In the opening narrative of the scifi TV classic, Star Trek, the mission statement of the USS Enterprise concluded with “to boldly go where no man has gone before” (or in the more politically correct version of today, “where no one has gone before”). Just as Star Trek was beginning the last season of its original network TV run in the fall of 1968 with fictional voyages in space, NASA was busy preparing a real space adventure which would boldly go where no one had gone before – the Moon. Called Apollo 8, it would be the most ambitious manned space mission flown to date and opened the way to the Apollo Moon landing missions to come.

The New Apollo Test Program

In the wake of the Apollo 1 accident on January 27, 1967 where astronauts Gus Grissom, Ed White and Roger Chaffee died in a cockpit fire during what should have been a routine countdown rehearsal (see “The Future That ever Came: The Unflown Mission of Apollo 1”), Apollo program managers were forced to reevaluate their plans as the cause of the Apollo 1 accident was investigated and corrective action taken. They eventually devised a series of seven mission types which would test Apollo hardware in a step-by-step fashion culminating in a manned lunar landing before the end of the decade.

The “A” series would consist of up to three unmanned test flights of the new Saturn V launch vehicle which would send Apollo to the Moon. The “B” missions would perform unmanned test flights of the Lunar Module (LM) launched into low Earth orbit on the smaller Saturn IB launch vehicle. The “C” mission would be the first manned test of the Apollo Command-Service Module (CSM) in low Earth orbit which would also to be launched by a Saturn IB. Next would follow the “D” mission where the CSM and LM would be tested in low Earth orbit with a crew aboard. Either the individual spacecraft for this mission would be launched on separate Saturn IB rockets or, if it were available, by a single Saturn V. This would be followed by the “E” mission which would be a repeat of the D test flight except that a Saturn V would be used to launch the CSM and LM into a high Earth orbit with an apogee of about 6,400 kilometers to build further confidence with this vital hardware. The “F” mission would test the CSM and LM in an even higher Earth orbit or possibly around the Moon itself in a final rehearsal for the “G” mission which would actually land on the Moon.

The first A mission, Apollo 4, used Saturn V SA-501 to launch the unmanned Block I CSM-017 (CSM number 17) and a simulated LM payload, LTA-10R (Lunar Test Article number 10R). This Block I CSM, which were prototypes of the Block II spacecraft which would be equipped to fly to the Moon, tested key systems and post-Apollo 1 modifications for the eventual manned missions. Launched on November 9, 1967, Apollo 4 successfully met all of its test objectives and ended with the splashdown of the CM in the Pacific Ocean after 8½ hours of flight (see “Apollo 4: First Flight of the Saturn V”).

Next up was the first B Mission called Apollo 5. Saturn IB SA-204R successfully launched the unmanned LM-1 (Lunar Module number 1) into low Earth orbit on January 22, 1968 (see “Apollo 5: The First Flight of the Lunar Module”). Although problems were encountered during the nearly eight-hour long flight, all of the mission’s major test objectives were successfully met opening the way for a manned test using the first LM certified for astronauts, LM-3.

Apollo 6 was the second A mission launched on April 4, 1968. For this flight, Saturn V SA-502 launched the unmanned Block I CSM-020 and LTA-2R on a repeat of the Apollo 4 mission which would more closely emulate an actual flight to the Moon and subject the CM to an even more stressing reentry test validating the CSM for manned flights. Unfortunately, a number of problems were encountered with the Saturn V during the Apollo 6 flight including the failure of its S-IVB third stage to reignite to push the Apollo spacecraft into a simulated trajectory to the Moon. While many of the important mission objective were met, the problems encountered raised much concern among Apollo program officials (see “Apollo 6: The Saturn V That Almost Failed”). Already being prepared for a third unmanned Saturn V test flight as early as mid-July 1968 was SA-503. Since the objectives of this original “AS-503” mission would not involve the Apollo spacecraft, SA-503 would carry a dummy payload consisting of BP-30 (Boilerplate number 30), which was the refurbished BP-18 used earlier in the Apollo program for structural testing, and LTA-B.

The Decision

Meanwhile, work was pushing forward on the first manned Apollo missions. The crew for the C mission consisted of veteran astronaut Wally Schirra commanding a rookie crew of Donn Eisele and Walter Cunningham. They were to fly the first flightworthy Block II Apollo, CSM-101, in low Earth orbit for an eleven-day mission after a launch by Saturn IB SA-205. The crew for the D mission was made up of veteran astronauts Jim McDivitt and Dave Scott as well as rookie Russell “Rusty” Schweikart who would test CSM-103 and LM-3 in low Earth orbit. After the nature of the issues encountered during the Apollo 6 mission were assessed and fixes confidently identified, NASA officials decided on April 27, 1968 that a third unmanned test flight of the Saturn V would not be necessary freeing SA-503 for the D mission which hopefully would get off the ground in January 1969. The E mission crew, who would test Apollo CSM-104 and LM-4 in extended Earth orbit, consisted of veteran astronauts Frank Borman and Mike Collins with rookie astronaut Bill Anders.

After numerous delays, the descent stage of LM-3 was delivered to Cape Kennedy (which reverted to its original name of Cape Canaveral in 1973) on June 9, 1968 followed five days later by the ascent stage. Not long after post-delivery testing of LM-3 began on June 11, it was clear that a lot of work remained to be done before the new spacecraft could be launched. As the delays mounted over the coming weeks, it became evident that LM-3 would not be ready to fly by January 1969 threatening the aggressive flight test schedule needed to get to the Moon before the end of the year.

George Low, who was the manager of the Apollo Spacecraft Program Office at the Manned Spacecraft Center (MSC) in Houston (known today as the Johnson Space Center), began to consider a new and much more ambitious mission eventually dubbed “C-prime” to work around the LM delays and keep the Apollo test program on schedule. He proposed that if the upcoming C mission, known as “Apollo 7”, was able to meet its objectives, AS-503 would launch CSM-103 and the dummy LTA-B towards the Moon. A CSM-only lunar orbital mission would then be flown with the objectives of demonstrating the combined performance of the crew, space hardware and ground support team during a Saturn V launched lunar flight as well as assess lunar orbit procedures. This mission would address the CSM-related test objectives of the D and E deep space test flights validating the design earlier than planned for operations in lunar orbit.

On August 7, Low began a series of meetings with key Apollo program managers to develop a flight plan for the C-prime mission and determined that a launch before the end of the year was feasible allowing time for up to five Apollo-Saturn V flights to be launched in 1969. On August 9, Low briefed the director of the MSC, Robert Gilruth, on his proposal and was given the green light to continue developing a plan and getting support from other Apollo program participants. Deke Slayton, the Director of Flight Crew Operations who oversaw astronaut activities, approached the commander of the D mission, Jim McDivitt, about flying the proposed C-prime mission. Considering the years of work he and his crew had already devoted to training for a LM test mission, McDivitt was not very keen on making the switch. Slayton then approached Frank Borman with the proposal. Since Borman and his E mission crew were already training for a deep space mission which included a CSM-only option, they were interested in the C-prime proposal and were quickly selected as the crew.

With the approval of George Mueller, who headed NASA’s Office of Manned Space Flight, as well as NASA Administrator James Webb, NASA officially announced on August 19 that the “Apollo 8” mission would fly to the Moon provided that the upcoming Apollo 7 mission was successful. Apollo 9 would then fly the D mission to test the LM in Earth orbit in early 1969 with McDivitt and his crew. With its objectives set, Apollo 8 would prove to be the most daring crewed spaceflight attempted to date.

The Mission Plan

The commander for the Apollo 8 mission was the 40-year old USAF Colonel Frank Borman. Borman was a West Point graduate with extensive experience as a pilot and instructor in thermodynamics, fluid mechanics as well as flight and spacecraft testing before he was chosen as part of NASA’s second group of astronauts in September 1962. Before being assigned to the Apollo program, he had been the command pilot on the two-week Gemini 7 long duration mission which flew in December 1965 and served as the rendezvous target for Gemini 6 (see “Gemini 7: Two Weeks in the Front Seat of a Volkswagen“).

Originally, USAF Lt. Colonel Michael Collins, who had flown as the pilot on the Gemini 10 mission in July 1966 (see “Gemini 10: Dual Rendezvous in Space”), had been chosen to fly as the Command Module Pilot (CMP) for this mission. Unfortunately, he was temporarily removed from flight status in July 1968 because of surgery to remove an arthritic bone spur from his spine. Collins’ backup, 40-year old US Navy Captain James A. Lovell, Jr., subsequently took his place on the crew. Lovell was an Annapolis graduate who had an impressive military career as a pilot and instructor before being selected with the second group of NASA astronauts. Lovell had previously flown as Borman’s pilot on the Gemini 7 mission and then as the command pilot on Gemini 12 flown in November 1966 (see “The Grand Finale: The Mission of Gemini 12”). At this point, Jim Lovell held the cumulative spaceflight record with just over 425 hours in orbit. The Apollo 8 mission would extend this record and make Lovell just the second person to fly into space three times after Wally Schirra who was to command the Apollo 7 mission.

The final crew member for the Apollo 8 mission was 35-year old USAF Major William A. Anders who was the Lunar Module Pilot (LMP). Although there was no LM to be carried on this mission, the LMP still had duties to perform to support other aspects of the flight. An Annapolis graduate like Lovell, Anders served as a nuclear engineer and pilot instructor at the Air Force Weapons Laboratory at Kirtland AFB in New Mexico before being chosen as part of NASA’s third group of astronauts in October 1963. While he served as the backup pilot for the Gemini 11 mission (see “Gemini 11: Preparing for Apollo”), this would be Anders’ first spaceflight. The Apollo 8 backup crew consisted of Neil Armstrong, USAF Colonel Buzz Aldrin and Fred Haise.

In order to observe the proposed site in Mare Tranquillitatis for the first manned lunar landing under ideal lighting conditions while in orbit, daily launch opportunities were available between December 20 and 27, 1968 with a backup period available between January 18 and 24, 1969. In order for the entire launch window to take place during daylight hours, December 21 was chosen as the date of the first launch attempt. In case an issue arose during the Apollo 7 mission which would prevent a safe mission to the Moon, Apollo 8 would be launched by AS-503 on a more conservative mission in an extended Earth orbit as early as December 6.

Launch of Apollo 8 would take place from Pad A of Launch Complex 39 – the third Saturn V launched from LC-39A. The first two stages of AS-503 plus an initial 152-second burn of the S-IVB third stage would place Apollo 8 into a temporary Earth parking orbit at an altitude of 191 kilometers with an inclination of 32.5°. The primary payload would consist of CSM-103 which, with a total mass of 28,897 kilograms, would be the heaviest manned spacecraft ever to fly with twice the mass of the previous record holder, Apollo 7.

Unlike the earlier Apollo missions, CSM-103 would carry a full propellant load for its Service Propulsion System (SPS) consisting of a 91-kilonewton Aerojet AJ10-137 engine. Altogether, the SM would carry 18.4 metric tons of consumables including propellant for the SPS as well as the SM’s four-quad Reaction Control System (RCS), liquid hydrogen and oxygen reactants for the fuel cells (which produced electrical power and drinking water) and life support consumables. Instead of the LM, Apollo 8 would carry LTA-B which was a simple cylindrical steel structure with a total mass of 9,030 kilograms. Much simpler than the test articles flown on the Apollo 4 and 6 missions which attempted to emulate the LM’s dynamic properties more closely, LTA-B was fitted with a half dozen accelerometers to characterize the g-loads during flight.

After two or three orbits around the Earth when systems would be checked before committing for the Moon, the S-IVB stage would reignite for the 312-second Trans-Lunar Injection (TLI) which would increase the velocity of Apollo 8 to 10,900 meters per second placing the spacecraft into an extended geocentric orbit with an apogee of about 550,000 kilometers which would intercept the Moon on its outward leg. About 20 minutes after TLI, CSM-103 would separate from its S-IVB stage using the RCS, pull ahead about 15 to 21 meters then perform a 13-minute station keeping exercise. Afterwards, Apollo 8 would perform a short RCS separation burn to move away from the S-IVB and continue on its way to the Moon. The spent S-IVB stage would then turn and vent its residual propellants to deflect its trajectory safely away from the CSM. It would later pass the trailing edge of the Moon and swing into a solar orbit.

During the 66-hour coast to the Moon, the Apollo 8 crew would test all aspects of spacecraft operation to verify its performance in deep space and then later lunar orbit. During the remainder of the mission, the crew would remove their A7L spacesuits they wore during launch and the early mission phases and don much more comfortable Teflon fabric coveralls over their one-piece constant wear garments which were similar to long johns. During the coast to the Moon, Apollo’s guidance system would be used for the first time in deep space with up to four course corrections included in the schedule as early as six hours after launch. The crew would sleep on staggered schedules so that one crew member was always on watch. Each crew member would be on a schedule with 17 hours of work followed by 7 hours of rest using a pair of Beta cloth sleeping bags strung beneath the left and right couches. The CMP and LMP would be scheduled for a common rest period with one-hour meal periods typically taking place so that all three astronauts could eat together.

The upcoming phase of the mission was entirely dependent on the performance of the SM’s Service Propulsion System (SPS). The SPS would have to ignite for Apollo 8 to enter lunar orbit and, more importantly, once again in order to return home. While the SPS encountered issues during its first use on the unmanned AS-201 mission launched in February 1966 (see “The First Flight of the Apollo-Saturn IB”), it had performed well during the subsequent four missions of the CSM including the manned Apollo 7 flight. In order to decrease the risks of an SPS failure during the flight to the Moon, a “free return” trajectory was chosen where the CSM would pass the leading edge of the Moon and loose speed with respect to the Earth as a result. The spacecraft would then fall back towards the Earth without the need of any propulsive maneuvers save for minor course corrections with the RCS. The Soviet Union used the same type of trajectory for their unmanned Zond 5 circum-lunar test flight of the 7K-L1 variant of the Soyuz launched on September 15, 1968. While NASA management was certainly aware that this and other test flights signaled Soviet intentions to fly a manned circum-lunar flight, there is no documentary evidence that this affected the decision by NASA officials to send Apollo 8 to the Moon.

Assuming that the SPS and other key systems on Apollo 8 were operating properly, the spacecraft would perform its Lunar Orbit Insertion (LOI) as it passed behind the Moon where it would be out of touch of ground controllers. The nominal 912 meter per second retrograde burn would then place Apollo 8 into an initial 111 by 315 kilometer lunar orbit with an inclination of 12° (actually, since Apollo 8 would be orbiting the Moon in a direction opposite of its rotation, Apollo 8 would be in a retrograde orbit with an inclination of 168°). After two orbits, the SPS would perform a second burn for a delta-v of 42 meters per second to place the spacecraft into a circular 111-kilometer orbit.

Once in orbit, the Apollo 8 crew would continue to test spacecraft systems to verify their performance in the vicinity of the Moon. They would also perform landmark tracking exercises and use a pair of Hasselblad 70 mm cameras to acquire photographs of the lunar surface during daylight overpasses including stereo views. A 16 mm Maurer sequence camera would be used to record key parts of the flight and activity inside the CM cabin. Apollo 8 would also carry a two-kilogram RCA television camera which would be used for seven scheduled live telecasts during the mission just as had been planned for the Apollo 7 mission.

Apollo 8 would spend about 20 hours making a total of ten orbits of the Moon before performing its Trans-Earth Injection (TEI). Originally, mission planners wanted Apollo 8 to stay at the Moon for a dozen orbits to ensure that Apollo 8 returned during daylight hours over the primary recovery zone in the Pacific. Frank Borman, who worked hard to keep mission objectives simple and do everything to mitigate potential risks, insisted on ten orbits with a splashdown at local dawn in order to minimize the time in lunar orbit. About 89¼ hours after launch, the SPS would ignite for a delta-v of 1,073 meters per second to begin the voyage back to Earth.

During the 57-hour coast back to Earth, up to three course corrections were scheduled to ensure the accuracy of the reentry trajectory. At entry interface 146 hours, 49 minutes after launch, the Apollo 8 CM would be at an altitude of 122 kilometers travelling at about 11,000 meter per second. Instead of flying a “double-skip” reentry profile originally envisioned for Apollo missions, Apollo 8 would fly a simpler descent profile with an average load of just 4 gs. Splashdown would occur in the mid-Pacific Ocean about 147 hours after launch with the Essex-class carrier, the USS Yorktown, serving as the primary recovery vessel. While there were many risks associated with this mission, a successful outcome would make the goal of a lunar landing before the end of 1969 attainable.

Getting Underway

The first piece of Apollo 8 mission hardware to arrive at Cape Kennedy was the S-II-3 second stage of Saturn V SA-503 on December 26, 1967 – almost a full year before the mission;s eventual launch. The S-IC-3 first stage arrived the following day and was erected on MLP-1 (Mobile Launch Platform 1) inside the Vehicle Assembly Building (VAB) at LC-39 on December 30. That same day, the S-IVB-503N third stage arrived at the Cape. This was a replacement for the original S-IVB-503 which was completely destroyed during a ground testing accident on January 20, 1967. Delivery of the Instrument Unit (IU), which controlled all aspects of the Saturn V during flight, was made on January 4, 1968. BP-30 arrived on January 6 followed by LTA-B on January 9 to support a possible third “AS-503” unmanned test flight of the Saturn V. Initial stacking of SA-503 was completed on February 3 with BP-30 and LTA-B enclosed in SLA-10 (Spacecraft Launch Adapter 10) finishing the stack two days later for the start of overall vehicle testing.

With the decision made on April 27, 1968 that a third unmanned test of the Saturn V was not needed, SA-503 was now assigned to support the first manned flight of the Moon rocket. The next day, BP-30 and S-IVB-503 were removed from the stack followed by the S-II-3 stage on April 29. The S-II-3 was then shipped to NASA’s Mississippi Test Facility (today NASA’s Stennis Space Center) for a series of inspections and modifications to “man rate” the stage and correct the issues uncovered during the Apollo 6 mission. Work on the S-II-3 stage was completed and it was returned to the Cape on June 27. On July 24, S-II-3 was reerected on top of S-IC-3 followed by the S-IVB-503 stage on August 14.

In the meantime, LM-3 arrived at Cape Kennedy in June with a lot of work still remaining before it could fly. CSM-103 had completed its factory systems test on June 2 with the SM and CM arriving at the Cape on August 11 and 12, respectively. Because of the delays preparing LM-3 for flight, on August 19 the decision was made to substitute LTA-B for LM-3 to support the C-prime lunar orbit mission. Instead of using SLA-10, LTA-B would be flown inside of SLA-11A which had been modified to correct problems encountered with the SLA during the Apollo 6 mission. The modules of CSM-103 were mated on August 23 and combined systems tests completed on September 5. CSM-103 was then moved to Kennedy’s high altitude chamber to begin tests under low pressure conditions. Borman, Lovell and Anders made their first simulation exercise on September 9 and CSM-103 was removed from the chamber for final launch preparations on September 22.

On October 7, 1968, CSM-103 along with LTA-B/SLA-11A were mounted on top of SA-503 with rollout of the complete Apollo-Saturn V to LC-39A taking place two days later to continue launch preparations there. With the successful completion of the Apollo 7 mission on October 22 where all major mission objectives had been met with an almost flawless performance of the new Block II CSM (see “Apollo 7: Rise of the Phoenix”), on November 11 Apollo program and NASA management officially approved the Apollo 8 lunar orbit mission. By coincidence, Zond 6 had been launched the previous day on another unmanned circumlunar test flight of the 7K-L1 spacecraft. With the final countdown demonstration test for Apollo 8 completed on December 11, Apollo 8 was clear to make its first launch attempt on December 21 during a window which extended from 7:51 AM to 12:32 PM EST.

The Launch

The countdown for Apollo 8 started at 7:00 PM EST on December 15, 1968 with the fast-paced terminal countdown sequence starting at the T-28 hour mark at 8:51 PM EST on December 19. While some minor issues were encountered, virtually all of the countdown tasks were brought back on schedule during a planned six-hour hold at the T-9 hour mark. After another planned one-hour hold, the countdown resumed at the T-3 hour, 30 minute mark at 4:21 AM EST on December 21.

In the meantime, Frank Borman, Jim Lovell and Bill Anders were woken up at 2:36 AM EST and received their preflight medical checks 15 minutes later. Because of the colds the Apollo 7 crew members had suffered during their flight, the Apollo 8 crew had been kept in medical isolation before launch as a precaution. At 3:30 AM, the crew had breakfast then they suited up for their flight. A transfer van then picked up the astronauts and who were taken to LC-39A where they entered their spacecraft at the T-2 hour, 53 minute mark. The countdown proceeded without incident until liftoff of the 2,782-metric ton Apollo 8 at 7:51:00 AM EST (12:51:00 GMT).

The ascending Saturn V under the power of its five F-1 engines hit Mach 1 61.5 seconds after launch and encountered maximum dynamic pressure 17.4 seconds later. The rocket continued to ascend smoothly with the modifications made to reduce the excessive strong “pogo” effect encountered during the Apollo 6 ascent working as planned. In order to lessen the g-loads as the S-IC stage was finishing consuming its 2,034 metric ton load of RP-1 and liquid oxygen (LOX) propellants, the center engine of the S-IC was shutdown six seconds earlier than on the previous pair of unmanned Saturn V test flights. Center engine cutoff was commanded at 125.9 seconds after launch followed by the remaining four outboard engines 27.9 seconds later at an altitude of 65.8 kilometers. After a nearly perfect performance, S-IC-3 stage was jettisoned 0.65 seconds after engine shutdown where the S-II-3 stage ignited an continued the ascent. After reaching a peak altitude of 120 kilometers, the spent S-IC stage impacted in the Atlantic Ocean 540 seconds after launch about 655 kilometers downrange.

The S-II stage completed its task and shut down its five J-2 engines eight minutes and 44 seconds after launch at an altitude of 191.5 kilometers some 1,504 kilometers downrange. The S-IVB-503N stage then ignited its single J-2 engine after separation to continue the ascent with its planned first burn of the mission. The spent S-II-3 stage then tumbled to Earth impacting about 19 minutes and 25 seconds after launch 4,161 kilometers downrange. The S-IVB-503N stage finally shut down its single J-2 engine 11 minutes, 25.0 seconds after launch just 3.2 seconds later than planned. Apollo 8 was now in a nearly perfect 184.4 by 185.2 kilometer parking orbit with an inclination of 32.5°. And with an in-orbit mass of 127.5 metric tons, Apollo 8 was the heaviest object ever placed into Earth orbit up until this time.

Once in its temporary parking orbit, ground controllers and the crew began checking out the spacecraft systems in preparation for the decision to commit to TLI. At 13:33 GMT, the crew jettisoned the optics cover for the Apollo guidance and navigation system’s built in sextant and performed star sighting while passing over Australia to verify the alignment of the guidance platform. As a result of venting, the apogee of Apollo 8 was raised by 11.9 kilometer while coasting in its parking orbit. All systems checked out and the crew was given the go for TLI which started at 15:41:37.9 GMT as Apollo 8 was passing within range of the Hawaii tracking station during its nighttime overpass after completing 1½ orbits.

The S-IVB stage burned for 317.7 seconds increasing the velocity of Apollo 8 to 10,830 meters per second placing Apollo 8 into an extended geocentric orbit with an apogee of 531,811 kilometers. At 16:11:56.3 GMT, CSM-103 separated from S-IVB-503N and used a short burn of the RCS to move ahead of the stage. Already at an altitude of 7,017 kilometers at spacecraft separation, Apollo 8 had shattered the previous manned spaceflight altitude record of 1,373 kilometers set during the Gemini 11 mission in September 1966 (see “Gemini 11: Preparing for Apollo”) and would continue to set records as it continued to the Moon. The crew observed the S-IVB-503N stage, whose attitude was being controlled by its pair of Auxiliary Propulsion System (APS) pods, as well as noting the clean separation of the SLA’s four panels during a station keeping exercise. Because of problems encountered with the SLA panel retention system on S-IVB-205 during the Apollo 7 mission which left one panel only partially open, the panels had been modified to be jettisoned instead on the Apollo 8 and subsequent missions.

About 19 minutes after beginning independent flight, the Apollo 8 crew used the RCS to perform a 0.3 meter per second separation burn to move away from the S-IVB stage. Another burn with a delta-v of 2.3 meters per second was performed 65 minutes later to further increase the separation rate. In the meantime, S-IVB-503N began procedures to move itself safely away from Apollo 8. The S-IVB stage was turned and at 17:46:56 GMT opened the vents on its liquid hydrogen fuel tank. About 12 minutes later, the residual LOX was dumped through the J-2 engine followed by a burn of the APS ullage engines starting at 18:16:56 GMT and continuing until propellant depletion . These activities resulted in a delta-v of 41.7 meters per second which placed S-IVB-503N into a new trajectory which would pass 1,262 kilometers above the Moon’s trailing edge at closest approach about 70 hours after launch. The flyby of the Moon would increase the velocity of S-IVB-503N by another 1.46 kilometers per second with respect to the Earth and place the spent stage into a 340.8-day solar orbit with an aphelion of 0.9876 astronomical units (AU), a perihelion of 0.9211 AU and an inclination of 23.47° where it remains to this day.

Going Where No One Had Gone Before

Once they departed their spent S-IVB stage, the crew of Apollo 8 changed out of their bulky spacesuits and settled down into their routine. All three of them experienced mild cases of space sickness brought on by rapid body movements inside the cabin. Fortunately, these symptoms abated and all the crew members were feeling better within a day.

One of the first tasks to be performed once on their way was for Jim Lovell to use Apollo’s guidance and navigation system to make star sightings to be used to update their trajectory. Lovell had become very adept at this task and was able to make very precise sightings as fast as he could input parameters into the computer. Initial calculations showed that the TLI had been very accurate resulting in a postponement of the first course correction scheduled for six hours after launch. The first course correction started just a fraction of a second before 11 hours since launch at 23:50:59 GMT. The 2.4-second burn of the SPS was to change the velocity of Apollo 8 by 7.6 meters per second and move the closest approach to the Moon from 848.4 kilometers to 122.8 kilometers. The burn was performed as programmed but a slightly lower thrust that expected from the SPS resulted in 1.3 meter per second shortfall in the desired delta-v – an issue which would be corrected in a subsequent midcourse maneuver.

At about this time, Borman took a Seconal sleeping pill to help him get some rest. He woke up at about 04:51 GMT on December 22 in order to relieve Lovell and Anders so that they could take their first seven-hour rest period of the mission. After sleeping fitfully, Borman woke up suffering from a headache, nausea, vomiting and diarrhea. The in-flight diagnosis was that, despite preflight isolation, Borman was possibly suffering from viral gastroenteritis of the sort noted in the Cape Kennedy area at the time. During the post-flight medical debriefing, Borman stated that he had suffered from similar symptoms during preflight testing of the sleeping aid and that this was the cause of his problems. Either way, the mission commander recovered over the following day and felt fine for the balance of the mission.

During the translunar phase of the mission, the Apollo 8 crew tested their spacecraft in deep space with its unique environment. Typically, the CSM was in a slow roll of about one revolution per hour, known affectionately as the “barbeque mode”, to maintain proper thermal control. The mission also successfully used the new high gain S-band antenna mounted at the base of the SM to transmit voice and data via NASA’s new network of 64-meter tracking antennas in California, Spain and Australia (which had been employed previously to track interplanetary spacecraft like NASA’s Mariner 5 – see “The Return to Venus: The Mission of Mariner 5”). The only troublesome issue noted was that the CM’s two side windows, and later the window on the crew hatch, had become fogged after TLI much as had happened during the Apollo 7 mission. This left only the two forward facing windows clear enough for photography. Obviously more work was required to determine the cause and correct the window fogging problem for future missions.

The first of two live television broadcasts to take place during the coast to the Moon started at 20:02:36 GMT on December 22. Viewers back on Earth got to see the Apollo cabin and Lovell preparing a meal. Views out of the window of the Earth during the 23-minute, 37-second telecast were poor because the telephoto lens for the television camera passed too much light. This was corrected for the second telecast which started 19:53:45 GMT the following day by taping still camera filters over the TV camera lens providing much improved views of our home planet during the 25-minute, 38-second transmission. As millions of television viewers were seeing the Earth live from cis-lunar space, Jim Lovell commented: “Frank, what I keep imaging is if I am some lonely traveler from another planet what I would think about the Earth at this altitude, whether I think it would be inhabited or not… I was just curious if I would land on the blue or the brown part of the Earth”. Bill Anders remarked “You better hope that we land on the blue part” alluding to the eventual splashdown which would conclude their mission.

At 20:29:40 GMT on December 23, the crew was informed that they had reached the point where the gravitational pull of the Moon, now just 62,600 kilometers away, had become stronger than that of the Earth 326,400 kilometers away. The spacecraft velocity, which had dropped to 994 meters per second as the Apollo 8 climbed out of Earth’s gravity well, would now begin to increase as the Moon grew closer. At 01:50:56 GMT on December 24, a second minor course correction with a delta-v of 0.43 meters per second was made using the RCS to fine tune the spacecraft’s trajectory for lunar orbit insertion (LOI). Lovell and Anders then went down for their last rest period before reaching the Moon.

Meanwhile back on the Earth, ground controllers were reviewing every aspect of the spacecraft in preparation for the next major decision milestone – LOI. If there were any doubts about the vital SPS or other crucial systems which could threaten the crew’s safety, LOI would not take place and Apollo 8 would simply loop around the back side of the Moon and follow a free return trajectory back to Earth. Just minutes before LOS (loss of signal) as Apollo 8 slipped behind the Moon as viewed from the Earth, the Apollo 8 crew got word that they were “go” for LOI which would take place during the 33 minutes after LOS.

As Apollo 8 pulled around the Moon, Borman, Lovell and Anders got their first look at our celestial neighbor and became the first humans to view the lunar far side with their own eyes. At 09:59:20.4 GMT on December 24 with Apollo 8 traveling at 2,558 meter per second, the SPS was ignited for LOI at an altitude of 140.0 kilometers above the Moon after a translunar coast of about 66¼ hours. After an SPS burn of 246.9 seconds with a delta-v of 913.5 meters per second, Apollo 8 was now safely in its initial 111.1 by 312.1 kilometer orbit around the Moon.

Christmas Orbiting the Moon

After the scheduled end of LOS, Frank Borman announced that LOI had been successful with cheers erupting from relieved ground controllers in Houston. The Apollo 8 crew quickly got to work performing navigation checks as well as beginning their lunar landmark spotting and photography tasks. For the first time, the lunar surface was being observed closeup by human eyes and directly photographed without the degrading effects of Earth’s atmosphere or the images being transmitted by radio. The astronauts remarked at the lack of color on the lunar surface quashing scientists’ hopes of using color contrasts to help differentiate various geologic units from orbit. During a 12-minute live telecast starting at 12:31:52 GMT on December 24, the crew was able to show the lunar surface to viewers back on Earth.

After four hours of tracking had updated the orbit parameters. Apollo 8 started a 9.6-second burn of the SPS at 14:26:06.6 GMT with a delta-v of 41.1 meters per second leaving the spacecraft in a nearly circular 110.6 by 112.4 kilometer orbit. The astronauts’ observations of the lunar surface under a range of lighting proved to be very useful for mission planners who were able to broaden the range of lighting angle which would allow sufficient visibility for a manned lunar landing. Altogether, about 600 good-quality photographs of the lunar surface were obtained including stereo views of selected areas. Probably the most famous of these were Bill Anders’ Earthrise photographs showing the Earth above the stark lunar horizon as Apollo 8 moved out of LOS.

By far the most memorable event of the Apollo 8 mission was the live telecast from lunar orbit starting at 02:34 GMT on December 25 (8:34 PM CST on Christmas Eve back in at Mission Control in Houston). The images of the lunar surface during the 26-minute, 43-second broadcast along with the crew’s reading of the first ten verses from the Book of Genesis as part of their Christmas greeting was heard live by an estimated one billion people in 64 countries around the globe (and many more subsequently). A portion of that historic event as broadcast by CBS News is shown below:

For the last two lunar orbits of the mission, Borman insisted that he and his crew get some much needed rest and concentrate on the tasks crucial for the upcoming Trans-Earth Injection (TEI) which would send Apollo 8 home. Tracking had shown that the lumpy gravitational field of the Moon caused by “mascons” (i.e. mass concentrations) were perturbing the orbit of Apollo 8 more than expected. Mascons had first been detected in 1966 by the Soviet Luna 10 and American Lunar Orbiter 1 spacecraft as they orbited the Moon (see “Luna 10: The First Lunar Satellite” and “Lunar Orbiter 1: America’s First Lunar Satellite”), but their full effects on navigation were still being assessed. As a result, Apollo 8 was now in a 108.5 by 117.8 kilometer orbit as TEI approached.

One last time, Apollo 8 slipped behind the Moon and out of touch with ground controllers back in Houston. During their time in lunar orbit, the crew of Apollo 8 reached a record setting maximum distance of 377,349 kilometers from their home planet and it was now time to return. Right on scheduled at 06:10:16.6 GMT on December 25, the SPS ignited for its 203.7-second TEI burn which increased its velocity by 1,073 meters per second allowing Apollo 8 to escape from the Moon and head back home. At the end of LOS, Lovell simply stated “Please be informed, there is a Santa Claus.”

The Return Home

With Apollo 8 now safely on its way home, the mood at Mission Control and onboard Apollo 8 lightened noticeably. The new spacecraft continued to perform as expected with no major problems encountered. At 20:51:00 GMT on Christmas Day, Apollo 8 started a 15-second burn of its RCS to change the spacecraft velocity by 1.5 meters per second. This would prove to be the only course correction needed for the rest of the mission. At 21:15 GMT, the first post-TEI live telecast from Apollo 8 started with the crew showing the cabin of their spacecraft. A final 20-minute telecast starting at 20:37 GMT the next day gave the audience a view of the Earth’s western hemisphere.

The only incident of note during the 57½-hour coast to Earth was a procedural error made by Jim Lovell during a navigation check at about 23:17 GMT on December 25. He had accidentally started an incorrect program during an update resulting in the guidance and navigation system losing its alignment. The problem was quickly corrected and navigation was back to normal in 19 minutes.

As Apollo 8 was approaching the Earth on its last day of flight on December 27, Borman, Lovell and Anders spent time stowing their gear and preparing for reentry. At 15:19:48 GMT, the SM was jettisoned and the CM was turned to present the blunt face of its heat shield towards the Earth. Entry interface at an altitude of 121.9 kilometers was reached at 15:37:12.8 GMT with Apollo 8 travelling at 11,040 meters per second for the fastest reentry by a manned spacecraft to date. Communications with the ground were blacked out as expected as ionized air heated by the high-speed reentry bathed the spacecraft interior with a bright blue glow as the CM streaked through the night sky. With the CM being automatically guided by its computer, the natural lift of the CM was used to steer the craft down to an altitude of 54.9 kilometers then upwards slightly to 64.0 kilometers before the final plunge to Earth as part of a descent profile which kept a nearly constant acceleration.

With reentry completed, the CM’s parachutes were deployed with Apollo 8 making a predawn splashdown at 15:15:42 GMT on December 27 at 8.10 N, 165.00 W in the central Pacific southwest of Hawaii. After a mission lasting 147 hours and 42 seconds, Apollo 8 had come down only 2.6 kilometers from its target point and 4.8 kilometers from its primary recovery ship, the USS Yorktown. Initially, the CM assumed a stable “apex down” position after splashdown but the capsule’s floatation system righted the spacecraft about six minutes later. While helicopters and aircraft immediately spotted the CM, pararescue swimmers did not enter the water until 43 minutes after splashdown as they waited for local dawn. The Apollo 8 crew was retrieved by helicopter and were on the deck of the USS Yorktown 88 minutes after splashdown followed by the five-metric ton CM-103 an hour later. The historic flight of Apollo 8 had come to a successful end.

What followed were a long series of crew debriefings as mission planners tried to glean as much information as possible from their experiences with the Apollo spacecraft and in orbit around the Moon. The recovered CM-103, which arrived at the North American Rockwell Space Division facility in Downey, California on January 2, 1969, was also inspected to see how it fared the six-day voyage to the Moon and back. Overall, Apollo 8 achieved essentially all of its primary and secondary mission objectives with only minor issues marring an otherwise perfect flight. With this success, the Saturn V and the CSM were cleared for further flights starting with the Apollo 9 mission to test the LM in LEO in February or March 1969.

Following the flight of Apollo 8, Frank Borman was offered command of the first lunar landing mission by Deke Slayton but turned it down. He retired from the astronaut corps and the USAF in 1970 to work as an executive for Eastern Airlines. James Lovell, who now held the cumulative spaceflight record with almost 24 days logged in space, would go on to serve as the backup commander for the Apollo 11 mission which would land on the Moon in July 1969 (see “Apollo 11: Preparing to Win the Moon Race“). He then was selected as the commander for the ill-fated Apollo 13 mission in April 1970 (see “The Original Mission of Apollo 13“). After the Apollo 8 mission, Bill Anders went on to serve on the National Aeronautics and Space Council from 1969 until his retirement from NASA in 1973. Although he still maintained his astronaut status during this time, he did not fly in space again. In August 1973 Anders was appointed to serve on the Atomic Energy Commission and in January 1975 he was named by President Ford to serve as the chairman of the recently reorganized Nuclear Regulatory Commission.

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Related Video

Here is a NASA documentary from 1969 about the Apollo 8 mission entitled Apollo 8: Go For TLI:

Related Reading

“Apollo 7: Rise of the Phoenix”, Drew Ex Machina, October 24, 2018 [Post]

“Apollo 6: The Saturn V That Almost Failed”, Drew Ex Machina, April 4, 2018 [Post]

“Apollo 5: The First Flight of the Lunar Module”, Drew Ex Machina, January 22, 2018 [Post]

“Apollo 4: First Flight of the Saturn V”, Drew Ex Machina, November 11, 2017 [Post]

General References

David Baker, The History of Manned Space Flight, Crown Publishers, 1981

Alan Lawrie & Robert Godwin, Saturn V The Complete Manufacturing and Testing Records, Apogee Books, 2005

Richard W. Orloff and David M. Harland, Apollo: The Definitive Sourcebook, Springer-Praxis, 2006

Apollo 8 Press Kit, NASA Press Release 68-208, December 15, 1968

Saturn V Launch Vehicle Flight Evaluation Report – AS-503 (Apollo 8 Mission), MPR-SAT-FE-69-1, NASA Marshall Space Flight Center, February 20, 1969

Apollo 8 Mission Report, MSC-PA-R-69-1, NASA Manned Space Center, February 1969

Final Flight Evaluation Report – Apollo 8 Mission, D2-117017-5, NASA Office of Manned Space Flight, April 1969