We all know and love the Saturn V
rocket... but what if it was bigger and
better? Today on Vintage Space!
Building the Saturn V rocket was no small feat;
individual pieces were constructed
around the country and then all shipped
to the Kennedy Space Flight Center in
Florida where they could be mated,
checked out, and then launched on a
mission to the Moon. By the late 1960s
there was already so much industry and
infrastructure built up around the
production of this vehicle that it made
a lot of sense to actually continue the
Saturn V program to build derivatives
that could not only launch human
missions to the Moon but into deep space,
and even take unmanned missions to
different planets. So what might some of
these Saturn V derivatives have looked
like? Well, there was one study done by
two engineers at the Marshall Spaceflight
Center in 1968 that gives at
least one window into the future that we
might have had had we continued the
Saturn V program. The idea was that by
using all of the facilities already in
place and all the infrastructure around
the Saturn V rocket, it would actually
be cheaper to build these larger
derivative rockets then come up with a
whole new space launch system. So they
looked specifically at vehicle
derivatives that would use what they
call a "common core," basically a core
stage of the rocket that could have
additional pieces added to it or taken
away depending on a mission's needs such
that the Saturn V would become a very
modular, multi-purpose vehicle, something
that could put payloads into low-earth
orbit between 50,000 pounds and 500,000
pounds. The first derivative
they look at is not a derivative at all --
it's the core Saturn five that we know
and love, only take the Lunar Module out
of the adapter and put in a different
payload. Using the volume of the LM's
shroud for a different payload, the
Saturn V could launch interplanetary
missions. There was even a different
study done by Bellcomm around the same
time in the late 1960s that looked at
replacing the lunar module with an
Environment Module for manned flybys of
Venus and Mars... albeit this was only a
concept study as well. So the Saturn V
derivative family was meant to address
two major issues with the existing
Saturn V family, which is basically the
Saturn I, the Saturn IB, and the Saturn
V. The first is the massive
discrepancy in lift capability
between the Saturn IB and the Saturn V.
Smaller derivatives of the Saturn V
could fill that gap, lifting
payloads into orbit that were somewhere
between the lift capabilities of these
two rockets. The second short coming of
the Saturn V program as it existed was
not really a short coming so much as the
derivatives would be used to look ahead
at what the authors say was the
inevitable expansion of human
exploration deep into the solar system...
and that means heavier payloads. The
second discrepancy isn't really a
discrepancy at all; the authors are
simply looking ahead and realizing that
Saturn V derivatives could help push and
be the muscle behind the inevitable
expansion of humans into deep space with
both robotic and manned missions. So here
is the family of Saturn V derivatives as
they are imagined in this study. Let's
start at the beginning with the "A"
Derivative. The "A" Aerivative of the
Saturn V is very similar to the Saturn IB
in that it uses the S-IC stage as the
first stage and then the S-IVB as the
upper stage, the second stage. It
basically takes out the S-II stage of the
Saturn V. But it's not just a Saturn IB.
The Saturn V "A" Derivative is able to
be customized depending on a mission.
Basically this rocket could be tailored
by only installing the number of F-1
engines that were needed for a specific
mission or a specific payload.
Additionally, the propellent loading in
that first stage could be adjusted to
achieve the needed thrust-to-weight
ratio for that specific mission. So say
you're launching a payload that's
between the lift capabilities of the
Saturn IB and the Saturn V. You could
put three F-1 engines on your Saturn V-A
Derivative and have that perfect launch
vehicle for that mission. And all of
these customizations were meant to be
reversible, so if you start building a
Saturn V-A with three F-1 engines in
that first stage then your payload gets
bigger, you'd be able to very easily add
two more F-1 engines to make it a Saturn V!
The Saturn V "B" Derivative was also
called the S-ID. It used a slightly
different core stage and this is a very
interesting version this is a one-and-a-half
stage... basically a single stage to
orbit version of the Saturn V rocket. The first stage was the same S-IC as the
Saturn V used but with only one
engine, the center F-1 engine. A half stage
would be added to
that center stage with four more engines
on it. This would effectively separate
the inboard engine from the four
outboard engines and their supporting
structure. So at the moment of launch all
five engines would fire at the same time.
At the moment of staging, the four
outboard engines on their own separate
stage structure would fall away and that
one central F-1 engine in the core stage
would continue firing until the payload
had reached orbit. Of course to make this
happen, that single F-1 engine would have
to have extended operations compared to
traditional F-1 engine on a Saturn V. It
would have to fire for 192 seconds
longer than a standard S-IC stage, and if
that SI-C stage were elongated to
take a larger payload, that central
engine would have to fire for an
additional 217
seconds. But because it was designed with
this one stage that would fall away
fairly early on in the flight, it was
conceivable that this half stage could
be recovered and reused making this a
more cost-effective version of the
rocket. The Saturn V "C" Derivative as the
authors envisioned it would use the same
stage and a half to orbit version of the
Saturn V but with an added S-IVB on
top. So you've got a one-and-a-half stage
plus the upper stage. It would also be a
more modular rocket. The first stage in
this setup would have either three or
five F-1 engines with that center engine
reprising its role as the sustainer
stage once the outboard engines and
their structure fell away. The S-IVB could
have minor adaptations depending on a
specific mission. So those are all
slightly smaller or slightly larger
versions of the Saturn V. With the
"D" Derivatives we get into much larger
versions and it starts to get kind of
fun. The idea with the "D" Derivatives was
to significantly increase the payload
capacity of the Saturn V. The core
stage would be the same 33-foot diameter
of the standard Saturn V but it would be
extended, not within reasonable limits of
the rocket's capability but within the
constraints of the launch facility. The
idea was to extend this vehicle in size,
not within the confines of what it was
needed for a mission but within the
confines of the Vehicle Assembly
Building and the existing launch
facilities at Kennedy. Remember the whole
point of the Saturn V derivatives was
to make better use of all the
infrastructure around the Saturn V
program. Other versions of the "D"
variation also called for the addition
of two or four
external solid rocket motors
strapped to the sides, very much like the
Space Shuttle used. The added weight of
this hardware and fuel could be offset
by increasing the propellant capacity of
the main central stage and upgrading the
liquid engines could add more power
making these rocket variations capable
of carrying even more mass into orbit. At
its largest, "D" variations of the Saturn V
would stand 410 feet tall... that was
basically the height limit imposed by
the VAB. And from there the rocket could
just keep growing with bigger stages or
more external boosters... basically really
helping us expand ourselves out into
space. The study's authors said that all
of these derivatives should be studied
and worked on at the same time. This
would keep production costs down,
ultimately lowering the overall cost of
the Saturn V. But depending on how
many flights a year it was still an
economical decision to extend the
program rather than scrap it for
something new... but as we know this did
not happen. The final Saturn V flew in
1973 with a lunch of Skylab. So what do
you guys think of this unrealized future
of an extended Saturn V program? Let me
know which derivative is your favorite
down the comments below and of course, if
you have other questions or comments on
the Saturn V rocket and the program
as a whole. Be sure to follow me on
Twitter and on Instagram for daily
Vintage Space-ish content, and with new
videos going up right here every single
week be sure to subscribe so you never
miss an episode!   :)
