Apollo 8, 40 years ago
Published on Dec 21, 2008 at 4:04 pm.
7 Comments.
Filed under space exploration.
Today is the winter solstice. That means that the Sun is the farthest south that it will appear in the sky. That would be a topic worth blogging about. However, I wrote a bit about the solstice several years ago, and there is nothing particularly different about this one. What is unique about today, though, is that this marks the 40th anniversary of the launch of the Apollo 8 mission to the Moon.
In May, 1961, President John F. Kennedy proposed that the United States take the lead in space exploration by setting a goal of a manned spaceflight to the Moon by the end of the decade. That speech set off a race with the Soviet Union to land the first man on the Moon. At the time, the best that anyone had been able to do was to put a man in orbit around Earth in a crude capsule, and that was accomplished by the Soviet Union. All that the United States had accomplished at this point was to launch a rocket high enough to get to space and fall back to Earth in the Atlantic Ocean (from the east coast of Florida, no less!). So, this was a dramatic statement of faith that NASA could pull off the feat of sending a manned mission to the Moon.
A lunar mission is far more complex than an Earth orbital mission. The physics of spaceflight dictated that a monster rocket was needed. Wernher von Braun had been planning such a rocket for years. His initial proposal had been for a massive rocket dubbed Nova. Technological advances in rocket engines allowed him to scale back his plans to a slightly smaller rocket called the Saturn V. Along the way, the Saturn 1B rocket was built using a combination of Redstone rocket technology and new technology that was to be incorporated in the much larger Saturn V. The Saturn 1B was actually used to fly many of the Earth orbital test flights of the Apollo missions, along with the post lunar missions, such as the manned Skylab and the Apollo-Soyuz Test Project mission.
There were missteps along the way in the race to the Moon. Three astronauts died in January, 1967, in a fire that occured during a test of an Apollo spacecraft on the launch pad. That mission, later dubbed Apollo 1, took the lives of Gus Grissom, Ed White, and Roger Chafee. The Soviets had their own accidents. In a desperate attempt to keep up with the Americans, they built the ill fated N-1 rocket, which resulted in a crash killing many of the Soviet rocket scientists. American intelligence agents knew that the Soviets were working on their own Moon program, but NASA wasn’t privy to details about how far along they were. While NASA worked in the public eye, the Soviet program moved along clothed in secrecy. But, in 1968, word reached NASA that the Soviets may be close to launching a mission to the Moon.
The Apollo missions called for a two spacecraft system. A mother ship would orbit the Moon, while a lighter lander would actually land on the surface of the Moon. The mother ship consisted of the Command Module (the crew capsule) and the Service Module. The lander was the Lunar Module (earlier called the Lunar Excursion Module, and hence commonly called the LEM). The LEM was designed with a sole purpose: to land on the Moon and for a portion of it, the Ascent Stage, to take off again and rendezvous with the orbiting mother ship. However, during the planning and training leading up to the first lunar missions, NASA realized that the LEM had another important backup function: as a lifeboat in the event that a major problem developed with the Command Module. The LEM was unable to survive a reentry through Earth’s atmosphere, so its usefulness as a lifeboat was simply to be used as a possible means of life support to be used in the event of a failure of the life support system of the Command Module. Though this contingency was never expected to be needed, NASA believed it important to have as a backup plan. That foresight was part of what kept the astronauts alive during the Apollo 13 mission when an explosion aboard the Service Module required the astronauts to use the LEM as a lifeboat. Had it not been available, the astronauts of Apollo 13 would have died in space.
But, as often happens, the development of the LEM experienced some delays. At the close of 1968, the LEM was not yet ready for flight. The first manned test flight for the massive Saturn V rocket was Apollo 8, and it was scheduled for the end of that year. Only two previous Saturn V rockets had been launched, both unmanned. The last unmanned flight, Apollo 6, had serious problems with its second and third stages. The second stage problems resulted in engine failures. Those failures required the remaining engines to fire for longer to compensate for the losses. The third stage failed to restart in orbit. Such a restart would be required to send the astronauts to the Moon. More troubling, the third stage only had one engine, and it was the same type as the five engines of the second stage: a Rocketdyne J-2 engine. If it failed during lunar insertion burn, then the Apollo spacecraft would be placed in a very difficult and potentially life threatening situation.
Apollo 7, launched in October of 1968, had been an Earth orbital test flight of the Command Module and Service Module. It lifted off using a Saturn 1B booster. Apollo 8 was to be an Earth orbital test flight using the complete Saturn V stack: the Saturn V rocket, the LEM and the Command/Service Modules. But, the LEM was not yet ready. It might have still made sense for NASA to delay Apollo 8 until the LEM was ready, or to launch the Saturn V stack, sans LEM, to more thoroughly test the Saturn V, particularly in light of the failures associated with the unmanned Apollo 6 mission. However, while NASA is often seen as a purely science and engineering entity, the reality is that it is a government agency. That means that sometimes decisions are made for political reasons rather than based purely on scientific and engineering considerations. Already, by 1968 political will to support the Moon program, strong when President Kennedy proposed it, stronger still after his assassination, was beginning to wane. Word reached NASA that the Soviets were actively pursuing their own lunar program. But, NASA didn’t know how far along the Soviets were in their lunar program. There was real concern that the Soviet Union might beat the United States in sending a man to the Moon, just as they did with launching the first satellite, sending the first man into space, and sending the first unmanned spacecraft to the Moon. Another defeat was simply not politically tolerable. So, perhaps to ensure that we could say that we got there first, NASA decided to go ahead and launch the Saturn V for Apollo 8, but sending the spacecraft to the Moon instead of Earth orbit. Obviously, without the LEM, there would be no lunar landing, but the Command and Service Modules could still orbit the Moon and return to Earth. The Soviets were not ready for a landing, either, and their first manned lunar mission would have been an orbital one, too. So, if we beat them to the Moon with an orbital mission, then we could say that we were first (and by implication, better). It was a matter of national pride and political expediency. It also provided another useful test of the Saturn V rocket. But, it was dangerous. There would be no LEM lifeboat. If something went wrong with the Command Module, the Service Module, or the Saturn V third stage (the S-IVB), then the lives of the astronauts may be in jeopardy. The astronauts, themselves, knew this, so it is a tribute to their bravery that they readily accepted those risks.
Thus, on December 21, 1968, forty years ago, today, at 10:51:42 am (Eastern Time), the massive Saturn V rocket (SA 503, in particular) lifted off from Launch Pad 39A at the Kennedy Space Center. The launch was controlled from Firing Room 1 at KSC, and the Saturn V stack was assembled in High Bay 1 of the Vehicle Assembly Building. Atop the stack, in the Command Module, were astronauts Frank Borman, Jim Lovell, and William Anders. Three days after launch, the Apollo 8 spacecraft entered orbit around the Moon. While in lunar orbit, the crew of Apollo 8 captured the following photograph, showing Earth with the Moon in the foreground. I have this picture in my office. It is a classic, and it is significant in history for a variety of reasons.
In another historic moment, on Christmas Eve, 1968, the crew of Apollo 8 read from the book of Genesis in the Bible during a live television broadcast. Then, after ten orbits of the Moon, the engine of the Service Module fired to send the Apollo 8 spacecraft back to Earth, where it would spashdown in the Pacific Ocean on December 27. The planned complete test of the Saturn V with LEM in Earth orbit was performed on the next Apollo mission, Apollo 9, in March of 1969. In May, 1969, Apollo 10 returned to lunar orbit to test the LEM in what was a full scale test to prepare for the first manned lunar landing of Apollo 11, which occurred on July 20, 1969.
The significance of the 40th anniversary of Apollo 8’s launch I feel warrants it displacing the solstice for today’s blogging.
-Astroprof
Images courtesy NASA
Akupunktur on December 21, 2008 at 4:20 pm: 1
Hello, I like your post so well that I like to ask you whether I should translate and linking back. Please give me an answer. Merry Christmas
Astroprof on December 21, 2008 at 5:11 pm: 2
Sure, go ahead. Just be sure to say where you got the original, and include a link.
Sili on December 22, 2008 at 1:50 pm: 3
Is it shallow of me to mention that I think that logo is quite clever?
Astroprof on December 22, 2008 at 3:45 pm: 4
Sili, I was actually thinking about mentioning the mission patch in my post. I do think that it was extremely clever.
CCPhysicist on December 25, 2008 at 9:23 pm: 5
There is a much higher quality version of that color picture on the NASA web version of the flight journal that I tracked down after reading the BBC article that mentioned the first (b/w) photo taken of earth rise. A cropped full-resolution version of that b/w photo is on my blog, but you should really follow the link to the flight journal to read the dialog as they scrambled to get a color film pack to shoot the picture you show.
Great bit of history here, by the way. People I know who saw all of the Saturn launches say it was amazing to see.
CCPhysicist on December 25, 2008 at 9:31 pm: 6
Oh, yes, one addition to your history. You mentioned in passing that Apollo 10 did a LEM test in lunar orbit. That must have been the toughest flight of any mission. Can you imagine being in the lander and dropping down to within 10 miles of the moon in a LANDER and resisting the temptation to land it? What discipline.
Donald A. Zaros on June 14, 2010 at 11:54 pm: 7
The contingency orbit was if the LEM while trying to rondevous with the CM in lunar orbit came up ahead of the CM, this would because of energy conditions require a 4 day precessing orbit to save enough fuel in the ascent engine to dock with the CM. All of the low energy modes and longer life support implementations were considered.
This study was made by Dr. Yagi in 1964. I at the same time made a study with him to determine maximum doppler shift on the S-band link while in lunar orbit to determine the parameters for the s-band receiver’s phase-lock loop.
I worked on LEM from 1/63 to 1967 and was cognizant engineer on the uhf, s-band and ICS at one time or another. In 1963 I was cognizante engineer on the first LEM communications specificatiion LSP-380.