28 ISE Magazine | www.iise.org/ISEmagazine
Apollo 11 at 50: Lessons from
humanitys greatest engineering feat
Anniversary celebration shines a spotlight on the moon mission’s
systems, models and connections
By Barrett S. Caldwell
The Apollo 11
lunar module
heads for
docking with
the command
module with the
earth rising in
the background
in this photo shot
by pilot Michael
Credit: Photos courtesy of NASA
Astronaut Buzz Aldrin salutes
the American flag during the
July 20, 1969, moonwalk in
this iconic image.
Astronaut Buzz Aldrin salutes
the American flag during the
July 20, 1969, moonwalk in
this iconic image.
Astronaut Buzz Aldrin backs
down the ladder of the lunar
module to the surface of the
moon on July 20, 1969, while
millions watched on earth.
The crew of Apollo 11
included (from left) Neil
Armstrong, Michael Collins
and Buzz Aldrin.
The Saturn V rocket,
the largest ever built,
propels the Apollo 11
astronauts into space
on July 16, 1969.
July 2019 | ISE Magazine 29
“What are you doing this summer?
During late May on the Purdue campus and
at many other research universities, this is a
common greeting among faculty. Normally,
it is a question addressing general hopes and
promises of unstructured time, chances to re-
turn to long-neglected projects and perhaps time for rest and
recovery. However, my answer was very focused with a mis-
sion countdown clock updating on a nearly constant basis.
T minus 51 days. “I’m working on the Apollo 11 anniver-
sar y.”
On July 20, 1969, there were “a bunch of guys about to turn
blue,” realizing that one of the most complex and challeng-
ing systems engineering projects in human history had come
down to a pilot from Ohio, trained at an Indiana engineering
school, working with less than 30 seconds worth of fuel and
a bunch of computer data overflow errors as he landed on the
It is said that more than a billion people, perhaps a quarter
of the worlds population, followed the progress of the Apollo
11 mission. Hundreds of thousands of children and adolescents
were in the midst of a life-changing experience of inspiration
and excitement to pursue careers in science and engineering.
I am one of those. Actually, my inspirational moment came
a few months earlier, on Christmas Eve 1968. Listening to the
crew of Apollo 8 send messages and pictures back from lunar
orbit, I could think of no better direction for my life path to
take: to pursue a career in astronautics and the grand dream of
engineering the space program.
However, 50 years later, I am planning the celebration of
those famous words displayed in front of the building named
for Neil Armstrong, the man who spoke them: “Tranquility
Base here. The Eagle has landed.” But many of the people
who will visit the campus for this celebration were not born
during the Apollo era. What lessons are there, in an event now
described as history, that can still inspire creativity, curiosity
and discovery?
I am eagerly searching out connections (I am always seeking
to make connections for understanding) and unexpectedly, I
nd several of them from souvenirs, artifacts and memories in
my own house.
The mission that inspired an engineer
Why are industrial and systems engineering tools and pro-
cesses so important to me, and when did I learn them? I teach
courses in systems engineering, and different considerations of
what it means to be and think like an engineer. There was a
photo in a box in my basement that brought back some of my
fondest memories of childhood (Figure 1), and in it you can
see the first genesis of an engineering approach to problem
denition and understanding.
My father was not an engineer; he was a car salesman. We
spent a lot of time talking about and experiencing cars – at the
dealership, looking at them on the delivery trucks, even driving
cars from one location to another on a “trade,” where a cus-
tomer buying a car at one dealership learned that the car they
wanted was at another maybe 50 to 150 miles away. The deal-
erships would exchange cars and sometimes special parts, so I
began to learn about supply chain and inventory management.
But most importantly, my father would teach me how to
build plastic models of antique cars. He would show me how
to read the instructions, separate the pieces, use structured
techniques to build a piece of the model as a subsystem of the
car and combine those subsystems into the finished model.
He would say: “Thats a leaf suspension.” “That’s a steering
mechanism.” “Read all the instructions first, so that you know
what youre trying to get done.
Before Apollo, and even before I could read all of the in-
An early love for problem-solving
The author and his father putting together a model car, circa 1966,
as he first learns to think like an engineer.
Credit: Courtesy of Barrett S. Caldwell
The footprint of astronaut Buzz Aldrin on the moon’s surface.
Credit: Photo courtesy of NASA
30 ISE Magazine | www.iise.org/ISEmagazine
Apollo 11 at 50: Lessons from humanity’s greatest engineering feat
structions, my father was giving
me a lesson I use to this day to
manage the Apollo 11 celebration:
Dene the system, organize the
system and work the system in a
structured way. Thanks, Dad.
Models and flavors
Even now, I use examples of a
plastic model of the Apollo lunar
module (LM) seen in Figure 2 to
demonstrate both the concept of
models, and one of five distinct uses
of the term, “systems engineering.
Clearly, the LM or the model car
with my father arent meant to do
exactly what their full-size, reali-
ty-based engineering systems do.
They are meant to teach concepts
and answer questions, and even to
help with considerations of how to
take component parts and struc-
tured procedures and use them to
complete a finished product.
Those are different models than
the Estes rockets I built out of balsa
and cardboard. Those didnt look
as much like a real Saturn rocket
as the Christmas 1969 present I re-
ceived but are better at taking off
from a launch pad and reaching
an altitude of 500 feet or more. So
these models are a form of systems
engineering: Take components
and rules and combine them to produce a product that allows
you to ask and answer questions.
Interestingly, the effort to work with a team to organize
the campus celebration is reminding me of other “avors” of
systems engineering. The planning for the Apollo 11 50th
anniversary project has been filled with elements of manag-
ing a complex engineering project: dening scope, managing
tasks, recognizing constraints and developing alternatives. In
my collection of spaceight artifacts, I found a document put
together by prior generations of engineers worrying about sys-
tem definition, planning and tracking: the “Apollo Manage-
ment System” manual, produced by IBM in January 1968, as
Volume 9 of the NASA/Apollo Program Management docu-
The figures seem so straightforward until you recognize
the complexity of managing not just all of the complex engi-
neering components but the interdependencies and data inter-
changes between them all (Figure 3), all in a document pub-
lished less than 12 months after the fatal fire on Jan. 27, 1967,
that killed the crew of Apollo 1 (including two other Purdue
alumni, Gus Grissom and Roger Chaffee).
No, the campus celebration is not as complex, nor does it
include the vast diversity of technical professionals as the origi-
nal Apollo 11 mission it is intended to honor. But many of the
elements of system integration are brought home to me with
each planning meeting, email and telephone call that requires
a response or resolution. Maybe I shouldnt be surprised to
learn that many of those elements can be described using the
same section headings the Apollo Management System docu-
ment used, so let me duplicate those headings as I describe
additional experiences and lessons of systems management and
mission execution.
The Mission Operational System” (Section 1.5.1).
As might be guessed from the name of the author (IBM) of
A model for systems engineering in a box
The Revell Apollo Lunar Module model. “I didn’t get this as a child; now, as an engineer, I value
the plastic and instructions more in their incomplete form,” the author writes.
Credit: Courtesy of Barrett S. Caldwell
July 2019 | ISE Magazine 31
the Apollo Management System report, the primary
system denitions in this report address computer hard-
ware and software as engineered artifacts. Each of the
components has a particular responsibility to complete
critical mission functions for the Apollo mission, rang-
ing from pre-launch to re-entry, according to phases of
ight and specific data flow requirements (see Figure 4).
In addition to the complexity of each of these com-
ponents, there was a special emphasis on a supervisory
control subsystem that “serves as the interface between
the applications programs and equipment systems” of
mission control and operational support teams. Note
that the supervisory control function is not there to
take over or replace these activities but to integrate
the components and their functions. This is one of the
most significant lessons of managing a team of people
with a variety of skills and specialty domain knowl-
Supervisory control is not a phrase that was in com-
mon use in this sense in the mid-1960s. People were
familiar with “command and control” in the sense of
someone giving orders and others taking them. But
empowering people to do excellent specialist work
and assigning a different function to strategic coordi-
nation? From a systems engineering perspective, that
is perhaps as radical an innovation as creating digital
computers to calculate and transmit position and tra-
jectory information in real time, or to congure en-
gines to generate a million pounds of thrust using ma-
terials that didnt exist a decade prior.
“Program Requirements Denition” (Sec-
tion Although the emphases on the com-
puter congurations and data flows are of primary fo-
cus of this discussion of mission operations, one point
is very obvious. The Apollo Management folks started
with the mission goal of getting to the moon, not build
the computer system. What is the mission goal for the
Apollo 11 + 50” celebration? This was a deceptively
challenging question, and one for which the differ-
ences in possible answers became critical in addressing
our sets of activities.
At its base: If the celebration was primarily a cam-
pus-focused event, July is not a great time. Most of the
campus is gone for the summer. Our university has
been celebrating its 150th anniversary since fall 2018,
and there have been many campus events, culminating
in an astronaut reunion set for this October (see ac-
companying article on Page 33). However, the Apollo
missions are milestones, historic national and inter-
national events that happen to have a unique Purdue
twist. You dont have to be a Purdue student or faculty
or alumnus to be part of this grand arc, and the content
A mission’s hierarchy
Command data flows for Apollo Command Module, from the Apollo
Management System.
A teamwork of systems
The various individual systems used in planning the Apollo 11 mission
during prelaunch, launch, orbit and re-entry.
32 ISE Magazine | www.iise.org/ISEmagazine
Apollo 11 at 50: Lessons from humanity’s greatest engineering feat
we are creating and sharing with the public
(including from NASA) is not just for our past
but for inspiring current and future innova-
tions (and innovators) in the STEM (science,
technology, engineering and math) fields.
In this context, the “Apollo 11 + 50” mis-
sion goal becomes one of highlighting a va-
riety of contributions to the national space-
ight and STEM innovation experiences.
Armstrong himself said, “400,000 people
went to the moon,” as both a description of
the magnitude of the effort and a concerted
attempt to highlight how Apollo is not just
one or two people.
We create a celebration that speaks to the
history, and also importantly to the future, of
human aerospace exploration. It’s glorious to
have Armstrong as a Purdue alumnus, as well
as Gene Cernan, who saw the surface of the
moon in Apollo 10 before being the last astro-
naut to leave footprints with Apollo 17. These
are only two of two dozen astronauts to note,
not to mention our legacy of contractors, engineers, techni-
cians, mission controllers and flight directors (several of whom
will be part of the events we need to manage). The next time
we go to the moon, and the first mission to Mars, will build on
the critical science work done in our departments and schools.
Managing the team, to me, means enabling these require-
ments and goals – not for my benefit, but for the thousands
who have contributed, the thousands who visit and the thou-
sands who arent even here yet but will be inspired in the fu-
“Change Control” (Section As a systems en-
gineer, I have a complex and bimodal response to uncertainty
and change. On the one hand, I enjoy teaching elements of
probability and statistics to help students and professionals un-
derstand distributions, local and deep uncertainty of estimates,
and even the boundaries of “appropriate precision” based on
appreciation of our limits of understanding.
However, I hate not knowing. Many of our challenges for
managing projects force us to confront that we dont know,
and we dont know when (or if) we will know. How about an
aircraft flyover? Can we get engineering alumni who worked
on Apollo 11? What happens if we change the schedule of the
archives’ open house?
These are all issues of change control – not change for the
sake of change, but because constraints prevent the original
idea from being executed, or because a new opportunity pres-
ents itself unexpectedly. Innovation and systems robustness
must embrace that conditions and environments and relation-
ships change. As the time gets shorter, the difficulty of manag-
ing change increases. Things that can be managed at T minus
150 days get much harder to accommodate at 50 days, or 15
days. Knowing what can be changed, and how, is a skill of
managing uncertainty.
Eventually, every practicing engineer must learn how to
manage uncertainty and recognize how to proactively prepare
for uncertain events in order to more effectively utilize re-
sources in advance of and in reactive response to both reason-
able and unexpected unknowns. At the center of this balance
for me is a simple rule to explain to people (but not at all
simple to live): Provide better information sooner. Dont wait
for perfect, dont wait until its convenient and certainly dont
hide it, hoping the problem goes away.
“Measurement of Effectiveness” (Section
Not surprisingly, the primary measure of effectiveness is ac-
complishment. That is the focus right now. The date is fixed,
and our performance is tied to that date. What are we plan-
ning, and how do we manage to enable those outcomes?
Since weather is a constraint, there are additional go/no-
go decisions to be made that morning, in order to maximize
health and safety of visitors during the day. There are addi-
tional effectiveness measures for the event as well, but these are
more difficult to quantify: satisfaction, education and inspira-
tion. Sometimes the most important measures of effectiveness
arent immediately evident, but the lessons of the project itself
will influence others in ways that we can only imagine – like
the Apollo program itself.
“System Engineering Support” (Section 1.5.3). “A
continuing effort is placed upon product improvement and
conguration management to ensure that the reliability re-
quirement of mission support are exceeded” (Pages 1-27).
Blueprint for America’s space pioneers
The Project Mercury documentation, signed by some of those who “wrote the book.”
Credit: Courtesy of Barrett S. Caldwell
July 2019 | ISE Magazine 33
A final word, and a note of thanks. While
we talk about system engineering support in
various congurations, there is a hidden debt
we owe. In order to recognize and improve
performance, we need to document our past
work, including our failures and painful les-
sons. In essence, the critical skill of mission
support is to turn operational experience into
available and usable reference material.
The success of Apollo did not start with
Apollo. The critical subsystems and capabili-
ties for Apollo 11, with the exception of actu-
ally landing on the surface of the moon, were
developed and tested during the Mercury and
Gemini programs. Long before I knew that
I would get to lead the Apollo 11 50th anni-
versary celebration, I made the acquaintance
of engineers who were deeply involved in
the development of the Mercury and Gemini
spacecraft (see Figure 5), and worked side by
side with the astronauts (including Grissom,
Armstrong and Cernan) during those criti-
cal development missions. They began before
there was a NASA, and before we knew how
to fulll the promise realized on July 20, 1969.
I stand in continued awe of their work, and
in appreciation that I have been able to learn
just a bit more about their experience, difcul-
ties and insights. They may not have recog-
nized the historic impact of their operational
experience until later, and they certainly have
not met nor received the thanks from all those
who have been impacted and inspired by their
But I am grateful that their work allows me
to describe to others the capabilities and di-
versity and scope of systems engineering, and
how it taught a young boy to make connec-
tions and dream of exploration.
Barrett S. Caldwell, Ph.D., is a professor in the
School of Industrial Engineering at Purdue Univer-
sity in West Lafayette, Indiana. He is director of the
Indiana Space Grant Consortium and a member of
the “Apollo 11+50” Mission Team. He was invited
to participate in “The Apollo Dialogues Workshop
earlier this year at the National Air & Space Mu-
seum, Washington, D.C., to help commemorate
this month’s Apollo 11 50th anniversary. He is
a member of IISE. Read more about Caldwell in
ISE magazine’s “Whats Your Story,” May 2019:
A summer of celebration for Apollo 11
Whether you were around to witness the giddy excitement of man’s first steps on
the moon or are first experiencing it a half century later, there are numerous ways to
celebrate humanity’s greatest engineering adventure. Numerous celebrations are on
tap to mark the 50th anniversary of the July 20, 1969, Apollo 11 lunar landing. Those
who can’t attend an event in person can relive the experience through TV, movies
and books. Here’s a short list of what is offered in the coming weeks; for more, visit
The Smithsonian National Air and Space Museum, July 19, Washington,
D.C. “Discover the Moon Day,” 3D tour of the moon, interactive displays, restored
version of Neil Armstrong’s iconic spacesuit worn for the first moonwalk.
Johnson Space Center, July 16-24, Houston, Texas. Behind-the-scenes NASA
Tram Tours to astronaut training facilities, panel discussions and Apollo 11-themed
science labs for kids.
Apollo/Saturn V Center at Kennedy Space Center, July 15-16, Merritt
Island, Florida. Interactive exhibits and re-enactment of Apollo 11 launch sequence
in real time.
U.S. Space and Rocket Center, through Dec. 31, Huntsville, Alabama. “Apollo:
When We Went to the Moon” exhibit includes artifacts and memorabilia, astronaut
Purdue University. Mission Week Schedule. July 18, Guest lecture “Go/No Go”
by Gene Kranz (sold out); July 19-20, “Apollo in the Archives” selections from
the Neil A. Armstrong Papers Open House, Purdue Libraries Special Collections;
viewing of “Armstrong” documentary movie; author panel and book signing; Purdue
spaceflight biographies; K-12 STEM activities; Purdue alumni panels representing
past, present and future NASA flight directors and Apollo 11 engineers and
technicians panel. For more, visit https://link.iise.org/PurdueApollo11.
The Museum of Flight, through Sept. 2, Seattle, Washington. “Destination Moon:
The Apollo 11 Mission” traveling exhibit by the Smithsonian Institution with artifacts
including lunar module and the rocket engines. Three-day festival beginning July 20
features a Lunar Block Party.
The Metropolitan Museum of Art, July 3-Sept. 22, New York City. “Apollo’s
Muse: The Moon in the Age of Photography” includes more than 170 photographs
plus prints, paintings, films, astronomical instruments and cameras used by
Museum of the Moon, touring exhibition replicates the moon on a 23-foot
sphere. Includes stops around Europe and the U.S.; for tour dates, visit https://my-
National Gallery of Art, July 14-Jan. 5, 2020, Washington, D.C. “By the Light of
the Moon: A Century of Lunar Photographs to Apollo 11,” nearly 50 photographs
from unmanned missions that precluded Apollo 11.
Summer Moon Festival, July 12-21, Wapakoneta, Ohio. Neil Armstrong’s
hometown celebration includes hot air balloon rally, parade, model rocket launches,
a 1960s-themed dinner at the Armstrong family’s church, concert, plane tours and
the world’s largest MoonPie.