The Bridge - Issue 1, 2023 - 38

History Spotlight
Guiding Apollo to the Moon
Burt Dicht
A spaceship landed on Earth after returning from an
uncrewed 26-day, 1.3-million-mile trip around the
Moon. On December 11, 2022, the Orion CM-002
spacecraft splashed down in the Pacific Ocean off
Baja California. This closed out the Artemis I mission,
NASA's first step to returning astronauts to the Moon
later this decade. With a sense of symmetry, the
splashdown occurred on the 50th anniversary of
Apollo 17's landing on the Moon.
The Earth and Moon as seen from the Orion spacecraft
(Image credit: NASA)
Apollo 17 (December 7-19, 1972) was the
last crewed mission to the Moon, ending the
monumental program that featured six lunar landings,
12 moonwalkers, 800+ pounds of moon rocks, and
tremendous advances in science and technology.
The Apollo program was born from President John F.
Kennedy's bold goal, set on May 25, 1961, to land
astronauts on the Moon and return them safely to
Earth before the end of the decade.
For those of us who grew up as part of the Apollo
generation, the successful Artemis I mission was
a reminder of the technological prowess needed
for the moon program. The Artemis program,
including the Space Launch System rocket and the
Orion spacecraft, incorporates the latest advances
in technology, including electronics and computing.
When comparing today's technology to that of the
THE BRIDGE
1960s and what made the Apollo program possible,
it's easy to ask, " How did we do it with what we
had? " The Apollo astronauts relied upon rudimentary
computer technology for guidance and control and
slide rules for on-the-fly calculations.
The Apollo program utilized the talents of more than
400,000 engineers, scientists, and technicians and
mobilized the resources of 20,000 companies and
universities. IEEE's fields of interest were very well
represented. As we celebrate the 50th anniversary
of Apollo 17 and the end of the Apollo program, we
also embrace the promise of Artemis and the return
to the Moon. Let us now look back at one of the key
contributions that achieved that " one small step. "
A critical component necessary for the moon mission
was the Apollo spacecraft's guidance and control
system. Only weeks after President Kennedy set
the goal, NASA awarded the contract to the MIT
Instrumentation Laboratory (now Draper Laboratory).
NASA wanted to use an inertial measurement unit
(IMU) like those found in submarines, ballistic
missiles, and aircraft that had been pioneered by
the lab's director, Charles Stark " Doc " Draper. While
designing the basketball-sized IMU, which made use
of three gyroscopes to measure changes in direction
and three accelerometers to measure changes in
velocity, was a challenge,
the long pole was the
digital computer that the
astronauts would use to
interface with the IMU.
In the movie " Apollo
13 " , astronaut Jim
Lovell (played by Tom
Hanks) touts advances
in technology by
referencing computers
" that can fit into one
room. " During the early
1960s, even the most
compact computers
Apollo Guidance Computer Core
Rope Memory (Image Credit -
Draper/Hack the Moon)
The Bridge - Issue 1, 2023

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