Category How to Find the Apollo Landing Sites

System Reliability, Availability, and Repairability

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.

Apollo 11

Dates: 16-24 July 1969

Crew: Commander – Neil Armstrong

Command Module Pilot – Mike Collins Lunar Module Pilot – Buzz Aldrin

Command Module Columbia Lunar Module Eagle

Lunar Touchdown: 20 July 1969, 4:10 PM EST Accomplishments: First manned landing 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_3, © Springer International Publishing Switzerland 2014

Apollo 11

Fig. 3.1 Apollo 11. Courtesy of NASA

Apollo 11

Fig. 3.2 Apollo 11 Insignia. Courtesy of NASA

Apollo 11

Fig. 3.3 Moon with Sea of Tranquility and Apollo 11 Landing Site. Courtesy of the author

Apollo 11

Fig. 3.4 First Zoom in on Apollo 11 Landing Site. Courtesy of the author

Apollo 11

Fig. 3.5 Second Zoom in on the Apollo 11 Landing Site. Courtesy of the author. (Insert three zoom-in views indicating landing site)

The Apollo 11 Tranquility Base is probably the easiest to identify of all the Apollo landing sites. Mare Tranquillitatis, or the Sea of Tranquility as its commonly known, is in the middle of three roughly circular dark “Sea” areas that are strung together which an observer can see through binoculars or telescope. The Apollo 11 site is located near the southern end of the Sea of Tranquility, in a seemingly flat and clear area of the Moon. Binoculars or spotting scopes will enhance the view. Backyard astronomers with any size (60 mm aperture or greater) telescope can zoom in on the seemingly smooth region where Tranquility Base was established. Although the general area of the Apollo 11 landing zone can be appreciated by the backyard observer, the exact landing area is difficult to pinpoint because of the rela­tively featureless area chosen for the first landing. Three craters in the region of the landing site have been named for Armstrong, Aldrin, and Collins. These named craters are a challenge for the amateur astronomer, requiring a clear night with a steady atmosphere, 100 mm or greater aperture telescope, and moderately high power to resolve them.

The final landing site for Apollo 11 was selected for a myriad of conservative and safe reasons.

The Sea of Tranquility site was chosen because it had few craters and boulders, and a less than 2° slope in the approach path and landing site. Ironically, the actual mission required Neal Armstrong to fly the LM Eagle over a small crater filled with boulders. There were no large hills, high cliffs, or deep craters at the Tranquility site that could reflect erroneous altitude radar returns to the lunar module landing radar. It is readily apparent from a backyard telescope that the Sea of Tranquility repre­sented a fairly featureless target area. The NASA mission planners tried to select a landing site that required the least expenditure of spacecraft fuel.

The actual landing required extensive maneuvering and resulted in the LM Eagle landing with only 20 seconds of fuel to spare. The Apollo 11 landing, as the first Moon landing, was risky and challenging. Five minutes into the descent burn, and 6,000 feet above the surface of the Moon, the LM navigation and guidance computer generated several unexpected 1201 (“Executive overflow – no vacant areas”) and a 1202 (“Executive overflow – no core sets”) alarms. The Guidance Controller, or GUIDO in NASA parlance, determined it was safe to continue the descent, and this was relayed to the crew. The executive overflows alarms meant the guidance computer could not complete all of its tasks in real time and had to postpone some of them. At the time, the cause for the alarms was diagnosed as the rendezvous radar switch being in the wrong position, which caused the computer to process data from both the rendezvous and landing radars at the same time. Software engineer Don Eyles concluded in a 2005 Guidance and Control Conference paper that the problem was actually due to a hardware design flaw, previously occurring once during testing of the first unmanned LM for Apollo 5. According to design and operational procedures, the rendezvous radar was warmed up in case of an emergency landing abort. The position of the rendezvous radar was encoded with synchros excited by a different timing reference source of 800 Hz AC than the one used by the computer. The two 800 Hz sources were frequency locked, but not phase locked, and small random phase variations made it appear as though the antenna was rapidly “dithering” in position even though it was completely stationary. These phantom shifts generated the rapid series of processing cycle “steals.” The extra spurious cycle stealing, as the rendezvous radar updated a coun­ter, caused the computer alarms. The Apollo onboard flight software for both the CM and LM was developed using an asynchronous executive so that higher priority jobs could interrupt lower priority jobs. The sequence that occurred in the Apollo 11 landing was a successfully executed work around because of the software global error detection and recovery system. This included the restart capability to “kill and start over again”.

A little known fact about the 1201 and 1202 alarms during the final descent was their occurrence close to what NASA insiders referred to as the “Dead Man’s Zone.” Throughout the landing phase of the LM, an emergency abort could be accomplished by firing the ascent engine of the LM and returning to an orbital rendezvous with the CM. However, during the last 3 minutes of the landing approach, there was a 10 seconds block of time where the velocity of descent exceeded the ascent engine’s capability of returning the LM safely. A safe abort could be accomplished 10 seconds prior to or after the Dead Man’s Zone with no consequence. Attempting an abort during this Dead Man’s Zone would cause a total expenditure of the ascent stage fuel to just counteract the descent velocity, resulting in the LM running out of fuel and crashing to the surface of the Moon. The 1201 and 1202 alarms occurred within 20 seconds of the Eagle entering the Dead Man’s Zone. A split second decision by the NASA guidance controller Steve Bales, who knew the Eagle’s proximity to the Dead Man’s Zone, and recognized and ignored the alarms resulted in a successful Apollo 11 landing. Bales was honored after the mission to accept a NASA Group Achievement Award from President Richard Nixon on behalf of the entire mission operations team.

With the recent passing of Neil Armstrong, there has been a discussion about his famous “That’s one small step for Man, one giant leap for Mankind”. For years, Neil Armstrong claimed that his first words included the word “a”, as in “…one small step for a Man.”, especially since the quoted line actually doesn’t make any sense. In 2006, Australian computer expert Peter Shann Ford conducted a computer sound analysis of the radio transmission of Armstrong’s first words from the Moon. The analysis indicated an acoustic wave from the word “a” spoken by Armstrong at a rate of 35 milliseconds. The word “a” was spoken too fast for it to be audible in the transmission, but the analysis confirms that Armstrong actually spoke the line as he had planned.

As an aside, the one small step was not so small. Neil Armstrong’s precise pilot­ing produced a landing that was so gentle, the LM’s shock absorbers did not com­press. Armstrong’s one small step was a leap of 3.5 feet!

Little known by the general public, the original video and telemetry captured by NASA during the first lunar EVAs has been lost. Over the years, the Slow-Scan Television (SSTV) video data tapes of the first steps on the Moon have either been lost, misplaced, or accidentally destroyed. The late 1960s state-of-the-art required a live video signal from the Moon to be 10 frames per second at 320 lines of resolu­tion, hardly high-definition television of today. This video signal was multiplexed in with the telemetry data and transmitted to Earth. In those years, NASA routinely erased and re-used data tapes due to the high cost of the tapes and lack of an alterna­tive archiving medium. NASA made efforts in 2006 to locate any surviving tapes, with some telemetry data tapes with no video being located. What remains are the now-famous low resolution, grainy videos that the television networks captured at the time. It is felt that if the original tapes are ever found, modern up-conversion techniques would yield improved video images.

Apollo 11

Fig. 3.6 Lunar Reconnaissance Orbiter view of the Apollo 11 Landing Site. Photo courtesy of NASA and Arizona State University

Apollo 11

Fig. 3.7 LRO view of Apollo 11 Landing site. The Lunar Ranging Retro Reflector (LRRR) and the Passive Seismic Experiment (PSE) are identifiable in this photo. Photo courtesy of NASA and Arizona State University

The distance to the Moon can be accurately determined by firing an earthbound laser off one of the LRRR’s, left behind by Apollo 11, 14, and 15. The information is used to study lunar recession due to Moon’s interaction with the Earth. The LRRRs are the only experiments currently used today. The PSE was used to provide data on moonquakes and other disturbances to study the Moon’s subsurface structure.

Apollo 11

Fig. 3.8 Mission picture of Astronaut Buzz Aldrin during the Apollo 11 extravehicular activity on the Moon. He is standing near the Early Apollo Scientific Experiments Package (EASEP). Shown in the foreground is the Passive Seismic Experiment (PSE); beyond is the Laser Ranging Retro-Reflector (LRRR). Photo courtesy of NASA

The EASEP was replaced in later missions with the Apollo Lunar Surface Experiments Package (ALSEP). The EASEP was a very limited science package, primarily because of the limited time allotted for the extravehicular activities of the Apollo 11 crew. The PSE, along with similar seismic monitors of the ALSEP of later Apollo missions, continued collecting data and relaying the information to NASA until 1977, when all six seismic experiments were turned off. To this day, the Apollo 11 LRRR, along with identical LRRRs deployed by the subsequent Apollo missions, remains as the only experiment still active. The LRRR is a passive experiment consisting of a series of corner-cube reflectors. Corner-cube reflectors are a special type of mirror with the property of always reflecting an incoming light beam back in the originating direction. Earthbound lasers aimed at the LRRR receive the reflected laser return to precisely determine the distance between the Earth and the Moon. Over the years of conducting precise measurement data using the Apollo LRRRs, scientists have refined the knowledge base as follows:

1. Improved definition of the Moon’s orbit.

2. The rate the Moon is receding from the Earth is 3.8 cm per year.

3. Discovered variations in the Moon’s rotation, with implications on the size of the Moon’s core.

4. Improved and refined the Earth’s rotational changes, and has given more preci­sion to the precession of Earth’s spin axis.

5. Useful in providing additional proof of Einstein’s Theory of Relativity.

Apollo 11

Fig. 3.9 Astronaut Neil Armstrong, at the modular equipment storage assembly (MESA) of the Lunar Module Eagle, on the historic first moon walk on the lunar surface. Interestingly, this is one of the few photographs that shows Neil Armstrong during the Apollo 11 mission’s time on the Moon. Photo courtesy of NASA

Apollo 11

Fig. 3.10 Here, astronaut Buzz Aldrin is photographed next to the Lunar Module “Eagle.” On Aldrin’s right is the Solar Wind Composition (SWC) experiment. Photo courtesy of NASA

Apollo 11

Fig. 3.11 Tranquility Base as seen from the Apollo 11 Command Module, taken by Astronaut Mike Collins. This is an opportunity to compare and contrast this photo taken in 1969, and the more recent LRO photos of the same area. Ironically, although Collins took this picture, he never visually sighted the LM Eagle on the surface from the orbiting CM. Photo courtesy of NASA


An interesting aside to the Apollo 11 mission was revealed many years later. Apparently, the U. S. Customs required the Apollo 11 crew to fill out a declaration form for the moon rocks and lunar samples returned from the Sea of Tranquility. As seen in Fig. 3.12, the Customs declaration form is signed by Astronauts Armstrong, Aldrin, and Collins, declaring moon rocks and moon dust samples, and their destination was the Moon.

Apollo 11 collected the first geologic samples from the Moon. The first task of the mission was for Neil Armstrong to take a lunar soil sample and place it in his space – suit pocket, such was the high priority placed in gathering lunar soil samples. This contingency lunar surface sample was made in the first 3.5 minutes in the case an emergency liftoff was required and the mission was cut short. Astronauts Armstrong and Aldrin eventually collected almost 50 pounds of lunar material, including 50 rocks, samples of the fine-grained lunar soil, and two core tubes that included mate­rial from up to 13 cm below the Moon’s surface. The Apollo 11 samples contained no water and provided no evidence for life at any time in the Moon’s history. Two main types of rocks, basalts and breccias, were found at the Apollo 11 landing site.

On Earth, basalts are a common type of volcanic rock. Basalts are generally dark gray in color; when one looks at the Moon in the night sky, the dark areas are basalt. The basalts found at the Apollo 11 landing site are generally similar to basalts on Earth and are primarily of the minerals pyroxene and plagioclase. The basalt sam­ples returned by Apollo 11 contain more of the element titanium than is usually found in basalts on Earth. The basalts returned by Apollo 11 range in age from 3.6 to 3.9 billion years, which scientists believe are from at least two chemically differ­ent magma sources.

The Moon has been bombarded by a countless number of meteorites over the eons. These impacts have broken many rocks up into small fragments. The heat and pressure of such impacts sometimes fuses small rock fragments into new rocks, called breccias. The rock fragments in a breccia can include both mare basalts as well as material from the lunar highlands. The lunar highlands comprise primarily of a light-colored rock known as anorthosite, which consists primarily of the min­eral plagioclase. It is very rare to find rocks on Earth that are virtually pure plagio – clase. On the Moon, it is believed that the anorthosite layer in the highland crust formed very early in the Moon’s history when much of the Moon’s outer layers were molten. This stage in lunar history is known as the magma ocean. The plagioclase – rich anorthosite floated on the magma ocean like icebergs in the Earth’s oceans.

Three previously unknown minerals were discovered in the lunar samples of Tranquility Base:

Armalcolite is a titanium-rich mineral first discovered in the Apollo 11 samples, and later appearing samples from the Taurus-Littrow Valley and the Descartes Highlands. This newly discovered lunar mineral was appropriately named after the Apollo 11 astronauts: ARMstrong, ALdrin, and COLlins. Armalcolite is a minor mineral found in basalt rocks high in titanium content. Armalcolite has been identi­fied on Earth, initially from samples taken from Smokey Butte, Garfield County, Montana. Scientists have also been able to synthesize Armalcolite in the laboratory, by using low pressures, high temperatures and a rapid quenching from about 1,000 °C to the ambient temperature.

Tranquillityite is a silicate mineral first discovered in Apollo 11 rock sample 10,047. Obviously taking its name from the site of the Apollo 11 landing, Tranquillityite has been found in rock samples from all the Apollo missions. It was long considered the only mineral found solely on the Moon, until 2011, when samples taken from six regions in the Pilbara region of Western Australia were found to contain this mineral.

Pyroxferroite is the third of the family of minerals discovered from the Apollo 11 lunar samples, . Pyroxferroite has since been discovered in meteorites of lunar and Martian origin. Terrestrially, the mineral has been discovered in Kyoto Prefecture, Japan, in Vaarmland, Sweden, in Lapua, Finland, and here in the U. S. in Anderson County, South Carolina. Like Armalcolite, Pyroxferroite can also be produced in the laboratory by annealing synthetic clinopyroxene at high pressures and temperatures.

Following the historic Apollo 11 mission, the Moon rocks and soil samples were distributed to over 150 scientific laboratories worldwide. In at least one case, 20 vials of moon dust were misplaced and lost for over 40 years. In May, 2013, an archivist uncovered vials of Apollo 11 moon dust while tidying up a storage space at Lawrence Berkeley National Laboratory in California. The samples, with handwritten labels marked 24 July 1970, were originally delivered to the Space Sciences Laboratory in Latimer Hall on the University of California-Berkeley campus. After the experiments were completed, the samples procedurally should have been returned to NASA. A mystery to all, the vials of lunar dust ended up in storage until the recent discovery.

Apollo 11

Fig. 3.13 Aldrin deploying the Solar Wind Composition Experiment. Photo courtesy of NASA

As part of every Apollo mission, a solar wind composition experiment was deployed in order to collect samples of the solar wind. The astronauts deployed 1.4 m x 0.3 m sheet of aluminum foil mounted on a five section telescoping pole, which exposed collected particles from the solar wind. The foil was gathered up and stored in the LM Eagle prior to lunar liftoff to be brought back to Earth for analysis. The Apollo 11 foil was exposed for 77 minutes. Subsequent missions allowed for longer exposures, culminating with the Apollo 16 exposure of 45 hours. The results of the Apollo 11 solar wind composition experiment measured embed­ded light noble gases, such as He-3, He-4, Ne-20, Ne-21, Ne-22, and Ar-36, and found the variations in solar wind composition. These variations correlated with variations in the intensity of the solar wind as determined from magnetic field measurements.

Armstrong and Aldrin’s departure from the Moon, although not as dramatic as the landing, was not without missteps. The astronauts planned to place mementos on the surface of the Moon, including a mission patch for the ill-fated Apollo 1 to honor their comrades Gus Grissom, Ed White, and Roger Chaffee. Also to be left behind were medals commemorating Soviet cosmonauts Vladimir Komarov and Yuri Gagarin who died in flight in 1967 and 1968. The goodwill messages of 73 world leaders and a small gold olive branch pin completed the package. However, the schedule for lunar surface activities had left little time for ceremony, resulting in Aldrin unceremoniously dumping the contents of his spacesuit pocket onto the Moon surface prior to boarding the LM Eagle for the last time. Upon re-entering the LM and preparing for the launch, the astronauts accidentally broke the switch responsible for igniting the ascent engine, potentially threatening to strand them on the Moon. Oops! Aldrin used a pen to toggle the switch, thus avoiding being marooned on the Moon. On liftoff from the Moon, the item which gave the astronauts the most problems during setup toppled over. Seen prominently in vid­eos and photographs from the mission, the American flag proved to be the most troublesome mission item to setup. The Moon surface proved to be harder than anticipated, and the flag pole was not securely implanted into the Moon’s surface. On liftoff, Aldrin reported seeing the Sears-made American flag topple over from the ascent engine’s exhaust.

Rendezvous with the Columbia CM had problems too. During the process of rendezvous and docking the Eagle to Columbia, the LM inadvertently reached gimbal lock, causing the spacecraft inertial guidance systems to lose orientation alignment in space and tumble briefly. Armstrong and Aldrin used the abort guid­ance system for attitude control and quickly recovered.

To top off the publicly-viewed “perfect” mission, after re-entry and landing in the Pacific Ocean, the Columbia landed in upside down “Stable 2” position. As designed, the inflatable air bags righted the spacecraft.

To the public, the Apollo 11 mission seemed flawless. In the bright light of real­ity, the crew and the Mission Control team were able to work around a number problems and made the mission a success.

In July 2013, an expedition funded and headed by Amazon founder and CEO Jeff Bezos recovered parts of at least two Saturn V F-1 booster engines from the

Atlantic Ocean. Using state-of-the-art sonar technology and tethered remote controlled underwater vehicles, a team of underwater archeologists, conservators, and underwater salvage experts were able to locate, map, catalog, and recover the F-1 engine components. Examination of the recovered thrust chamber revealed the number 2044, which was the serial number given by the F-1 manufacturer Rocketdyne. This number correlated to the NASA assigned number 6044, which was the number five F-1 engine of the Apollo 11 Saturn V launch vehicle. This discovery positively identified the final resting place of the first stage of the Saturn V that hurled Armstrong, Aldrin, and Collins into space in their historic journey to the Moon.

The Scientific Investigations

The primary objective of Surveyor was developing and testing the soft landing technology for on the Moon. These lessons learned were then applied to the Apollo spacecraft design. The Surveyor program also had the objective of gaining scien­tific knowledge of the Moon. A number of experiments were designed into the Surveyor lander for scientific purposes. A comparison of the pre-Apollo Surveyor experiments and the Apollo ALSEP suite shows a continuity of scientific inquiry into the nature of the Moon.

Each spacecraft weighed 1000 kg at launch, was 3.3-m high, and had a 4.5-m diameter. The tripod structure of aluminum tubing provided mounting surfaces for scientific and engineering equipment. Onboard equipment consisted of a 3-m-square solar panel that provided approximately 85-W output, a main battery and 24-V non­rechargeable battery that together yielded a 4,090-W total output, a planar array antenna, two omnidirectional antennas, and a radar altimeter. The soft landing was achieved by the spacecraft free falling to the lunar surface after the engines were turned off at a 3.5-m altitude. Operations began shortly after landing.

Moon Geology

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.

Food in Space

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.

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

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

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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


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Apollo 12

Fig. 4.7 LROviewidentifyingApollo 12. PhotocourtesyofNASAandArizonaStateUniversity

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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.

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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.

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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.

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

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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.

Television Observations

Each Surveyor spacecraft carried a television camera, and more than 86,000 70-mm pictures were obtained at very high resolution (to 1 mm). This photography pro­vided information on the nature of the surface terrain in the immediate vicinity of the spacecraft as well as the number, distribution, and sizes of the craters and boul­ders in the area. In addition to lunar terrain studies, the photography supported investigations of soil mechanics, magnetic properties, and composition of the sur­face material.

Lunar Surface Mechanical Properties

Mechanical property estimates are the result of interpretations of landing telemetry data and television pictures as noted above. Measurements from strain gauges mounted on the spacecraft landing gear were analyzed. The surface sampler, flown on Surveyor 3 and Surveyor 7, also obtained data on mechanical properties. To study soil erosion effects and to determine soil properties, the vernier engines and attitude jets were operated after the landings and the results observed with the television camera. This type of scientific investigation continued during the Apollo missions, with Apollo crews radioing observational information during landing, the impact of rocket exhaust with the surface produced dust clouds, trench digging, and providing core samples for study back on Earth.

Moon Observing Basics

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.

Impact on Society and Culture

To the post World War 2 generation, the Apollo Program represented the hopes and dreams of a bright future and great adventure that was tantalizingly within reach. But the main driver for the race to the Moon was international politics. Created during the height of the Cold War, the rivalry between the two great superpowers, the United States and the U. S.S. R,. provided the impetus for the push into space, culminating in the success of the Apollo Program. The technical challenges were great, but the basis of science supported the idea of landing on the Moon. The technical groundwork of physics, chemistry, and engineering had been laid decades before, and the national focus and challenge of accomplishing a manned lunar mis­sion within a decade provided the necessary energy, commitment, and funding to achieve the goal.

The generations following the Apollo triumphs have lost their way in space. The goals of space travel have become muddled. There is no superpower rivalry that is driving nations to race into space and achieve the goal of landing on Mars. There is no international or national imperative that is pressuring mankind to go to Mars, other than curiosity and the need to explore. The society of the common man has lost sight of the benefits attained by striving towards a common, far reaching goal. The focus on immediate financial accountability has fogged mankind’s vision of the future.

A manned mission to Mars benefits man’s need for exploration, knowledge, and adventure. On the practical side, a program to launch a manned mission to Mars, or even a return to the Moon for potential colonization, represents an opportunity for job creation. New jobs are created from programs directly supporting the space effort to spinoff industries that apply new technologies which provide beneficial products and services. A forward looking approach to space will benefit better edu­cation for the populace, more employment, and better and more meaningful jobs.

Rose colored glasses? Maybe. But the evidence shows the benefits of space – related research and development in a trickle down transfer to every day use.

Every year, NASA publishes a book entitled Spinoff, which highlights products and industries created as off-shoots from space technology. Examples from a recent issue of Spinoff listed the following recent NASA-derived technologies transferred to everyday use:

• Spacesuits incorporating sun-blocking fabric have been adapted to clothing offering protection to ordinary beach goers and people with light sensitivities.

• Gravity-loading technology designed to help astronauts exercise in space have been incorporated into anti-gravity treadmills for rehabilitating after surgery.

• A device NASA invented to study cell growth in simulated weightlessness has been applied to medical research into treatments for heart disease, diabetes, and cirrhosis.

• A star mapping algorithm developed for the Hubble telescope has been adapted to identify unique migrational patterns of endangered species.

• NASA research and development into materials and manufacturing techniques are bringing carbon nanotubes into greater use in everyday applications, such as nanofiber filters to eliminate contaminants.

• Thermal insulation technologies developed for isolating the cryogenic tempera­tures of Saturn V and Space Shuttle fuel tanks have been transferred to applica­tions in the home, resulting in thermal insulation strips that easily apply to wall studs, providing an affordable and environmentally friendly boost to a home’s insulation factor.

These are just a handful of thousands of products derived from the research and development of the space programs such as Apollo, the Space Shuttle, and the ISS. Many new innovations and breakthroughs in technology will result from a focused effort to land a manned mission on Mars. And the public ultimately benefits from these discoveries and innovations in everyday life.

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

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

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

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

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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.

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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!