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Apollo program

The Apollo program was a series of human spaceflight missions undertaken by the United States of America, conducted during the years (1961-1972). It was devoted to the goal of landing a man on the Moon and returning him safely to Earth within the decade of the 1960s. This goal was achieved with the Apollo 11 mission in 1969. The program continued into the early 1970s to carry out the initial manned scientific exploration of the Moon.

Table of contents
1 Background
2 Choosing a Mission Mode
3 Lunar Orbit Rendezvous
4 Flights
5 End of the Program
6 Reasons for Apollo
7 Miscellaneous information
8 Missions
9 See also
10 Further reading
11 External links


The Apollo Program was the third United States manned spaceflight program, following the Mercury program and the Gemini program. Apollo was originally conceived late in the Eisenhower administration as a follow-on to Mercury for advanced earth-orbital missions. It was dramatically reoriented to an aggressive lunar landing goal by President Kennedy, announced at a special joint session of Congress on May 25, 1961:

"...I believe that this nation should commit itself to achieving the goal, before this decade is out, of landing a man on the Moon and returning him safely to the Earth. No single space project in this period will be more impressive to mankind, or more important in the long-range exploration of space; and none will be so difficult or expensive to accomplish..." (Excerpt from "Special Message to the Congress on Urgent National Needs" [1])

Choosing a Mission Mode

Having settled upon the Moon as a target, the Apollo mission planners were faced with the challenge of designing a flight plan attaining Kennedy's stated goal while minimising risk to human life, cost and demands on technology and astronaut skill.

Three possible plans were considered. The first was to boost a spaceship directly to the moon. This would have required a Nova booster more powerful than any planned at the time. The second known as Earth orbit rendezvous (EOR) would have required the launch of two Saturn V rockets, one containing the space ship and one containing fuel. The spaceship would have docked in earth orbit and be fueled with enough fuel to make it to the moon and back.

Apollo Command and Service Modules

Lunar Orbit Rendezvous

The plan which was actually adopted is credited to John Houbolt and used the technique of 'Lunar Orbit Rendezvous' (LOR). The spacecraft was modular, composed of a 'Command/Service Module' (CSM) and a 'Lunar Module' (LM; pronounced LEM, for Lunar Excursion Module, its initial name). The CSM contained the life support systems for the three man crew's five day round trip to the moon and the heat shield for their reentry to Earth's atmosphere. The LM would separate from the CSM in lunar orbit and carry two astronauts for the descent to the lunar surface.

The LM itself was composed of a descent stage and an ascent stage, the former serving as a launch platform for the latter when the lunar exploration party blasted off for lunar orbit where they would dock with the CSM prior to returning to Earth. The plan had the advantage that since the LM was to be discarded, it could be made very light and allow for the moon mission to be launched with a single Saturn V rocket. However, at the time that LOR was decided, some mission planners were uneasy at large number of dockings and undockings needed to make the plan succeed.


The Apollo program included eleven manned flights, designated Apollo 7 through Apollo 17, all launched from the Kennedy Space Center, Florida. Apollo 2 through Apollo 6 were unmanned test flights; the Apollo 1 designation was applied to the originally planned first manned flight which ended in a disastrous fire during a launch pad test that killed three astronauts. The first of the manned flights employed the Saturn 1-B launch vehicle, the following flights all used the more powerful Saturn V. Two of the flights (Apollo 7 and Apollo 9) were earth orbital missions, two of the flights (Apollo 8 and Apollo 10) were lunar orbital missions, and the remaining 7 flights were lunar landing missions (although one, Apollo 13, failed to land).

Briefly, Apollo 7 tested the Apollo command and service modules (CSM) in earth orbit. Apollo 8 tested the CSM in lunar orbit. Apollo 9 tested the lunar module (LM) in earth orbit. Apollo 10 tested the LM in lunar orbit. Apollo 11 achieved the first manned lunar landing. Apollo 12 achieved the first lunar landing at a precise location. Apollo 13 failed to achieve a lunar landing, but succeeded in returning the crew safely to earth following a potentially disastrous in-flight explosion. Apollo 14 resumed the lunar exploration program. Apollo 15 introduced a new level of lunar exploration capability, with a long-stay-time LM and a lunar roving vehicle. Apollo 16 was the first manned landing in the lunar highlands. Apollo 17, the final mission, was the first to include a scientist-astronaut.

End of the Program

Originally three additional lunar landing missions had been planned, as Apollo s 18 through 20. In light of the drastically shrinking NASA budget and the decision not to produce a second batch of Saturn Vs, these missions were cancelled to make funds available for the development of the Space Shuttle, and to make their Apollo spacecraft and Saturn V launch vehicles available to the Skylab program. Only one of the Saturn Vs was actually used; the others became museum exhibits.

Another excerpt from Kennedy's Special Message to Congress:

"I believe we should go to the moon. But I think every citizen of this country as well as the Members of the Congress should consider the matter carefully in making their judgment, to which we have given attention over many weeks and months, because it is a heavy burden, and there is no sense in agreeing or desiring that the United States take an affirmative position in outer space, unless we are prepared to do the work and bear the burdens to make it successful. If we are not, we should decide today and this year.

"This decision demands a major national commitment of scientific and technical manpower, materiel and facilities, and the possibility of their diversion from other important activities where they are already thinly spread. It means a degree of dedication, organization and discipline which have not always characterized our research and development efforts. It means we cannot afford undue work stoppages, inflated costs of material or talent, wasteful interagency rivalries, or a high turnover of key personnel.

"New objectives and new money cannot solve these problems. They could in fact, aggravate them further--unless every scientist, every engineer, every serviceman, every technician, contractor, and civil servant gives his personal pledge that this nation will move forward, with the full speed of freedom, in the exciting adventure of space." (Excerpt from "Special Message to the Congress on Urgent National Needs")

Reasons for Apollo

The Apollo program was at least partly motivated by psycho-political considerations, in response to persistent perceptions of American inferiority in space technology vis-a-vis the Soviets, in the context of the Cold War. In this respect it succeeded brilliantly. In fact, American superiority in manned spaceflight was achieved in the precursory Gemini program, even before the first Apollo flight. The inability of the Soviets to perfect their N-1 rocket prevented them from reaching the moon. Until the 1990s they denied that they had even tried.

The Apollo program stimulated many areas of technology. The identical flight computer design used in the lunar and command module were the first to use integrated circuits and magnetic core memory. The computer were called AGC (Apollo Guidance Computer). Apollo rapidly forced Texas Instruments to make them work, and provided the crucial first customer when simple integrated circuits cost more than $1000/chip (in 1960 dollars). The fuel cell developed for this program was the first practical fuel cell. Computer controlled machining (CNC) was pioneered in fabricating Apollo structural components.

Many astronauts and cosmonauts have commented on the profound effects that seeing earth from space has had on them. One of the most important legacies of the Apollo program was the now-common, but not universal view of Earth as a fragile, small planet, captured in the photographs taken by the astronauts during the lunar missions. These photographs have also motivated many people toward environmentalism and space colonization.

Miscellaneous information

The cost of Apollo program: $25.4 billion

Amount of moon material brought back by Apollo program: 381.7 kg

The name Apollo refers to the Greek god.


Something to note with Apollo flights is that Marshall Space Flight Center who designed the Saturn rockets referred to the flights as Saturn-Apollo (SA) whereas Kennedy Space Center referred to the flights as Apollo-Saturn (AS). This is the reason why the unmanned Saturn 1 flights are referred to as SA and the unmanned Saturn 1B are referred to as AS.

Unmanned Saturn 1

Unmanned Pad Abort Tests

Unmanned Little Joe II

Unmanned Apollo-Saturn


Cancelled Missions

Follow On Missions

See also

Previous Program:
Gemini program
Next Program:
Space Shuttle program

Further reading

External links