Welcome to the Apollo 15 Learning Hub
A project to assemble, preserve, and make available primary source records of Apollo 15 for research, education, and preservation as an example of a unique human endeavor.
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Apollo 15

The Apollo 15 Learning Hub

The Apollo 15 Learning Hub is a project in the Emory Center for Digital Scholarship that has as its mission to assemble, preserve, and make available primary source records of Apollo 15 for research, education, and preservation as an example of a unique human endeavor. The Hub offers access to a digital archive of Apollo 15 onboard materials, an interactive 3D model of the Lunar Module, as well as links to reliable primary sources of Apollo history. In this section of the Apollo 15 Learning Hub, we present information about the flight path of Apollo 15 to the Moon and back. The original flight documents presented here are part of the Learning Hub’s collection and were provided by Commander David R. Scott.

NASA’s Apollo program started in the 1960s and continued into the early 1970s, achieving the first and only human missions around the moon, including six lunar landing missions, with the first moon landing of Apollo 11 being the most famous. The Apollo 15 mission was the fourth lunar landing mission and the first extended scientific exploration of the moon. The Apollo 15 mission involved several groundbreaking scientific experiments as well as innovative space travel features.

The four primary objectives of the Apollo 15 mission in terms of science and engineering were to explore the Hadley-Apennine region of the Moon, set up and activate surface scientific experiments, make engineering evaluations of new Apollo equipment, and conduct lunar orbital experiments and photographic tasks .

The crew of Apollo 15 was now embarking on the next phase – the first extended scientific exploration of the Moon -- NASA was to term our mission “the most complex and carefully planned expeditions in the history of exploration.” (Scott, 2011:p.1)

On March 26, 1970 NASA announced the crew for Apollo 15, which was planned to be the fifth Moon landing mission. The three astronauts selected for the mission were David R. Scott, the mission commander, Alfred M. Worden, and James B. Irwin.

The Apollo 15 crew and their backups underwent training that lasted about 20 months before their mission. Part of that training took place in Antarctica for a habitability study in January 1970, as the following video donated by Commander David Scott shows.

A NASA contingent of six visited the Antarctica from the 9th through the 15th of January [1970] for the purpose of assessing environmental conditions and observing scientific investigations in progress under the United States Antarctic Research Program (USARP). (Scott, 1970:p.8)
Training in the Antarctic
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Extensive geology training was another part of the process, with training exercises in the Orocopia Mountains and the Mojave Desert in California and the area around Flagstaff, Arizona, among other places. Apollo 15 would also be the first mission to utilize the Lunar Roving Vehicle (LRV) to enable the astronauts to travel farther from their Lunar Module to explore areas of geologic interest.

Launch

The Apollo 15 mission launch date had been scheduled for July 26, 1971. The last few weeks before the launch, the astronauts’ training as it related to the launch and everything else about the mission had intensified. Every detail about the flight plan, the Command and Service Module (CSM), the plan of action after the CSM had left the Earth’s atmosphere was exhaustively examined and checked.

The planning and preparation for our mission had been so thorough that there was no doubt in our minds that we really knew “how to fly to the Moon” -- and in any conceivable situation. (Scott, 2008:p.1)

The Apollo 15 crew and their backups had been placed in quarantine for two weeks before the launch to ensure that they would not contract any viruses and that they would be in peak physical condition at the time of the flight. On the day of the launch, the crew started their day by undergoing a thorough physical exam by the mission doctors.

Scott, Worden, and Irwin were helped into their spacesuits several hours before the launch. They had to wait for NASA technicians to finish the final check of the launch vehicle while wearing their spacesuits, which took the whole morning of that day. Finally, the three crew members entered the CSM. After the crew had entered the CSM a new round of checks followed.

The following image, which is part of the Apollo 15 Learning Hub’s collection, shows the first page of the Launch Checklist booklet that the Apollo 15 crew had with them inside the CSM.

CSM Launch Checklist (NASA, 1971b)
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Finally, after everything had been checked and had been found OK, the launch process started at 9:34:00.6 AM EDT at Cape Canaveral, Florida (NASA 1971, 1).

The following photograph shows the moment the Saturn V rocket blasted off from the launch pad.

Apollo 15 Launch (NASA 1971r)
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Ascent

The ascent of the spacecraft was one of the most dangerous parts of the whole mission. There were a number of things that could go wrong during this phase that could force Commander Scott to take the decision to abort the mission. What made this part of the flight even more stressful was the difficulty of replicating the ascent of the CSM in a flight simulator. The time-frame within which an abort could be activated was less than a second.

And at any point in the mission, the crew had to be prepared to operate on their own without any contact from Earth, using only the equipment and computers on board and some pre-calculated maneuver data. (Scott, 2008:p.4).

The following cue card that was donated by Commander David Scott to the Apollo 15 Learning Hub shows two different abort procedures that Commander Scott would need to initiate if the crew ran into unresolvable trouble (NASA, 1971e:p.7).

Cue Card with Mission Abort Steps (NASA, 1971e)
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The following is a detailed view of the forward panels inside the Lunar Module (LM). We can see the Velcro patches where the cue cards where placed inside the LM and the CSM (NASA, 1971n).

View of the Lunar Module (LM) Panels (NASA, 1971n)
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The cue cards inside the LM and CSM were used to provide necessary information to the astronauts regarding the operation of the spacecrafts in different situations and under different conditions. For example, the following cue card, also provided by Commander Scott, shows the steps that the crew had to follow in case communication was lost with mission control back in Houston (NASA, 1971e:p.2)

Loss of Comm Cue Card
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The Apollo 15 space craft safely went through the various stages of the ascent from earth without encountering any issues that could jeopardize the safety of the crew. When the space craft was out of the Earth’s atmosphere and into orbit, Mission Control and the Apollo 15 crew realized that they had gone through this dangerous part of the flight without any problems.

It would take the Command and Service Module three days of free flight – “translunar coast” – to reach a position near the Moon from which they could light our big engine and enter lunar orbit (Scott & Leonov, 2004:p.285)

Moon Landing

When the Apollo 15 Command and Service Module (CSM) “Endeavor” entered the Moon’s orbit, David Scott and James Irwin descended to the Moon in their Lunar Module, the vehicle that was designed to transport them from the CSM to the surface of the Moon.

They flew their Lunar Module to a perfect landing 104 hours, 42 minutes, and 29 seconds after launch (6:16 pm EDT on July 30) at Hadley Rille about 550 meters (about 1800 feet) north and slightly east of the targeted landing point. They touched down with two of the Lunar Module’s landing pads just over the edge of a small crater, causing the lunar module to tilt (NASA 1971, 62-63). But they were stable enough to continue their mission. They landed in the Apennine Range, a high, sloped area that permitted diverse opportunities for geological exploration and sampling (NASA 1971, 14).

The following cue card, which is also part of the Apollo 15 Learning Hub’s collection, contains hand-written notes by Commander David Scott. The cue card was inside the Lunar Module and presents a list of steps that the crew of the LM had to follow during the landing on the Moon’s surface.

LM Cue Card with List of Steps for Moon Landing (NASA, 1971f)
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In the following picture, we see a page from the Lunar Landmark Maps book that the astronauts had with them in the Command and Service Module. The hand-written note is about the Proclus Crater on the surface of the Moon (NASA, 1971c) and on the next page we see actual photos of the area around the crater from the same Lunar Landmark Maps book (NASA, 1971d).

Handwritten Note about the Proclus Crater and Photographs
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Commander Scott describes the moment right after the Lunar Module had landed:

With an abrupt jar, our lunar module, or LM, strikes the surface and shudders to rest. We have hit our target squarely - a large amphitheater girded by mountains and a deep canyon, at the eastern edge of a vast plain (Scott, 1973:p.326).

Landing on the Moon (NASA, 1971q)
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It took Apollo 15 104 hours since they left Earth to reach the Moon’s surface. After they landed on the Moon, Commander Scott removed the upper hatch of the LM, stood on the engine cover and spent 33 minutes photographing the surroundings and describing what he saw to scientists in Houston. This procedure was known as a SEVA (Stand-Up Extra Vehicular Activity).

Eight years training in lunar geology make me instantly aware of intriguing details (Scott, 1973:p.327).

After the SEVA and after all of the necessary preparations for the two astronauts to exit the LM were completed, they climbed down the ladder of the LM:

When we descend the ladder of the LM and step onto the moons surface, Jim and I feel a gratifying sense of freedom. For five days we have been crammed into the tight confines of the spacecraft that brought us here. Now, all at once, we regain the luxury of movement (Scott, 1973:p.327)

On the Moon’s Surface

After they had taken some rest following their landing on the Moon, Scott and Irwin unfolded and deployed their Lunar Roving Vehicle (LRV) or simply "lunar rover" the following day. Specially designed for operation at 1/6 Earth’s gravity, it could carry 180 pounds of astronauts, gear and samples on the Moon (which would weigh 1,080 pounds on Earth), more than twice the rover’s weight (NASA 1971, 248). It greatly expanded the amount of ground the Astronauts could traverse during their extravehicular activities (EVAs).

We quickly discover, locomotion on the moon has its own peculiar restrictions. At one-sixth of earths gravity, we weigh only a sixth our normal poundage. Our gait quickly evolves into a rhythmic, bouncing motion that possesses all the lightness and ease of strolling on a trampoline (Scott, 1973:p.327).

Describing his experience driving the lunar rover on the Moon’s surface, Commander Scott writes:

the Lunar Roving Vehicle (LRV) ... meant significantly greater exploration capability, especially the capability to range to several different geologic areas from the Lunar Module, significantly more scientific equipment and experiments, and quite importantly, a mobile TV camera to view and record the distant activities of the crew. As a result, using a rover to explore multiple geologic areas at one landing site became almost equivalent to exploring multiple landing sites without a rover. Correspondingly, subsequent Apollo crews became even more proficient in “planetary field geology.” (Scott, 2008:p.XXIX)

The importance of the geological study of the Lunar surface was highlighted by the intense training in geology that the Apollo crew members had to undergo

Among the 30 original astronauts, none (0) had any formal geology training - NASA had to teach pilots how to be proficient planetary field geologists; adding science to engineering as a primary discipline. Again, the NASA training was superb; and because of their previous spaceflight experience, the mission Commanders had a major role in planning the training. And after many hours of practical and effective geology training (classroom, laboratory, and field), the results justified the selection and training process (Scott, 2011:p.XXX)

The Apollo 15 mission was the first one that provided astronauts with a vehicle to facilitate movement across the landscape of the Moon (NASA 1971, 100). Having the lunar rover allowed Scott and Irwin to complete over 18 hours of exploration and to travel 27.9 kilometers (just over 17 miles) on the Moon’s surface during the three days (from July 31 to August 2) they spent on the Moon. The two astronauts were also able to collect approximately 170 pounds of lunar samples and to provide extensive oral descriptions and photographic documentation of geologic features in the vicinity of the landing site (NASA 1971, 2-3).

The following pictures show photos and descriptions of specific types of rocks that the astronauts were supposed to look for while on their EVAs on the surface of the Moon. The photos were part of the Lunar Surface Checklist booklet that the astronauts had with them in the LM.

Geology Example from the Lunar Surface Checklist
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Geology Example from the Lunar Surface Checklist
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In this photo that is part of the Apollo 15 Learning Hub’s collection, Commander David Scott tests the steering mechanisms of the Lunar Rover before the EVA-2 traverse. The lunar module was controlled by a joystick instead of a steering wheel because it would have been difficult for the astronauts to grasp in their spacesuits (NASA, 1971i).

David Scott on the Lunar Rover
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Thanks to the television camera mounted on the rover, scientists back on Earth could for the first time see live coverage everywhere the astronauts went, not just at the landing site. The camera could be controlled from Earth, enabling scientists to look around for interesting features while the astronauts conducted their tasks (Apollo 15 - Apollo Flight Journal).

Video from the Rover Camera
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Despite the usefulness of the lunar rover, the astronauts conducted most of their geology exploration of the Moon’s surface walking, which turned out be rather challenging given the lower gravity of the Moon.

One of the most important aspects of the Apollo 15 mission was the study of the Moon’s geology, which was still not well understood at the time of the mission. Astronauts Scott and Irwin collected several samples during their EVAs. Among the rocks they collected was one that was later dubbed the “Genesis Rock.” It was a very pure specimen of anorthosite, a type of rock believed to have been a principal constituent of the moon’s primordial crust. Estimates of the sample’s age identify it as roughly 4.1 billion years old (Scott and Leonov 2004, 308). The rock would later be the analyzed in numerous scientific studies over the following years (Meyer 2011).

Another important objective of the mission was the experiments conducted on the surface of the Moon with the help of the Apollo Lunar Surface Experiments Package (ALSEP). The ALSEP consisted of a set of scientific instruments placed at the landing site by the astronauts. One of the components of the ALSEP, the Solar-Wind Spectrometer, measured the fluxes and spectra of the electrons and protons that emanate from the Sun and reach the lunar surface (NASA, 1971i). The ALSEP instruments were arrayed around a central station which supplied power to run the instruments and communications so data collected by the experiments could be relayed to Earth.

Data collected from the instruments were converted into a telemetry format and transmitted to Earth. The ALSEP system and instruments were controlled by commands from Earth (NASA 1971, 19-21).

Photo of the Solar-Wind Spectrometer Experiment, prior to removal of the instrument’s dust cover.
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Jim Irwin breaks off a sample of the Genesis Rock during EVA 2 (NASA, 1971k)
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At the end of the final EVA, Scott performed a televised sequel to the experiment Galileo is purported to have conducted at the Tower of Pisa. He dropped a hammer and a feather together in the lunar vacuum and observed that they struck the ground at the same time. Commander Scott describes how he conducted the experiment:

I wanted to prove the law, proposed more than three centuries before by the Italian astronomer and mathematician Galileo Galilei, that all objects fall with equal speed in a vacuum. Taking into one hand a falcon feather I had brought along for the purpose and in the other my trusty aluminium geology hammer, I positioned myself in front of the cameras, raised my arms and let both objects fall (Scott & Leonov, 2004:p.273)

This video that is part of the Apollo 15 Learning Hub’s collection shows how the feather and hammer experiment was shown on TV back on earth (NASA, 1971l).

EVA 3: 2 - The Hammer and Feather experiment on the surface of the Moon as shown on TV
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Sub Satellite

On August 2, the Lunar Module fired its ascent stage engine and lifted off the Moon for its rendezvous with Command Module, or CM, Endeavor. For the first time, the lunar liftoff was seen on Earth via the LRV television camera. The two spacecrafts docked as Endeavor began its 50th lunar orbit. On the 74th revolution, the Particles and Fields sub satellite was spring-launched from the service module bay (NASA 1971, 13).

This photo shows one page of the flight plan that was used by the crew of Apollo 15 onboard the CSM with handwritten annotations by the crew. It delineates one hour of the schedule that the crew followed after Commander Scott and James Irwin had returned back to the CSM after their lunar landing (NASA, 1971g:p.114).

CSM Flight Plan
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While travelling back to Earth, the Apollo 15 crew had several tasks to complete, the first of which was to launch the sub-satellite:

We still had a fairly full program of scientific experiments to perform during our return journey. First, before leaving lunar orbit, we had to deploy a small hexagonal satellite, the first sub-satellite to be launched in space, which would continue to orbit the Moon and send back data on its magnetic field for over a year (Scott & Leonov, 2004:p.277).

Subsatellite Launch
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Subsatellite Launch
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This small satellite was designed around a hexagonal structure 30 inches in length that was equipped with three instrument booms. The power supply came from solar panels and chemical batteries. The instruments measured the strength and direction of interplanetary and terrestrial magnetic fields, detected variations in the lunar gravity field, and measured proton and electron flux (NASA 1971, 257).

Return to Earth

On August 5, while the CSM was on its way back to Earth, Alfred Worden had to perform a deep space extravehicular activity - “the first ever performed in deep space” (Scott & Leonov, 2004:p.227).

In this photo, we see Worden outside the spacecraft during his trans-Earth EVA. During his EVA, Worden made an inspection of the Service Module’s Scientific Instrument Module (SIM) bay and retrieved the film cassettes from the Panoramic Camera and the Mapping Camera before the SIM was discarded into space (NASA, 1971m).

Worden During His Trans-Earth EVA
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This is a color photograph capturing the Apollo 15 CSM impact with the ocean. The two successfully deployed parachutes are visible (NASA, 1971p).

Splashdown
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At approximately 4:46 p.m. EDT on August 7, Apollo 15 splashed down in the Pacific Ocean north of Hawaii, about 476 miles away from Honolulu, ending a flight of 12 days, seven hours. The USS Okinawa, a helicopter carrier, was supported the recovery efforts, allowing the astronauts to come back home (NASA 1971, 154).

Astronauts
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Conclusion

The return of the Apollo 15 mission included a long series of talks and presentations for the crew members who were informed about the accomplishments of their mission regarding the scientific experiments they had conducted, as well as the engineering and other technical achievements.

Apollo 15 set several new records for crewed spaceflight: heaviest payload in a lunar orbit of approximately 107,000 pounds, maximum radial distance traveled on the lunar surface away from the spacecraft of about 17.5 miles (previous high was 2.1 miles on Apollo 14), most lunar surface EVAs (three) and longest total of duration for lunar surface EVAs (18 hours, 37 minutes - almost the total time spent in lunar orbit by Apollo 8), longest time in lunar orbit (about 145 hours; only two hours less than the entire Apollo 8 mission), longest crewed lunar mission (295 hours), longest Apollo mission (295 hours - previous high was 244 hours, 36 minutes on Apollo 12), the first satellite placed in lunar orbit by a crewed spacecraft, and first deep space and operational EVA (NASA 1971, Apollo 15 Mission Report).

In the following photo, we see Astronauts David R. Scott, left foreground, and James B. Irwin, right foreground, join the Manned Spacecraft Center’s geologists in getting first looks at some of the first Apollo 15 samples to be opened in the Non-Sterile Nitrogen Processing Line in the MSC Lunar Receiving Laboratory (NASA, 1971o).

The MSC Lunar Receiving Laboratory
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The samples that the mission brought back had been deemed as especially valuable by NASA scientists and it would turn out to be one of the more noteworthy contributions of the Apollo 15 mission. -Dimitri Zaras, 2021

Works Cited

Jones, Eric M. and Ken Glover. (2019) "View from the Lunar Rover with Commander David Scott". Apollo Lunar Surface Journal. Available from: https://apollo15hub.org/items/show/226

Meyer, C. (2011) 15415: Ferroan Anorthosite. Lunar Sample Compendium. Available from: https://www.hq.nasa.gov/alsj/a15/LunarSampleCompendium15415.pdf

NASA (1970i) Apollo in Antarctica (I) · The Apollo 15 Learning Hub. 9 January 1970. Available from: https://apollo15hub.org/items/show/175

NASA (1971) Apollo 15 Mission Report. Manned Spacecraft Center, Houston, TX. December 1971. Available from: https://www.hq.nasa.gov/alsj/a15/ap15mr.pdf

NASA (1971a) Aeronautics and Space Report · The Apollo 15 Learning Hub. 1971. Available from: https://apollo15hub.org/items/show/176

NASA (1971b) Apollo 15 Flight Data File: CSM Launch Checklist (S/N 1002). Available from: https://readux.io/volume/tz844/page/tz844_004.jpg

NASA (1971c) Apollo 15 Flight Data File: CSM Lunar Landmark Maps. Available from: https://readux.io/volume/spj23/page/spj23_00000029.jpg

NASA (1971d) Apollo 15 Flight Data File: CSM Lunar Landmark Maps. Available from: https://readux.io/volume/spj23/page/spj23_00000030.jpg

NASA (1971e) Apollo 15 Flight Data File: Cue Cards with Handwriting, p. 7. 1971. Readux. Available from: https://readux.ecds.emory.edu/books/readux:v016s/pages/readux:v01fr/

NASA (1971f) Apollo 15 Flight Data File: Cue Cards with Handwriting, p. 23. 1971. Readux. Available from: https://readux.ecds.emory.edu/books/readux:v016s/pages/readux:v0202/

NASA (1971g) Apollo 15 Flight Data File: Flight Plan Vol. 1, p. 114. 1971. Readux. Available from: https://readux.ecds.emory.edu/books/readux:tsnhf/pages/readux:tssfk/

NASA (1971h) Apollo 15 Flight Data File: Lunar Surface Checklist. Available from: https://readux.io/volume/v3mrz/page/v3mrz_227.jpg

NASA (1971i) Testing the Lunar Rover · The Apollo 15 Learning Hub. 1971. Available from: https://apollo15hub.org/items/show/86

NASA (1971j) Solar Wind Spectrometer · The Apollo 15 Learning Hub. 1971. Available from: https://apollo15hub.org/items/show/25

NASA (1971k) Genesis Rock Discovery · The Apollo 15 Learning Hub. 1971. Available from: https://apollo15hub.org/items/show/62

NASA (1971l) EVA 3: Hammer and feather experiment · The Apollo 15 Learning Hub. 1971. Available from: https://apollo15hub.org/items/show/11

NASA (1971m) Worden’s Spacewalk · The Apollo 15 Learning Hub. 1971. Available from: https://apollo15hub.org/items/show/43

NASA (1971n) LM Interior Forward Panels Detailed · The Apollo 15 Learning Hub. 1971. Available from: https://apollo15hub.org/items/show/147

NASA (1971o) First Looks at Lunar Samples · The Apollo 15 Learning Hub. 1971. Available from: https://apollo15hub.org/items/show/88

NASA (1971p) The Moment of Splashdown · The Apollo 15 Learning Hub. 1971. Available from: https://apollo15hub.org/items/show/78

NASA (1971q) Touchdown - landing video - test · The Apollo 15 Learning Hub. 1971. Available from: https://apollo15hub.org/items/show/193

NASA (1971r) Launch Closeup 1 · The Apollo 15 Learning Hub. 1971. Available from: https://apollo15hub.org/items/show/68

Scott, D. (1970) NASA Antarctic Visit.p.8.

Scott, D. (1973) What Is It Like to Walk on the Moon? National Geographic.144 pp.326–329.

Scott, D. (2008) Foreword to How Apollo Flew to the Moon by W. David Woods 1st Edition (2008). Springer-Praxis. 1st edition. 2008. Available from: http://www.hafttm.com/index.htm

Scott, D. (2011) Foreword to How Apollo Flew to the Moon by W. David Woods 2nd Edition (2011). Springer-Praxis. 2nd edition. 2011. Available from: http://www.hafttm.com/index.htm

Scott, D. & Leonov, A. (2004) Two Sides of the Moon: Our Story of the Cold War Space Race. New York, Thomas Dunne Books.

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Flight Path is designed and produced by Joanna Mundy, Jay Varner and Yang Li at Emory Center for Digital Scholarship. Thank you to Dina Thornton for the Command Module and Lunar Module graphics.