Category How to Find the Apollo Landing Sites

Many of the readers of this book already own a telescope, on a stable mount, with a case or two of eyepieces and accessories. These readers are suitably equipped to observe the Moon and search for Apollo.

To the readers without a telescope, get one. Astronomy is a wonderful hobby, filled with potential personal discoveries. For the price of a pair of bifocal high index eyeglasses, a nice 80 mm refractor on an alt-azimuth mount with two Plossl eyepieces can be obtained. This setup serves as a great care free introduction to the hobby, and when aperture fever takes hold (it always does) and a larger telescope is procured, the 80 mm refractor still has a role as a grab-and-go scope. The 80 mm refractor’s sharp images are always appreciated.

The ultimate observational challenge (and extra-extra credit!) is sighting and identifying the impact sites of the Saturn IVB third stages and LM ascent modules. Not all impacted on the Moon. As with the Apollo landings sites themselves, the impact craters of the Saturn IVB and LM stages are not large enough to be viewed directly with backyard telescopes. The third stage impact craters are about 100 feet or so in diameter, far too small to be seen with Earthbound telescopes. The S-IVB and LM impact sites tended to be in the same general vicinity as the landings them­selves, as seen in Fig. 12.1. Good luck in identifying these sites!

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

The Patrick Moore Practical Astronomy Series, DOI 10.1007/978-3-319-06456-7_12, © Springer International Publishing Switzerland 2014

Apollo 15 KM Impact

Apollo 17 LM Ascent Stage

Apollo 14 LM AscenDStage Apollo 12 Landing Site

Apollo 15 S-IVR Impact & Agollo irS-IVB. .

Apollo 13 S4VB

. Apollo 14 S-1VB – ^ * 2^-

Apollo_16 S-IVB

Fig. 12.1 Locations of Saturn IVB and LM Ascent stage Impacts. Courtesy of the author

The Apollo 13 third stage Saturn-IVB was the first deliberately sent to impact the Moon. The spent S-IVB third stage separated from the Command/Service Module and later impacted 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. Figure 12.2 was taken by the LRO in 2009.

LPY –

LPZ

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 1,166 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.

Upon the return of the Apollo 14 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 LM Falcon, after returning Apollo 15 astronauts Scott and Irwin to Endeavor, was jettisoned and impacted the Moon on August 3, 1971 at 26.36° N and 0.25° E. The empty discarded LM impacted west of the Apollo 15 ALSEP on the other side of valley, roughly 6 miles away from the Apollo 15 ALSEP deploy­ment. Backyard observers viewing the Apollo 15 landing site need only shift their attention to westward to view the impact area of the Falcon.

The Saturn S-IVB third stage impacted the Moon on an earlier of July 29, 1971 at latitude 1.51° S and longitude 11.81° W. The Apollo 15 Saturn IVB impacted relatively near the Apollo 14 ALSEP. So viewing the Apollo 14 landing site will encompass to the east the impact site of the Apollo 15 third stage.

Both the Falcon and the S-IVB impacts were recorded by the PSE network which now included the PSE at the newly deployed Apollo 15 ALSEP at Hadley Rille and the Apennine Mountains.

Upon the return of the Apollo 16 crew to the CM Casper, the ascent stage of the LM Orion was intended to impact the Moon to provide seismic data. The ascent stage of LM Orion separated 24 April 1972, but a loss of attitude control rendered it out of control. It orbited the Moon for about a year. The Orion impact site on the Moon is unknown.

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

Fig. 12.5 Apollo 17 Saturn IVB Third Stage after Jettison. Courtesy of NASA

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

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

As an additional note, the LM that did not land on the Moon from Apollo 10, called Snoopy, is lost in heliocentric orbit and efforts are underway to re-acquire it. British amateur astronomer Nick Howes embarked on a mission to find Snoopy. He’s looking for Apollo 10’s lunar module Snoopy, which is believed to be in an orbit around the sun, and is the only intact lunar module used operationally from the Apollo program. Howes is using a blink comparator, a machine that allows astronomers to rapidly shift back and forth between two images of the same part of the sky taken days or weeks apart. Movement of Snoopy can be detected by a change in position of an image against the background of stationary stars. Blink comparators used to be a manual devices, alternately shining a light behind two different images; modern astronomers have the luxury of computer software that shifts between images for them. Historically, a blink comparator is how Clyde Tombaugh found Pluto, painstakingly and manually flipping between two images at a time at the Lowell observatory in Flagstaff, Arizona. This technique is also how Mike Brown found the trans-Neptunian object Eris, which ultimately lead to Pluto being demoted from planet to a dwarf planet.

After Apollo 10 completed its successful rendezvous in lunar orbit, Stafford and Cernan transferred from Snoopy back into CM Charlie Brown. With all three men settled in their return spacecraft, they closed the hatch between the LM and CSM and separated, sending the LM Snoopy into deep space. The craft had no purpose beyond the dry run for a landing and like all lunar modules wasn’t equipped to come back to Earth. Mission control fired Snoopy’s ascent engine for 239 seconds to full depletion, using up all of its available fuel. This depletion firing sent the lunar module into an orbit around the Sun. The crew watched Snoopy gain speed as it disappeared into the distance.

With Snoopy’s portion of the mission complete, Stafford, Cernan, and Young went back to tracking landmarks on the moon’s surface. Their survey lasted 31 lunar orbits, after which they fired CSM Charlie Brown main engine for the return to Earth.

Neither the crew nor NASA paid attention to Snoopy’s fate after the jettison. NASA does, however, know where and when the LM separated and how fast the spacecraft was going. With this data, Howes can calculate its rough orbit and effec­tively shrink the area where the hunt for Snoopy will take place. The search for Snoopy will be difficult, but with enough photographic data and an approximate area to search, and a little luck that the lost LM will reflect enough light into the telescopic CCD chips to register, Snoopy may be found.

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

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.

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.

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.

(Outward/Inward)

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.

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.

There were originally twenty Apollo missions scheduled to fly in the initial Apollo plan, with nine Moon landings. Three missions were cancelled due to the geopoliti­cal success of Apollo and the decision of President Nixon and Congress to reallo­cate the U. S. Federal Budget to support other national objectives. Apollo 20 was cancelled in January 1970. Two more flights were cancelled in September, 1970, with the remaining missions renumbered 15 through 17.

The original list of planned missions following Apollo 12 were:

• H-2 (Apollo 13) Fra Mauro

• H-3 (Apollo 14) Littrow

• H-4 (Apollo 15) Censorinus

• J-1 (Apollo 16) Descartes

• J-2 (Apollo 17) Marius Hills

• J-3 (Apollo 18) Copernicus

• J-4 (Apollo 19) Hadley

• J-5 (Apollo 20) Tycho

After the failure of Apollo 13, Apollo 14 was rescheduled for Fra Mauro. After the cancellations, the remaining missions were changed to:

• J-1 (Apollo 15) Hadley Rille

• J-2 (Apollo 16) Descartes

• J-3 (Apollo 17) Taurus-Littrow

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

The Patrick Moore Practical Astronomy Series, DOI 10.1007/978-3-319-06456-7_13, © Springer International Publishing Switzerland 2014

The lost Apollo missions at Censorinus, Marius Hills, Copernicus Crater, and Tycho Crater were missed opportunities for greater exploration and scientific discovery of the Moon.

Apollo 18 became the U. S. portion of the Apollo-Soyuz Test Project.

After the Apollo-Soyuz Test Project in 1975, the United States did not return to manned spaceflight until 1981 with the launch of the Space Shuttle Columbia.

The three missions were canceled for multiple reasons. Tighter budgets, imposed by Congress and the Nixon administration, were a major factor. The public’s interest in the program had also waned after the excitement of Apollo 11. The drama of Apollo 13 reminded the public of the dangers and risks of spaceflight. The cost for the Apollo Program peaked in the mid-1960s, with the labor force of federal work­ers and contractors in the neighborhood of 400,000. By January 1970, the workforce had shrunk to 190,000, with another 50,000 jobs lost following the final Apollo flight. Many skilled engineers and technicians found themselves without jobs.

Ironically, the Saturn V launch vehicles and other mission hardware already had been procured and delivered at the time of the cancellations. The only budgetary savings realized were the operational expenses of executing an actual mission. The remaining hardware has been placed on display, and can be seen at various sites in the U. S., as listed in Appendix 5.

The cancellations also reflected competition among NASA priorities, as orbital projects vied with the moon program for money and hardware. Skylab and the future re-useable launch vehicle program that became the Space Shuttle had begun diverting attention at the agency.

The lost Apollo missions missed the opportunity to collect additional scientific information about other areas of the Moon. An early proposed landing site in the Tsiolkovsky crater on the far side of the Moon would have yielded a unique sam­pling that differed from the Earth-facing side where all the Apollo missions occurred. A far side lunar mission never made it to the planning stage, as it was perceived as too costly and risky. One of the Tsiolkovsky crater requirements was the additional cost for a communication satellite beyond the moon to maintain a radio link with Earth.

Located near the southeastern zone of the Sea of Tranquility is the crater Censorinus. The proposed landing site was the ejecta blanket in the northwest sec­tion of the Censorinus crater, with the hope of sampling both highland material and fresh impact crater material. The original scheduling would have made this mission the last of the H-series missions, with the astronauts investigating the 2.5 mile diameter crater entirely on foot.

Marius Hills is a region of domes and cones near the crater Marius in the center of the Ocean of Storms. Photographs of the region suggested formations similar to Earth’s shield volcanoes, with scientists believing the area was subject to intense and prolonged volcanic activity. As originally scheduled, the mission to Marius Hills would have been the debut of the lunar rover.

The two major craters Copernicus and Tycho were also proposed landing sites. Both craters featured central peaks that were thrust upward at the time of the meteor impact. These impacts caused material from deep within the lunar crust to rebound to the surface to form the central peaks. Samples from these crater peaks would have provided a record of the Moon’s, and possibly the Solar System’s, early history. This early history information is unavailable on Earth because of the destructive processes caused by plate tectonics, erosion and other natural occurrences.

A technical missed opportunity from the Apollo cancellations was the termination of the Saturn V program, and the loss of “corporate” knowledge and technical exper­tise on building large launch vehicles. The Saturn launch vehicles had reached a level of technological maturity by the early 1970s, and the continued manufacture of Saturn would have enabled a variety of deep space or heavy lift missions. An argu­ment can be made that the Space Shuttle missions, from deep space launches to ISS assembly, could have been easily and more efficiently accomplished using the Saturn. Deep space probes launched from the Space Shuttle relied on the finesse of gravity assists from planets to accomplish their missions, with many deep spacecraft taking years to reach their goals. The powerful Saturn V lift capability could have allowed for more direct routes for timelier missions, and possibly allowed the probe designs to carry additional sensors and experiments.

Ironically, the current NASA effort to develop the Space Launch System, con­sisting of the Ares 1 and Ares 5 launch vehicles, strongly resembles the Saturn 1 and Saturn V rockets of the Apollo era. In fact, the proposed Orion manned space­craft can best be described as an Apollo CM on steroids. The current design for Orion features an Apollo command module shape, carries a crew of up to six, and will return to ocean landings.

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

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

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 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.

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.

Fig. 4.6 LRO view of Apollo 12 Landing site in 2009. 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.

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.

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.

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.

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.

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.

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.

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.

Gore, VA January 25, 2014

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

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.

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.

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.

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!

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.”