hallo its scott manley here many of you
have gone to see the Apollo 11
documentary and man if you have agreed
with my assessment it is very much worth
seeing but also some of you have had
some questions and there's one
particular question which I did not know
the answer to and I was equally
perplexed when I saw the footage so what
did it this shows is the lighting of the
third stage of the Saturn 5 that is this
s4b
upper stage which is a hundred-plus tun
hydrogen oxygen stage propelled by a
single j2 engine this gets the
spacecraft into its initial parking
orbit and then after a couple of orbits
they reel it it and that would carry the
spacecraft all the way up into
translunar injection it was a very short
clip and I thought it might have been
shot from the ground but that wouldn't
have been possible with Apollo 11
because the engine was relit in the dark
side of the earth and so we wouldn't
have seen that but the movie had been
quite happy borrowing some footage from
other missions most notably this stage
separations were from engineering
cameras which were not carried on Apollo
11 in fact this very famous shot isn't
even from a Saturn 5 is from a Saturn 1b
you can tell because the interstage
isn't tapered and because it has three
stage separation Rockets before the main
j2 engine lights up the Saturn 5 version
used a different configuration because
they needed to be able to relight the
engine later anyway it's kind of cool
that these images they come from a film
camera that was located inside there and
it was designed to be ejected and
recovered later if you skip to the end
of this segment then you get to see the
camera starting to leave the interstage
just as it's film runs out so the
cameras would then parachute back into
the ocean and be recovered although I
believe in one case they parachuted into
the middle of a storm and it would be
something like a month before they were
recovered after afterwards but coming
back to the footage of that upper stage
relighting it
turns out that this is from apollo name
so apollo name was gonna be the first
major test of the lunar module it was
gonna fly around in low-earth orbit and
for that they needed to have the fuel
saturn v to launch the payload into
orbit so after they got into low-earth
orbit the crew did the regular
transposition docking and extraction of
the lunar module for testing this would
actually be the only time this manoeuvre
was performed in low-earth orbit because
and all the other missions this would be
done after they had performed the
translunar injection and were already on
their way to the moon because they
hadn't made that burn to send them on a
course towards the moon the upper stage
still had a lot of propellant left
inside it and of course they're gonna be
doing all sorts of experimental
operations in the command module and the
lunar module so it's not a good idea to
have 50 tons of fuel and oxidizer
sitting around in in well somewhere that
could just explode so the decision or
the design of the mission was that they
would relight the engine to test it and
send it off further away from the
spacecraft so that they can actually
test in peace without worrying about
something that might say explored if
they looked at at the wrong way and so
the crew of Apollo nine were able to
document this both in photographs and in
a film
showing the engine relighting and
sending the spacecraft off into a
distant orbit it's also worth noting
that that footage was taken when the
spacecraft was pretty much sitting
behind the engine and you may think that
sounds pretty scary because you got a
rocket engine facing towards you but
there was something like five hundred to
a thousand feet away and that was way
safer than being in front of it or to
the sides of it say if it were to
explode that would be the most likely
place debris would go anyway while the
crew were readying themselves the next
part of the mission the upper stage
would actually perform a second burn
later in this orbit which would take it
up to escape velocity and into
heliocentric orbit they actually had a
problem with the engine possibly and it
was not really clear but the thrust
dropped and the spacecraft did actually
complete its entire
burn this would have been very courier
this could have been critical if it
happens during a crewed mission to the
moon but in this case the spacecraft or
the upper stage was just heading off
beyond Earth's sphere of influence and
it's in a heliocentric orbit as of today
Apollo 9 would also be the first proper
test of the Apollo spacesuit with the
onboard life support previously every
spacewalk in had been done used an
umbilical connected to the spacecraft's
life-support but this was the first one
with a backpack that was all
self-contained and it would be the first
time they tested it really before going
to the moon one of the astronauts
performing this Eevee a is rusty
Schweickart who is one of the founders
of the b612 foundation of course we I'm
a big fan of as it would turn out this
would be his only spaceflight he was
also the pilot of the lunar module here
and on that they would take it out and
they pretty much went for a joyride
traveling out 100 miles away from the
command module before coming back and
demonstrating that the spacecraft was
controllable anyway yeah I wanted to
talk a bit more about the s4b
upper stage that was the designation of
for the upper stage of the Saturn 5 and
for the Saturn 1b the original s4 was
actually a slightly different design
that was used on the Saturn one launches
it had instead of a single j2 engine it
had a cluster of six rl10 engines the
reason for this cluster of engines was
because the Saturn one was Canada felt
very early before the new JFK gave his
whole let's go to the moon speech it was
built out of the stuff they had laying
around the main tank instead of
developing a new bigger tank they took 8
redstone missile tanks and strung those
around the outside and then they had
another tank in the middle they had
eight h1 Rockets and then the upper
stage of course as I said they have six
rl10 engines on it this was what they
could find to make a big heavy lift
rocket and it was used early on in the
Apollo program to you know to basically
test
stuff but by the time they were ready to
put people on top of this it had evolved
into their Saturn 1b and the upper stage
was of course this s4b
it was would be practically the same
upper stage that was used on the Saturn
5 so look while it wasn't as sexy as the
space capsules of the lunar landers it
did launch more as part of the Apollo
program and it was a critical part the
guidance for the entire Saturn 5 was in
the top of this stage when Apollo 12 was
hit by lightning and the command module
lost all its instrumentation the IMU on
the upper stage kept running it kept the
mission under control until the crew
could find the SCE
and switch it to aux so I think it's
kind of cool there are some of these
things still floating around in deep
space
you know like monuments to the Apollo
program it wasn't just apollo names
upper stage that could boost it into a
heliocentric orbit it was all from
apollo 8 through 12 that were boosted
out this way and missed the moon but
they're not all lost in the depths of
space in 2002 astronomer Bill Young
found what looked like an asteroid
orbiting the earth when a spectroscopy
was applied to it the colors were
consistent with the white titanium
dioxide paint that was used on those
upper stages so it was look they trace
the orbit back and they discovered that
back in 1971 it had been kicked out of
its a loosely bound orbit into deep
space and then spent a bit 31 years
orbiting the Sun before it returned
close enough to the earth and had an
interaction with the moon allowed the
spacecraft or the debris to be captured
in a bound orbit for a few years in 2003
it was kicked back off into deep space
again and it may return in about 2040 or
there abouts most people believe this
was from Apollo 12 which is
coincidentally the last time a stage
ended up going into deep space from
Apollo 13 onwards they started crashing
them into the moon to collect more
science most of the Apollo missions
included surface science packages which
had seismometers
the one on Apollo 11 failed after 21
days but the one on Apollo 12 it kept
going and so from Apollo 13 onward they
were smashing those stages into the moon
to make seismic waves that would enable
them to collect more data about the the
lunar interior also these servers really
nice examples to people they like to
tell me that craters on the moon aren't
created when things hit the moon at very
high speeds there is one case of an s4 B
which didn't make it to space before
getting destroyed it decided to blow up
on the test stand which was well rather
dramatic unfortunately we didn't have
any good camera recordings off it but
perhaps the most storied s4b
upper stage was the last one launched on
a saturn v it has undergone a bit of
conversion instead of carrying a large
hydrogen tank and an oxygen tank they
had cleared out all that space and
decided to put crew quarters a shower
solar panels they had turned it into
Skylab so you can see what was the
hydrogen tank became the main
accommodation area the oxygen tank was
actually used for storing garbage the
Skylab never really dumped any of its
garbage
during its time in fact it still had a
bunch of supplies left when it was
finished the because it was so much
larger than the International Space
Station you're able to see these crazy
acrobatics that are just not possible in
the space station these days because it
had to fit into a much smaller area but
of course skylabs life turned out to be
a bit more limited than originally
planned the space shuttle was never
developed in time to enable it to be
reboosted and eventually it fell back to
earth scattering debris over the
Australian outback
I'm Scott Manley fly safe
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