“HOUSTON, THE EAGLE
HAS LANDED”
ABOUT THE COMPUTER THAT TOOK MAN TO THE MOON
O
ver the years and years of
Technology).
evolution of mankind, the
The necessity of an onboard computer was justified by several requirements and
Moon could steal the cu-
factors at the early stages of the development of the program.
riosity of human beings. It
1. Preparing for long duration manned missions to planets
became an ornament to many poems
2. Avoiding 1.5-seconds of time delay in a signal path from the earth to the
and songs worldwide while it fasci-
Moon and back
nated many scientists to conduct re-
3. Acting upon quick decisions and feedback during landing conditions
search that shot the Moon.
4. Maintaining less reliance on ground-based computing in critical situations
On 18th of June 1959, ‘Luna 2’ from
that might arise during the entire mission duration
Soviet Russia became the first space-
5. Guiding the flight in Lunar rendezvous method over direct flight to the Moon
craft to reach the lunar space. Since
During the mission planning, direct flight to the Moon; flying straight to the
the first manned mission to space
Moon and landing directly on the surface was rejected. Instead, Lunar Orbit Ren-
in 1961, people dreamt of land-
dezvous concept (LOR) was developed. In this method, a spacecraft consisting of
ing on the Moon. On 21st December
the Command Module (CM) with a separate lander would be placed in Earth’s or-
of 1968, ‘Apollo 8’ launched by NASA
bit preparing to enter an intercept orbit with the Moon. When the entire space-
became the first manned mission to
orbit around the Moon. A few months
later, in 1969, NASA was able to land
a human on the Moon. The ‘Apollo 11’
spacecraft boarded with three astronauts landed on the Moon on the 20th
July 1969 at 20:17 UTC (Coordinated
Universal Time). This mission became
one of the immense achievements of
the 20th century.
I N T RO D U CT I O N
In Apollo 11 mission, it was necessary
to guide the spacecraft into the lunar
orbit and then to land on the Moon
successfully. During the mid-20th century, it was a significant challenge to
develop an onboard computer to support the navigation of Apollo 11 without relying on the ground controlling
all the time. The development of a
digital comp