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Apollo 8 Earthrise
The famous “Earthrise” image taken by the crew of Apollo 8 as they orbited the Moon. (credit: NASA)

Apollo 8: humanity’s first voyage to the Moon

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During the epic adventure that was the Apollo program, there would have to be a first human mission to circle the Moon in prelude to an eventual lunar landing. The purpose would be to validate many systems and communications, make visual observations of the lunar surface by the astronauts as well as photograph potential landing sites, and monitor the astronauts during the mission. However, even during the mid-1960s, the mission planning was very fluid and contingent on achieving milestones and hardware reliability before certain missions could be scheduled and announced.

Gen. Samuel Phillips, Apollo Program Director, urged complete secrecy regarding this mission until NASA top management made the final decision.

It was not until the closing months of 1967, and dealing with the aftermath of the disastrous Apollo 1 capsule fire, that Apollo Flight Operations Director Christopher Kraft and George Low, manager of the Apollo Spacecraft Program Office, worked to establish the first manned mission to the Moon. Much rested on the program progress of the lunar module itself, as opposed to the command module and the service module (jointly, the CSM) which were progressing well. The lunar module was proving far more problematic for is builder, the Grumman Corporation.

The first unmanned Saturn V would not be launched until November of that year. AS-501 was moved by crawler transporter to launch complex 39-A in August 1967 and underwent months of checkout and tests. The mission, identified as Apollo 4, was an “all-up” test of all three stages of the Saturn V and an Apollo CSM, but not lunar module. It was launched on November 9. On this mission the S-IV-B third stage was reignited and the CSM later separated from the lunar module adapter section and was fired for more than 250 seconds in order to accelerate the capsule to the Earth re-entry speed of a lunar mission. All these mission objectives were achieved.

In April 1968, the second launch of the Saturn V for Apollo 6 was not at all nominal, to use the subdued aerospace descriptive. The S-IC first stage suffered an episode of “pogo,” a longitudinal oscillation of the vehicle. During the S-II second stage burn, two of the five J-2 engines shut down prematurely. The remaining engines of that stage burned longer in an attempt to compensate. The J-2 engine of the third stage S-IV-B initially operated well, but failed to restart as part of the mission profile. The remainder of the Apollo 6 mission had to be significantly altered. These engine anomalies had to be addressed before any manned Saturn V mission could be launched.

Apollo 8 mission planning

The first lunar module was successfully flown unmanned in January 1968 as part of Apollo 5 and the second such test was canceled. When it was evident by August of 1968 that LM-3 would not be ready for an Apollo 8 mission, it was removed from the Apollo 8 checkout schedule and a lunar module test article weighing slightly less than 9,000 kilograms was substituted. On August 9, Low met with Robert Gilruth, Director of the Manned Spacecraft Center in Houston. Low methodically and convincingly explained the proposed mission for Apollo 8 to orbit the Moon, hopefully before the end of the year. Gilruth was enthusiastic and supportive. At Kennedy Space Center, center Director Kurt Debus and Rocco Petrone, Director of Launch Operations, evaluated the workload there and concluded they could be ready to launch by the first week in December. Gen. Samuel Phillips, Apollo Program Director, urged complete secrecy regarding this mission until NASA top management made the final decision.

At Marshall Spaceflight Center in Huntsville, Dr. Wernher von Braun and his staff and contractor teams were resolving problems experienced by the second Saturn V. The pogo effect was caused by fluctuations in the pressure of the propellants fed to the F-1 engines of the first stage. Von Braun’s team solved this by adding a sump to damp out such fluctuations. It turned out that the second stage had lost two engines when only one was at fault; a crossed wire meant that a good engine was shut down inadvertently. The cause of the third stage failure to restart was also resolved.

Deke Slayton had by this time spoken with Frank Borman about the new mission profile for his crew and he enthusiastically accepted.

On August 12, Kraft informed Low the optimum launch date in December would be the 20th. Two days later at NASA headquarters, a meeting was scheduled with Deputy Administrator Thomas O. Paine involving the agency’s top brass and prime contractor heads. (NASA Administrator James Webb and Dr. George Mueller were attending an international conference in Vienna, Austria.) The meeting in Washington ended in universal agreement on the Apollo 8 lunar orbit mission. A draft text of the meeting and decision was sent by cable to Webb the following day. He was startled by the decision and conferred with Mueller, who was skeptical. Webb cabled Paine and said no mention of the lunar orbit mission should be made for the moment. This was prudent, as NASA and its contractors wanted to see the results of the Apollo 7 mission that would test the CSM in Earth orbit in October.

With this internal decision, astronaut crew assignments shifted. Deke Slayton had by this time spoken with Frank Borman about the new mission profile for his crew and he enthusiastically accepted. Subsequent training by the Apollo 8 prime and backup crews reflected the new lunar mission profile. Borman’s crew included James Lovell, his crewmate on Gemini 7 and who also commanded Gemini 12; and William Anders, who would be entering space for the first time, but unfortunately without the lunar module that he had trained to operate.

The pace quickened with the successful Apollo 7 mission that October. A critical milestone was achieved at the executive meeting on November 10 when NASA management and contractors all agreed the spacecraft and launch vehicle were ready. The launch date was set for December 21. The news of the real goals of Apollo 8 stunned and excited many in the aerospace media and major news outlets. American astronauts were finally going to the Moon.

Launch day arrives

In the weeks leading up to launch of the Saturn V, ground crews continued to test and check the rocket’s countless systems, from the F-1 engines up to and throughout the Command Module. The crew of Borman, Lovell, and Anders, and their backups Neil Armstrong, Edwin “Buzz” Aldrin, and Fred Haise spent many hours in the CM simulator and performed other training duties. This was all done against a tumultuous backdrop of events that year, from the assassinations of the Martin Luther King and Robert Kennedy to continued violent campus protests against the Vietnam War.

On the morning of December 21, the Apollo 8 prime crew was awakened at 2:36 AM, given their final physical examination, then went for their traditional breakfast of filet mignon, scrambled eggs, toast, and coffee or tea. With the crew were Armstrong and Aldrin. Then the prime crew left to don their flight suits. They departed the crew quarters at 4:42 AM and were transported by van to the launch pad, where Guenter Wendt’s team was waiting in the white room that adjoined the capsule to assist the crew’s ingress. Borman was first in, taking the commander’s couch on the left. Anders was next taking the couch on the right, and finally Lovell took his place on the center couch. They were tightly cinched in place and the capsule hatch closed and locked at 5:34 AM.

The countdown proceeded smoothly and, with 8.9 seconds remaining, the ignition sequence of the cluster of five F-1 engines of the S-IC stage began. At 7:51 AM, the four hold-down arms released and the Saturn V lifted off. The entire boost phase was perfection. Just as important was the nominal separation of the S-II stage and burn of all of the engines, followed by the uneventful engine burn of the S-IVB to put the crew into an Earth parking orbit of 190 by 181 kilometers. The crew was informed they were “go” for translunar injection and, at an elapsed time of 2:50:37, the J-2 engine reignited and burned for 319 seconds to send them toward their ultimate destination.

The objectives of Apollo 8 were to validate command and service module performance to the Moon, in lunar orbit, and return to Earth; evaluate the crew performance and medical readings; prove spacecraft to ground communications throughout the mission; and to take high resolution photographs of the lunar surface during its orbit of the Moon.

Apollo 8 creater group
A group of craters on the lunar surface photographed by the Apollo 8 crew. (credit: NASA)

Mission to the Moon

The CSM separated from the S-IVB stage, which was later put into a solar orbit. During the translunar coast, the crew performed spacecraft systems checks, navigation sightings, and conducted two television broadcasts. Just after the 69th hour of the mission, the CSM fired its engine to slow the spacecraft and enter its initial elliptical lunar orbit with a low point of 110 kilometers over the far side and 300 kilometers over near side. The crew then busied itself with lunar photography, but on the first orbit coming from behind the Moon, the astronauts saw their home planet for the first time since the start of the mission. The first group of photos they took of this splendid sight was dubbed “Earthrise.” Between the rugged, stark, and unforgiving surface of the Moon they saw below and the beautiful blue and white sphere of Earth, all the astronauts experienced a profound sense of wonder of it all. After two orbits of the Moon, the engine was fired to put the spacecraft in a circular 110-kilometer orbit.

A significant portion of the mission during lunar orbit was devoted to photography of the nearside and far side of the Moon. Hasselblad 70mm film cameras used both color and black and white film. These would be the highest resolution photographs of the lunar surface ever taken and would be vital in assisting in potential landing site locations, as well as better understanding the formation of craters, the broad expanses of lava flows called mare, rills (linear or meandering depressions), and the peaked elevations called massifs. The main hatch window was fogged over for much of the mission so astronauts used side windows No. 1 and 5 for this photography.

“Roger,” Lovell came back. “Please be informed there is a Santa Claus.”

The crew viewed Tsiolkovsky Crater, measuring an impressive 151 kilometers in diameter; Behaim with its prominent central peak; Giordano Bruno with its bright rays of ejecta; and the crater group made up of Goclenius, Magelhaens, Magelhaens A, and the smaller but relatively deep Guenberg D. The crew took 600 photographs of the lunar surface. The mission schedule called for ten orbits of the Moon. Between the 9th and 10th orbits, a television broadcast showed the lunar surface passing below while the three astronauts took turns to read the first ten verses from the Book of Genesis in the Bible. As mission commander, Borman was given complete latitude about what to read that Christmas Eve, and although a militant atheist complained, most historians agree this was most appropriate, and certainly moving. Borman then ended the broadcast with an equally appropriate closing.

“And from the crew of Apollo 8, we close with good night, good luck, a Merry Christmas and God bless all of you—all of you on the good Earth.”

Return to Earth

The critical Trans-Earth Injection burn of the Service Propulsion System engine would occur some 28 minutes after loss of signal as the spacecraft went behind the Moon, hopefully for the last time. Mission Control would not know of a successful burn until reacquisition of signal from the crew. To break free of lunar gravity and return to Earth, the engine had to fire at full thrust for 3 minutes and 23 seconds. Astronaut Ken Mattingly was the capcom during this phase of the mission. At the point where Mattingly knew there should be reacquisition of signal, he repeatedly said, “Apollo 8, Houston” for two and a half minutes with no reply from the crew. The atmosphere at Mission Control in Houston and at Cape Kennedy was very tense.

Finally, at 89 hours, 34 minutes, and 16 seconds, Lovell responded by saying, “Houston, Apollo 8, over.”

“Hello, Apollo 8. Loud and clear,” Mattingly answered.

“Roger,” Lovell came back. “Please be informed there is a Santa Claus.” Everyone on the ground knew what that meant—a successful burn. However, when Lovell gave the burn report, he incorrectly stated the burn duration at two minutes, twenty-three seconds, giving Mission Control a heart-stopping moment.

“Apollo 8, reconfirm your burn time, please,” Mattingly queried.

“Roger,” Lovell came back. “We had two minutes, twenty-three seconds. Our—wait one. Stand corrected on to that. Three minutes, twenty-three seconds.” There was a collective sigh of relief and smiles all around. The crew of Apollo 8 was on their way home to Earth, and none were more relieved than their wives.

During the return to Earth, the crew performed additional photography, navigational measurements, and routine spacecraft housekeeping duties. Separation of the command module from the service module occurred at 146 hours and 26 minutes and the capsule was oriented for re-entry. It landed in the Pacific Ocean under its canopy of three chutes 34 minutes later. The crew and then their capsule were retrieved by the recovery ship USS Yorktown.

All the Apollo 8 mission objectives were met. The photography taken of the lunar surface provided valuable information to aid the selection of the first lunar landing sites, although the eventual landing site for Apollo 11 was in darkness during this mission. NASA and its contractors were now fully confident in the Saturn V launch vehicle and the spacecraft. The next mission, Apollo 9, would test the lunar module in a complex series of maneuvers and rendezvous in Earth orbit. This would be followed by the mission of Apollo 10 to test the lunar module’s performance up to but just short of a lunar landing.

Apollo 8 was Borman’s last spaceflight. Lovell eventually rotated to the crew of the Apollo 13 mission that was both a shocking failure and stupendous success in returning the crew to Earth. Anders left NASA in 1969 and held a number of government and private industry positions. The Apollo 8 capsule is currently on display at the Chicago Museum of Science and Industry.