Apollo 11 – Making history

“That’s one small step for [a] man, one giant leap for mankind”; Today marks the 50th anniversary since Neil Armstrong said these words while he was setting foot on the Moon surface.



An Adventure like no other

On mankind history there are many admirable and inspiring events, but certainly no one like the Apollo missions, a program that is probably the one that has had the major number of participants in history (almost half a million people worked on this program); making it a result that is truly a community effort and unique in our civilization, achieving the realization of a dream shared by a large number of people; the dream of putting the first human being on the surface of the Moon.

The promptness and hard work of this large number of individuals is what allowed us to go from an idea to a result of this magnitude in such a short time. From the moment in which this commitment was made, with the speech of President Kennedy in May of 1961; till the arrival of the “Eagle” Lunar module to the moon’s surface, only eight years elapsed; time in which they had to conceptualize multiple elements for this mission, apart from the simple fact of devising the best way to do it.

Buzz Aldrin descending from the Lunar module (nasa.org)

Buzz Aldrin descending from the Lunar module (nasa.org)

F1 engines

The stories are countless, one example is the design of propulsion systems, the F1 engines, which in the beginning were plagued with problems; this because by being so big they suffered from inconsistencies in the mixture of fuel and oxidant, causing an unequal combustion that created strong vibrations (The term used was “Tangential spinning oscillation”), and as a result caused that such oscillations ended up affecting the the motor’s structural integrity, causing its failure; failures that were spectacular, having a sudden engine explosion.

The aerospace engineering of that time was a combination of science and art, as there was no way to simulate how the fuel and oxidant fluids worked. So, to control this issue they tried a radical idea; if the combustion was unstable, then they decided to create instability on demand, making use of explosive charges in the same engine; with which they could control and in this way reestablish the motor and its vibrations. In short, fight chaos with a chaos in demand. This solution, plus the use of a baffle arrangement, solved the problem of the engines dynamic instability, making them 100% reliable, with 65 engines in 13 launches working perfectly.

F1 Engines (nasa.org)

F1 Engines (nasa.org)

Navigation computers

At the beginning of the 60’s the state of the art in computers was still based on mainframes, gigantic computers that occupied multiple rooms; so the mere idea of thinking of a “transportable” computer was far fetched. But this was the need in the Apollo missions; and they required not only one, but four computers, needed for launch control purposes, navigation of the command module and lunar module and an extra emergency computer.

These should be no larger than a portfolio; and the control module should fit in a space of 1 cubic feet; These computers made use of the first integrated circuits, since microprocessors were not yet commercially available, so the processing module was also designed exclusively for this program.

The computer had six read-only modules (ROM), which formed its code, with a total of 36 K-bytes; and with 2 K-bytes of RAM for instruction processing. This was something so unusual that the contract to manufacture them didn’t had specifications beyond the required weight and dimensions; and some information on the elements that should be controlled. The ROM code was manufactured manually, by assembling and connecting six modules.

To have a reference on the information that 36 K-bytes represent, a typical email message today uses on average about 75 K-bytes of memory.

Another peculiarity of this computer was its ability to recover after a failure; maintaining its state and reestablishing itself to continue with the same state it had before such failure.

Apollo mission computer (Wikipedia.org)

Apollo mission computer (Wikipedia.org)

The Saturn V rockets.

The mission that reached the moon was Apollo 11, but this does not mean that there were 10 previous manned missions. The first Apollo mission with a crew was Apollo 7. Apollo 8 was the first mission that visited and orbited the Moon, it did not have a lunar module onboard, because this still had many technical difficulties and therefore decided not to take it in this mission. It was until Apollo 9 when the first lunar module (Spider) was tested; while being in Earth’s orbit.

The Apollo 10 mission was a “rehearsal mission” prior to the moon landing, using the Lunar module to travel up to 2 Miles above the moon’s surface.

The manned Apollo missions began on October 11-22 of 1968 with Apollo 7, continuing with Apollo 8 on December 21-27 of 1968, Apollo 9 on March 3-13 of 1969 and Apollo 10 on May 18-26, 1969. Accumulating a total of 6 successful missions with moon landings.

The Apollo 17 mission was the last mission of this program, where the astronauts maintained a base on the lunar surface for a total of three days. What I think can be considered the first extra planetary base.

Saturn V rocket (nasa.org)

Saturn V rocket (nasa.org)

My perspective

Even though I did not have the opportunity to directly witness these missions; These have always been a source of personal inspiration. When I was about 12 years is when I read my first book about the lunar missions “The Apollo on the Moon”, where they described in detail what the astronauts did on the moon, commenting on the tools that were used, the experiments they installed, and the details of how to solve simple problems, from the creation of a specific color that was easily distinguishable (International Orange), to the simple consideration of using pencils to have no problem with the absence of gravity, given that pens did not work without it.

Multiple stories like this resulted in this great achievement; If you are interested in learning more about the Apollo missions, I recommend the site “Hack the moon“, this has invaluable material about personal stories, technical elements and the missions themselves.


Earth rising, picture from Apolo 11 (nasa.org)

Earth rising, picture from Apollo 11 (nasa.org)

In these fifty years, I can only recognize the legacy of the Apollo missions, and I hope to be able to witness the following missions to the Moon. Best of success and godspeed Artemis project!

Best regards
Alex, ScienceKindle



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