaged. Procedures for future Apollo missions were re-written in order to prevent such damage, including the addition of a lens cap to protect the tube when the camera was repositioned. Fortunately, the loss of the TV camera was not crucial from a technical point of view, and did not impact the success of the mission. However, the loss of television coverage of the Apollo 12 mission disappointed millions of viewers in the United States and the world.

In the early Apollo lunar missions, the Saturn V S-IVB third stage that propelled the CSM/LM towards the Moon during the trans-lunar injection phase was lost in space and allowed to enter a heliocentric orbit following separation. Apollo 13, 14, 15, 16, and 17 used the spent S-IVB stage as an opportunity to perform seismic studies and were deliberately crashed into the Moon. The third stage impact pro­vided seismic data to the ALSEP seismometers.

The Apollo 12 Saturn third stage did not impact the Moon, but was supposed to be sent into heliocentric orbit, and was considered lost. Then on September 3, 2002, an amateur astronomer named Bill Yeung discovered what was then considered an asteroid, and officially given the designation of J002E3. At the time of its discovery, J002E3 was in a highly elliptical orbit around Earth. University of Arizona astrono­mers found that the object’s spectrum was consistent with titanium dioxide paint, the type of paint used on the Saturn V launch vehicles. An analysis of the orbit has identified the Apollo 12 third stage as the likely candidate for J002E3. The Apollo 12 S-IVB did not achieve a true heliocentric orbit, having not achieving escape velocity for the Earth-Moon system. After flying past the Moon on November 18, 1969, J002E3 attained a semi-stable orbit in which the third stage entered a highly elliptical orbit around the Earth-Moon system, then flung into deep space by the combined gravity forces of Earth and the Moon, and then re-captured by the Earth – Moon system at a later date. Following its discovery, J002E3 left Earth orbit in 2003, and is expected to return in either 2032, or the mid-2040s, depending on the orbital model used.

The mystery of the mascons has finally been solved. In May, 2013, NASA released the findings of the Gravity Recovery and Interior Laboratory (GRAIL) mission to the Moon. GRAIL consisted of two lunar orbiting probes, GRAIL A and GRAIL B, launched in September 2011, orbiting in near circular orbits at an alti­tude of 55 miles. The distance between the two GRAIL probes, nicknamed Ebb and Flow, were precisely measured as they passed over gravity variations caused by mountains, craters and mascons until the data collection ended in December of 2012. NASA reported that the GRAIL data confirmed the lunar mascons were generated by large asteroids and comets impacting the young Moon when it had a thin crust and dense molten mantle. The impact created a circular ripple effect of material that cooled beneath the visible surface of the Moon consisting of rings of dense and lighter lunar material.

Moon, Mars,. and the Future

On September 12, 1962, President John F. Kennedy spoke at Rice University and spoke these immortal words that launched the United States on its quest to the Moon:

We choose to go to the moon. We choose to go to the moon in this decade and do the other things, not because they are easy, but because they are hard, because that goal will serve to organize and measure the best of our energies and skills, because that challenge is one that we are willing to accept, one we are unwilling to postpone, and one which we intend to win, and the others, too.

In an era of international and geo-political competition, President Kennedy launched the United States into its decade long quest that culminated in the Apollo landings that are the subject of this book.

Now over 40 years after those historic manned Apollo landings, a number of other countries including Japan and China, are taking aim at our satellite neighbor. During the writing of this book, China soft landed a robotic rover onto the Moon.

Meanwhile, the United States and NASA, with a number of fits and false starts, inches its way towards a manned mission to the other legendary celestial objective, Mars. Robotic Mars rovers such as Curiosity, Opportunity, and Spirit have landed and explored Mars, and have expanded our knowledge of our red planet neighbor.

The Moon and the planet Mars dominate the imaginations of mankind. Literature of all cultures, both poetry and prose, are filled with the romance, the science, and the adventure of traveling to the Moon and Mars. Well-known authors, such as H. G. Wells, Edgar Rice Burroughs, Ray Bradbury, and Isaac Asimov, have penned books about the Moon and Mars.

To each generation, the Moon and Mars represents a challenge, impacting its technology, medical sciences, society, and culture.

A look at the challenges that the Apollo program faced, and the comparison that a Mars effort will have to overcome, is in order.

Preface

Preface

Courtesy of NASA

Sunday, July 20, 1969. 4:10 pm EDT.

For readers of a certain age, this is a date and time that can never be forgotten. A moment in time in which everyone remembers where they were, and what they were doing. And unlike other dates that live in infamy, such as December 7 or 9/11,
this is a moment of history that brings awe, inspiration, and pride. For this was the day that Neil Armstrong and Buzz Aldrin landed the LM Eagle on the Moon.

Decades later, generations of people look to the Moon, and know that mankind has been there. But many have no idea where the landings occurred. The Moon has been visited by both robotic and human visitors, with landing sites scattered across its surface. It is the goal of this book to enlighten the reader, and show where to look upon the Moon for mankind’s landing sites.

As a child of the Sixties, I grew up entranced by the burgeoning Space Age. I received as a Christmas present my first telescope at the age of eleven, and my first target was to view the Moon. It was thrilling. I grew up to become a professional engineer, spending most of my career in the field of aviation. But my love for tele­scopes and astronomy never waned. Since my retirement, I have devoted a great deal of time supporting local Washington D. C. telescope stores and giving lectures on telescopes and astronomy equipment to astronomy clubs in Maryland and northern Virginia. And for those of sharp memories and a stack of old astronomy magazines in their basements, you’ll find an article written by yours truly in the November, 1989 issue of Astronomy magazine on the subject of building a Dobsonian telescope.

Now that I am retired from my professional engineering life, I’ve found that I can spend more time viewing the skies through my telescopes. (Yes, that is plural. I’m afraid I’m slightly on the lunatic fringe of the hobby, pun intended.) Photos from NASA’s Lunar Reconnaissance Orbiter, showing the Apollo landing sites from an altitude of 50 miles, inspired me to search for the lander locations using my telescopes. And, with a subtle nudge from my older son Adam is the inspiration for this book.

The intent of this book is twofold: to serve as a visual guide, stepping the reader through a process for locating and viewing the Apollo landing sites, and an appreciation of what was accomplished there. The reader should look elsewhere for a more historical accounting of the Apollo Program, as there are many fabulous books on the subject written by former Apollo astronauts, Apollo flight controllers, engineers, and other well-known authors. There is a conscious informality that I’ve used in referring to the astronauts and their missions and equipment. This book serves as an observational guide, allowing the casual and serious observer a chance to locate the Apollo landing sites visually (with or without visual aid), and appreci­ate the historic experiments and equipment left behind. A review of the scientific results is included, and interestingly enough new knowledge is being added about the Moon from Apollo data to this day!

Also included are photos from the lunar probes leading up to Apollo. The long – forgotten Ranger series and the Surveyor series of lunar probes provided valuable information to NASA, both in terms of science and in terms of engineering require­ments and techniques needed to getting to the Moon.

Maybe someday in the future, Mankind can reach out to the Moon again. And provide a reason for a Volume 2 to this book.

Подпись: James L. ChenGore, VA January 25, 2014

Apollo 13

Dates: 11-17 April, 1970

Crew: Commander Jim Lovell CM Pilot Jack Swigert LM Pilot Fred Haise

Command Module: Odyssey Lunar Module: Aquarius

Accomplishments: Successful return to Earth after an on-board explosion.

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

The Patrick Moore Practical Astronomy Series, DOI 10.1007/978-3-319-06456-7_5, © Springer International Publishing Switzerland 2014

Apollo 13

Fig. 5.1 Insignia. Courtesy of NASA

Apollo 13

Fig. 5.2 The original Apollo 13 crew of Lovell, Mattingly, and Haise. Courtesy of NASA

Apollo 13

Fig. 5.3 The revised Apollo 13 crew picture ofLovell, Swigert, and Haise. Courtesy ofNASA

Apollo 13

Fig. 5.4 Pre-Launch Apollo 13 Service Module. Photo courtesy of NASA

Apollo 13

Fig. 5.5 Damaged Apollo 13 Service Module that caused the mission to abort. Photo courtesy of NASA

The inclusion of the Apollo 13 mission in a book about Apollo landings on the Moon may seem odd, since obviously the Apollo 13 failed in its mission to land on the Moon. Apollo 13 is one of the most famous and best remembered manned spaceflights in history, exceeded only by the history making Apollo 11 mission. However, the story of Apollo 13 does include its Saturn S-IVB third stage being targeted to impact the Moon and providing seismic data for the Apollo 12 ALSEP seismometer. Thus, the historic Apollo 13 mission’s inclusion.

Books have been written, a long-forgotten made-for-television movie aired, and a very successful theatrical movie have been produced about this ill-fated mission. Apollo 13 is often described as NASA’s finest moment as the agency successfully returned the astronauts safely home. It is a testament to the many NASA engineers and scientists who brought Lovell, Haise and Swigert to a safe landing.

The genesis of the mission failure was the Oxygen Tank No. 2. The oxygen tank was originally to fly as part of the Apollo 10 mission. The Apollo 10 mission, with the crew of Tom Stafford, John Young, and Gene Cernan, was a planned dry run and prelude to the actual landing on the Moon mission, with all procedures and maneu­vers rehearsed with the exception of an actual landing.

During pre-flight testing, Oxygen Tank No. 2 caused a major problem in the Apollo 10 service module. It was removed from the Apollo 10 service module for further testing, inspection, and repair. During the removal, the oxygen tank was dropped and damaged. After repair work was performed, the oxygen tank was then installed onto the Apollo 13 service module, whereupon it failed again during test­ing. Again, NASA performed some adjustments and deemed the oxygen tank flight worthy. Apparently, the continual maintenance actions performed and the acciden­tal damage resulted in the teflon insulation of the wires to the cyro stir fans becom­ing frayed.

Oxygen Tank No. 2 was part of a redundant fuel cell system for the CSM that provided power to the CSM system, with the by-product of drinkable water. The redundant fuel cell system was designed with separate units each having a cryo­genic hydrogen and cryogenic oxygen tank, separate power buses, and separate indicator and control systems. The hydrogen and oxygen liquid gases tended to settle into layers of different temperatures and densities as the Apollo spacecraft was exposed to the heat of the Sun on one side, and the cold of the unlit side. Since the hydrogen and oxygen tanks were chilled down to their liquid states, it was nec­essary to perform a “cryo stir” in each of the tanks to maintain a constant internal tank temperature and pressure, and enable sensors to produce consistent readings for the crew and Mission Control telemetry. By flipping on the cryo stir switch, the CM pilot would activate two small fans within each hydrogen and oxygen tank to mix the tanks contents, hence the term cryo stir.

The night of the Apollo 13 explosion, Mission Control was receiving signals from one of the hydrogen tanks that necessitated an extra cryo stir. When Swigert received the order from CapCom Jack Lousma, he flipped the switch for the cryo stir, which caused a spark across the frayed fan wire in Oxygen Tank No. 2, igniting the pure liquid oxygen, and causing the explosion in the service module. The cause of the explosion was not the extra cryo stir. The explosion would have occurred the next day during a scheduled cryo stir. Disaster was inevitable.

As a side note, the actual quote from this historic mission was “Okay, Houston, we’ve had a problem.”, spoken by Jack Sweigert. After CapCom Jack Lousma called back “This is Houston. Say Again, please,” Jim Lovell responded “Houston, we’ve had a problem We’ve had a Main B Bus under volt.” The public’s collective memory has misquoted the line, much of it cemented as a result of the Hollywood movie Apollo 13, replaced the “had” with “have”, changing it to “Houston, we have a problem.” with Tom Hank’s Jim Lowell speaking the line, thus changing the line from past-tense to present-tense. The director of Apollo 13, Ron Howard, changed the line in the movie script in order to create a dramatic effect, but as a result has perpetuated the misquote.

Apollo 13

Fig. 5.6 (a) Deke Slayton (check jacket) shows the adapter devised to make use of square Command Module lithium hydroxide canisters to remove excess carbon dioxide from the Apollo 13 LM cabin. Photo courtesy of NASA. (b) Interior view of the LM Aquarius during return to Earth. Note: The jerry-rigged lithium hydroxide canister beside Astronaut Swigert. Photo courtesy of NASA

The impact of the explosion is well documented in books and movies. The loss of the lunar landing, loss of power, the power up issues, the carbon dioxide issue and the jury-rigged oxygen scrubbers (Fig. 5.6a, b), and the computer-less course correc­tions are all well known. One issue caused by the explosion that is often missed by the public is the loss of drinking water. The fuel cell system, when properly operat­ing, provided both power and water to the spacecraft and the crew. The water could be used to both cool the electrical systems and for drinking by the crew. The Apollo spacecraft therefore did not have to carry huge stores of water to make the flight. The destruction of the fuel cell system caused by the Oxygen Tank No. 2 explosion deprived Lovell, Haise and Swigert of drinking water. Normal water intake for the crew was 75 ounces per person. From the moment of the explosion to splashdown, the Apollo 13 astronauts were limited to 6 ounces of water per day! All three astro­nauts returned extremely dehydrated, and the kidney infection that Fred Haise suf­fered during the latter part of the mission was a result of the water shortage.

Apollo 13

Fig. 5.7 LRO view of the Apollo 13S-IVB Third Stage Impact Site. Photo courtesy ofNASA and Arizona State University

Apollo 13
While the primary mission of Apollo 13 was landing on the Moon, it was forever blasted away by the Oxygen Tank No. 2 explosion. However, one scientifically significant objective was achieved. The Saturn V rocket that rocketed Apollo 13 towards the Moon consisted of a 3-stage launching system. While the first and second stage of the launch vehicle dropped back to Earth after launch, the third stage, known as the Saturn-IVB (or alternatively S-IVB) was used to propel the docked Apollo Command Module and Lunar Module from Earth orbit into a lunar trajectory. The spent S-IVB third stage separated from the Command Module, and was sent on a trajectory to impact the moon north of Mare Cognitum. From the tracking of the radio signals of the rocket, the impact locations on the moon and the impact times were fairly well known, with the impact site confirmed with photos from the 2009 LRO mission.

Seismogram of the Apollo 13 S-IVB impact recorded at the Apollo 12 seismic station in digital units (DU). The three traces designate the signal of the 3 orthogo­nal components of the ground motion at long wavelengths. The arrows mark the arrival times of the p (primary) and the slower s (secondary) seismic waves. Image modified from: Ewing et al. (1971), Seismology of the moon and implications on internal structure, origin and evolution, in: De Jaeger (Eds.): Highlights of Astronomy, IAU, pp. 155-172)

At the time of the Apollo 13 mission, only the seismometer at Apollo 12 was available, which had been deployed 5 months earlier. The S-IVB impact occurred on April 14, 1970, at a distance of 135 km from that seismic station at longitude 332.11°, latitude -2.56°, elevation 1166 m. The later Apollo missions all took advantage of their third stages by impacting them on the Moon. With an expanding network of seismometers with each subsequent mission, impacting the known size and weight of the S-IVB third stage served as a calibration tool for all the ALSEP seismometers. The impacts by the S-IVB stages represented unique calibration signals for the Apollo seismic station network, which operated on the lunar surface from 1969 to 1977. Since the rocket impacts occurred at known times and places, the seismic wave velocities, in particular those within the upper lunar crust, could be measured directly.

Apollo 13

Fig. 5.9 Apollo 12 ALSEP including Passive Seismometer Experiment (PSE). Photo courtesy of NASA

Apollo 13

Fig. 5.10 Apollo 12 Passive Seismometer Experiment. Photo courtesy ofNASA

In 2010, a company called Analytical Graphics, Inc. (AGI) used Satellite Tool Kit (STK) software to perform an analysis of the Apollo 13 mission with the some­what fatalistic assumption that the course corrections failed and NASA was unable to get the Apollo astronauts home safely. The previously accepted thought was the Apollo spacecraft would miss the Earth, the astronauts would die and the CM would drift through space. The AGI analysis revealed a much different outcome. The command module would have missed the Earth by 2,500 miles and entered into an elongated orbit that would have apogee of 350,000 miles. Upon returning Earthwards, Apollo 13 would have passed within 30,000 miles of the Moon, close enough to perturb its orbital path and send the CM towards the Earth and its atmo­sphere. The STK software then predicted a re-entry on May 20, 1970, 5 weeks after Oxygen Tank No. 2 exploded. Unfortunately, the simulation predicted a steep

re-entry path, with the CM burning up in the atmosphere. This simulated scenario did not take into account the limited expendables on board Apollo 13, such as water, food, and oxygen. Either way, in the case of a failed course correction, the fate of the astronauts was fatal. The results of the AGI analysis was confirmed by Apollo 13 flight controller Chuck Dietrich using historic Apollo 13 flight data. Thank goodness Apollo 13 had a happy ending!

As the CM Odyssey splashdown safely in the Pacific Ocean, some pieces of the LM Aquarius survived re-entry. NASA’s projected trajectory data indicated that pieces of Aquarius landed in the open sea between Samoa and New Zealand. Although the mission was not a complete success, a lunar flyby mission was accomplished, with three planned experiments completed: lightning phenomena, Earth photography, and the S-IVB lunar impact.

After the safe return of Apollo 13, Grumman Aerospace Corporation, the designers and builders of the LM sent a spoof invoice A441066 to North American Rockwell, the designers and builders of the CSM, for towing Apollo 13 around the moon and home to Earth. The bill was submitted by Sam Greenberg, a pilot for Grumman Aerospace, and was written by workers at Grumman’s Flight Control Integration Lab in 1970. Greenberg was apparently fired for it, but was reinstated 2 hours later as Lou Evans, president of Grumman signed the invoice and sent it to Rockwell. It included towing at $4.00 first mile, $1.00 each additional mile, battery charge, oxygen and addition guest at $8.00/night. Water and baggage handling was free. With a 20 % commercial discount and 2 % cash discount (net 30 days), the total bill came to $312,421.24. Rockwell responded in a press conference that they still had not received payment for shipping four of Grumman’s LMs to the Moon!

Propulsion

The development of the Saturn-V rocket was key to the success of the Apollo pro­gram. The accomplishments of Werhner Von Braun and his team of German and American engineers are undeniable. The liquid rocket technology that began with the early efforts of Robert Goddard in the 1920s, the wartime development of the A-4 and V-2 missiles of World War 2 Germany under Von Braun’s leadership, the continuing development of ballistic missiles through the Cold War years of the 1950s and 1960s, led to the crowning achievement of the Saturn-V.

Current rocket propulsion technology does have its limitations. Using current rocket technology for Moon travel has been demonstrably practical. However, lon­ger trips into space beyond the Moon and within the Solar System demonstrates the limitations of current technology. Just to travel within the confines of the Solar System demands a staggering amount of fuel and rocket power for direct trips to adjacent planets. Deep space probes, such as Cassini, Galileo, and New Horizons, takes years of planning and reliance on planetary gravity assists to achieve the goals of the designed missions. Any manned mission to Mars and return to Earth becomes a multi-year effort, with considerable scientific, technological, logistical, and human health risks involved. Any attempt to travel to Mars with current rocket technology becomes an extraordinary expensive proposition.

Truth be known, a new propulsion technology is needed. If years of space travel can be cut to months, or even days, an attempt at Mars becomes more than a pipe dream. Unmanned probes, such as the Mars Orbiter, and the aforementioned Mars rovers are laying the groundwork, just as Ranger and Surveyor did for the Apollo program. Current propulsion technology works for remote probes, robotic landers, and rovers. But the exposure to the harsh realities of space renders a manned Mars mission a very risky business.

Like the chemical liquid fueled launch vehicles that NASA and the rest of the world relies on now, alternative space drive systems have been in slow development for over a century. Propulsion systems utilizing ion/plasma reaction engines have been proposed, with several designs undergoing some form of development.

The most promising of these alternative drive systems is the Variable Specific Impulse Magnetoplasma Rocket, or VASIMR. VASIMR uses radio waves to ionize and heat argon gas, and subjects the ionized argon to magnetic fields in order to accelerate the resulting plasma which provides thrust to a space vehicle. This plasma rocket technology was first introduced in 1977 by Franklin Chang Diaz, a Costa Rican scientist and astronaut.

A VASIMR driven spacecraft will allow for a mission to Mars with a travel period of just 39 days, almost 6 times faster than current rocket technology. The VASIMR driven spacecraft can develop speeds estimated at 35 miles a second, and will conceivably cover the distance between Earth and Mars in a more timely manner.

NASA rates new systems on a scale of one to ten based on its readiness to be deployed. The VASIMR system is currently rated by NASA as a six, which means that testing in space is the next step. NASA is testing a 200-kW VASIMR engine on the International Space Station in 2015. The engine is envisioned to provide periodic boosts to the ISS, which gradually drops in altitude due to atmospheric drag. ISS boosts are currently provided by spacecraft with conventional rocket thrusters, that consume about 7.5 tons of fuel per year. By cutting fuel use down to 0.3 ton per year, a huge cost saving can be realized in ISS operations. A success for VASIMR on the ISS will lead to a possible Mars application, with a nuclear reactor approximately equivalent to those carried aboard nuclear submarines. A reactor capable of generating 10-12 MW of power is required. Dr. Franklin Chang Diaz stated in a paper called The VASIMR Rocket which appeared in the November 2000 issue of Scientific American, that a 10-12 MW nuclear reactor is required for a 39 day journey from Earth to Mars. In addition, on September 29, 2009 Dr. Franklin Chang Diaz stated the following. “In fact, with the power close to what a nuclear submarine generates, you could use VASIMR to fly humans to Mars in 39 days.”

Moon Observing. Basics and Book. Tutorial: What. You Need to Know

Moon Observing. Basics and Book. Tutorial: What. You Need to Know

Fig. 1.1 Courtesy of NASA

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

The Patrick Moore Practical Astronomy Series, DOI 10.1007/978-3-319-06456-7_1, © Springer International Publishing Switzerland 2014

The Moon has long held the fascination of mankind. It is the biggest and the brightest object in the night sky. Man has gazed upon the Moon for centuries with awe and imagined journeys there. Great, and not-so-great, literature has been written over the centuries, both prose and poetry, about the Moon. Nature itself has adapted to and has synchronized to the rhythms and timing of the lunar cycle in determining reproduction, migrations, and other organic activities. The contribution of the Moon to life on Earth, and to mankind and his culture is extensive.

Before proceeding to the pictorial portion of this book, there are some basics about the Moon that will help with observing it and appreciating the photos herein.

The Moon is the largest natural moon in proportion to its primary planet in the solar system. It orbits the Earth in an elliptical orbit, with a perigee of 225,741 miles and an apogee of 251,968 miles at an orbital inclination to the ecliptic of 5.125°. This inclination translates to between 18.29° to 28.58° to the Earth’s equa­tor. The Moon has a mean radius of 1,737.1 miles, is spherical in shape, although it is slightly flattened due the gravitational force of the Earth. The lunar mass is

0. 0123 that of Earth. Gravity on the Moon is 0.165.4 g. To launch back into lunar orbit, Apollo Lunar Module (LM) astronauts needed only an escape velocity of 2.38 km/s, as compared to the escape velocity of Earth of 11.2 km/s.

The Moon is the second brightest celestial object that can be seen from Earth, with only the Sun outshining it. At full phase, the Moon shines at -12.74 magni­tude. Unlike the Sun, where direct viewing can cause permanent eye damage with­out proper equipment and eye protection, the Moon can be readily observed safely. The Moon has an albedo of 0.136, which is the ratio of reflected sunlight to the sunlight that hits it. Moonlight does not possess the heat that is characteristic of direct sunlight, and thus cannot cause eye damage. A full Moon can be uncomfortably bright, but it is safe to view. The angular diameter of the Moon for Earth bound observers varies from 29.3 to 34.1 arc minutes.

Commonly thought of as being airless, the Moon possesses a very, very slight atmosphere. Atmospheric pressure varies from a daylight level of 0.0000001 to 0.0000000001 pascals This thin lunar atmosphere consists of argon, helium, hydro­gen, potassium, and radon gases.

The Moon is in synchronous rotation with the Earth, thus always showing the same face towards Earth. Because of the Moon’s orbital inclination and it’s ellipti­cal orbit, roughly 64 % of its near face can be seen and mapped from Earth, but not all at one time.

Apollo 14

Dates: 31 January – 9 February 1971

Crew: Commander – Alan Shepard CM Pilot – Stuart Roosa LM Pilot – Edgar Mitchell

Command Module: Kitty Hawk Lunar Module: Antares

Accomplishments: Third Lunar Landing, completed Apollo 13 mission for Fra Mauro Region. Most famous for Alan Shepard’s golf shots on the Moon.

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

The Patrick Moore Practical Astronomy Series, DOI 10.1007/978-3-319-06456-7_6, © Springer International Publishing Switzerland 2014

Apollo 14

Fig. 6.1 Apollo 14 Insignia. Courtesy of NASA

Apollo 14

Apollo 14 was the third lunar landing, the last of the H series missions, and marked the return to space by America’s first astronaut in space, Alan Shepard. Apollo 14 featured Stuart Roosa as the CM pilot and Edgar Mitchell as the LM pilot, both on their first and, as it turned out, only space missions. With two space rookies, and one astronaut with only a suborbital 15 minutes space ride under his belt, the crew of the Apollo 14 were affectionately called “The Rookies.”

The Apollo mission almost did not happen for Shepard. From 1964 to 1968, Shepard found himself grounded because of Meniere’s Disease, an inner ear condi­tion that affects hearing and balance. It is characterized by episodes of vertigo, tin­nitus, and hearing loss. Meniere’s Disease greatly affected Shepard’s sense of balance, resulting in random and debilitating attacks of extreme vertigo. The condition obvi­ously prevents pilots and astronauts from performing aviation and space related tasks.

According to Andrew Chaikin, in his book “A Man on the Moon,” original Mercury Seven astronaut Gordon “Gordo” Cooper was scheduled to serve as mission commander of Apollo 14. However, since his remarkable Mercury flight of “Faith 7”, Cooper had gradually fallen out of favor with NASA officials due to his casual approach to training and his critical attitude towards NASA management. The best assignments for Cooper were as backup pilot for Gemini 12, and as backup commander for Apollo 10. Historically, a backup crew at NASA would receive a prime crew assignment two or three missions later. Faith 7 proved to be Cooper’s only spaceflight, and Alan Shepard became the only Mercury Seven astro­naut to reach the Moon. NASA had lost faith in Gordo.

Alan Shepard’s inner ear condition was cured with a new surgical method for treating Meniere’s Disease. And with the internal politics of NASA and Gordon Cooper’s somewhat casual and rebellious attitude, Shepard worked hard to regain flight status, and was named mission commander of Apollo 14, over the protests of Gordon Cooper.

As with the previous Apollo flights, not all went as planned on Apollo 14. The mission experienced an extended early problem in its mission. At the beginning of the mission, the Kitty Hawk had difficulty achieving capture and docking with the LM Antares. The standard Apollo maneuver called for the Command/Service Module to separate, turnaround and dock with the LM stored in the fairing behind the CSM. Problems for CM pilot Roosa occurred immediately. Although the docking probe was properly maneuvered, the docking latches did not engage. Repeated attempts to dock went on for 1 hour and 42 minutes, until CM pilot Roosa received directions from Gene Cernan at Mission Control to hold Kitty Hawk against Antares using its thrusters. The docking probe was then retracted out of the way, with the hope of triggering the docking latches. The docking was successful, and no further docking problems were encountered during the mission. The best guess for the problem was that a stray piece of debris had gotten caught up in the docking mechanism.

The docking problem was just the first of three events that could have caused a mission abort. After separating from Kitty Hawk in lunar orbit, the Antares experi­enced two other major problems.

The first occurred when the LM computer began getting an abort signal from a faulty switch. NASA initially believed that the LM computer was receiving errone­ous readings from a rogue solder bead shaking loose and closing the circuit as it floated between the switch and the contact. Tapping on the panel next to the switch to dislodge the debris seemed to work at first, but the circuit soon closed again. If the erroneous signal recurred after the descent engine fired, the computer would think the signal was real and would initiate an auto-abort, causing the ascent stage to separate from the descent stage and climb back into orbit. Or if the problem occurred during the Dead Man’s Zone, a major disaster was in store for the mission and would prove fatal for its crew. NASA and the software development engineers at MIT struggled and fortunately found a solution by reprogramming the flight software to ignore the false signal. With time being of essence, the software modi­fications were communicated to the crew verbally, and Mitchell manually entered the machine language changes into the LM computer.

A second problem occurred during the powered descent, when a previously unknown design bug in the LM radar altimeter caused the radar to fail and lock auto­matically onto the Moon’s surface, depriving the LM computer of critical LM altitude and groundspeed information. The radar altimeter successfully acquired a signal near 18,000 feet after the astronauts toggled the landing radar breaker off and on, just in time to save the landing. Shepard then manually landed the LM, a landing that historically was closer to its intended target than any of the other six Apollo Moon landings.

Apollo 14

Fig. 6.3 Wide view of Apollo 14 site. Courtesy of the author

Apollo 14

Fig. 6.4 Closer view of Apollo 14 landing site. Courtesy of the author

Apollo 14

Fig. 6.5 Close-up zoom of Apollo 14 landing site. Courtesy of the author

Assuming success in sighting the Apollo 12 landing site, the amateur astrono­mer probably has spotted the Apollo 14 site in the same field of view. The Fra Mauro landing site is basically next door to the Apollo 12 Sea of Oceans site. The starting point for the backyard observer is again the terraced crater Copernicus. South of Copernicus, and east of crater Reinhold, is the crater Gambart. From there, the observer needs to go south and slightly west to locate Fra Mauro crater. The Apollo 14 landing site is actually just outside the Fra Mauro crater on the northern end.

Apollo 14

Fig. 6.6 LRO view of Apollo 14 Landing Site. Photo courtesy of NASA and Arizona State University

Apollo 14 inherited the Apollo 13 mission, which was targeted to land in the geologic unit known as the Fra Mauro Formation. The landing site selected for Apollo 14 was in the Fra Mauro Formation near Cone Crater, with the primary objective of sampling material excavated by the Imbrium impact.

With the successful pinpoint landing of Apollo 12, NASA mission planners were more confident in achieving landings in more challenging but geologically more interesting regions. However, planned landing sites were still restricted to regions near the equator. Also factored into the site selection was the requirement for the astronauts to accomplish scientific objectives within the confines of two 4-hours-long walking EVAs.

Fra Mauro was formed from ejected lunar material from the large impact that formed the Imbrium Basin. The widely distributed Fra Mauro material can be seen through backyard and research telescopes across the nearside of the Moon.

The Apollo 14 landing site therefore provides a geologically stratified or layered marker, dividing features that are older than the Imbrium impact from those that are younger. A precise age could be assigned to this geologic transition by geolo­gists studying the returned samples from Fra Mauro. Also, because the Fra Mauro was ejected by the Imbrium impactor, scientists hoped that samples col­lected would have originated deep in the Moon’s crust, perhaps from tens of kilometers below the surface. The specific landing site within the Fra Mauro was near the younger Cone Crater. Cone Crater was chosen because it is large enough to penetrate through the lunar surface and exposed the layered rocks that were to be sampled.

Apollo 14

Fig. 6.7 Apollo 14 ALSEP. Courtesy of NASA

Figure 6.7 shows a photo taken by Alan Shepard of the SIDE/CCIG toward the Central Station, which is northwest of the instruments. The Suprathermal Ion Detector Experiment (SIDE) is at bottom center and the Cold Cathode Ion Gauge (CCIG) is at bottom right. Nearer the Central Station, from left to right are the MET, the geophone anchor (the stack tilted to the right), the Central Station, the mortar package for the Active Seismic Experiment, the Radioisotope Thermoelectric Generator (RTG), the Passive Seismic Experiment (PSE), and the Charged-Particle Lunar Environment Experiment (CPLEE). Note the inbound MET track coming into the picture at the right.

Apollo 14

Fig. 6.8 Apollo 14 RTG, Central Station, and part ofLRRR. Courtesy ofNASA

The radioisotope thermoelectric generator, or RTG, was used as a power generator using an array of thermocouples to convert the plutonium-238 decay heat into electricity. The RTG served as the main power source for each ALSEP deployed by the Apollo missions.

Apollo 14

Fig. 6.9 Apollo 14 CPLEE, some of the equipment Apollo 14 astronauts Alan Shepard and Edgar Mitchell set up on Fra Mauro landing site. Courtesy of NASA

The Charged Particle Lunar Environment Experiment, or CPLEE (in Fig. 6.9), was deployed on Apollo 14 to measure plasmas on the Moon. It measured electrons and both positively and negatively charged ions near the Moon’s surface with ener­gies between 50 and 50,000 eV. Less energetic ions were studied by the Suprathermal Ion Detector Experiment and more energetic particles were studied by the Cosmic Ray Detector experiment.

An unexpected result of CPLEE was recorded as the Apollo 14 lunar module ascent stage impacted the Moon after the crew had returned to lunar orbit and jetti­soned it. Not one, but two distinct clouds of material from this impact were recorded by the CPLEE. The ascent stage impact occurred at a distance of about 66 km from the Apollo 14 landing site with approximately 180 kg of unspent rocket fuel left on board. The two clouds were about 14 and 7 km across and had expanded away from the impact site at velocities of about 1 km per second. This expansion velocity is simi­lar to that measured by the Suprathermal Ion Detector for other impacts on the Moon.

Apollo 14

Fig. 6.10 Modular Equipment Transporter (MET) with Apollo 14 Commander Alan Shepard nearby. Courtesy of NASA

Nicknamed the “rickshaw,” the MET seen in Fig. 6.10 was a cart for carrying around tools, cameras and sample cases on the lunar surface. Shepard can be identi­fied by the vertical stripe on his helmet. After Apollo 13, the commander’s spacesuit had red stripes on the helmet, arms, and one leg, to help identify them in photo­graphs. Apollo 14 was the only mission that the MET was used, as the functionality of the MET was superseded by the lunar rover.

Apollo 14

Fig. 6.11 The results of Shepard and Mitchell’s Lunar Sports. Courtesy of NASA

Alan Shepard’s extraterrestrial six-iron golf shot became the most famous extracurricular lunar activity ever planned and executed. Shepard smuggled on board a golf head from a six-iron, modified to attach to the handle of a lunar excavation tool, and two golf balls. As designed, the Apollo lunar spacesuit was limited in flex­ibility and range of motion. Shepard had to take single handed swings at the two golf balls. The first golf ball was topped, and can be seen in the small crater in Fig. 6.11. The second ball went “miles and miles and miles” according to Shepard, but was later estimated to have traveled a distance as 200-400 yards, which to a golfer is a remarkable distance for a six-iron. Mitchell then threw a lunar scoop handle as if it were a javelin, landing it near the first golf ball, and also seen in Fig. 6.11.

Even Stuart Roosa joined in with his own extracurricular activity of sorts. As a young man, Stuart Roosa worked in forestry, and for Apollo 14 he took several hundred tree seeds on the flight. These were germinated after the return to Earth, and these commemorative Moon Trees were widely distributed around the world.

Apollo 14

Fig. 6.12 ALSEP showing the CCG/SIDE with the Central Station, RTG, PSE, and CPLEE in the background. Courtesy of NASA

In the same implementation as Apollo 12, the Cold Cathode Gauge (CCG) mea­suring the atmospheric pressure of the lunar atmosphere is mounted on the Suprathermal Ion Detector Experiment (SIDE). These experiments provided data on the lunar environment by measuring the various properties of positive ions in the lunar ionosphere, collecting data on the plasma interaction between solar wind and the Moon, and measuring the electrical potential of the Lunar surface. In the ALSEP setup, the Central Station served as the command and control center for the ALSEP station. It received commands from Earth, transmitted data, and distributed power to each experiment. Communications with Earth were achieved through an antenna mounted on top of the Central Station and pointed towards Earth by the astronauts. Transmitters, receivers, data processors and multiplexers were housed within the Central Station.

Figure 6.12 includes the PSE that added additional seismic recording capability to that available from the Apollo 12 PSE. Apollo 14 also carried an Active Seismic Experiment, where seismic data was gathered from a “thumper” carried in the MET and activated as the astronauts traversed. Some explosive charges were also part of the setup. These charges were to be activated after the astronauts returned, but the charges failed.

As with the previous Apollo missions, our old friend the Solar Wind Composition Experiment (SWCE) was part of the Apollo 14 experiment complement. Additionally, a Lunar Portable Magnetometer (LPM) was included to measure how the Moon’s magnetic field varies in local regions. The LPM was not part of the ALSEP, but was mounted on the MET. Its data was measured as the astronauts traversed the local lunar region during their two EVAs’.

Apollo 14

Fig. 6.13 Astronaut Edgar Mitchell, LM pilot, photographed this view showing astronaut Alan Shepard Jr. and the LM Antares. Mitchell took this picture during the second scheduled moon walk, on February 6, 1971. Courtesy of NASA

In addition to the lunar surface activities, Stuart Roosa kept busy performing several studies of the Moon from lunar orbit. Two experiments performed specifi­cally from the CM Kitty Hawk while in orbit over the Moon were as follows:

The S-Band Transponder Experiment measured regional variations in the Moon’s gravitational acceleration. The S-band Transponder Experiment was per­formed on Apollo 14 and all the following Apollo missions. The frequency of radio waves transmitted by the spacecraft was accurately measured by Earthbound receivers, and compared with the frequency of the waves as transmitted by the spacecraft. The Doppler Effect caused by changes in the frequency of the radio waves from the Apollo 14 spacecraft’s motion was measured. By comparing the difference between the frequency of the radio waves from the spacecraft and at Earth reference, the spacecraft’s velocity was determined with very high accuracy. As the Apollo CM passed over gravity variations, the changes in the spacecraft’s velocity were measured. The primary gravitational influence on the spacecraft is the Moon’s gravity. Other objects, particularly the Earth and Sun, also affect the spacecraft, but the contributions of these objects can be readily calculated and fac­tored out of the equation. As a result, this experiment provided maps of how the Moon’s gravity varies with location across its surface. This experiment attempted to explain the gravity variations of the Moon and the presence of mascons. This experiment predated GRAIL, as mentioned in Chap. 5 that finally solved the vari­able gravity caused by mascons.

The Bistatic Radar Experiment measured scattering of radar waves from the lunar surface. The Bistatic Radar Experiment was performed on Apollo 14, 15, and 16. In this experiment, radio waves were transmitted from the Command and Service Modules, bounced off the Moon’s surface, and recorded at tracking stations in California. The properties of the waves recorded on Earth were analyzed to determine the roughness of the Moon’s surface in the region where the radio beam was reflected. In addition, the electrical properties of the lunar surface, specifically the dielectric constant of the lunar rocks, were also determined. The region ana­lyzed by this method was a swath of about 10 km across the Moon’s surface as the spacecraft moved in its orbit.

Performed primarily to and from the Moon, the Apollo 14 crew performed sev­eral experiments intended to explore various aspects of the space environment:

• The Window Meteoroid Experiment studied impacts on the windows of the Apollo 14 Command Module to obtain information about the size and distribu­tion of very small micrometeorites. Only two micrometeorite impacts were identified following Apollo 14s return to Earth and examination under an elec­tron microscope. One meteoroid impact was identified as 25 qm in diameter, while the other measured 85 x 130 qm.

• The Composite Casting Experiment studied the solidification of immiscible compositions in microgravity. Eleven samples of various immiscible composi­tions were heated, mixed by either premixed or mixed by shaking, and allowed to solidify by cooling in 0-g. The samples were heated in a small chamber and returned to Earth for examination and testing. Post-mission laboratory analysis indicated that a more homogeneous mixing was achieved than is possible with similar samples on Earth.

• The Electrophoresis Demonstration studied the separation of organic molecules in an electric field. Many organic molecules, when placed in water solutions, will migrate if an electric field is applied. Molecules of different substances move at different speeds; thus, they will separate. Gravity and thermal convection tend to diminish this separation if the solution density changes upon concentration of these molecules. A small unit was used to demonstrate the separations obtained with three sample mixtures having widely different molecular weights: (1) a mix of red and blue organic dyes, (2) human hemoglobin, and (3) DNA from salmon sperm. Post-mission review of the filmed data reveals that the red and blue organic dyes separated better and sharper than on Earth, as expected; however, separation of the hemoglobin and DNA could not be detected. Post-flight exami­nation of the apparatus indicated that the samples were not released effectively (due to injection problems caused by the slide valve) to permit good separation, causing the dyes to streak. The hemoglobin and DNA samples did not separate because they contained bacteria that consumed the organic molecules prior to activation of the apparatus. Oops!

• The Heat Flow and Convection Demonstration studied convective flow and heat transport driven by surface tension. Three different types of test cells were used to detect convection directly, or detect convective effects by measurement of heat flow rates in fluids: radial, flow pattern, and zone. The heat flow rates were visu­ally displayed by color-sensitive, liquid crystal thermal strips and the color changes filmed with the Data Acquisition Camera. It was demonstrated that sur­face tension in fluids under weightless conditions develops a regular pattern of convection cells known as Benard cells. Zone heating of liquid samples pro­duced an unexpected cyclic heat-flow pattern.

• The Liquid Transfer Demonstration studied how different types of tank design influenced the pumping of liquids between tanks in microgravity. The demon­stration had two sets of tanks, one set containing baffles and the other without baffles. Transfer of liquid between the un-baffled tanks was unsuccessful, as expected. Transfer between the baffled tanks demonstrated the effectiveness of two different baffle designs. The liquid-transfer demonstration clearly showed that suitable baffles inside a tank at 0-g permit positive expulsion of liquid con­tents, taking advantage of the surface-tension properties of the liquid. Orderly inflow into the receiver tank with no liquid loss through the gas vent was also successful.

• The Light Flashes Experiment studied light flashes seen by the crew that are related to charged particles in space. This experiment concluded that some of the flashes observed in space may be caused by direct ionization interactions of cosmic rays with the retina.

An experiment on extra-sensory perception, ESP, was independently performed

by Edgar Mitchell. This ESP experiment was not sanctioned by NASA. Prior to the

mission, Mitchell made arrangements with test subjects to receive his mentally

“transmitted” images of random symbols that he would project during his rest periods. This somewhat “New Age” experiment produced some unexpected results. The test subjects were wrong far more often than random probabilities would dic­tate. Mitchell provided a possible explanation for this result. He felt the test sub­jects did not factor in the 40 minutes weather delay that occurred during the Apollo 14 launch. Hence, Mitchell’s projection of these images were not synchronized with the test subjects ESP reception periods. Mitchell proposed that the test sub­ject’s subconscious minds knew something was amiss, and that the experiment was not a failure. The more likely grade for the experiment would be that the results were inconclusive, at best, and at worst “New Age” pablum.

The return of the Apollo 14 astronauts marked the final time that returning Apollo astronauts were subjected to quarantine following their mission. The Apollo 11, 12, and 14 crews were isolated in a special quarantine chamber following their missions as a precaution to any potential lunar microbes infecting them and pre­venting any spread to the Earth environment. It was concluded that the Moon was lifeless, with no microbes, viruses, or bug-eyed monsters. The crews of Apollo 15, 16, and 17 were able to intermingle with the NASA and U. S. Navy personnel immediately following their reentry and landings. As a reminder, quarantine for Apollo 13 was not necessary, since they never landed on the Moon.

Upon the return of the crew to the CM Kitty Hawk, the ascent stage of Antares was sent to the surface of the Moon to provide seismic data. The ascent stage of Lunar Module Antares impacted the Moon on February 6, 7:45 PM EST, at longi­tude 3.42° S latitude 19.67° W. Both the Apollo 12 PSE and the newly setup Apollo 14 PSE recorded the Antares’s impact, which occurred between the two seismom­eters. The resulting impact rang for an hour-and-a-half, with both ASE setups recording the event. Antares’ descent stage and the mission’s other equipment remain at Fra Mauro at 3.65° S and 17.47° W.

With the precedent established with the Apollo 13 S-IVB third stage, the Apollo 14 Saturn third stage was intentionally impacted onto the Moon at longitude 8.09° South and latitude 26.02° West. Again, this event provided data to the Apollo 12 PSE using a known size and mass.

The Apollo 14 Command Module Kitty Hawk is on display at the Apollo/Saturn V building at the Kennedy Space Center.

Human Risks and Safety

Throughout the history of manned spaceflight, both astronauts and cosmonauts have experienced both short term and long term effects from their time away from Earth’s gravity. In the relatively short period the Apollo astronauts traveled to the Moon and back, mostly short term effects were experienced, but the longer periods spent on the ISS have shown some long term effects that can be detrimental to Mars-bound space explorers.

The human cardiovascular system circulates fluids through the body, pushing against gravity to prevent blood from pooling in the legs and bringing blood to the brain. In the microgravity of space, the cardiovascular system is not taxed as hard, triggering a fluid shift. As fluids move up from the lower body to the trunk, the heart rate increases and blood pressure rises. Astronauts experience puffy faces, headaches, nasal congestion and skinny “bird” legs as a result. Additionally, over a third of all astronauts experience some form of motion sickness in space because of the blood circulation changes. Symptoms of space sickness, including nausea and vomiting, headaches, malaise and dizziness, usually subside within 2 or 3 days.

Some evidence suggests that microgravity causes astronauts’ red blood cells to change. The red blood cells appear to change shape in space, becoming more spherical, and fewer cells populate bone marrow. Cells do return to normal once back under Earth-normal gravity however, even after a long-term mission.

Astronauts returning from missions have been found to be more prone to infec­tion, both viral as well as bacterial and fungal. Long term studies in space and Antarctica have shown that isolation and sleep deprivation may result in a weakened T-lymphocyte system, leading to compromised immunity. A high probability of increased allergy symptoms has been noted. The immune system is unable to adapt under microgravity conditions. A future Mars-bound crew will need a supply of antibacterial, anti-fungal, and antiviral drugs and medications. A Mars mission that extends beyond 6 months will mean these drugs will reach their expiration dates, thus inviting the need for some pharmaceutical capability onboard. A shorter 39-day-to-Mars mission reduces this risk.

A well known effect of microgravity is the atrophy the muscular structure. Astronauts onboard the ISS counter these effects by exercising up to 2 hours a day.

The microgravity of space triggers the human body to excrete calcium and phos­phorus (in urine and feces), resulting in rapid bone loss. On the shorter duration Apollo missions, the calcium and phosphorus loss was minimal, and the Apollo astronauts quickly recovered their bones density. A 2 year or longer Mars mission can result in an astronaut’s bone density loss to be equivalent to a lifetime on Earth. Like osteoporosis on Earth, bone loss in space can lead to fractures, weakness and painful urinary stones. The most dramatic changes occur in the heel bone, femoral neck, lumbar spine and pelvis. Exercise in space and upon return can help slow the loss, but it will take 2 years or more of dedicated, consistent training upon return to repair it. Artificial gravity would also serve to mitigate this problem if it is a part of the mission design.

All Apollo missions conducted the Light Flashes Experiment in an effort to explain the flashes of light that seem to appear behind the astronaut’s eyelids. The result of the experiment showed that galactic cosmic rays passed through the astro­naut’s brains causing the retinal flashes. These flashes are just symptomatic of a much larger problem. Cosmic rays and the radiation effects of solar flares expose astronauts to high levels of ionizing radiation. The Apollo astronauts were fortunate that during their missions, other than the light show they experienced when they closed their eyes, no solar flares occurred. A solar flare had the potential of causing the loss of the LM crew on the lunar surface. The LM construction and the lunar spacesuits provided minimal radiation shielding.

Unrelated to the light flashes, medical doctors and scientists are showing some concern over a possible loss of eyesight from extended microgravity exposure. NASA has reported that 15 male astronauts returning from extended missions in space have experienced confirmed visual and anatomical changes during or after long-duration flights. It is continuing to be studied, with current thought being related to ocular fluid shifts due to microgravity as a contributing factor.

The radiation in deep space can damage atoms in human cells, leading to decreased immunity and a higher risk of cataracts, cancer, heart disease, damage to the central nervous system and brain damage. Recognize that Mars does not have a global magnetic field to shield the planet from solar radiation particles, nor does it have a thick atmosphere to help filter out cosmic rays. Long-term exposure to ion­izing radiation in open space and on the planet surface is a significant concern for the crew of the Mars mission.

The Radiation Assessment Detector (RAD) aboard the Mars rover Curiosity produced detailed measurements of the absorbed dose, and dose equivalent from galactic cosmic rays, and solar energetic particles en route and from the surface of Mars. The numbers from the RAD are startling high. For the round trip, based on Curiosity’s RAD data, an astronaut would receive radiation from both cosmic gamma rays and solar activity approximately 0.66 Sv during a 180 day flight to Mars.

A 500 day exposure on the surface of Mars would result in each astronaut receiv­ing approximately 1 Sv. Long-term population studies have shown that exposure to radiation increases a person’s lifetime cancer risk; exposure to a dose of 1 Sv is associated with a 5 % increase in fatal cancer risk. NASA has established a 3 % increased risk of fatal cancer as an acceptable career limit for astronauts in low earth orbit, such as extended stays on the ISS. NASA has not established a limit for deep space missions.

A number of solutions are being explored to help protect astronauts, including antioxidant-rich foods, such as blueberries and strawberries and close monitoring of radiation levels combined with the use of radiation shields. Protection from solar flares, however, poses a technological problem that is solvable at the price of addi­tional weight of protective shielding.

Astronauts returning to Earth risk low blood pressure. A sudden reintroduction of gravity makes the blood in astronauts’ bodies rush down, resulting in dizziness and lightheadedness. Tiny muscles in veins that send blood uphill can atrophy after prolonged periods of microgravity, and can fail to push blood back up to the heart. Astronauts can experience fainting or be unable to remain standing. Mir cosmo­nauts had to be carried off their landing craft by stretcher due to the severe drop their blood pressure following long missions. A prolonged mission to Mars will result in returning astronauts needing to drink salt water to increase the volume of fluids in their bodies, wear G-suits (rubberized full body suits which are inflated to squeeze the extremities) or potentially use new drugs to increase blood pressure.

Apollo moon missions took several days to transition from Earth orbit to the Moon, with the Earth within of a few days reach and communications links with only a handful of seconds latency. The manned mission to Mars will not have those luxuries. The travel time to and from Mars will be measured in terms of months or years, not days. Communication latency will be measured in terms of a maximum of 22 minutes, not seconds.

Medical aid for Space Shuttle missions and ISS missions can be accommodated with near real-time communications, on board supplies, and in an emergency, a relatively timely re-entry and return to Earth. A Mars mission, as it progresses towards its goal, will not have the luxury of a quick and timely return to Earth in case of medical emergency. Any real-time communications to guide the crew through a medical procedure will be severely handicapped by the communications delay because of the distance.

A different medical philosophy is required, utilizing lessons learned from the Apollo, Space Shuttle, long-term Antarctic, and ISS experiences. Five decades of American and Russian spaceflight have yielded a greater understanding of space medicine and the effects of weightlessness on the human body. The development of a comprehensive Mars healthcare system will allow for autonomous health care, with a combination of advanced medical instrumentation, medical training of the crew, and the possible selection of a medical doctor for inclusion as part of the Mars crew. It will need to support the Mars crew members for both the journey to and from Mars, and surface activities. The medical system must accommodate a wide array of human illness and conditions, while being prepared for emergencies caused by accidents. In addition, the medical system will incorporate both environ­mental monitoring and exercise countermeasures to ensure wellness and maintain crew health.

The return to Earth from Mars will likely require a quarantine period for the same reasons the crews of Apollo 11, 12, and 14 experienced. It is unknown if there is any microbial life on Mars, harmful or otherwise. A quarantine in an environment external to Earth would be prudent to avoid any possible contamination of Earth. A likely site might be at or near an established Moon base. Isolation could be conducted on an Earth-orbital quarantine module, perhaps in conjunction and monitored by personnel with the ISS.

Lunar Phases

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.