Hi, it's me, Tim Dodd, the Everyday
Astronaut. If you're anything like me, maybe you've heard all about different
rocket engines that have come from the Soviet Union with very similar names. And you get really confused about which
ones, which, and which engines go on, what rocket and which ones changed and
evolved into something else. I mean, they all sound pretty much the exact same
and changing just one small number can lead you on a completely different route. It's honestly really
hard to keep track of. So today we're going to actually try
and straighten out the confusing family tree of the Soviet rocket engines by
drawing out what might be the most comprehensive chart of almost every single
engine that has ever flown to orbit. Now, although we'll really only be focusing
on chemical rocket engines that were on rockets and not really even
getting into spacecraft engines, we will be walking you through some
incredible stories and fun anecdotes behind these engines because boy, oh boy, are there some crazy stories. After all, these are still some of the most powerful, the most advanced and downright ridiculous
engine concepts that have ever been developed. So open wide, my friends you're about to be drinking
from a fire hose of information. What took me over two years
to learn and research. You're about to try and
digest in just one sitting. So get your notepads
ready and hold on tight. Let's get started. Okay. Right up front I just need to point out
that we could only do this massive video thanks to my awesome supporters. If it weren't for the support of
my Patrons and YouTube members, I wouldn't be pursuing such
in-depth and hard to make videos. So if you like the work
that you see in this video, maybe consider becoming a Patreon member
at Patreon.com/everyday astronaut, or become a YouTube member
by clicking down below, or maybe get yourself
one of our awesome new, R-7 shirts that we made
just for this video, as well as these awesome RD-171 shirts
that after you watch this video, you'll probably think this is one
of the coolest engines ever made. And best of all, we made posters
of our incredible family tree. You can get all of this and more at
everydayastronaut.com/shop. Okay. Like always since this
is a long, long video, here's the timestamps for each section.
There's links in the description too. The YouTube play bar is
broken up into these sections. And we have an article version of this
video with sources and links as one mega reference for you everydayastronaut.com. [ Soviet National Anthem]. There's a few notes and tricks
that we need to talk about. That will be very helpful.
No, I take, I take it back. Actually they're downright necessary. So
in order to best understand this video, you might not want to skip this section,
but do it at your own risk. First note, the aerospace community
tends to say Russian engines. And although that's
actually mostly correct, as far as the origination
of the physical units built, most engines we'll talk about are
technically Soviet meaning former Soviet Union. By calling them Soviet engines
where applicable it also
helps give credit to the scientists and engineers from
now former Soviet republics, who weren't Russian we'll be talking a
lot about open cycle engines and closed cycle engines. As those of you who have watched my video
about SpaceX's Raptor engine may know the difference between these two cycle
types is what happens with the exhaust gas that spins the turbine that
powers the propellant pumps. Open cycle engines simply dump the
exhaust gases from the gas generator overboard, which is generally simpler, but less efficient close cycle or
stage combustion cycle engines. Don't really have a gas generator. Instead it's considered a preburner and
runs either all of the fuel or all of the oxidizer through the turbine. And then it routes that now hot gas
into the main combustion chamber. So no propellant is wasted. On our chart, the border around each engine will tell
you whether it's open cycle or closed. Open cycle engines, won't have a border around them while
closed cycle engines will have a solid white border around them. Another thing we're going to be
talking about a lot is fuel types. Hypergolic propellants are those that
will spontaneously combust when they come in contact with each other, which makes for a very simple and
reliable ignition sequence. They're also, storable at room temperature
for years and years, but are extremely toxic
and corrosive. Meanwhile, liquid oxygen or LOx based fuels
often go by a shortened name. There's T-1 and RG-1 or
in the U S we use RP-1, which are kerosene based fuels
that are often called Kerolox. Then there's hydrogen or Hyrolox
and there's methane or Methalox. But notice we said T-1 and RG-1
for Kerolox and not just RP-1. This is a very important
and fun little note. T-1 is similar to aircraft
kerosene that's right. Some of these rockets pretty much
just run on regular old jet fuels, similar to our Jet A that powers our
airliners while newer rockets use RG-1, which is also called naphthyl. The hardest part about LOx
based propellant is keeping
everything at working temperatures. So not having the cryogenic propellant
warm-up and boil off before we need to use them. Our chart will show Kerolox
engines in red alcohol engines in teal hydrolox in blue and
hypergolic engines in some shade of orange or yellow, the shade of orange will vary depending
on what exact combination of propellant they are. We'll talk about
specific impulse, a decent amount, which is how efficient a rocket engine is. Specific impulse is abbreviated
as ISP and is measured in seconds. The higher, the number, the better kind of like the gas
or fuel efficiency of a car. We'll be quoting engine specs in vacuum
and or sea level if they were used at sea level. And with thrust
measured in kilonewtons. You'll hear us talk about combustion
instability quite a bit. In this video. The combustion chamber of a rocket
engine is where the fuel and oxidizer get pumped in and meet at high pressures
so they can combust and produce thrust. The larger you make the combustion chamber
and the higher your thrust output is the harder it generally is to
maintain stable combustion. You can have large pockets
of sudden pressure changes, and those can completely
destroy the engine. Another thing you're going to
hear me say a good amount is OKB. OKB stands for this. I'm
not even going to try, which translates to
experimental design bureau. Now these were state owned design bureaus, mostly dealing with weapons and jets
and advanced military technology. Despite them being state owned, they were super competitive with each
other and often had strong figureheads who were competing for projects against
each other. Now for the naming, I just honestly really wish there was
an easy set of rules with the naming convention that I could teach you, but there really isn't as much
of an order as you might crave, but you will notice us mostly talking
about RD series of engines and NK series of engines. RD literally
translates to rocket engine. And you'll see us talk about RD
zero XXX series engines RD one XX and RD 2 XX engines quite a bit, but the names primarily stem from
which OKB the engines come from. The majority of engines we're
going to talk about came from, OKB. 456, home of legendary propulsion
engineer Valentine Glushko. OKB-456 engines will almost
always be an RD One XX or an RD 2 XX. RD one XX are engines that
use LOx as their oxidizer. So kerlox, metholox and hydrolox. While RD 2 X X means the engines
run on hypergolic propellants. Then there's OKB 154 led by Semyon Kosberg who
developed RD zero XXX series engines. They tended to focus on upper stage
engines or at least engines that primarily operated in a vacuum. But of
course, that isn't always true. There are a few exceptions. We'll
also talk about engines from, OKB 276 led by Nikolay Kuznetsov, which are NK XX series engines. Yes. N K are just his initials. OKB-276 was primarily an aircraft
engine manufacturer who wound up making some of the most advanced engines. So for example, it could be confusing that the NK 32
engine was a jet engine used on the TU 160 strategic bomber. And then the NK 33 is a rocket engine
meant for a variant of the N1 moon rocket. OKB-1, the headquarters of the Soviet space
program was led by chief engineer Sergei Korolev. You'll actually see very few
engines come from, OKB-1 on our charts, but most of them are just RD XX engines, but then there's OKB-2 led by Aleksei
Isaev who made some engines that are S5.XX, But really mostly just made smaller
missile engines that we won't be talking about. Next. We won't be talking
about many of these at all, either, but there was OKB 165
led by Arkhip Lyulka. That was also primarily an aircraft
engine manufacturer would also make a couple RD XX engines that
were also meant for the N1, but these were advanced
hydrolox engines. Lastly, there was OKB 586 led by
Mikhail Yangel who developed RD 8XX engines that are often
either steering engines or occasionally main engines. We won't see it on the chart that often
because the steering engines are usually accompanying main engines, but they were a pretty influential
design bureau based in Ukraine. But at the end of the day, the naming schemes tend to
follow internal technology, commonalities like injectors or turbines, and they might have no rhyme or reason
on the outside or to the average person other than which design bureau made them. But I hope this helps to just kind of
keep in the back of your head throughout this video, but just in case you want
to make things 10 times more confusing, there's also a number or index for almost
every engine called the GRAU index. For instance, the RD 268 has
a ground number of 15D168, while the RD 270 has a GRAU of 8D420, but that's all just way too confusing. So just scratch it from your memory
because we're not going to use it in this video at all, but it is a fun,
albeit confusing little fact. And lastly, we're going to be drawing
lines between the engines on our chart. Following a white line with an arrow
will mean you're going to the next evolution and, or there's a common
link between the two engines, a greenish yellowish line just means
it's literally the same rocket engine, but it's on our chart more than once
because it's used on multiple rockets. In general, going from left to right is getting
newer and newer with the oldest rocket engines on the left and the
newest engines on the right, but it's not really exact overall. So
just think of it kind of more generally. If the engine flew on an orbital rocket, you'll see the rocket name on top
or underneath the engine or engines. So a stack of engines would be their
stages with the first stages on the bottom and the upper stages on the top. We've also put these rocket engines into
their respective families in a gray box outline. Okay, these are the terms and tips you should
be familiar with in order to make best sense of this already confusing
topic that's going to ensue, trying to untangle the Soviet
rocket engine family tree. Let's start off with a little important
history lesson of early pre orbital rocket engines. Not only because
there's some fascinating history here, but it also sets the stage for some
key players and it all stems from one important moment,
WW II, coming to an end. After all most modern rocket
technologies stem from WWII, with the Nazi designed V2, rocket.
Rockets were a terrifying weapon, a way to deliver warheads vast
distances in a real hurry, no need to fly planes over enemy
territory. Rockets were quick, hard to detect and virtually
impossible to shoot down. The A4 engine at the
heart of the V2 rocket. Wasn't the first liquid fueled
rocket engine developed, but it was certainly the first one
to be reliable enough to become the heart of a formidable weapon and become
the first system capable of reaching space by crossing the Karman line. The Germans had solved one of liquid
fueled rockets, biggest problems, combustion instability, the German solution to making an engine
more powerful wasn't just to scale up the engine, but it was to take smaller injectors
that they knew worked well and put multiples of them into a
single main combustion chamber. The A4 wound up with 18
injector cups in this super weird basket head configuration. This is where it all started, and it's our first benchmark that we
can compare other engines against. It would accomplish 265 kilonewtons of
thrust at sea level and 294 kilonewtons in a vacuum with just over 200 seconds
of specific impulse at sea level and 239 seconds in a vacuum.
Although these numbers, aren't impressive by today's
standards. This was just the beginning. The engine was only running
at 15 bar of pressure. The pumps of these engines were
powered by a separate system, basically steam powered. They would run a hydrogen peroxide over
a potassium permanganate catalyst to create high pressure steam, which would spin the turbine
that would then power the pumps. So fast-forward to the end of WW II and
the start of the Cold War and both the United States and the Soviet Union were
working to outdo each other with more powerful and longer range missiles capable
of delivering warheads to the enemy territories in a hurry. The U S and the Soviet Union
gathered thousands of former German, rocket scientists. Most of whom were members of the Nazi
party to help develop their own rockets. In the United States, Werner Von Braun, a former German who the U S snatched
up post-war helped lead this effort, but in the Soviet Union, it
was Ukrainian born Sergei Korolev, who was tasked with leading the former
German scientists Korolev and his team of Soviet and former German engineers
and scientists went about reverse engineering, the V2 rocket, and the A4 engine that powered it
and began basically rebuilding it. These engine remakes
were dubbed the RD 100, and they were nearly a clone of the
A4, at least externally. In fact, some of the parts were
being machined in Germany, still from the old factories at the same
time Korolev and propulsion engineer Valentine Glushko started making
a modified version of the RD 100, that would have no German
scientists direct involvement. And it was using only
Soviet fabricated parts. It was called the RD-101. The RD-101 would have very minor tweaks
and take inspiration from some of Glushko's former works such as his
RD-1. For a little bit of time, the RD 100 and the RD 101
were both studied tweaked and prodded and upgraded, but it was pretty quickly realized
that the RD 101 path could be upgraded quicker. By the end of 1949, there would be an RD 102 and RD 103
upgrades that would see substantially shortened engine thrust frames, but they also did a few other tweaks
allowing for a more concentrated ethyl alcohol fuel. But they did end up basically doubling
the thrust output of the original A4 by reaching 500 kilonewtons
of thrust in a vacuum. So the RD 103 was pretty impressive. But it was still time
to go bigger, better, and more powerful cause a war around this same time Korolev was
given his own experimental bureau. OKB-1 known today as RSC Energia. This would be where the future of the
Soviet space program would be developed. The German scientists who were working
in the Soviet Union were revisiting some old German research and began to play
around with simple new chamber shapes and injector concepts based on some old
tests and ideas up to this point, all of these engines we've talked
about still had that weird basket head designed with 18 separate injector cups, but there was a design that was
patented in Germany that was more of a showerhead design for the injector. Now they originally just wanted to
test the injectors in a very simple cylindrical chamber instead of putting
multiple injectors into a complex basket head, and then firing the whole engine. They built just this little test bed
for the injector and made a new style of engine called Lilliput or the
KS 50 that had pure copper walls that were only about one millimeter
thick that could handle higher combustion chamber temperatures with
greater thermal conductivity, making it easier to keep cooled. It wound up being one of the first
engines capable of running on kerosene, which would potentially offer much
greater performance with the negative side effect of much higher temperatures. It was the last engines that the German
engineers got to work on directly. The lessons learned from the
KS 50 Lilliput would come
in handy when Glushko was trying to create a massive new engine
with almost 1200 kilonewtons of thrust at sea level, about five
times the thrust of the original A4, it was called the RD 110, and would have been used on a radical
new R 3 rocket that would have lacked any exterior aerodynamic fins for stability. And it was to rely on gimbling the
engine to steer and control the rocket. The plan for the RD 110 was to have
18 injectors in that same basket head configuration each with about 70
kilonewtons of thrust in order to reach the intended thrust levels. But in order
to develop 70 kilonewton injectors, they would put them in a, another
experimental combustion chamber. They called the ED-140, which was kind of similar to the KS 50
as they tested the ED-140 the engine wound up being very reliable, capable of running continuously
and had very consistent startups. When all of a sudden done the RD 110
never actually was even test fired, likely due to concerns over cooling, but the ED-140's DNA would see the
light of day in another engine. In fact, this combustion chamber is still at the
heart of one of the most famous Soviet rockets ever. And it's still flying today. The Soyuz, which is part of the incredible
R-7 family of rockets. [MUSIC]. Oh, the R-7 one of my favorites. This is the first rocket to reach
orbit. We have to start here since, well, it kind of all started here and there's
been so many versions of this vehicle with so many different engines flown
on just this one, rocket family. The R-7 originally had a simple goal, be able to carry a three ton
warhead 8,000 kilometers, which yes, as you maybe could guess that makes it
capable of hitting mainland United States from the Soviet Union. In
order to accomplish this, the OKB-1 design bureau realized they
would need to develop a more powerful engine Valentin Glushkoo was tasked
with trying to scale up the ED-140 we had just talked about into
a new design called the RD 105, but he ran into some problems. As usual
when you're trying to increase thrust, scaling up the combustion chamber was
leading to combustion instability. So what if you took one large
chamber and split it up into four smaller chambers problem solved. I want to explain real quick what exactly
we mean by multiple chambers and why this isn't considered multiple engines. So instead of one large combustion
chamber where you pump in your fuel and oxidizer, you could make four smaller combustion
chambers that equal pretty much the same output. And these multiple chambers are
all fed by a common turbo pump. And the turbo pump is really
the heart of the engine. It's generally easier to scale up your
turbo pump machinery than it is to scale up the main combustion chamber due to
that combustion instability that we talked about earlier. So although this isn't necessarily more
mass efficient to have multiple chambers over one big one, it can reduce
complexity and combustion instability, but if you lose your turbo pump,
the entire engine is a goner. Now oddly Glushko made this realization
while working on another engine. But we'll talk about
that more in a second. You'll notice this concept of multiple
combustion chambers is a staple of many Soviet era designs, and will be a
reoccurring theme throughout this video. The engine they ended up developing
was called the RD 107 and its twin sibling, the RD 108 and believe it or not, they're pretty much still in
use today. The RD-107 and 108 are virtually identical. The only difference is the number of
steering nozzles known as vernier engines. The outer boosters with the
RD-107s only have a pair of vernier engines while the center core with
the RD 108 has four vernier engines. These engines first flew on May 15th, 1957 on the first R-7 rocket, which featured four strap-on
boosters surrounding a single core, all running on Kerolox. This allowed for a really simple ignition
process where all of the cores and all of the engines could be lit
on the ground simultaneously. And it didn't require the complication
of trying to start an engine mid flight. But my favorite thing about the ignition
process is that their solution to lighting all of the engines is basically
to put some giant wooden matches up inside the combustion
chambers. That's right, engineers stick giant wooden T-shaped
structures up the nozzle into the main combustion chamber
of all of the engines. So each of the 32 chambers
get their own matchstick. That's 20 for the main nozzles
and 12 for the vernier nozzles. On the tip of the giant matchstick. There's a pair of pyrotechnics that only
need one of them to light successfully. And once there's confirmation of
all 32 pyros firing they'll then flow the propellents into the main
combustion chamber for full ignition. And yes, they still use giant wooden
matchsticks to light the engines today. The staging is relatively simple. Where all four boosters
fall away simultaneously. And while they're falling away, a valve
pops open in the liquid oxygen tank, which helps propel the tanks away from
the core stage in a beautiful formation now known as the Korolev cross.
Some notes on these engines, the RD 107 and RD 108 have nearly
the same performance figures with the RD 107 being slightly better
optimized at sea level and the RD 108 being ever so slightly
more efficient in a vacuum, which makes sense since it operates
in a vacuum, more than the RD, 107. The RD-107 was the first
to hit that magic number of 1000 kilonewtons of thrust. These
are some pretty impressive numbers, huge improvements over
the early RD 100 engines. The turbo pump of the RD 107 and
RD-108 is essentially powered by steam. Just like the A4. Yup, they still just run hydrogen
peroxide over a catalyst, which creates high pressure searing
hot gases that then spins the turbine, which powers the liquid oxygen
pump and the kerosene pump. This also means that there's a fully
separate tank just to store the hydrogen peroxide, which although it's not mass efficient
to require another tank to spin your pumps. It is a very simple and effective
solution still in use today. Some cool innovations of this engine
include those multiple combustion chambers variable mixture ratios, which helped
each core drain its propellant equally. And it used regenerative cooling another
innovation where those vernier engines for steering, which was a lot more elegant solution
compared to the heavy graphite control veins that would help steer the
original V2 engine by just diverting the flame. Since it was first flown in 1957, the RD 107 / 108 has
gone through very little changes. There was the RD 117/118, which flew 786 times from 1973 to 2017 on the Soyuz U and U2. They are very similar to the original, mostly having some small structural
changes, different injectors, which offered minor performance increases
and had parts of slightly varying origins compared to the RD 107 and 108. The RD 117 / 118 also
sometimes ran on a fuel called synthin. It's a hydrocarbon based fuel,
which offered increased performance, but the fuel is much more expensive. So it's just often not really
considered worth it. Finally, we see the RD 107A/108A, which would fly 70 times
from 2001 through 2019 on the Soyuz FG. And they're
also on the new Soyuz 2, which started flying in
2004 and is still flying. The RD 107A and 108A offered
slightly higher thrust compared to the RD 107 and 108. Here's the 107 and the 107A side by side. You can see the A's had a modest bump
and thrust and a nice little bump in efficiency too. Here's an important note. If you're ever looking
up info on these rockets, the common staging scheme tends to be
that the side boosters are stage one, the core stage, which runs at the same time and is lit
simultaneously to the side boosters is considered stage two. Then on top of that is stage three
and sometimes there's even a 4th stage. In the U S we tend to say that the
core stage of a rocket is stage one. And if there's boosters that
also ignite with it at launch, they're either just simply called
boosters or sometimes stage zero and not to be confused with how SpaceX
calls their launch and landing pad at STARBASE stage zero, we'll be following
the Soviet naming scheme in this video. So that does it for the first
stages of the R-7 rocket family. But in order to increase capacity, the R-7 needed an upper
stage or a third stage. And the first upper stage they
develop had a mighty task at hand, reach the moon. The Soviet Union began developing
a missile called the 8K73 in 1957. For this Glushko developed
an engine called the RD 109, which would increase its specific
impulse to an impressive 334 seconds and produce 102 kilonewtons of thrust. It ran on LOx and unsymmetrical
dimethyl hydrazine also known as UDMH, which is an interesting combo since it
has the pains of both cryogenic liquid oxygen, plus the pains of
the terribly toxic hydrazine, which Korolev just hated. So it was scrapped and would never
actually see flight. Instead. It would be reborn on a, another rocket
that we'll talk about here in a second, the Vostok variant of the R-7 wound
up being the first R-7 rocket to have a third stage called Blok E, which made it much more capable. The engine that made this
possible was called the RD 0105, not to be confused with the RD 105, which was that failed attempt
at the original R-7 main engine. But the RD 0105 was based on
the Vernier engines on the RD 107/108, and it also ran on Kerolox. Glushko passed the torch off
to Kosberg to build the engine. It wound up developing 49 kilonewtons of
thrust in space and hit 316 seconds of specific impulse. Meanwhile, Glushko was busy upgrading the engine
for an even more impressive upper stage for a version of Vostok
called the Vostok K for this, he would take the RD 0105
and modify it to be the RD 0109. It also had a lower mass
and increased reliability, thanks to its new lightweight
combustion chamber. Now, these tweaks made it capable enough
to put Yuri Gagarin into orbit on April 12th, 1961. It always wows me that the first human
in space didn't just do some suborbital 20 minute flight, but instead he
actually went full blown orbital. The United States didn't accomplish
this feat until John Glenn's flight on Mercury / Atlas 6 onboard Friendship 7 on February 20th, 1962. A fun note about these upper stage engines
is they start their ignition sequence while they're still
attached to the core stage. Now this is called hot
fire staging, and boy, is it wild? Have you ever noticed that graded fence
looking section of the R-7 rocket that's the interstage and it's open like that
so they can start the engine while the two stages are still connected. This makes it so they didn't have to
utilize any other ullage motor or a secondary motor to accelerate the upper
stage to settle the propellents on the bottom of the tanks before
turning on the engine, which you need to do to
avoid sucking up gas bubbles, and having rough starts you'll notice
that truss work interstage on other Soviet rockets. It was a simple
solution to a tricky problem. So keep your eyes open for
that as we continue this video, but you may also know that the
United States did hot fire staging of their Titan rockets as well. So from here on out the third stage of
the R-7 got modest updates or changes, and each time it did, it basically became a different
engine with different numbers. So just in case you're not confused yet. Here's one that baffles me
after the RD 0105 and RD 0109. There was an RD 0106, which was a 4 chamber version and
offered over four times the thrust. This was used on the Blok I third stage
for an R-7 variant called the Molynia rocket that flew for
the first time in 1960. The RD 0106 would then be tweaked
a little to become the RD 0107 and then the RD 0108, which would fly 300 times on
the Voskhod R-7 from 1963 to 1976. And then the RD 0110, which saw its first
flight in 1965. And it's, what's still being used today on
the Soyuz 2.1 A that currently flies humans. So I wish I could say this was the final
version of the third stage engine for the R-7 family because
no, it's, it's, it's not, there's also the RD 0124, which is a pretty fancy closed
cycle engine intended to be used universally amongst several vehicles. It doesn't have any vernier engines
and it uses RG 1 a first for the sole use instead of the usual T1
kerosene. Because it's closed cycle, its specific impulse is
increased from 326 seconds to 359 seconds and is used for larger or higher energy payloads. It first started flying in 2006 and
is still in use today on the Soyuz 2.1 B. So that about does it for
the third stage of the R-7. However, it even ended up growing a 4th stage and
it would actually do that before Yuri made his famous flight. A fourth stage was flown way back
in 1960 on that Molniya rocket. So it was actually on a really early
variant of the R-7 that would fly 40 times over all with a 50%
success rate, but coolest of all, it was high enough performance
for interplanetary missions. And here ladies and gentlemen is where
the Soviet Union did something that the U S engineers literally thought was
impossible until they got their hands on Soviet rocket engines in
the 90s. Already in 1958, they began developing a closed
cycle oxygen rich engine called the S1.5400. It may have initially only
had 64 kilonewtons of thrust in a vacuum, but it achieved an impressive
338 seconds of specific impulse. It was way ahead of its
time for a Kerolox engine, and it would fly successfully
already in 1961 on an interplanetary mission to Venus. That was
the very interplanetary probe. The real breakthrough
was developing metals, such as titanium alloys that could
withstand having searing hot gaseous oxygen blasting at them without
just turning them into soup. This trend would continue and the
Soviet Union made it look really easy. Now I remember
this one, the S1.5400, because it kind of became the basis
of a ton of upcoming engines for other rockets, despite having very
limited presence on the R-7 family, having only flown four times in total, the Soyuz U was the next R-7 to have
a 4th stage that was powered by the S5.92 on the upper stage known as fregat, which first flew in 1973. This is a small open cycle hypergolic
fueled engine producing 19.6 kilonewtons of thrust with 327 seconds in a vacuum. One of its cool features is the ability
to light 50 times in space with up to 300 days between ignitions. Now, wouldn't it just be fantastic if I could
say this was it for the R-7 variants, but there's one bastard child in
the set and it's missing all of its boosters. Now we'll get to that
rocket and that engine in a second. But for now we're going to
go into confusion town as if it wasn't confusing already.
So hold onto your butts. [ MUSIC]. While the R-7 is easily. One of the most notable rockets
and was on its way to fulfill many important tasks. The Soviet
Union wanted more options. Although the R-7 had plenty of
performance because it used Kerolox. It had a relatively narrow window
of operation. Once it was fueled up, this is far from ideal for something that
may need to deliver a warhead at quite literally the push of a button working
with storable propellants is something that Glushko actually preferred. In fact, when he was having problems
scaling up the RD 105, he was also working on engines that
would run on nitric acid for the oxidizer instead of liquid oxygen. Like we had mentioned with the RD 109
he'd even started playing around with nitric acid and kerosene fueled
aircraft engines in the 1940s. Now scaling up a rocket engine is hard, but nitric acid is even more difficult
to get stable combustion running. So Glushko's solution wasn't
to try to scale up the engine, but it was to actually scale down the
combustion chamber and then create multiple nozzles. Now he did this while working on an engine
called the RD 211, ding, ding, ding. We have finally connected
some dots here. My friends, this little bit of history is what sparked
the Soviet's love for multi chambered engines. Like we already
discussed with the RD 107. So now Glushko was working on
this RD 200 series of engines, which would first see use on rockets
called the R 12 and the R 14. These medium range ballistic
missiles were led by chief designer, Mikhail Yangel from OKB 586 in Ukraine. And were a major leap in range for
missiles. The R 12, our rockets, you may be familiar with if you've
ever heard of the Cuban missile crisis. Yes, the R 12s were deployed to
Cuba where they could hit mainland United States. The R 12
featured a spinoff of the RD, 107 called the RD 2 14. It still featured a hydrogen
peroxide gas generator, but it ran on nitric acid and kerosene, but that's not all Yangel
would be working on. In fact, he had a lot of his sleeves, a
whole family of rockets. In fact, the next one would be a bigger
brother to the R 12, the R 14. So he took the R-12's RD
214 first stage engine and upgraded it split up the four
chambers into a pair of dual chambered engines called the RD 215. This upgraded RD 215 would fly in pairs, which would together be called the RD 216. So yes, that's correct. The RD 216 is literally
just two dual chambered RD 215s that, yeah, this stuff just gets so confusing, but these little rockets would actually
go on to become the second orbital rocket family to come from
the Soviet Union. In fact, the R 12 was actually studied to become
the basis for an orbital launch vehicle as early as 1956. That's right. The Kosmos launchers were
based on the R 12 and R 14, but featured a second stage on top of
it with an engine called the RD 119. Remember when Glushko was working on
the third stage for the R-7 and Korolev didn't want to use hydrazine
well, here's where that work went, but there was a problem.
The R 12 was a small rocket. So in order to make it an
orbital launch vehicle, it'd need a very efficient
second stage engine and the RD 109, although decent wouldn't cut it. Glushko started tweaking the RD 109 and
wound up putting a much larger expansion ratio nozzle on it to help it be more
efficient in space in order to reach a higher specific impulse. They also did something pretty cool
instead of gimbaling the engine or using vernier engines, it just took the exhaust from the gas
generator and sent it out through four fixed pipes. Then an electronically driven gas
distribution system would change how much exhausts would be flowing through each
of these pipes in order to give it steering control. The exhaust from
the gas generator was decomposed fuel, not oxidizer like most other Soviet
engines tended to use at the time, such as hydrogen peroxide. These tweaks help them get the
RD 119 to reach an impressive 352 seconds specific
impulse, the Kosmos 1, 2, 3 3m, and a special variant
called the K 65M- RB5 would go on to launch
625 times with about a 90% success rate. Overall, that's crazy that a rocket,
I didn't even know existed, flew so much and pretty
successfully at that. Seeing the success of the R 12 and R 14, it was time to develop a more capable
rocket one that could be used as a powerful Intercontinental
ballistic missile, and be a more rapidly launchable
counterpart to the R-7. The rocket Yangel developed
for this task was the R 16. And let me tell you, there's a whole heck of a story here
that we don't have time to go into with this video. Have you ever
heard of the Nedelin catastrophe? If you haven't heard of it, maybe consider yourself lucky because
the stories that come out of it are so gruesome, a part of me wishes I had
never heard about it. Long story short, the first attempt of launching this
rocket left at least 90 people, dead, dying, horrific and violent
deaths. In an ironic twist. Perhaps one of the few times in history, smoking a cigarette actually
saved someone's life. And it happened to be chief designer
Yangel who left the launchpad to go smokes and smoking next to a fully fueled
Brocket was prohibited. Okay. But back to the rocket powering, the first stage of the R 16 was
an engine called the RD 218, which was actually just three
dual chambered RD 217s that were upgraded RD 215s. These
engines had fixed nozzles. So the RD 218 was accompanied
by a 4 chambered steering engine called the RD 68, much like
the vernier engines on the RD, 107 / 108. Then there was a second stage on the R
16 that featured an engine called the RD 219, which was a derivative
of the RD 217s in the RD 218, but slightly more optimized for vacuum
and had its own quad chambered steering engine called the RD 69. After the roughest start ever
to the program and several
replacement workers and managers, for those who were
lost in the Nedelin disaster, the R 16 went on to prove to be a
formidable enough weapon, to see Yangel, be tasked with designing
an even bigger rocket. This would be the R 36 for this rocket. They would opt for a less corrosive
alternative for a storable oxidizer swapping out the nitric acid based
oxidizer for nitrogen tetroxide, along with unsymmetrical
dimethyl hydrazine, which would become a staple
of hypergolic rockets. Now this combination is
also called N204 / UDMH. The engines that they developed would be
an upgraded and evolved version of the RD 218. This engine would be called
the RD 251 and similar to the RD 218. It was made up of a cluster
of three dual nozzled RD 250s. On the second stage of the R 36, there was a vacuum optimized
version called the RD 252. I love the RD 252 because even
its gas generator exhaust pipe is optimized for vacuum operation. It was a healthy upgrade
over its predecessor, the RD 219 and achieved
26 seconds better specific impulse, despite being
relatively the same mass, the R 36 would become the basis for a
space launch vehicle called the Tsyklon. It would evolve into one of the most
reliable rockets ever made. The Tsyklon, Tsyklon 2, which was a two-stage rocket that
made 106 flights with only two failures between 1969 and 2006. There was also a three-stage
version called the Tsyklon 3. The third stage had a small hypergolic
open cycle engine called the RD 861, which had a single combustion chamber
with four Vernier nozzles that were fed from the gas generator
exhaust. The Tsyklon three
also featured an upgraded RD, 251 called the RD 261 / 262. They changed it to be able to handle a
wider range of operating temperatures since it would only be used as a space
launch rocket and would always be launched from a pad
instead of a missile silo. There was actually an R-36
orbital launcher that was
still a silo-based launcher meant to launch nukes into orbit. Spooky. The Tsyklon 3 halted production in 1991
with the collapse of the Soviet Union, but was still flown until 2009. There'd be some interesting politics
involved with a Tsyklon 4 and Ukraine is still in pursuit of
a Zenit rocket based Tsyklon 4M, but it has yet to fly. And some of these leftover RD 250 based
engines would wind up in the hands of North Korea and Iran today, which has led to tensions between the
United States, Ukraine and Russia. The R 36 is actually known
by another name, the Dnepr, and this is the missile that Elon Musk
tried to purchase from Russia when he wanted to send something off to Mars. And the Russians actually laughed him
out of the room when he tried to buy it. And that kind of led to the
start of SpaceX in the long run, maybe they should have just
sold him that one missile. In the 1960s Yangel and Chelomey started
working on new projects that are aimed at further development of their
ballistic missile program, Yangel proposed and new
version, the R 36 M. As a result in 1969, the R
36 M project was approved. The first stage of the R 36 M rocket
would use for single chambered RD 263 engines, which
formed one RD 264 engine. These were oxidizer rich closed cycle
engines with impressive performance Yangel had been partnered up with OKB 456 for
most of his propulsion needs up to this point, but then he ended up reaching out
to OKB-154 feeling like OKB-456 was currently overworked
on other projects. These
engines ran on N204/UDMH, had a total thrust of 4,158
kilonewtons at sea level and 4,511 kilonewtons in vacuum had an
ISP of 293 seconds at sea level and 318 seconds in a vacuum. A fun note about these engines is they
had pretty large combustion chambers. In fact, so large, they were actually experiencing those
problems with combustion instability and the flame getting crazy
around the injector face. So guess what they did? Nope. They didn't split it up into multiple
combustion chambers for once they did what the U S did divide the
injector face, using dividers. Since the R 36 M is a ballistic missile, let's not even talk about the rest of it, but keep that RD 264 in mind, since we'll see its
heritage up down the road. The RD 200 series proved
hypergolic fuels to be useful. And like we mentioned, Glushko preferred developing
engines that ran on hypergolics. This knowledge would sure come in
handy for the next family of rockets. One of the most successful rockets
to come from the Soviet Union, the Proton Korolev's R-7 rockets were doing quite
well and Yangel was doing big things with his ICBM's, but there were other design bureaus
looking to get funding for their designs. Chief designer of the
OKB 52 design bureau, Vladimir Chelomey had his own
plans for a modular rocket. Chelomey was developing the
universal rocket family, otherwise known as the U
R series. Initially, this
was supposed to be a UR100, UR 200, UR 500, UR 700 and even the UR 900, which would have been powerful enough
for a direct ascent moon mission. Chelomey, turned to Glushko who of
course turned to hypergolic fuels. It was also easy to sell a rocket
concept as an ICBM when it used hypergolic fuels. Chelomey's idea was to have a large
number of relatively cheap UR 100 missiles that had simple designs. Mr - UR-100 and the UR 100 N were approved and
were being developed, but on a competitive
basis against the R 36 M. For the MR UR 100, he was able to get
fast-tracked and RD 268 engine, which was an improved version
of the RD 264's RD 263 from the R 36 M and would
actually be developed in parallel to it. But it wound up being higher
performance. And for some reason, it wasn't plagued with those same
combustion instability problems at the injector face, which
required those dividers, but they ended up keeping the dividers
inside the combustion chamber anyway, just in case. They had a thrust of 1,149
kilonewtons at sea level and 1,239 kilonewtons in vacuum had an
ISP of 296 seconds at sea level and 319 seconds in vacuum. The main difference between
these two engines was the. RD 268 engine was fixed while
the RD 263 engines could gimbal seven degrees. But that's
not all Chelomey was working on. He was also developing
a larger UR 200 rocket. So he turned to design
bureau OKB-154 to develop a high performance close cycle hypergolic
engine kind of blending the S1.5400 and the RD 250 that we
had talked about earlier. The engine they built
was called the RD 0202, and they were hoping this would be the
engine to use across the entire lineup of his universal rockets. The RD 0202 was actually
a module composed of three RD 0203's' and one RD 0204, which included a heat exchanger to
pressurize the fuel tanks for the first stage. So, yes, let me repeat that, cause this is just one of the hardest
things with some of these engines, the RD 0202 defies, all
naming scheme logic. It has a zero first, which typically means
it's an upper stage engine, but Nope, this is a sea level fired engine
and the RD 0202 is actually just three RD 0203s and one RD 020 4. Yep. Uh, good luck remembering that one, but they also built a vacuum
optimized version called the RD 0205, which was a single RD 0206, based on the RD 0204 with an
auxiliary vernier steering engine, the RD 0207. Are you getting more confused
or less confused at this point? Because I have no idea. The U R 200 only saw a few test launches, but its work wouldn't go unused the RD 0205 would wind up on the
second stage of Chelomey's next, even bigger rocket, the UR 500, which was originally designed to be
an Intercontinental ballistic missile capable of delivering 50 to
100 megaton warheads. Well, it turns out the rocket wouldn't really
see any light of day as an ICBM and instead would become a
space launch vehicle, also known as the Proton, but Chelomey and Glushko would soon
realize they needed a more powerful closed cycle engine for the UR 500 rocket
because it wasn't going to make sense to use the RD 0202 on the first stage. The engine they developed was the RD 253, which was a huge leap
forward in performance, reaching a record setting 147
bar in its main combustion chamber. This leads to a high thrust
level of 1,470 kilonewtons at sea level and 1,630 kilonewtons
in vacuum and an impressive 285 seconds of specific impulse
at sea level and 316 seconds in a vacuum that also has an extremely
high thrust to weight ratio all around. It's an awesome engine fun fact, the RD 253 started development
while the RD 250 was on the test stand right next
to it. OKB 456 in 1964. They would take lessons learned
from the troubled RD 250 to make the RD 2 3, getting
it certified in a hurry. It would quickly become
a solid work horse. The RD 253 first successfully flew
on the very first Proton rocket on July 16th, 1965. And it continued flying as
either an upgraded RD 253F or RD 255 for a total of 314 times until its last launch on a Proton K in 2012 in 1965, the first Proton to fly
an upgraded engine called the. RD 275 would see flight. They increased the chamber
pressure to an impressive 157 bar, which in turn raised its sea
level thrust to 1,590 kilonewtons with its efficiency going up to
287 seconds at sea level and 316 seconds in a vacuum. But in 2007, one more upgrade to the RD 275
would be made called the RD 275M also known as the RD 276 for some reason, which would first see action on the
maiden flight of the Proton M and again, featured higher chamber pressure. Now up to 165 bar allowing it
to hit even higher thrust and a little bit better specific impulse to a
fun little note about the Proton rocket, despite looking like it's a cluster of
booster engines attached to a core stage. Those are not detachable boosters. The reason it's shaped like that is
because of its size constraints of getting segments of the rocket to the pad by rail. This definitely threw me for a
loop when I first learned it. So the outer tanks are the UMDH
tanks and the central tank is the N204 oxidizer tank. This allows all engines to be connected
directly to the fuel and oxidizer tanks. So they have no need for a large down
comer pipe through one of the tanks. It's actually pretty cool. The second stage of the Proton originally
was going to use a vacuum optimized version of the RD 0203/4 called the RD 0208/9. But as they continue to
develop and grow the UR 500, they ended up upgrading
the thrust and burn times, creating a set of engines
called the RD 0210/0211. Similar to the other clusters of engines. There'd be three RD 0210s and one RD 0211 with the heat exchanger. But
of course, for whatever reason, they didn't just give it its own name,
like all of the other ones. Instead, they just kind of called it the RD 2010. And you're just supposed to know what
that means. Then there's a third stage, which would feature an upgraded
version of the RD 0205, that was developed called the RD 0212, which was an RD 0213 main engine and four RD 0214 vernier steering engines. But the Proton did something kind
of weird considering the whole thing runs on hypergolic propellants
except for the fourth stage in the Proton K and M, which believe
it or not ran on Kerolox. This is unusual because normally the
first stages are LOx based since liquid oxygen boils off so easily. And then upper stages are the ones that
are hypergolic since they can be stored for so long without worrying about boiling
off. But this is quite the opposite. Despite the boil off issues,
the Blok D as it's called, has done 24 hour long missions. The engine that powers the fourth
stage is the RD 58 and it's a direct descendant of the S1.5400. It was originally developed to be the
final stage of the N1 moon rocket. That we'll talk about
more here in a second, but it actually would fly
first on the Proton in 1967. There's an upgraded version called the
RD 58M which offers a little better specific impulse for the Proton Blok D
there's also a special version of that engine that has a carbon
carbon nozzle extension. There's also an RD 58MF
upgrade that hasn't flown yet, and we don't really have good specs on it. So we'll just leave it off
of our chart to be safe. But then there's also the Briz
M, and the Briz K fourth stages, which were hypergolic,
but didn't fly until 1999. These are powered by an
engine called the S5.98m, Which is a gas generator hypergolic
engine producing just 19.6 kilonewtons of thrust. And it's a sibling to
the S5.92 on the Fregat, but there's one last engine that Glushko
and Chelomey would work on for the UR 700 and the UR 900 mega rockets
that they were originally trying to push instead of the N1 and
it's way too cool to not talk about, remember how Yangel ended
up turning to OKB-154 to work on the RD 263, because he felt like Glushko
was too busy at the moment. Well, there was good
reason for him to be busy. He was working on perhaps the
most epic engine ever made in 1962. The development of the RD 270 began. Now what's awesome about the RD
270 is it was the holy grail of combustion cycles. The full
flow stage combustion cycle, much like SpaceX is Raptor engine.
They took a lot of lessons from the RD, 264 and RD 253 to make the RD 270 and boy, was it a masterpiece including how to
scale up large combustion chambers and not be plagued by combustion instability. This would be the most
powerful single chamber engine, the Soviet Union ever built and would
come darn close to the thrust output of the F1 engines that the
US built for the Saturn V. It reached a mind-boggling 6,272 kilonewtons at level and 6,713 kN in a vacuum with a very impressive 301 seconds at sea
level and 322 seconds of specific impulse in a vacuum. This is much better specific
impulse than the F1, which only achieved 263 seconds of
specific impulse at sea level and 304 seconds in a vacuum. Although the F1 was a
good 15% more powerful at 6,770 kilonewtons at sea level
and 7,700 kilonewtons in a vacuum. They test fired it
27 times with one engine, even seeing three fully successful
full duration fires between 1967 and 1969. Oh, and just to add insult to injury, they even ran the RD 270M
version on pentaborane, which was 15% more efficient. This would have made it probably the
ultimate engine likely still today and would have been just so close to the
thrust output of the F1 with much higher efficiency. Unfortunately, the engine was canceled
alongside the UR 701. The N1 was chosen as a Soviet moon rocket. So we keep tossing around the N1
and talking about it here and there. But I think now it's time, we actually dive into the awesome
engines that powered the most powerful and downright crazy rocket
to ever fly well for now Getting humans to the moon and home
requires an awful lot of rocket. Of course, the United States developed
for the Saturn V, but meanwhile, Korolev had actually succeeded in
pursuing his own mega rocket. The N1, as we mentioned before, he was in competition with Chelomey
to get funding for his moon. Rocket after Chelomey is UR
700 and the UR 900 proposal got shot down. And with Korolev having sworn off the
use of hypergolic altogether for the majority of the rocket, he had to find a powerful
Kerolox based engine capable of lifting the massive N1. Since propulsion engineer Glushko had
already buddied up with Chelomey for the RD 200 series hypergolic engines, Korolev turned to an aircraft
engine design bureau, OKB 276, which was headed by Nikolai
Dmitriyevich Kuznetsov. Korolev and Kuznetsov set out to design
the Soviet Union's most powerful Kerolox engine knowing he'd need an awful lot of
power to lift a rocket that would weigh almost 3 million kilograms. The first engine they'd
build was called the NK 9. It was an oxygen rich close cycle engine, and it became the basis for an
upgraded engine called the NK 15, that would achieve the thrust numbers
necessary for the massive 17 meter wide first stage booster called Blok A. Blok A would feature a whopping 30 NK 15s with 24 engines around the outer
perimeter and six more on an inner ring sounds kind of like SpaceX's SuperHeavy, doesn't it at 1,526
kilonewtons of thrust each, they would offer a total of
45 mega Newtons of thrust. So 45 million Newtons, yes, that's almost 30% more thrust than the
Saturn Vs first stage which had 35 mega Newtons of thrust. This is a number that's still unmatched
as of the making of this video, because once SpaceX is
SuperHeavy fires and flies, it become the new record holder
at around 75 mega Newtons. And that's just for now because it's
likely to increase the N1's engines would steer the rocket via thrust differential
and not through engine gimbling. This is where the engines can provide
more or less thrust on one side of the rocket to steer where it's going. It's actually a pretty complicated
control scheme and relies on advanced computers to make it work reliably and
advanced computers is exactly what the Soviet Union didn't
have in the late 1960s. Their primitive KORD computer was
pretty limited and alongside the rest of the avionics package, they just really weren't up to
the task of managing 30 engines. Then those engines had very little testing
and not to mention the rocket had to actually be flown in order to even
test the engines in the first place. It was the ultimate in all up testing. One big flaw with the NK 15 is it had
many pyrotechnic valves in order to save weight and complexity. So in other
words, once they fired the engine, they couldn't be refired. This led to only about one in
every six engines being tested before flights with none of the engines
that were tested being put on the rocket. Of course, they were basically just testing in order
to validate manufacturing and ensure that there weren't big flaws
with batches of engines. The second stage or Blok B would utilize
eight vacuum optimized versions of the NK 15 called the NK 15
V which had an extended nozzle and air start capabilities and
was more efficient at 325 seconds of specific impulse. The third stage known as Blok
V would four NK 15s each with about 450 kilonewtons of thrust
and 346 seconds of specific impulse. These were direct
descendants of the NK nine, that Korolev and Kutnezov initially
developed. They of course, ran on Kerolox as well. Then there was the fourth
stage called the Blok G, which was the stage that was to
perform the trans lunar injection. It had a single NK 21, which again was a direct descendant of
the NK 9 ran on Kerolox and had about 392 kilonewtons of thrust and
346 seconds of specific impulse. And lastly there was that RD 58 on the
Blok D stage that we mentioned earlier with the Proton. Now it was the final stage on N1 and
it was intended to be a lunar breaking engine, kind of similar to how the US's Apollo
service module would slow the vehicle down to put it into lunar orbit. And trust me on these
numbering schemes Wikipedia, and a lot of other sources are simply
wrong about which engines were on which stage. I had to go to my N1 expert, someone who has been studying
the N1 for years and years, French space guy on YouTube and
Twitter for the actual facts. Unfortunately, we don't have time to really dive into
all the wild things that came from the N1, The problems, some of the
largest rocket explosions ever, or the unfortunate and untimely death
of Korolev before it would ever get a chance to fly. But long story short,
there were four failed launch attempts, none of which made it
through the first stage burn. Meaning out of all the engines we just
talked about only the NK 15s would get their chance to run in flight on the N1. But by this time there were already tons
of upgrades in the works for different future N1 varients like
the N1F and the N1M but their plans were never
really solidified fully. Despite that many engines
were fully developed, such as big upgrades to the NK
15 for an engine called the NK 33, which had some important new features
like being able to be tested and refired thanks to simplified pneumatic
and hydraulic systems. It also had more advanced controls
upgrades to the turbo pumps, as well as the combustion chamber. Come to find out this engine would be
regarded as one of the most advanced engines ever made kind of still
today. And for that reason, because it's so good. It actually still flies today
in Russia on the R-7 family. Remember when we said there was a weird
booster list version of the Soyuz? Well, this is the Soyuz 2.1 V and
it started flying in 2013. The first stage is powered by the NK 33,
but since it's a fixed nozzle engine, it has a 4 chambered steering
engine called the RD 0110R to provide control authority. The
second stage is the RD 0124. It's actually a pretty cool little
rocket, but now back to the N1, there was also work being done on a
vacuum optimized version of the NK 33. This engine was called the NK 43. It was a nice upgrade to the NK 15
hitting an impressive 346 seconds of specific impulse. They had also already
developed high-performance hydrolox, upper stage engines called
the RD 56 and the RD 57. That would be the first hydrolox
engines to be built in the Soviet Union. They were impressive engines with
extremely high specific impulse. The RD 57, I think was the first
closed cycle hydrolox engine ever made, hitting an impressive 457
seconds of specific impulse and 392 kilonewtons of thrust and
developed around that same time, the RD 56 would hit 462 seconds of specific impulse and 70
kilonewtons of thrust. But unfortunately after the N1s,
four failed flights, Glushko, who is now the head of the Soviet
space industry after Korolev's death canceled the program
completely and ordered all the
engines and the two unflown, but fully assembled N1's, to be scrapped. But since the NK-33s were
developed by Kutnezov, who was in the aviation industry,
Glushko wasn't his direct boss. So he just chose to kind of
ignore his orders more or less. So about 80 completed NK
33's were secretly taken to a warehouse in a single night in
order to avoid becoming scrap. Now, we'll talk more about what happened to
these secret hidden engines in a minute, but Glushko was moving on. He had his
own plans for a super heavy lift rocket, and now that he was in charge,
he got to do things his own way. A lot of stuff done in the Soviet Union
was done in complete secrecy and things would come out of nowhere
that would shock the world, insert the Energia rocket, the world's second most capable
rockets only after the Saturn V. And it was even more capable than the N1. Desiring super heavy
lift launch capabilities, and also wanting to match the capabilities
of the United States's Space Shuttle, the Soviet Union began work on the
Energia rocket and the Buran orbiter in 1976, but it would be over 10 years
before the system would fly. Powering this monster rocket was also
the most powerful liquid rocket engine ever made. No, not the
Saturn Vs F1 engine, which was the most powerful single
combustion chamber rocket engine. The Soviets developed a
beast known as the RD 170. So now we get to see Glushko
taking on his ultimate challenge. This engine would prove
to be quite problematic, even for perhaps the best
rocket engineer in the world. Glushko had already developed
an engine called the RD-150, which was a cluster of six
RD 151's for a project in 1974 and would never fly. But he'd use this design as the
blueprints for this new engine. He would also take a lot of experience
and knowledge from the RD 270 and the RD 268 to solve a lot of problems
despite all of his expertise and prior experiences Glushko met his match, trying to increase the thrust while
attempting to make it capable of 7,250 kilonewtons of thrust. In fact, one time an engine blew up
so energetically that it
apparently sent parts of its turbo pump flying several kilometers away. Taming the beast was so troublesome that
there would be proposals to replace it with the NK 33's. But luckily for us rocket nerds that
didn't end up happening and in the end, Glushko was successful in
hitting the target performance, reaching 7,257 kilonewtons of thrust and 309 seconds of specific
impulse at sea level. The RD 170 had a twin called the RD 171. Now the biggest difference between the
RD 170 and the RD 171 is that the RD 170 could only swivel it's
four chambers on one axis. While the RD 171 can swivel on two. Which then would provide it
with an extra axis of control, making it a better option
for a single core rocket. They RD 171 would be the first of the
two variants to actually fly on a rocket called Zenit in 1985. There was another version of the RD
171 called the RD 171M which had lower mass and increased reliability. It would go on to power the
Zenit 3SL rocket 30 times. The second stage of the
Zenit would utilize a fresh
closed cycle Kerolox engine known as the RD 120, which could hit 350 seconds
of specific impulse. It was a fixed engine paired with an RD 8, which is a quad chambered vernier
engine that provided control authority. The third stage of the Zenit rocket would
have two different engine options that we've already discussed.
Finally, some commonality, the Blok DMSL version utilized
the RD 58 that as we mentioned, was the direct descendant of the
original S1.5400 closed cycle Kerolox engine. The other choice of
third stages was the Fregat SB, the Fregat upper stage we
already mentioned as the
hypergolic stage on the Soyuz U, the Soyuz FG and Soyuz 2
and it utilized the S5.92 hypergolic gas generator engine. Here's a fun little fact about the
Zenit is it also used to launch from a repurposed oil rig sea launch platform, much like SpaceX wants to
do with their Starship. From 1999 through 2014, it launched 36 times from
that sea launch platform. So almost half of its
84 launches in total. The Zenit is still an active rocket, but hasn't flown since 2017. Now I wish I could report that the main
use of those incredible RD 170 engines was lifting a super heavy lift rocket, but unfortunately it's life on the flamey
end of a formidable super heavy lift launcher was short-lived. It would only see two flights on
the Energia rocket once with the classified Polyus space station. And
once with the Buran Space Shuttle. The Energia rocket consisted
of four boosters each with a single RD 170. So there are basically four Zenit boosters
strapped onto a massive hydrogen and oxygen tank, much like how the space shuttle solid
rocket boosters were strapped onto the external fuel tank. But here's where there's a big difference
between the US's Space Shuttle and the Energia/Buran. On the Energia's center large tank had four engines, whereas the Space Shuttle had its
main engines attached to the orbiter, so they could be recovered and reused, and it actually had no engines on
that orange, external fuel tank. The Energia center tank was
the biggest single tank. The Soviet Union would build
offsite of the launchpad, which required it being flown on the
back of the Myasishchev M-4 bomber. Now, we should note that despite the
N1's tanks being much larger, they were smaller segments shipped by
rail and then assembled at the launch pad. The engines on the core of the Energia
rocket were heavily inspired by the United States' space shuttle
main engine, the RS 25, the Soviet RD 0120 was a fuel rich close cycle hydrolox engine. It also happens to be the most powerful
single chambered engine to ever fly from the Soviet Union. At 1,526 kilonewtons of
thrust and 353 seconds of specific impulse that sea level and
an impressive 455 seconds of specific impulse in a vacuum. And I should
probably add here that this is a, another cool feature of the Energia. It could be a stand alone rocket and
launch payloads that weren't the Buran, which of course the U S Space
Shuttle was not capable of doing, but what's funny is that they would
just strap about 100 tonnes on the side of the rocket and the impressive guidance
and navigation would sort out the lopsided nature of it. Energia was an expendable rocket and
would ditch the four boosters with the RD 170s, as well as the RD 0120's
on the center core, but there was a plan for the
RD 170 to be reused up to 10 times. They intended to first recover the side
boosters with parachutes and softly touchdown using solid retro rockets, but even more awesome was they wanted
to actually have foldable wings and fly the booster back to a runway
landing for the Energia 2 version, and they wanted to recover the center
tank in kind of a similar fashion, which would have meant the Energia /
Buran system could have been a fully reusable launch vehicle that
would have been incredible. But lastly, on the Buran, there was one more engine in the Energia
/ Buran system that we need to talk about. The only engines attached
to the Braun orbiter itself, where a pair of modified RD
58m's that were called DOM's, which is the Russian acronym
for orbital maneuvering engines. But they went only by their GRAU
number for their name, which was 17D12. These were an awesome choice
for orbital maneuvering engines, since they could be restarted many times. And they had an impressive
specific impulse of 362 seconds because they ran on
synthin. Unfortunately, I don't think we really have time to talk
about just how awesome Buran was like how it flew 100% autonomously
on his first flight, or how could lift more than the
shuttle or how it had 500 abort and ejection scenarios, potentially
keeping a crew much safer. We'll definitely talk more about this
and everything Buran and Eneriga in a future video, and we'll compare it
to the United States's space shuttle. So stay tuned for sure. So although the Buran and Energia
didn't get much use at all the RD, one seventies heritage lives on today. And what's crazy is that it lives
on in rockets well outside the former Soviet Union's borders. [MUSIC]. With the collapse of the
Soviet Union in 1991, rumors began to swirl about
Soviet rocket engines. People in the aerospace industry
were beginning to catch wind of some clandestine high-performance rocket
engines that existed behind the secretive borders of the Soviet Union. It didn't take long for us engineers
from aerospace companies to rush over to Russia and try and get their hands
on. Some of this incredible hardware. Aerojet was one of the first companies
to get their hands on some engines. The engineers were floored, but not only by the sheer number
of leftover NK 33's destined for the upgraded N1 that would never see the
light of day, but also the performance, the Russian engineers were proclaiming. They thought there was some error in
translation or something because they just didn't think there could be a rocket
engine with such high performance that ran on Kerolox. But fortunately for the former Soviet
engineers involved in the program, they got the chance to show their hard
work off to the rest of the world. An NK 33 was shipped to the United States
in the early nineties so Aerojet could put it through its paces. To the absolute
shock and all of everyone involved, the old engines still
performed exactly as designed, but despite being test fired in 1995, it wouldn't see its first
flight until April, 2013, over 40 years after being made. And the first rocket to fly one was
flown in the United States of all places. How crazy is that? The first rocket to utilize the
Soviet NK 33 in flight was the Antares rocket. Aerojet
refurbished, NK 33, and created a version called the AJ 26, which wound up with a few control
changes, and slightly upgraded, maximum throttle setting. It would go on to fly four
times successfully on Antares, but unfortunately on the fifth
flight on October 28th, 2014, for NASA as CRS ORB3,
it experienced a failure only a few seconds into flight. One
of the two engines LOx, turbo pumps, exploded and led to a loss of power
resulting in the rocket falling right back onto the launchpad, creating one heck of
a fireball. This led Orbital Sciences, now Northrop Grumman to look
for a more reliable replacement for their Antares rockets, with every
option in the world on the table. Guess what they chose. Yep.
You may have guessed it. Another high-performing Russian engine
and this one owes its existence to the RD 170. The RD 170 became
the basis for three more, very notable engines. The RD 180 the RD 181 and
the RD 191. The RD 181 is what north of Grumman chose to
replace the NK 33 based AJ 26's on Antares after its 2014 failure. Now we should note they do use
two RD 181's because the RD 181 and the RD 191 are
basically just a single chamber off of the RD 171 with the turbo pumps scale
down to one quarter. The output, as you may have guessed, it
has about exactly one quarter, the thrust and gets pretty
much the same specific impulse. The only difference between the RD
181 and the RD 191 is some plumbing and mounting changes that make
the RD 181 work with Antares. The RD 191 has only flown three times
on a new rocket called the Angara, which as of the making of this
video is only flown twice in 2014. And once in December of 2020. So it's not a very
frequently launched vehicle. Angara will feature up to four
boosters around a center core. It also features some engines. We already know a variant of the
RD 0124 on the second stage and an optional S5.92 for
a Briz M third stage. In its biggest configuration, the Angara A5 can take
24,500 kilograms to LEO, which would be a modest upgrade over the
Proton rocket its intended to replace. An RD 191. ariant was also used on a South Korean
launch vehicle known as the Naro-1 or K S L V 1, which was pretty much just a single
booster from an Angar with a second stage solid rocket booster made in South Korea. It's basically a de-tuned RD 1
91, but it's called the RD 151, but it actually shares no commonality
with the RD 150 and RD 1 51 that we talked about earlier that was
developed prior to the RD 170, it only launched three times with only
its last launch being successful in 2013. Then there's the RD 180 and the
RD 180 is perhaps one of the most well-known Russian engines in the United
States since it powered the Atlas three and still powers the Atlas V today, it also was the first Soviet derived
rocket engine flown outside of the Soviet Union. They RD-180 is pretty much
just two chambers off of the RD 171 with half scaled, turbo pumps. It was modified to run on RP 1 since
that's what the United States uses. And again, as you might guess, it has about half the thrust
of the RD 171 and has similar specific impulse. The Atlas III was the first American
rocket with the RD 180 to fly in May, 2000. It would only launch six times in total
with its last flight in February, 2005. It would continue flying on Lockheed's
follow-up the Atlas five that as of the making of this video has launched
89 times and still flies today. It's had a virtually
flawless track record. Pratt and Whitney were also quick to
create connections in Russia and they got their hands on the RD 120 at about the
same time the Aerojet got their NK 33's. They were considering
purchasing RD-120's., But decided not to it ended up that China
would actually purchase these engines and would use the experience they gained
while testing them to develop their own YF 100 engine that they use on
their Long March 5, 6 and 7. It's the only non Soviet
closed cycle Kerolox engine to fly to date. Another engine that's still flying
today that has direct lineage to Soviet engines is the CE 7.5 that
India developed for their GS V rocket. India purchase to complete RD
56 engines and plans from the upgraded. And once under sanctions, the Indian space research organization
or ISRO was forced to actually develop its own cryogenic program
leading to the hydrolox engines we see on their awesome GSLV rockets. And lastly, we should mention that Soviet derived
engines have made it into orbit in both Iran and North Korea with
variants of the R 11 Scud missile, an ICBM that we
didn't really talk about. The upper stages of the rockets are pretty
much just an entire Scud missile with the booster, featuring more of a homegrown and scaled
up engine with one or four of them powering the first stage. Now, granted, this technology is extremely
primitive by today's standards. Not much more advanced than
the original, A4 or RD 101, but they have been able to scale up the
thrust and produce their own versions that are capable of reaching orbit
while my friends that about does it for engines that have flown, but there's still just a few more
engines that we need to talk about quick because they're just too
cool to not talk about. [ MUSIC]. There's a few more engines I figured
we should talk about before we wrap up. And` although most of the engines
here never flew on an orbital rocket. These were fully developed engines, meaning that they were completely
ready to go and certified, not just some paper rocket engine
or something sketched out on a napkin. First up as an engine
that I wanted to talk about, because I think they got way too far
into development before they were like, wait a minute, this probably
isn't even a good idea. That was the RD 301. The RD 301 didn't use
oxygen as the oxidizer or nitrogen tetroxide or any of the other
oxidizers most of us might be familiar with. Instead they went with the oxidizer
with the most energy potential fluorine. Fluorine wants to react
with absolutely everything. You can't even store it in glass tubes
or pipes because it will react with it. Leave a fingerprint inside the engine.
The second fluorine touches it. It's now on fire by by
engine, despite this, they fully developed the RD 301, which of course used fluorine as the
oxidizer and ammonia as the fuel two nasty nasty chemicals. They wanted to build confidence working
with fluorine so they could make the ultimate high efficiency chemical engine
a fluorine / hydrogen engine someday. A fluorine hydrogen engine could
potentially reach 475 seconds of specific impulse and is literally
at the absolute limit of chemical rocket efficiency. But who cares how efficient it is if it's
the most ridiculous thing ever to have to handle and deal with, it was considered as an option for a
high energy upper stage for Proton, but was abandoned in
1977 after qualification. The original RD 301 could hit 97
kilonewtons of thrust and 400 seconds specific impulse in a vacuum.
So not quite the full 475, but 400 is still pretty good
considering it used ammonia for fuel. There was another exotic propellant
engine developed for the Proton called the RD 501 / 502. It ran on hydrogen
peroxide and pentaborane, despite the potential for a lot
of energy and high efficiency, its toxicity reactivity, and
the general pains of handling. It led to its cancellation in 1966. Along with that RD 270 M
that also ran on pentaborane. Next there's the RD 0410. Based on what we know about numbering
schemes, what do you think this one is? Well, we haven't seen the
number four anywhere else, but that's because this
engine is very special. It was a nuclear thermal rocket
engine that used hydrogen as its fuel much like the United States is Nerva
rocket engine that was highly successfully tested, but never flown. The RD 0410 would have a similar fate. Where the US's Nerva would
have 330 kN of thrust. The RD 0410 was pretty small
producing only 35 kilonewtons of thrust, but it had a record setting 910 seconds of specific impulse in a vacuum. This also means the engine was small
and light enough to be flown by a medium lift rocket like the Proton,
unlike the Nerva engine, which was so big and heavy, only a super heavy lift vehicle
could even get it into orbit. It was tested all the way through
the 1980s with great success. Unfortunately it would never fly
again, just like the Nerva engine, which is just a complete
shame. In the future, I'll do a video diving into nuclear
engines and talk about why they're so awesome, how they work and
why we haven't seen one fly. Another engine we absolutely need to
mention is the RD 701 and its sibling the RD 704. So it starts with a seven, huh? Well, I don't think you're going to be
guessing what this one runs off of. It's a tri propellant
engine. Yeah, that's right. It runs on liquid oxygen,
kerosene and liquid hydrogen. The engine was based on the RD
0124 closed cycle hydrolox engine and was supposed to be used on a
reusable space playing called MAKS, which began development in 1988, just before the collapse of the Soviet
Union essentially embraced the convention of pretty much every other Soviet
engine by flipping the one to many relationship around instead of having
multiple combustion chambers with one turbo pump, it has multiple turbo
pumps per combustion chamber. On start-up. It ran on
all three propellant, but then switched modes to just run on
hydrolox when the high thrust output wasn't needed, which increased the efficiency of the
motor because it was just using hydrogen. It was very high performance capable of
reaching record setting chamber pressure at 300 bar, which was only just recently beat by
SpaceX's Raptor engine on a test stand in 2020.. When running on
all three propellant. It could achieve 4,000 kilonewtons
of thrust in a vacuum at 415 seconds of specific impulse. And in
mode two running purely on hydrogen, it would still produce 1600 kilonewtons
of thrust and its specific impulse would increase to 460 seconds. How cool is that? And last little note,
there might be one thing you noticed. We never once mentioned
solid rocket boosters. There is one very fun little rocket
called the start one that has eight grid fins on it. If you like grid fins,
we've got you covered on grid fins here. My friends, I think my favorite thing about this
little launcher is the simple plop of the cover coming off the launch tube at the
beginning of launch, listen to this. Well, other than that, the Soviet
Union really didn't touch large. SRBs like at all, it's just super weird considering how
much the United States leans on them still today. Believe it or not,
there's still four orbital rockets. We didn't even talk about there's Volna
and Shtil that are orbital rockets that are launched from nuclear submarines. And there's the Strela and Rokot, which
are derived from that little, UR 100, but other than that, I
think that's about it. Okay. Let's finally wrap this thing up. [ MUSIC]. So to summarize the Soviet seemed
to make new engines more often than most of us go to the grocery store. I swear they were just looking
for excuses to make new engines. I kind of imagine that someone
couldn't even finish the sentence. What if and someone from across the room
was already yelling way ahead of you and they're just sitting there drawing
out new plans for a new engine. This obviously has led to an absurd
amount of incredible engines, but that's pretty much the entire
history of Soviet rocket engines. These engines are still some
of the best made engines ever, and they really set an extremely high
bar for everyone else to try and match. They mastered the closed
cycle ridiculously early
on in space flight history and made it seem normal. I love that almost every engine made in
the sixties was considered impossible by the United States who by the way, has still never built and
flown a purely oxygen rich closed cycle engine. I think my favorite thing about the
philosophy of these engines is it's a complete mixture between
if it ain't broke, don't fix it like using wood while
also pushing engines and hardware further and further and further constantly
what engines stood out to you the most? I think my favorites is
probably, I think probably the RD 270, because you know, it's full
flow stage combustion cycle. So that's just super cool, but it's still be a really
formidable engine today yet. Either that or the RD 170, because I
just think it looks absolutely awesome. And it's simply a beast. Let me know if you have any other
questions or if you need me to touch on a certain topic, more in an
upcoming video. And again, I owe a really big thank you to my team, including Casper Stanley
for those incredible renders
of all of these engines. Without his help. This video would have been a lot more
confusing and definitely a lot less visually pleasing. Be sure to check out his awesome Rocket
Explorer app on steam and follow him on YouTube and Twitter because he has
some of the best workout in there. So thank you Casper. Also, thanks to
Ryan Weber and the French space guy, Amarui B Maria Kisleava and the
DREAM rocket team from Russia. Thank you all so much for
your extra help. And again, thank you to my incredible
Patreon supporters. I would not be pursuing videos that are
this hard and took this much time to make, because I don't, you know, I don't think this is going
to be a high-performing video. I could make a video that
says SpaceX, anything. And it's probably going to get 10
times the views of videos like this are extremely important and I hope that
this is a good resource in the future. So if you want to support
what we do here at everyday, astronaut consider becoming a Patreon
supporter where you'll gain access to some exclusive live streams, our
incredible discord community, early cuts and reviews
of videos like this, and lots of other fun stuff at
Patreon.com/everydayastronaut. And while you're online, be sure and
check out our awesome web store. For sure. It's like this... The R-7 shirt that I
think is super cool by the way, this is, this is actually a secret
little teamspace shirt. You guys have wanted a
teamspace shirt for a long time. This is actually one because
it says basically in Russian, the equivalent of team space, I thought that was kind of a fun little
nod and hot off the presses are these awesome RD 171 shirts in short sleeve, but also these awesome
long sleeve shirts too. And don't forget about these awesome
posters we had made of the family tree. Hang it up on a wall, maybe study it for awhile and good luck
trying to remember which engines went on, which rockets,
because I still struggle, but we have tons of other really cool
stuff like our full flow stage combustion cycle, hoodie and shirt and our Future Martian
shirt and our schematics collection. And just lots of other fun accessories
for you or any other space nerd. You can find it all on
everydayastronaut.com/shop.
Thanks everybody. That's going to do it
for me. I'm Tim Dodd, the everyday astronaut bringing space
down to earth for everyday people. [Inaudible].
Congrats to you and the team for finishing this piece, Tim. Excited to share it with the young space enthusiasts in my life over the holiday. Big fan of the channel and the work you all continue to do. Excited to see future coverage of starship and other cutting edge stuff along with these historical deep dives. Much love and appreciation this thanksgiving 🙌👍
Bravo! Tim and team!
this is criminally underupvoted
I love that we live in a time where I can take out my screen, connect to an essentially free WIFI connection and get all this free knowledge. Thanks Tim!
This was a great vid. I've actually been very curious to learn more about Soviet rocket engines ever since I started getting interested in orbital rocketry about a year ago, so, was really happy to see a full, deep-dive on them from Tim. I never knew they made a tri-propellant engine! (among other things!), haha.
One thing I think would potentially be really interesting to investigate even further (although, I would understand if Tim is a bit "Sovieted out" at the moment after how much research he did for this vid):
I've seen on numerous previous occasions, even from u/everydayastronaut himself, actually, on a previous occasion, people mentioning how the idea of running an oxygen-rich closed cycle kerolox engine was considered so ridiculously difficult (especially back then in the 1960s or 70s when they started doing it), that the U.S. considered it "impossible" and figured it was just a false rumor when we heard rumors the Soviets had managed to do it with some of their engines.
But, one thing I've never seen or heard anyone explain:
How did they pull it off? Like, what are the insider deets on that. The story of it being this crazy thing we couldn't believe they were managing to do, is fairly well known at this point, but the actual, "yea, but... how did they manage to do it, if even we couldn't figure out how"... that's something I've never seen explained anywhere, you know?
Not sure if it's just sort of some insider info that will (or already has, I guess, in most cases) died with the people who were around in the USSR back in the 1960s? Or if maybe there are still a few of them alive who speak some English and would be willing to chat about what it was like trying to create the world's first oxygen-rich closed cycle kerolox engines.
To me, in the past 10 or 11 months or so that I've begun learning about orbital rocketry, of all the various cool things I've found out about so far, that one, in particular has been my favorite anecdote by far, and the one I've always wanted to know more about.
Also: another thing I think could potentially be interesting to explore (although, seems like such a huge topic in its own right that someone could probably write a series of full fledged books about it), is the social dynamic, drama, power battles, and so on, between the main players in the soviet engine and rocketry field (i.e. Korolev, Kuznetsov, Glushko, and so on). Probably would have the potential to make for an interesting tv series, tbh, if it was done the right way.
Anyway, one other thing:
Tim mentions that there would probably be easier ways to get more views than spending countless hours doing research for a somewhat obscure, or niche (from the general public's point of view, at least) topic like this one-
-but one thing I wanted to point out, which might hopefully take some of the sting of the lopsided effort to reward ratio that goes with a topic of this sort:
I've noticed, over the years, that there is a hidden value, of sorts, in sticking to your guns, when it comes to this sort of stuff. Basically, it is true that you can get a temporary, quick boost in numbers if you go to the easy, obvious topics like everyone else, of whatever is hot at the moment. But, I think in the longer run, there people slowly pick up on the idea of a person who goes with what is actually interesting, in the grander scheme of things, and what they are genuinely interested in and passionate about researching and explaining like this. It builds a stronghold of a reputation of sorts, where people realize that you're that guy, which has some value in it, that builds up over time.
It's also just cool, to be willing to do that (regardless). But, even from a purely pragmatic standpoint, I'm not so sure that in the long run (like years and years down the road, not weeks or months, that is) that it would actually necessarily even be detrimental from a brand building standpoint and viewer base standpoint. I think it just has a long delay (like a bungee cord effect, if you made a graph of it) associated with it sort of.
I could be wrong about that, of course. But, just something to help stay optimistic about maybe, if sometimes it feels a bit rough putting in that much work on something that is maybe a less blatantly popular topic than certain other topics.
Well, in any case, I'm glad you were willing to put in the time and effort to create this video, because I have definitely never seen anything like it anywhere, and it was really fun to learn about. Great work, as usual!
It’s interesting to think about an alternate timeline where Gorbachev kept the union together through the 90s, where a new space-station race took place between the Buran and Shuttle. I think in most ways the Buran was a better design, though the USSR was still leagues behind in computer tech.
Very comprehensive.
It's amazing how, despite all their disadvantages in terms of funding and technology, the Soviets actually produced more energy efficient engines than the US. Till recent developments by SpaceX, Arianespace etc. their engines were still superior; that's why they were used in a few American launch vehicles(the Atlas V and Antares) as well.
Really fantastic work Tim
It's so good! Thank you!