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  • Writer's pictureSven Piper

Apollo Program

Buzz Aldrin on the Moon
Buzz Aldrin on the Moon

Since time immemorial, many have been fascinated by the moon and dreamed of visiting it. Galileo Galilei pointed his telescope at it and began to study it. Jules Verne wrote a book about traveling to the moon in 1865, in which people were shot to their destination by a cannon, even though this idea would not make much sense due to the G-forces involved. The German director Fritz Lang also thought about this topic in 1929 and shot the film “The Woman in the Moon” after “Metropolis.”

From December 1968 to December 1972, 24 astronauts traveled to the moon and 12 people walked on it. Before the Apollo project, the Gemini program was launched to gain initial experience in rendezvous missions in Earth orbit so that the manned moon flight could be realized at all.

This was necessary because Wernher von Braun proposed two possibilities for a manned moon landing. The first option envisaged a gigantic rocket, which would have been difficult to realize at the time; nevertheless, parts of this concept were adopted for the moon rocket. The second option was a rendezvous mission in Earth orbit, which was later changed to a rendezvous mission in lunar orbit. Although this plan initially met with little approval, as the risk was considered too great, the plan was approved in July 1962.

The Apollo program was based on a promise made by then-President JFK in 1961 to be the first nation to land on the moon before the end of the decade, as the Soviet Union had been more successful up to that point. A race to the moon began, which NASA eventually won.

Rocket type

Saturn V
Saturn V

As there was no rocket that had sufficient thrust to propel the lunar spaceship out of the Earth's gravitational field and towards the moon, one had to be developed first. This was developed under the direction of Wernher von Braun, and thus the most powerful rocket to date (140 tons payload) was born: the Saturn V.

Together with the Apollo system, the three-stage Saturn V was 111 m high and delivered a thrust of 3,402,000 kg in the first stage. It consumed 13,608 kg of fuel per second. The first stage had five F-1 engines, which required liquid oxygen and kerosene, and was jettisoned after 160 seconds. The second stage was then ignited, which, like the third stage, used J-2 engines powered by liquid oxygen and hydrogen. The second stage delivered a thrust of 500,000 kg and was jettisoned after 6 minutes and 30 seconds, after which the third stage was deployed to deliver the thrust towards the moon.

Apollo spacecraft

The Apollo system consisted of three components. In addition to the command module (CM), there was also the service module (SM), which housed the thruster unit, among other things, and the lunar module (LM).

Command module

Command module
Command module

The instruments to control the lunar spaceship were located here. It was docked with the service module, and only at the end of the mission, shortly before re-entry into the Earth's atmosphere, did the CM and the SM separate. The command module landed in the water with the astronauts and was recovered from there. For this purpose, it was equipped with a heat shield and parachutes.

Service module

The service module contained the electrical systems, life support, control thrusters, and communication systems for this mission. The main engine and fuel tank were also located here. It was powered by an oxygen-hydrogen mixture. This main engine was needed to enter an orbit around the moon and to leave the lunar orbit again and fly towards the Blue Planet.

Lunar module

Ascent unit of Apollo 17
Ascent unit of Apollo 17 (Copyright NASA)

The sole purpose of the 2.35 m wide lunar module was to set two astronauts down on the lunar surface. For this purpose, the shuttle actually consisted of two separate parts: a descent stage, to the underside of which four landing legs were attached for a soft touchdown, and an ascent stage. After undocking from the CM in lunar orbit, the LM flew to the landing zone. Before the astronauts could leave the LM, they first had to perform a pressure equalization. During the entire stay on the moon, the LM was the astronauts' home, even though it was very cramped and the astronauts stood in the module during landing and were only held to the ground by double-sided adhesive strips. After the mission was completed, only the ascent unit flew back into lunar orbit and docked with the command module.

Moon car

Lunar Roving Vehicle
Lunar Roving Vehicle

The first mission to use the moon car was Apollo 15, which allowed the astronauts to explore the area around the landing site and collect a wider variety of different rocks. It was a two-seater electric car and could transport two astronauts in their spacesuits. Because it was foldable, it could be stored in the lower part of the lander.


The Apollo program consisted of several unmanned test missions and 11 manned space flights. The astronauts' tasks on the moon included collecting rock samples, seismic investigations, magnetic field, and solar wind experiments.

Apollo 1

Apollo 1 was a routine test on the launch pad that ended in disaster and was only given this designation later. The original designation was AS-204. Here is a list of the radio traffic between the command module and Flight Control.

As with previous tests, there were again communication problems between the CM crew and the Control Center. This annoyed Commander Gus Grissom and forced him to say: “How are we going to fly to the moon if we can't even communicate within our buildings? This is getting ridiculous.” Then Flight Control heard a whistle that sounded as if a microphone was open somewhere. “Fire” then came from the capsule. “We have fire in the cockpit.” The Flight Control staff couldn't believe it at first and asked: “Did he say fire?”. The capsule then announced: “We have a serious fire here.” The alarm was then triggered. “We're burning up.” “Get us out.” “Hurry up.” Then an explosive flame shot out of the capsule and wounded several North American Aviation technicians who were trying to open the hatch with fire extinguishers. However, this only succeeded after 5 hours.

What had happened, and how could this catastrophe occur during a routine test? The command module was built by North American Aviation in Downey, California, and routine tests had been conducted in this manner since the Mercury program.

During the investigation following this accident, astronaut Frank Borman led the team responsible for disassembling the capsule. Several unfortunate factors came to light. For example, the hatch only opened inwards and the crew was unable to open it due to the fire pressure. This hatch was a new design, as the capsules of the Mercury project still had explosive pressure hatches. All you had to do was pull a lever and you were out very quickly. However, in a near-miss involving Gus Grissom, in which he almost drowned, it turned out that the hatch's explosive charge also went off by itself. It was therefore decided not to use explosive pressure hatches in the Apollo program.

A socket wrench found behind a console got NASA and NAA into trouble at the hearing before congressmen because it had been there from October 1966 to January 27, 1967, and no one had discovered it, even though it didn't belong there. It also came to light that NAA had used ten times more Velcro in the construction of the space capsule than originally approved by NASA. This had been requested by the crew in advance. The problem was that Velcro was not flammable under normal air conditions, but the tests were carried out with 100% pure oxygen under pressure and under these conditions, the material was explosively flammable.

Presumably, a cable rubbed against the inside of the console and by opening the hatch several times, the Teflon insulation was worn through. When electricity then flowed through the cable, an electric arc occurred, which triggered the catastrophe.

The final report, which was presented in April 1967 and led by the Director of the Langley Research Center, Dr. Floyd L. Thompson, led to a whole series of improvements. The accident killed Gus Grissom, who was the first astronaut to have the opportunity to go into space for a third time, as he had already been on Mercury and Gemini, Ed White, the first American to perform a spacewalk and a graduate of West Point Military Academy, and astronaut Roger Chaffee, who was to fly into space for the first time.

Apollo 8

Could not take place with the Lunar Module due to delays in its production (LM was not tested until Apollo 9). The commander of this mission was Frank Borman. The mission took place at Christmas 1968, as spy pictures from Russia revealed a large Russian rocket with four stages (N1) ready for launch and the Russian Zond-5 had successfully orbited the moon unmanned. In order to test the operational readiness of the CM and SM modules, the spacecraft entered lunar orbit thanks to its engine and completed ten orbits. Difficulties arose due to the commander falling ill (vomiting several times), which almost led to the mission being aborted. Particularly noteworthy is the first observed earth rise from lunar orbit; the crew was simply thrilled by this sight.

Apollo 9

A variety of new technologies were tested here, including the first time the Lunar Module was tested in Earth orbit by separating from the CM and flying independently. The LM was the third lunar spaceship built by Grumman and was named Spider. However, this mission did not go smoothly either, as the pressure in the helium tank of the LM was too high at launch and the mission was about to be aborted. Furthermore, the pilot of the LM fell ill (vomiting several times) and at first, it appeared that an external mission was too dangerous, as the astronaut could have suffocated. However, as he felt better the next day, the mission was carried out successfully, even though the high pressure in the helium tank led to a bumpy flight. The first EVA in history with two astronauts is also worth mentioning.

Apollo 10

The first mission to test the LM in lunar orbit. The mission took place two months after Apollo 9.

Apollo 11

"One small step for a man, one giant leap for mankind”

Crew from Apollo 11
Crew from Apollo 11

Launched on July 16, 1969, Apollo 11 was a highly anticipated event, with over a million people attending the launch of the Saturn V rocket live. The crew of this mission consisted of the commander Neil A. Armstrong, the pilot of the landing module Edwin E. Aldrin, although on each mission the commander flew the lander and the officially designated pilot only supported him, and the pilot of the Apollo spacecraft Michael Collins, who did not walk on the moon but orbited the moon in the command module. All three were experienced pilots and had already gained their first experience in space during the Gemini program. On July 20, 1969, the time had come. Neil Armstrong announced that the Eagle had landed and became the first man to set foot on the moon. He and Edwin “Buzz” Aldrin went for a walk in the “Sea of Tranquillity.”

The name of the lunar module used here was Eagle and it was the fifth LM to be built. But before Neil Armstrong could announce that the Eagle had landed, extensive tests were carried out with an LM capable of flying on Earth, during which Neil Armstrong crash-landed and was only able to save himself with the ejection seat. The landing on the moon was also spectacular, as there was only one attempt and only a limited amount of fuel on board, which Neil Armstrong used to the limit.

Apollo 11 on the Moon
Apollo 11 on the Moon

It is also worth mentioning that Aldrin would have liked to have been the first man on the moon, but the design of Grumman's LM, with the exit hatch on the commander's side and the inability to change positions due to the backpacks, determined the order. In addition, Neil Armstrong had to pull a lever on the way out to activate an automatic camera that recorded the first step of a man on the moon.

Apollo 12

“Man, that may have been a small one for Neil, but that's a long one for me.”

On November 14, 1969, Apollo 12 was launched in pouring rain, and the rocket was also struck by two bolts of lightning. The new flight director (who was to receive his baptism of fire on the Apollo 13 mission) did not have a good debut, as several warning lights flashed in the Yankee Clipper CM module during the launch. Further problems were caused by two cameras, for which LM pilot Alan Bean was responsible. First, he forgot to shield the lens of the camera from the sunlight on the lunar surface, so that nothing came of the first color film shots of the moon. He also forgot to secure his hand-held camera during the landing approach, which subsequently flew into his face and briefly put him out of action.

The landing on the moon was the first in which a fixed landing target was used, even if the landing with the Intrepid LM was heavy. The target zone was near the lunar probe Surveyor 3 in the “Ocean of Storms,” whose camera had taken the first live images of the lunar surface and was now recovered. Two four-hour moonwalks were carried out on the lunar surface. In addition, the two astronauts smuggled a self-timer onto the moon so that - unlike on Apollo 11 - both astronauts could be photographed together. Unfortunately, the LM pilot messed this up too, but there was still a happy ending for him when his commander Charles “Pete” Conrad let him control the LM for a short time.

Apollo 13

“Houston, we have a problem.”

The Apollo 13 mission was launched at a time when media interest in the moon flights had waned considerably, and the Soviet Union also changed its plans and from then on concentrated on developing space stations in Earth orbit. It was only when a loud bang occurred during a routine test after 55 hours and 55 minutes of flight and a voltage drop was measured that public interest increased. The crew was also able to observe the escape of oxygen. As if this wasn't bad enough, the carbon dioxide content also increased during the 23rd manned American space flight. A solution to this problem was made more difficult by the fact that LM and CM had different filter connections. As a result, the planned landing on the Fra Mauro plateau, where Apollo 14 later landed, came to nothing and the only thing left to do was to bring the astronauts back.

The three astronauts spent the entire four-day return flight in the LM Aquarius before switching to the CM Odyssey shortly before re-entry and reviving the command module. It remained unclear until the end whether the three astronauts would suffer the same fate as the Russian cosmonaut Vladimir Komarov on Soyuz 1, when the braking parachutes failed to open and the cosmonaut did not survive.

Apollo 14 - Golf on the moon

The commander of this mission was Alan Shepard, the first American to be launched into space, even if it was only a suborbital flight. Alan Shepard was also considered the favorite for the first manned Gemini mission, but an inner ear disease with severe vertigo led to the temporary end of his career. He was only able to regain his active flying status after an experimental operation.

However, the first mission after the near-disaster of Apollo 13 also had to contend with difficulties. Computer problems in lunar orbit meant that the lunar module Antaris was initially unable to land as planned. Even a reset for the abort signal did not bring any change and the computer still threatened to abort the landing approach automatically. The LM software, which had been developed by M.I.T. programmers, had to be reprogrammed by the astronauts with their assistance. However, this did not solve all the problems, as the landing radar had difficulties and the lunar module landed on a slope, causing it to tilt. Fortunately, the LM's ascent unit was able to start without any problems. But before that, Alan Shepard played golf in the landing area of the Fra Mauro Highlands.

Apollo 15 - Galileo was right

As NASA was struggling with budget cuts, the 15th Apollo mission turned out differently than initially planned. Scientific interest took center stage on this mission, which is why the astronauts, who were almost exclusively test pilots, were trained in geology. They received help from Professor Lee Silver from Caltech (California Institute of Technology) in Pasadena. Several field trips were made to areas of geological interest. In order to take additional geological equipment with them, although the weight level had already been reached, the astronauts even gave up some of the fuel.

As this mission was the first mission to be equipped with a lunar rover, an improved LM was also used, which now also had a hatch at the top.

As only equatorial landings were possible on the moon, there was a bitter dispute over the landing site. In the end, the commander decided in favor of the difficult landing site in the Apennines, which seemed to be geologically more valuable. It is also worth mentioning that an old law of physics was experimentally proven during this lunar excursion. A falcon feather and a hammer were dropped to the ground at the same time and, due to the lack of air resistance, both landed on the moon at the same time. This proved Galileo Galilei's old knowledge.

Apollo 16

NASA was already turning its attention to the Skylab project and it was clear that Apollo 17 would be the last Apollo mission. Apollo 16 was launched in April 1972 to land in the Descartes crater. Commander Young succeeded with the LM Orion, even though it was not a smooth landing. Young later incurred the wrath of scientists when he stumbled on the moon, destroying an important experiment to measure the temperature inside the moon. It was also here that Ken Mattingly, the Apollo 13 pilot who was passed over for suspected rubella, got his chance.

Apollo 17

For the last time to date, a human left his footprints in the lunar dust. Commander Gene Cernan was the last man on the moon in the Taurus-Littrow Mountains. Cernan and geologist Harrison “Jack” Schmitt, the only scientist on the moon, carried out the longest EVAs, moving 8 kilometers away from the LM Challenger. Among other things, they discovered orange-colored moon dust, which turned out to be of volcanic origin. Jack Schmitt also practiced throwing a hammer.

But problems also occurred during this mission. During the first EVA, which lasted 7 hours and 12 minutes, the lunar rover's wheel cover broke and had to be patched up in a makeshift manner. In addition, there were two more moonwalks and the best images of the lunar surface to date, with the only perfectly filmed launch of the ascent unit to date.


The total cost of the Apollo program was 19.4 billion dollars.

The problems and the astronauts' subsequent careers on Earth

Not all of the astronauts were able to cope well with their experiences and reintegrate into life on earth. Some of the moon visitors had alcohol problems or tried their hand at unusual tasks.

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