 This is again a buzz about space, largely due to the three billionaire kids, Amazon's Bezos, Virgin's Branson and Tesla's Musk. Musk and Bezos are talking about colonizing Mars and outer space straight out of science fiction, popular when we are growing up. In this episode of The Science Show, we are going to look at not space or Mars colonies, not space science fiction, but what makes going to outer space possible? Rockets. Yes, the rockets, the kind we played around as kids. The same principle that makes those rockets possible also makes it possible to have designs and space exploration. We all think Americans won the space race as they went to the moon. It seemed like that was a race and there was only one winner, the United States. And it was over with Apollo astronauts landing on the moon. What about the rockets that still power all our satellite launches? What about the rocket engines that powered these rockets? Are you aware that most rockets that the US today uses to power its military and civilian space launches use Russian rockets? If the US won the space race, why does it use Russian rockets today? All of which came out of the Soviet space program. As intrigued by recent MIT review that talked about the decades old Russian engine with which Musk and Bezos engines are competing. So let's look at those engines, those rocket engines and let's start with the rocket engine RD-180 that has powered the US Atlas launch vehicles from 2000 onwards. The Atlas rockets were manufactured by Lockheed Martin, now by United Launch Alliance, a joint venture between Lockheed Martin and Boeing. Where did this RD-180 rocket engines come from? Why did the US switch from their indigenously designed engines to RD-180? The origin of RD-180 is an older engine, RD-170, which was developed for the Soviet-planned Buran space shuttle. RD-170 was to power the energy launch vehicle. The energy launch vehicle made only two flights, the last one in 1988, shortly before the Soviet Union collapsed. It was followed by Yeltsin's kleptocratic years that saw Russia become virtually a vassal of the United States. Its state entities were dismantled and its assets sold. The company that survived the Yeltsin years was NPO Enerjomash and it was one that sells the RD-180 engine to the US. These rocket engines were developed in the 80s and are still in use today by the United States military and NASA. They are almost 30-35 year old rocket engines. Both the US and the Soviet Union built on the V2 rocket that Germany had developed and used in the Second World War. Warner Von Braun, the head of the German program, brought over a large number of German engineers to the United States. Von Braun worked on the US Apollo Moonshot program as can be seen here. For those who remember Kubrick's film, How I Stopped Warring and Started to Love the Bomb, the character of the mad scientist wanting to build bigger and bigger bombs was based on Von Braun. The Russians also had German scientists working on the rocket program, but they were able to radically improve the V2 design and develop better rocket engines than the Americans. To compare various rocket engines, let us look at what happens in a rocket engine. When you have what is called an open cycle rocket engine, this has fuel and liquid oxygen. These are the two things you need to go to the combustion chamber for it to fire and the exhaust gases coming out of the combustion chamber leaves at a certain velocity and that is what powers the rocket forward. When you want to pump fuel and oxygen at a higher pressure, if you have higher pressure you get a better and more efficient engine. Then you need to provide pumps which will therefore pump at a higher pressure both fuel and oxygen into the combustion chamber. Now for powering those pumps we use a turbine. As you can see the open cycle rocket engine, there is a turbine which powers both the fuel pump and the liquid oxygen. So what powers this turbine? We take a little bit of fuel, we take a little bit of the oxygen, we fire it in a pre burner and the exhaust gases of the pre burner expand in the turbine powering both the two pumps. Now this exhaust from the turbine in an open cycle rocket engine is exhausted into the atmosphere or outside the rocket which means whatever unburned fuel is there and whatever oxygen is left after the combustion both get exhausted. If they go out of the rocket then what happens is that we lose some fuel and some oxygen which could have entered the combustion chamber and participated in the rocket propulsion. This is where the Russians and the Americans parted ways. The Apollo program which was the American moonshot program was powered by Saturn rockets. These Saturn rockets were quite large, they were very impressive. They had high lift capacity but that was not an efficient engine which they used. The rocket engines used were essentially open cycle with the losses we talked about. The Soviet engineers invented something clever, they designed something more clever. They developed what is called a closed cycle rocket engine. This is what we have in front of us, a closed cycle design in which we have the same configuration as earlier which is you have liquid oxygen pump, you have the fuel pump being rotated by a turbine, this is a common shaft that is because the fuel used and the liquid oxygen used have roughly similar specific densities that you could use a common pump. This turbine exhaust as you will see was fed back into the combustion chamber. While it was fed back into the combustion chamber, what was done was all entire oxygen which as you can see which is being pumped was fed to the pre burner through the turbine and it was fed into the combustion chamber with some of the fuel which might or might not have been burned completely. Now, why was oxygen rich exhaust of the turbine used in this way because that meant that the fuel was completely burned but it had a problem. The problem was metallurgy. This required relatively high sophistication for the metallurgists to try and see how this extremely hot gases with oxygen would not cause melting of those components which came in contact with it in the combustion chamber. Remember this is like a oxyacetylene torch through which we cut steel. So, that is what we are really seeing here when you talk about the exhaust of this turbine entering the combustion chamber. This was a difficult metallurgical problem with the Soviet engineer solved. The Americans did not believe that this was a solvable problem. So, they moved to a different configuration which is what we will show you now. They used what is called a fuel rich stage combustion rocket engine. Here and we have the first the simplified version that turbine pump configuration is all of it is same and we are seeing the turbine exhaust which is now fuel rich does not have enough oxygen to burn completely entering the combustion chamber. That means unburned fuel is now being pumped in the combustion chamber which means that it will be completely burnt in the combustion chamber itself when it gets the liquid oxygen or the oxidizer which is coming otherwise which is being pumped into the combustion chamber. The problem here is that if we use a fuel which for instance is say a high form of what is called kerosene or P1 fuel if we use any fuel of that kind then you have the problem or what used to be called glycol based fuels then you have the problem that we generate soot and if you generate soot it gums up the piping the valves and other stuff and that makes it much more difficult. So, what they had to do in order to avoid this kind of soot exiting the turbine or the pre burner in this case was to change the fuel. When you change the fuel to something like liquid hydrogen which is what they did then of course this problem is avoided but you have a different problem that the hydrogen fuel has a very different specific density the liquid oxygen therefore you need a different pump therefore you need also two turbines not one. This is what the Americans did for their fuel rich stage combustion as you can see their fuel rich stage combustion becomes more complex because it now uses two pre burners two turbines and two pumps and this was the more difficult engineering feat that they had to do because they did not solve the metallurgical problems which the Soviets had solved by which with better metallurgy they could handle the oxygen rich exhaust from the turbine. Now, this was the major difference between the two what happens with in this case is that oxygen rich stage combustion is much more efficient in terms of its bang for the buck how much can certain amount of fuel provide in terms of impulse and we are not going to the details of that but the same size with the same amount of fuel you seem to get better efficiencies and a better bang for the buck. This is why when you come later to what the Americans were looking for for their engines rocket engines to power their rockets they found that the Russian RD-170 was a much more powerful engine rocket engine but unfortunately for them it is too big what EnergoMash did for the Americans was to split the RD-170 which is what the Energia rocket launch vehicle was it had four compartments the split into two compartments and that is from RD-170 the transition to RD-180 and the RD-180 is the one which was then used for a huge number of launches the American military and NASA carried out the Atlas III Atlas V engines rocket engines then became the Russian RD-180 engines that is one part of the story that is the second part of the story which is even more interesting you had another group in the United States which is also sending rockets they were planning to send for the space shuttle the basically rockets which are called Antares rockets now this is Northrop Grumman which were at that point developing the Antares rocket in the 90s they had come to Russia and they heard about the NK-33 rocket engine now NK-33 was a part of the moonshot program of the Soviet state at that point of time this was 60s now that was called the N-1 launch vehicle that didn't work very well in fact they were trying at a very short compressed period to try and develop their own moonshot program which they again abandoned once the Apollo program successfully put the Americans on the moon they actually started they had started later but what they had is this NK-33 rocket engines which also had the same property that we discussed earlier they were oxygen rich they were that way relatively more efficient and they handled the metallurgical problems of oxygen-rich combustion as well so the Americans heard about it they didn't actually believe it these engines however had been preserved 40 of them were kept in a quasi mothball state under atmospheric conditions air conditioning and so on and then the Russians said here we had solved the problem and if you want you can take one of them and experiment on it and see whether it works or not the Antares group of Northrop Grumman found that it actually worked they did experiments on it found that yes what was promised was true it was a more powerful rocket than what they were using and this was something better than what they had planned for and it was off the shelf available of course 40 year old engines so these 40 year old engines powered the first Antares rocket launches and test bench results were there after four of these engines were used one of them blew up then of course as you and cry why are you using 40 year old mothball engines reconditioning them and trying it like this so they had to give up that attempt but the point is the N-33 rocket engines worked even 40 years after they had been mothballed Antares switched their rockets the rocket engine then was not the NK-33 as they had tried they switched to RD-181 now RD-181 is again derived from RD-180 which you've already seen and discussed for the Atlas launch vehicles except instead of the two chambers that we talked about it has one chamber so RD-181 is effectively half of RD-180 just as RD-180 is half of RD-170 so this are the progression of Russian launch engines rocket engines which Americans have used and continue to use even today except for the fact that we have what is now a renewal of a kind of Cold War between the United States and Russia following what would be called the Crimean Crimean Peninsula issue where United States objects to the referendum that took place in Crimea by which Crimea joined Russia now without getting into the geopolitics of this today because we are really talking about engines there was a then a move that the American space program should decouple from Russian rocket engines except for the fact there was no rocket engine readily available so there was a talk about not using Russian rocket engines but trying to develop their own rocket engines and also a talk about manufacturing RD-180 in the United States itself so it is theoretically possible given the fact that transfer of technology agreement had been signed for these rocket engines which were coming from Energomash to also possible to be developed or manufactured in the United States what they found was the cost was too high that the investment they would have to make to manufacture wasn't really worth it so the hunt started for alternate engines and this is where Elon Musk and Bezos come in they would like their engines to be used they also have been funded in different ways both Bezos and Musk have been funded by NASA and the US military for developing alternate rocket engines and these are the rocket engines that today are competing with the Russian engines even today the Americans continue to use the Russian engines by 2022 they will stop using Russian engines for military launches which is basically the programs which put satellites in the sky of course you have a huge range of satellites the military uses and Russians are also not comfortable about this they have said they would like to ban the use of their rocket engines for putting essentially military's hardware into space so from both sides there is now a decoupling on the issue of military launch vehicles what we are now seeing is the B-4 engine of Bezos as well as Musk's various engines the Raptor engine being the largest of the family which are trying to compete with the Russian engines yes probably by 22-24 the Russian engines should be slowly phased out of the American space program particularly as NASA is funding now both Blue Origin as well as Elon Musk SpaceX for their rocket engine we have to now see whether when the Americans decouple completely from the Russian engines which they probably do in the next two to five years whether Musk's Raptor engines and the other SpaceX engines as well as Blue Origin's B-4 engine can successfully replace the Russian engines so we will have to watch and see how this competition today develops in space