Project Apollo was a series of human spaceflight missions undertaken by the United States of America using the Apollo spacecraft, 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 hands-on scientific exploration of the Moon. As of 2005, there has not been any further human spaceflight beyond low earth orbit.
The Apollo Program was the second United States human spaceflight program, though its flights followed both the first such program (Mercury) and the third (Gemini). Apollo was originally conceived late in the Eisenhower administration as a follow-on to Mercury for advanced manned earth-orbital missions. It was dramatically reoriented to an aggressive lunar landing goal by President Kennedy with his announcement 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" )
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 minimizing risk to human life, cost and demands on technology and astronaut skill.
Three possible plans were considered.
Direct ascent: The first was to boost a spaceship directly to the moon. This would have required a Nova rocket far more powerful than any in existence at the time. The entire spacecraft would land on and return from the moon.
Earth orbit rendezvous: 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. The entire spacecraft would have landed on the moon in this case as well.
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.
Grumman Apollo LM
2; CDR, LM pilot
Landing gear span:
LM RCS (N2O4/UDMH) x 16:
100 lbf ea
Ascent Propulsion System (N2O4/UDMH) x 1:
3,500 lbf ea
Descent Propulsion System (N2O4/UDMH) x 1:
9,982 lbf ea
Spacecraft delta v:
Apollo LM diagram
Apollo LM diagram (NASA)
Grumman Apollo LM
The Lunar Module 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 the large numbers of dockings and undockings needed to make the plan succeed.
To learn lunar landing techniques, astronauts practiced in the Lunar Landing Research Vehicle (LLRV), a flying vehicle that simulated the Lunar Module on earth.
The Apollo program included eleven manned flights, designated Apollo 7 through Apollo 17, all launched from the Kennedy Space Center, Florida. Apollo 4 through Apollo 6 were unmanned test flights (officially there was no Apollo 2 or Apollo 3); the Apollo 1 designation was retroactively 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 IB 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).
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 human 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.
Apollo Applications Program
In the speech which initiated Apollo, Kennedy declared that no other program would have as great a long-range effect on America's ambitions in outer space. Following the success of Project Apollo, both NASA and its major contractors investigated several post-lunar applications for the Apollo hardware. The "Apollo Extension Series", later called the "Apollo Applications Program", proposed at least ten flights. Many of these would use the space that the lunar module took up in the Saturn rocket to carry scientific equipment.
One plan involved using the Saturn IB to take the CSM to a variety of low-earth orbits for missions lasting up to 45 days. Some missions would involve the docking of two CSMs, and transfer of supplies. The Saturn V would be necessary to take it to polar orbit, or sun-synchronous orbit (neither of which has yet been achieved by any manned spacecraft), and even to the geosynchronous orbit of Syncom 3, a communications satellite not quite in geostationary orbit. This was the first functioning communications satellite at that now-common great distance from the Earth, and it was small enough to be carried through the hatch and taken back to Earth for study as to the effects of radiation on its electronic components in that environment over a period of years. A return to the moon was also planned, this time to orbit for a longer time to map the surface with high-precision equipment. This mission would not include a landing.
Of all the plans only two were implemented; the Skylab space station (May1973 - February1974), and the Apollo-Soyuz Test Project (July1975). Skylab's fuselage was constructed from the second stage of a Saturn IB, and the station was equipped with the Apollo Telescope Mount , itself based on a lunar module. The station's three crews were ferried into orbit atop Saturn IBs, riding in CSMs; the station itself had been launched with a modified Saturn V. Skylab's last crew departed the station on February 8, 1974, whilst the station itself returned prematurely to Earth in 1979, by which time it had become the oldest operational Apollo component.
Originally three additional lunar landing missions had been planned, as Apollos 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.
Lunar lander LM2 in a museum
"This decision demands a major national commitment of scientific and technical manpower, material 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 and Space race. 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 Apollo program stimulated many areas of technology. The flight computer design used in both the lunar and command modules was, along with the Minuteman Missile System, the driving force behind early research into integrated circuits. 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. The most famous of these photographs, taken by the Apollo 17 astronauts, is "The Blue Marble." These photographs have also motivated many people toward environmentalism and space colonization.
The cost of the entire Apollo program: USD $25.4 billion -1969 Dollars ($135-billion in 2005 Dollars). See NASA Budget. (Includes Mercury, Gemini, Ranger, Surveyor, Lunar Orbitar, Apollo programs.) Apollo spacecraft and Saturn rocket cost alone, was about $ 83-billion 2005 Dollars (Apollo spacecraft cost $ 28-billion (CS/M $ 17-billion; LM $ 11-billion), Saturn I, IB, V costs about $ 46-billion 2005 dollars).
Amount of moon material brought back by the Apollo program: 381.7 kg (841.5 lb). Most of the material is stored at the Lunar Receiving Laboratory in Houston.
The Apollo program used four types of launch vehicles:
Saturn I - unmanned suborbital and orbital hardware development.
Saturn IB - unmanned and manned earth orbit development and operational missions.
Saturn V - unmanned and manned earth orbit and lunar missions.
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 why the unmanned Saturn 1 flights are referred to as SA and the unmanned Saturn 1B are referred to as AS.
Apollo 17 - final Apollo lunar mission, first mission with a geologist
The original pre-lunar landing programme was more conservative but as the 'all-up' test flights for the Saturn V proved successful missions were deleted. The revised schedule published in October 1967 had the first manned Apollo CSM earth orbit mission (Apollo 7) followed by and Earth Orbit Rendezvous of the CSM and LM launched on two Saturn 1Bs (Apollo 8) followed by a Saturn V launched CSM on a Large Earth Orbit Mission (Apollo 9) followed by the Saturn V launched dress rehearsal in Lunar Orbit with Apollo 10. In the Spring of 1968 the CIA informed NASA administrator James Webb that the Soviet Union was preparing a manned circum-lunar mission within the year. As the LM was delayed Webb opted to switch the planned Apollo 9 to a CSM only Lunar Orbit mission as Apollo 8. The original idea for this switch was the brainchild of George Low. As a consequence this decision resulted in Neil Armstrong becoming the first man on the moon.
Chaikin, Andrew. A Man on the Moon. ISBN 0140272011. Chaikin has interviewed all the surviving astronauts, plus many others who worked with the program.
Murray, Charles ; Cox, Catherine B. Apollo: The Race to the Moon. ISBN 0671611011. This is an excellent account of what it took to build and fly Apollo.
Cooper, Henry S. F. Jr. Thirteen: The Flight That Failed. ISBN 0801850975. Although this book focuses on Apollo 13, it is extremely well-researched and provides a wealth of background information on Apollo technology and procedures.
Wilhelms, Don E. To a Rocky Moon. ISBN 0816510652. Tells the history of Lunar exploration from a geologist's point of view.
Pellegrino, Charles R.; Stoff, Joshua. Chariots for Apollo: The Untold Story Behind the Race to the Moon. ISBN 0380802619. Tells Grumman's story of building the Lunar Modules.
Lovell, Jim; Kluger, Jeffrey. Lost Moon: The perilous voyage of Apollo 13 aka Apollo 13: Lost Moon. ISBN 0618056653. Details the flight of Apollo 13.
Collins, Michael . Carrying the Fire; an Astronaut's journeys. Astronaut Mike Collins autobiography of his experiences as an astronaut, including his flight aboard Apollo 11, the first landing on the Moon
Slayton, Donald K.; Cassutt, Michael. Deke! An Autobiograpy. ISBN 031285918X. This is an excellent account of Deke Slayton's life as an astronaut and of his work as chief of the astronaut office, including selection of the crews which flew Apollo to the Moon.