Skyroot Aerospace Factory Tour

So, this is the one which will be flying in the first flight, let us say is more like a football you know it is more round and. Yeah. Separation systems are like very tricky. Correct. And they have to be like tested really well, they should have like good design. The complicated part of the fairing is it has like two separations, it is horizontal separation, vertical separation. The seal is surviving and then the flex seal we flex it, we have a nozzle that blue color nozzle you know. If you were to name one small thing that became a big engineering challenge, what would it be? Realign things to get into that zone. So, that is how this is quite useful. The super light composite structure. Right. Which you can just lift with your hand. Oh. You know. You just lift with your hand, but it takes the loads of a rocket. Stage 2 flex seal, you can see the metal here inside there. Welcome to Gareeb's Scientist. Recently, I had the opportunity to do a factory tour of Skyroot Aerospace for context, especially for people outside India. Skyroot Aerospace is an Indian private space startup. They are working on orbital class space rockets. It was founded by Pawan and Bharat in 2018, both are ex ISRO as in Indian Space Research Organization. The rocket they are actively working on and which you will see in the video is Vikram 1, which is a orbital class rocket with four stages. Three of its stages are solid and the final stage is a liquid stage. Previously, they have also done a suborbital test with a rocket called VKS, Vikram S, parts of which also you will see in this video. Some parts of this interview get very technical. Mostly it is fine. Also, just like all my videos, there are no mid-roll ads in this video. So, you can watch this entire long video without any interruption. Enjoy. This is big. Every time I open, it's like huge. Like if I pan, I can pan around this side. Yeah. Yeah. So, this is Vikram S, but you said this is not fully. I think, yeah, slightly bigger than what it actually is. Right, very big. So, how smaller will be the other that is outside, I can show the outside. Outside, yeah, outside one. So, actual one is like 6 meters, you know. Ok. Also, this is my, I think maybe 7 meter, 8 meters, yeah. So, you had a plan of a scaled up Vikram S or? No, no, no, because you know, so now our full focus is on orbital only. Right. So, we will keep it to orbital now, yeah. Ok. So, this is the rocket. Yeah. We will start from behind. Yeah. So, yeah. So, this is, this is a Vikram 1. Yeah. So, this is like you can see, I think, you know, you can say it is actually 22 meters tall. Right. So, it will be like 7 storeyed building, tall vehicle. Yeah. And these are actual stage 1, stage 2 and stage 3 motors. Correct. And this is the one actually is going to fly. Ok. So, the first one which will go for static test is in our other facility. Ok. So, that is all painted now and all. Right. So, this is yet to get painted. So, this is the one which will be flying in the first flight. And the stage 2 is like, this is a third motor that will be flying in our second flight, you know. Ok. So, whatever you see there, second. So, you had, you used to post images of sky route folks. Yeah. Yeah. So, this is the first stage 2. Yeah, that is this one. This is this one. Yes, correct. Yeah. Ok. Yeah. So, that, but that is the second launch stage 2. This is the, this is the, sorry, that is the first launch stage 2 and this is the second launch stage 2. Ok. So, you. So, we build like, I think, may be overall 4, 4, 5 hardware, 4 hardwares. Ok. One for pressure, pressure test. Yeah. Yeah. So, so, one for static test and 3 for flights. Yeah. So, ok. I think we will come there. Yeah. So, this, this is conical. Yeah. Yeah. Yeah. It will always be conical? No, we will, in fact, the first flight we will have it cylindrical, because in between we redesigned to be conical to have a good, what we call it as Cp Cg distance, you know. So, it is a distance between Cp of the center of pressure and center of gravity of the rocket. So, the less it is, the better controllable the rocket is. Right. So, we thought like, you know, to have like better control for the first flight, we will keep it conical, but we, once the, all the hardwares are realized, once we have all the, you know, masses ready and everything, we realize that Cp Cg distance is decent enough. And the first stage also, like we increase the angle of the nozzle, we can. Ok. The actuation angle of the nozzle also we slightly increase. So, so, all the controllability fell in good limits and good margins. So, we thought like, you know, we will go with cylindrical pressure itself, because that will give us better payload. Right. That cylinder, the metal ring is so, it does not collide with the shroud. You know, that is for, you know, that is for attaching the actuators. Ok. Ok. Yeah. So, you have like two actuators and we have two additional sensors called LVDTs, you know. So, in fact, for solid motors, they are called mirror imaging sensors. Ok. So, exactly opposite to each actuator, there is one mirror imaging sensor. Right. You know, so, it will exactly mirror the movement of this. Ok. So, this is specifically required for solid motors, because what happens is the solid nozzles not only actuate in pitch and yaw and all other directions. Right. They also move forward, because as, because there is a flex seal in between. Correct. Which compresses with a combustion pressure. So, as suddenly the pressure comes up, you know, the nozzle will get pushed outside. Ok. So, for that you need a mirror imaging sensor, which will help you control the vehicle very well. Yeah. Oh, that was, that did not think about it. Yeah. So, again point up. Yeah, sure, sure. Ok. So, submerged flex seal as in you, the flex seal thing will, I do not know if you have it here. Yeah, yeah, that is submerged, you know, you can see the nozzle projecting inside the rocket. Right. Yeah, yeah. So, that is like the submerged nozzle. Submerged nozzle means like it is submerged inside the case. Ok. You can see the nozzle top portion is inside the motor. Right, right, right. Yeah. So, that is where, that is what makes it submerged. Yeah. And then that is the flex nozzle, which will flex to. Correct, correct. So, flex nozzle is used for thrust vector control of the vehicle. So, you know, you can, you can change the direction of the nozzle, you can change the direction of the rocket. So, you will have both axis x and as in pitch and. Yeah. So, when you put two actuators in 90 degrees, you can actually rotate the nozzle in whatever direction you want. Correct, correct. Yeah. Ok. Yeah, here I think, I think we can only see one actuator. Yeah, one actuator, but 90 degrees opposite there will be another actuator and then opposite to these actuators, you have something called mirror imaging sensors, you see. Right, right. Yeah. So, just like they are, they are called LVDTs, there is a sensor which will sense the displacement. Ok. Yeah. So, you said these are not fins, right. Those are not fins, those are called like, so, there we have like sensors which identifies that the rocket lifted off. Ok. They are called last minute pull or last minute plug. Ok. LMPs. So, they are like electrical connectors, which after the rocket moves by certain mm, maybe 5 mm or 10 mm, it detaches and then you know that the actual lift off of the rocket happened. And then you start the control of the vehicle. Ok. Yeah. So, everything seems like carbon fiber here, is the whole rocket mostly composite? Yeah. So, every all structures are composite. So, it is like you know all carbon fiber rocket, one of the very few vehicles with all carbon fiber. Correct. Rocket in the world. Yeah. So, you have to wrap this in a way that it has directional strength. Yeah. Yeah. So, we call it like filament winding. Yeah. So, what happens is that we have a 4 axis robot which you know puts the fiber in the right direction. Right. So, it takes like hoop loads, tensile loads, you know axial loads, hoop loads and also it has like this strength in all directions basically. Right. Mostly this is like we can take it as a pressure vessel, you know inside you have like. Correct. Pressure at 80 atmospheres or so. So, it has to have that, so, it should have a dome as well. So, we can see the dome also. So, the dome can take and you can also see the fibers woven in different directions. Right. Right. So, and this has to be super precise also. Yeah. So, that you know you have really good distribution of stresses. Correct. And also this mass has to be lower as well. So, that way I think this you need this 4 axis winding to get this and also we need a specific shape of the dome. Correct. So, which you know which calls it which we call it as isotensoid dome. Ok. So, which has like very good distribution of stresses. Right. To reduce the mass of the dome because domes are super thick and super heavy. Oh. You know. So, we want to reduce as much as possible. So, that it is a lighter hardware. And this must be have been challenging to engineer. Yeah. In fact, I think it took us 2-3 years just to master building the these carbon fiber structures. Correct. Because in fact, we had we coded it from scratch. We coded we actually give that M codes you know into and on to the you know on to the machine. So, we build a software which gives directly the CNC codes. Right. And that CNC code will you know wind the rocket motor. So, we had to build everything from scratch software. And then, but we are happy that you know till now every hardware we build is has worked. Ok. So, you must have started on some small scale something. Yeah. What was the smallest thing? So, I do not know whether you remember we fired something called Kalam 5. Correct correct. Long ago. I remember. I think 3, 2, 3 years 3 years back or 4 years back. Yes yes. So, it is a very small motor. Correct correct. So, it is like 1 is to 4 scale of our stage 3. Right. Ok. So, that we built it and then we pressure tested it, we fired it. Correct correct. So, that we got some good confidence and then we had to do lot of trial windings to get some confidence on it and you know building it straight from the equations is very challenging. You know this has lot of fundamental equations. Right right. Which define how the stress distribution happens, how we have to wind the fiber. Right. What direction it has to go. Right. And then there is also something like there are factors like friction factor which you know if you do not maintain that it starts slipping. As you as you wind it starts slipping. And when it slips you gone hard the whole hardware is gone. You have to. So, you have to restart everything. You have to build everything. Oh. And so, it is quite challenging, but I think we are good that we have mastered in a reasonable way till now. So, that we can make lightweight structures because margins on these are not very much. Right. You know if you if you go for very high margins your mass goes very up. Correct. You know very high. And if you go very light then you know the chances of exploding. Correct. Right. So, it has to be like very. Delicate. Delicate margins which we have to maintain and that is where like the challenge comes into attain those margins and manufacture it reliably again and again multiple hardware's multiple times. Right. Yeah. So, we I mean we you have said you have shown engines a metallurgic engines. Yeah. Running. Yeah. So, you have to build this with liquid stages in mind. So, they do not leak or. For solids you mean. For no for your metallurgic stage. Yeah. Yeah. Future metallurgic stage. Yeah. Yeah. So, we need to have a liner. Right. Yeah. So, there are two types of tanks liner liner tanks and liner less tanks as well. So, now, the trend is even for cryogenics you do not need a liner if you if you actually build a composite hardware which the right resin you do not need a liner. And we can do it with multiple methods one is through filament winding you can also do it with you know hand layups you can also do it with you know robots which add layer by layer it is called automated fiber placement machines. So, different methods are there. Today you can build cryogenic tanks without liners at all yeah. So, I see a design change here. Yeah. There is a cone the earlier end is a straight. Yeah. So, what has happened to the first stage? Yeah. So, first stage we were slightly increase the diameter you know to load in more propellant and so, that is where like you can get slightly better payload. So, that is why like first is slightly bigger you know around I think around 200 mm diameter you know more diameter than the rest of the vehicle that is why you have a cone to transition from that cylindrical to the you know this cylinder to the that cylinder you know. Right. So, slightly higher diameter cylinder to a lower diameter cylinder. So, almost 1200 kilo Newton. Yeah. Lots of thrust. Lots of thrust. Lots of thrust. Lots of thrust. Yeah. Lots of thrust. So, static test happens right it is going to shake up. Right. Ok. This what is I forgot the name what you call this interstages. Interstages. Yeah. So, what will reside what so, every stage will have its own electronics for. Yeah. Correct. Every stage will have its own electronics and, but the mission computer will be one for the entire vehicle. Right. Right. You know. So, that will stay in the top most stage, but for example, you need like batteries large batteries and you need a control electronics to control the actuators and the nozzle. Right. For the TVC system that goes along with each stage and also there is a like a long plumbing you know the for example, this is a 10 meter long hardware. So, we have a very long wire going from top to bottom. So, that also gets separated you know whatever mass we can let go we let go with each stage. So, you have to build separation system for the wires or is it like passively they will get pulled up. No, our separation system is little bit different. So, we use instead of using pyros we use pneumatic system where like there are gas bottles again and then they store high pressure gas and then you know that gives a signal to a mechanism which opens it up. Right. Etcetera. So, that needs lot of plumbing etcetera all that separate along with the stage. This nozzle I is this the final size of the nozzle. Yeah, this is the actual size of the nozzle yeah. It looks so close to that inter stage. Yeah that is it I mean see with all rockets have very thin margins. So, if you want to have like lesser size than this you lose error ratio you know. So, that means, when you lose error ratio you lose the ISP and so, when you lose ISP you do not get much payload. So, you have to have as big nozzle as possible and then. So, what you have to do is you have to design the separation system such a way that you know it does not collide during separation. Right. Yeah. So, stage 2 this is Kalam. This is Kalam what is that 250. Kalam 250. Because the thrust is around 25 tons or 250 kilo Newton's. Right. So, you name your motors after thrust values. Correct yes yeah yeah yeah. So, when will we expect a static fire off. Soon I mean just few weeks away probably you know. Ok. So, this was actually casted I think months ago. We just like waiting for the stage test to happen soon. Yeah this is nothing, but like a stretched version of a stage 3 which happened like you know 2 years ago. Right. So, it is like the same diameter just like stretched in length of course, with a bigger nozzle and you know. So, all everything is ready for a static test we have to just assemble and test soon yeah few weeks more probably. What are the challenges of scaling it like this like going from Kalam 100 right. Yeah. Kalam 100 to. Yeah. So, what are the challenges like engineering challenges with going. Going big one thing is that you know the winding program also changes because the length is different. Right. Actually you know etcetera and then in fact, lengthier ones are easier to wind. Ok. It is better and easier and so, this third stage is more like a football you know it is more round and. Yeah yeah yeah. It is slightly more difficult to wind and so, it is actually easier and you have to build a new tool you know because that length is different this length is different and this is heavier. Right. So, the tool will be different and stage 1 tool is like massive you know it is a 12 meter tool. Correct correct. You know it is like a 12 meter high precision tool which only few people can manufacture itself. So, that way the once the size becomes bigger the tooling becomes more complicated and handling becomes more complicated. Ok. You know handling all these structures you know moving them out you know putting them aligning them. Right right. So, that becomes a challenge otherwise like tech is more or less the same. Ok. Yeah. So, here the second stage third stage inter stage looks big. Yeah. This this scales with the diameter nozzle. Correct correct correct correct yeah yeah yeah. So, so here in fact, you cannot we would love to go for a much bigger nozzle actually because you get even more error ratio. Right. So, but there are like lot of systems inside this inter stage which which does the roll control of the entire vehicle. So, the roll control will be in this inter stage. Yeah correct correct yeah. So, that you know so, if you put roll control originally our plan like several years ago was to have single roll control the top of the vehicle. Correct correct correct. And the like final kick stage of the vehicle. Right. But then, but then like that has a good loss of payload. Right. So, you know because we need to add like bigger tanks there, you need to add you know lot of more propellant than required, you need to add bigger thrusters. Right right. To for roll control of the entire vehicle top to bottom. Correct. So, because of the first few stages, you require more thrust and after it the vehicle gets lighter you need less thrust to roll control. So, what you do is that if you put it at the top, you put bigger engines continuously and those will be carried up to the satellite. Correct correct. And it causes like you know payload loss. Right. That is where we moved it down and so, there we have tanks and other systems. So, we need to maintain some gap between the nozzle and this. So, that is where that limits the error ratio of the third stage. Ok. Yeah. What is the loss like ok fine fourth stage 1 is to 1. So, what is the third stage or second stage how much do you add and how much do you add? It depends on each stage you know like for example, third stage will be like 1 is to 2 around or even less. Ok. 1 is to 1.8 or something like that. Ok. And first stage is like the least you know sensitive it is you know 1 is to you know 30 plus number. Oh ok. Yeah. So, even if you add 30 kgs you will lose only a kilogram of payload. Yeah. That is that is nice. Yeah. Ok. So, this is column 100. Yes. Yes. This is what was test fired I think more than couple of years ago. Correct. Correct. Yeah. Does anything anything is changed or. No we have upgraded it I made it much lighter and if you remember like I think that was a fixed nozzle concept and for a fixed nozzle you need a separate pitch yaw control right. Now, we made this also into a TBC thrust vector control. So, this also nozzle rotates it has its own actuators nozzle rotates. Right. So, it rotates the vehicle and so, you avoid like big pitch yaw thrusters which will be required for a fixed nozzle and we realize that that gives a good payload gain. Right. So, we put a TBC system here as well. So, all three stages have TBC. All three stages have TBC. Which means they require big batteries to go in along. Not very big I mean depends on the actuator. Ok. First stage requires like a decently big batteries. And then second much smaller third is much much smaller yeah. Right. So, you were talking about some will require retro motors some might not require. Yeah yeah yeah. So, basically what happens in solid motors is that there is a residual thrust after the . you know action time is over, still there is some sort of thrust which is you know residual after the motor is off as well. Correct, correct, tail of thrust. Yeah. So, and the tail of thrust can often be very long as well. Right. It can be very long tail of thrust as well. So, what we do is that we have some smaller solid motors which fire for few second, few seconds typically you know 1 to 2 seconds. Around that and then they fire and they negate this extra tail of thrust which is built up and immediately separate the stage. So, that way what happens is that the second stage can ignite immediately. And you avoid losses you know. So, there are multiple losses which and there is a no control zone. The quicker you start the control of the second stage, you reduce this no control zone. Ok, ok. Because what happens the first and second stage the atmosphere is very thin, but still there is. Still there is ok. Decent you know what we call dynamic pressure. Right. There is still some decent dynamic pressure. So, and if you just leave it for long time you know the rocket completely will tumble. So, you have to immediately start control the moment the second stage first and second stage separate. The second stage should ignite as quickly as possible to reduce that no control zone. Ok. So, that is where first to second we use retros and other stages we use like springs and other pneumatic pushers or things which can assist in separation. So, the first wire tunnel ends here. Yeah, yeah. No. So, there is a wire tunnel continuously going you know. So, what happens wherever there is interstage the wires go inside, the routing is inside and then it comes out again. You see some cutouts one below the other it again comes out. Then on the motors anyway you cannot put inside the motors because it is all propellant. Right. So, again it happens on the rocket you know on the surface of the rocket you have some wire tunnels, then again it goes into the structure and again it comes out yeah. Just curious have you aero modeled with wire tunnel without wire tunnel does it. Yeah, yeah absolutely you know it is because see for a smooth vehicle with no projections aerodynamic is quite simple and these small small projections create lot of issues. Right, right. And in fact, they have to be so well modeled and because all the coefficients especially even there is something called roll coefficient. Roll coefficient decides how much roll thrusters you have to you know you have to size for. So, what happens is that if you do not like model them properly you start getting like non actual non realistic numbers. And then you size things non realistically and that can like compromise the mission. Right. So, you have to be very super accurate on the aerodynamics that is why we do wind tunnel testing to validate as well which we completed for Vikram 1. So, we see that all the coefficients we require are as close to accurate as possible and then based on that we see that all the sizing is done with some margins. So, that even if accounts for some delays. Or like some changes like for example, during the design process we keep changing slight dimensions and all. We keep some margins to absorb them yeah. Right. So, this wires how they separate they get just pulled out or they have a cutter mechanism. Yeah. So, there are some special kind of connectors which have a separating mechanism. Ok. Very small mechanism. Ok. Along with the rod and so, they have certain beyond certain force they separate. So, as the stages are pushed either with a retro motor or with a springs right. So, these connector also separates. Oh interesting. Yeah. So, they could not like pull the stage little here and there it is very smooth. They can, but we design for that. Ok. You know and also there are too many wires what we do is that we put them opposite to each other. So, that when force is there forces are opposite. Ok. So, that do not create a torque you know. Right. So, all that all considered in the design. So, that you know we can get a very stress free separation because most of the failures you see is in separation. Right. Yeah. So, propulsion more or less works well and lot of systems work well, but separation systems are like very tricky. Correct. And they have to be like tested really well they should have like good design margins. Yeah. So, something has changed here in the fourth stage. Yeah, I think you can see a central engine right. So, the Raman 2 whatever you see is the central engine. So, previously I think you are quoting the old like 4 thrusters around the vehicle. Yeah. Yeah. So, that is long back change we change the design to central thruster. Correct. Where like there is only one engine in the center and then that purpose the final stage and that is a 3D printed engine where like even the pipes over 3D printed along with the engine etcetera. And so, this has all the channels inside itself. And which cools it is a regenerative cooled engine and then, but this is a fixed engine. So, it does not have a TVC because a TVC will call for new actuators, control electronics, batteries. Correct. Etcetera. So, because this is a small engine we can actually manage with small thrusters few Newton's of thrusters to manage the pitch and yaw, but still you have projections 4 projections on the vehicle if you see. Correct. So, those are like small Newton thrusters for pitch and yaw control there we call them Raman mini thrusters. Right. They control the they do the pitch and yaw control of this engine. So, putting them outside on the surface. Yeah. Versus putting them on the base plate. Yeah. There is a difference. Yeah. So, see when you put it outside know you get more torque. Right. So, you should keep it as away as possible when you do pitch and yaw right from the center what is the torque is what I mean force into distance. So, the moment you move as much distance as possible with a small thruster you can actually manage a good torque. Right. Good control. Right. So, that is where we need to keep it as away as possible. Ok. You know and so, that is why like you know we put it as away from thruster as possible. Ok. So, coming to the satellite now what with this latest configuration what is the max payloads. So, it depends on the orbit you know we could. So, target is to reach like 400 plus and so, we will keep having like updates and upgrades small small upgrades with each flight you know. So, because from generally the first two flights we get a lot of data and we see like how much propellant is left how much guidance margin is actually required. Right. What are the different fluctuations we see in the flight etcetera etcetera. So, all that we get to know I think we will get a fair amount of idea on the exact payload after the first flight. Ok. You know we get lot of data and the whole target is to for low inclination orbits etcetera we have to cross like 400 kgs. Ok. Yeah. So, fairing simple to design or because this is not cylinder. Yeah yeah fairing is again here also the tooling is complicated. Right. So, you should build the tool big steel tool. I do not know I think maybe in some of the pictures might be there you know this is a quite a big steel shining. Tooling which we need to make. Right. So, that is that is I think that takes good amount of time after that I think it is it is fine I mean it is it is all lay up and then you build the carbon composite shell and then it is anyway light enough and then, but but the complicated part of the fairing is it has like two separations. It is horizontal separation vertical separation. Correct. Because fairing has to open like a clam shell. Right. So, there will be vertical separation plane horizontal separation plane. So, you should have separation in both that in both planes. Right. And it should work really well and very reliably. While it is thrusting. Yeah. So, yeah while it is thrusting it has to separate, but thrusting part may not be a challenge you know, but but in general just separation of two parallel planes not parallel planes I mean perpendicular planes, but parallely separating them parallely there is also like we need to give a small gap between them. So, there is there is some science physics associated with it to have a very successful clam shell opening of the payload fairing. So, will you also have a seal and air vent external air vent and all those. Yeah. So, we need to have a seal because there are like two structures. Correct. Together and then in launch vehicle structural dynamics is complicated because. So, we build lot of thin shells to save weight. And then they have dynamics their own dynamics. Correct. So, what happens is that they will open as the statics also dynamics also. So, there is like force which opens it up and there is also like dynamics which opens it things up even if locally if something opens up what happens the clean air which is to be maintained for the satellite that escapes out. Correct. You know and we have vents for venting slowly, but we do not want the air dust or you know air to get inside. Right. So, that will pollute the atmosphere inside. So, we want things moving from inside to outside because naturally there is vacuum outside, we have to vent out to reduce the stresses. So, we have a vent we will have vent adapters to vent things out, but we have we should have all protection. So, that the dust from the external atmosphere does not get in. So, you need to have like good seals. As it is going up it has to slowly release the clean air from inside. Yeah. Yes. Yeah. Otherwise what happens is there will be like it is like a one one atmosphere of pressure. Correct. Which is big enough if you calculate over the surface area, this is decently big enough. Yeah, but still I mean it is better to vent it. Right. When you have like to reduce the stress, but it can also survive. Yeah. The pressure. So, even if in cases like when valve fails also it is or payload fairing will survive. Do you have to put any material on the tip? What is your max heating going to be as you go up? No temperature we should not cross like more than 100 degree centigrade of the skin. So, based on that like we put a thermal protection system on top. So, we have certain materials which will which will take this temperature and thickness will change depending on the heat flux. So, the tip of course, the heat flux is high. So, you will have more thickness. And as you go down the requirement is reduced. So, you reduce the thickness of the thermal protection system. Yeah. So, we will we will see right a fairing separation test of. Yeah sure we will I think the hardware is in final stage and now we are like busy completing the stage separation test. Right. So, once that is done I think we should see them soon yeah PLF separation as well. Yeah beautiful rocket. Yeah. Very big as well people just how much you said 17 meter? 22. 22 meters. 22 meter. So, it is like yeah it is I mean equivalent to 7 storeyed building tall vehicle. Yeah. Yeah and actually it is become slightly longer than when we designed 4 years ago. Yeah 18 meter I think no. No no it was like around 1920. 1920. So, slowly slowly you know you need some gaps and then you know yeah. Right. And then like the first stage also slightly increased and all that when actual detailing happens that is gone longer. Yeah. Yeah. This was good. Yeah. Yeah. So, I think this is I think you have recently done this. So, these are like 2 test rigs basically. So, first is that test rig where we test all the flex seals you know. So, flex seal is used for like you know you want to rotate the nozzle and you need to have a flexible member and you cannot have a regular bearing because. Right. It should also survive the loads and the temperatures. Correct. Correct. So, we have a specific type of seal called flex seal which has layers of rubber and metal and to protect the rubber we have another layer of high temperature rubber. Ok. And all that. So, that can flex up to you know whatever the angles we want may be up to 7 8 degrees it can flex maximum in the maximum scenario. And then so, what we do is that this one we pressurize up to the actual pressure which is required in the motor with some margin additional margin we give. Right. So, we pressurize it up and see that the flex seal is surviving and then the flex seal we flex it we have a nozzle that blue color nozzle you know which we see here yeah. So, there is like simulated nozzle which we have which we will use for every other this nozzle. So, this is not the actual nozzle, but this is a simulated nozzle we simulate the moment of inertia etcetera and then we have these actuators which move it and this is for flex seal we put the flex seal with different pressures and then do it and then this is the actual nozzle. So, that we do with dummy nozzle. Right. With different actuators and here we do with actual nozzle with actual actuators and then this gets assembled to the actual motor and then we fire it or go for flight. Right. Yeah. So, you will be going full closed loop since launch or. No. So, initial phase will be open loop to reduce the loads. You know slowly there will be a switch from open loop guidance to closed loop guidance. Ok. So, that will so, it is more to manage the loads even though it is not optimum on the payload perspective, but we do it to manage the loads. Ok. Yeah. So, similar to PSLV and other. Yeah, yeah, yeah, but we do that wind biasing which will see that the errors are lower than what we expect, but yeah and also like it helps us manage the stress on the vehicle as we go further. So, last minute based on winds and all you will have to feed different models. Yeah, correct, correct, correct. So, in fact, we did that for Vikramas as well. So, Vikramas is like a highly aerodynamic driven vehicle. Correct. You know so, we need to we need to check winds on that particular day and then so, they have wind profiler which checks the exact way how the winds are and then based on that we you know we feed that angle of the launch based on that. Right. So, similarly here it will be a slightly different, but the concept will be somewhat similar as well. Right. So, where we detect we do wind biasing we get all the wind data based on that we record that program to the vehicle which will go the guidance will take it in open loop initially based on the winds and then it goes to closed loop. How close this happens to the launch? What you plan to do? So, it is not very close to the launch, we want ideally it should go as close to the launch as possible. So, we do few hours depending on the wind biasing limitations and few hours before we try to complete it and then feed it. I have heard of cassettes and something is being put. So, now, it is all digital right so, yeah. So, one last thing on this nozzle this shape is optimized for what domain in speed? So, aerodynamics and acoustics both you know. So, it should be like smooth for aerodynamics the flow should be quite smooth. And, basically the satellite right the satellite environment is nothing, but the acoustic environment. Right. As the rocket goes up basically the acoustics comes from one is from the plume during lift off right the huge sound which comes. Correct. So, that affects the satellite. Another thing is during this transonic regime when the rocket like crosses the mach 1 right and there will be like a good amount of acoustics which comes in. So, this shape which is called an agive shape which is quite good for less acoustics and also decently you know good for the aerodynamic flow as well. Right. And, the flow also decides the acoustics. So, it is all like quite related and agive is like a very good optimum shape for payload fairings, but we also see that conical and cylindrical as well, but the conical and cylindrical what happens is the manufacturing is easy, but it is not as good as the agive shape. Ok. And, since you spoke about max Q is your like grain geometry and star optimized such that. Yeah. There the thrust is lower. Absolutely, you need that because see the so, one beauty about solid fuel vehicles is that you can design the thrust time curve as it is you can design without requiring a you know throttling valve or you know or any algorithm or nothing you know. Right. So, you can design the shape of the grain and you can design whatever shape you want and you can see that you know it throttles sometimes even 30-40 percent during the flight again it comes up as per required. So, what we do is that initially before reaching max Q we see that the thrust goes down. So, that our Q comes down Q is maximum dynamic pressure max Q is maximum dynamic pressure and so, Q comes down and so, overall max Q also during the flight comes down. Right. So, what happens we have like a thrust which goes up initially and then comes down just before the max Q design after that zone is fast again it goes up. So, you we design the curve such that you have very less overall stress on the vehicle. Yeah. Small details. Yeah. I mean like so, building rockets is like so, many engineering judgments to be made. Yeah. So, you know you have to work on different margins and across various systems. Right. Hundreds of systems working together everything related to each other. Correct. It is quite a challenge and that is why it keeps evolving the design keeps evolving with time and I think several iterations even I think for each grain we do several hundreds of iterations. Oh. Which grain is ideal you know even like 2-3 kilo Pascals of dynamic pressure reduction you know and then that affects the burn time and you know there is so, many everything is related to everything else. Yeah. So, it is like you know building an optimum vehicle is a good challenge very, but very exciting to do all the iterations and identify something and sometimes the actual hardware comes different than what we design. Correct. So, and then we have to again keep on iterating even on the hardware side also. So, one on design simulation side we have to iterate hardware side we have to iterate you know. So, it is a continuous evolving process. If you have to name one small thing that became a big engineering challenge what would it be? Anything small which like which general public would not appreciate as such. Is it on Vikram 1? Anything aerospace or in this in this sky route. I think VKS was a tough flight. Oh. I think even I never imagined that it was it would be so, difficult, but I think the simulation was very challenging because it is a highly aerodynamic driven vehicle. Right. And it also has a lot of dynamics dynamic characteristic you know pitch your role you know linking up. Correct. All that stuff and you know we have to rely on previously what you do is that you if you have like lot of flights you do few few flights and then you learn. Correct. You do not have that you know flexibility you have to have the first flight right. Right. And also very thin very small amount of time we thought like you know you would complete well took lot of time and so, many simulations I cannot believe how many simulations we have done on thermal aspects because it is a very fast moving vehicle. Yeah. The heat generated is also very high. Right. And and then like the aerodynamics even slight change in the fin can affect the dynamics of the vehicle. Right. And it can you know it can go from a successful flight to you know completely a disaster in just like few few small changes in the design not done properly or not simulated properly and we cannot simulate everything on ground. Right. So, it is that is been quite challenging even on the small vehicle on Vikram 1 I think even I think separation dynamics is one challenge you know because lot of multi physics comes into picture. And then even separation mechanism also something new which we have built and there is also new it required new materials. Correct. Than what we expected. So, you know and then it also requires like it is consistent like you do hundreds of tests it works. Right. So, make. taking it to that kind of liabilities also quite challenging separation part is a bit of a challenge right quite here and also like winding as I said initially you know building up that expertise to do big motor winding right because here you know what we call these as these are like openings are different the motor openings are different when openings are same it is a different kind of it is it is easier to wind when openings are there is an opening ratio very difficult to wind and our opening ratios are like quite large making the winding very very difficult. So, we have to make the right program for it and do some trails we have to do some winding trails see that it is not slipping you know and all that. Hardware is expensive not to develop. Hardware is very expensive and we cannot iterate because it is too expensive to iterate multiple times you have to get it first time right. So, we will small prototypes then we went to the stage 3 then stage 3 became a success then like we went to stage 2 then stage 1 right. So, like that I think we have built like quite a good expertise with time the lot of small minor things which we have many of them which we have learned step by step right and yeah. So, that is one challenge and even the flex nozzle system has been like much more challenging than what we imagined you know because actuators building the actuators to the required reliability you know. So, what happens is that when you test the actuators you see some small spikes and some inconsistencies from what we what we design for. So, then like that also becomes challenge here you know fixing them understanding the root cause fixing all the bugs which has originated then there is some because of software some because of hardware right and then you have like a massive control electronic system which manages all the power from the battery and then goes up. So, I think the building the actuation system is I think very very challenging I never imagined that that will end up a big challenge, but it happened to be a very big challenge and that is also like a learning process it took time to get that learning curve to get to a enough level where you know we can build any new actuation system which is very robust and it works right and then and there is a lot of elements like I said like software, hardware and then even small tolerances change would you know cause issues in the actuation system. It has to be perfect it just has to be perfect it cannot be have any small like and you will see like the data not being very good if you in small even with small issues it can create that. Yeah ok I think before wrapping up on this one last question. Yeah. You might have cameras on inter stages and. Correct. Yeah yeah. What is the challenge with having high bandwidth or high say HD streaming? Yeah. What will limit you there what is the constraint? So, it is the hardware. So, like you know because you have an Ethernet cable Ethernet line inside and you have and also like you have. So, internally also there is some bandwidth limitation whatever maximum the Ethernet cable which actually takes quite a good MBPS, but from vehicle till the ground right. So, there is antennas which beam down the electromagnetic. Right. Radiation you know and then which gives to the radars etcetera. So, that also has a limitation. So, we can actually make it very big, but you will have to you know make slightly more you lose some payload that is it is just a balance of it and especially for small vehicles payload is very very tough to get. Right. You know because every small for example, if you build a vehicle with let us say 4 tons of capacity. They are like you know maybe you know getting payload compromises is slightly changes here and there even design with slightly bigger. Vehicle, but in small vehicles what happens is that getting the payload is super challenge. Right. And everywhere you are try to optimize even here also like you know we would love to have like wonderful cameras beaming like very in high very high bandwidth continuously throughout the flight right, but that becomes a luxury. Right. Where you have to let go some payload some hardware becomes like little bit more bigger you need to have high bandwidth communications internally and externally as well. So, your TTC and your camera feed will be two separate or will be there on the same channel there will be. Same channel. Same channel, but the channel will get heavy you know the entire. Right. Yeah. So, it has to be designed for this high bit rates. And it also has to be like for example, you can go with ultra HD for example, ultra HD if you camera if you go you need to like have like high GBPS kind of a system where you know it beams out. So, that requires like heavier hardware right. So, yeah. So, that way, but we have like a decent I think VKS if you have seen right. It is a HD camera. It was good yeah. Slightly I think slightly smaller than HD or something it was decent yeah yeah. Yeah that was good VKS. So, yeah. So, I think with slowly with as we go further we can get this thing also better. As you optimize the payload better. Correct. We can also have like better hardware which can be more really high definition. Yeah. Much much high definition video yeah. Yeah. Yeah. So, this is like a center of gravity measurement machine. So, we put all the sections on this and see that because we design for a center of gravity and, but what we see is from a 3D model which will remain different from what is actual. So, we put the actual section on this with so many components inside and then we measure the CG anything off than what we design again you know your control power plant is not designed for those offsets. So, you have to realign things to get into that zone. So, that is how this is quite useful. How does it work I mean it will tilt if it is off? So, it has a principle where like you know it is a 3 point it has 3 sensors which will give you load if it is exactly at the center the CG is exactly at the center you get the same value in all the 3 sensors. Right. So, if you have like slight offset it will give you different values based on that you can back calculate what is the CG offset. Will the launch clamp also have something like that? Pardon. When you assemble on the launch pad. Yeah. Will it also be able to do this CG calculation? No. For a full strike vehicle you want just each element. No. So, that yeah. So, because see we want that launch ground to be super rigid. Right. So, this is not rigid because it has sensors in between and then on very thin sections to measure it etcetera. Right. So, we wanted to be super rigid. So, yeah. So, generally on launch we do not do that and that is that much is not required anyway because section wise we anyway do and wherever propellant is there propellant takes care of the CG. You would not like you know several tons of propellant and you see that the tool you know the for example, sword motor you have a mandrel in between it is very accurate then you get the CG right at the center. Yeah. I think this is one we have one of the sections here I think this is. Ok. Yeah. So, this is 1 2. I thought that is real person for some time. So, this is yeah. So, this is one of this 1 2 L I think this is one of the hardware's which is yet to get assembled yeah. So, this is like this is like a super light composite structure. Which you can just lift with your hand. Oh. You know. Oh. You just lift with your hand, but it takes the loads of a rocket you know. Yeah. So, you can just I was able to lift two structures with two of my hands. Yeah. And you can see like this is how the radius I mean like the diameter of the vehicle will look. So, this is what you are calling the honeycomb thing. Yeah. So, it has it is a very light honeycomb section inside which makes it like super light and still has that section modulus which you require. Wow. Yeah. So, this is like one of the structure, but like. So, we have like 7 8 of such structures in the vehicle yeah. This is such a big crane. Yeah. It moves along the whole. Whole facility. Whole facility. Yes. Yes. So, that stage when you had moved out it was through this and this is a main. Yeah. This is the main way. Oh, you will have to have to design the whole thing around this as well. Also it directly goes to the road. So, basically all these openings of the shutters and you know the how the length and turning radius all that has to be considered to design the facility. So, this limits your stage potential length for future. You can can you make it bigger? Pardon yeah this one. Yeah. No, no I mean like. So, this facility I think is good enough for maybe like slightly bigger motors than what we build. But not more than that. Shipping this must be ok, these are as of now these are small. Yeah, but we have this shipping container. So, each one of these again it is a container right. So, and then like we also have like big trucks 40 feet trucks etcetera moving the bigger ones the bigger hardware's. And here I think you can see a flex seal maybe this is yeah. So, this is our stage yeah. So, this is our stage stage 2 flex seal you can see the metal here inside there are layers of rubber. Oh it literally looks like. Yeah. Yeah. This is not what I expected. Yeah. Yeah. Yeah. I have not seen this mark 3. Big one. S 200. Yeah. Yeah. That is a very big thing. Dark black flex seal. Yeah. Yeah. So, this is another flex seal. Also it is like this big. Yeah. That big. That is it. Oh. But stage 1 will be bigger. Stage 1 is big. Later we went to this other facility where unfortunately I was not recording video. So, while I will play this video, I will talk on the video and explain what I saw. So, here there was another stage 2. This is Kalam 250 motor, right. And if you see behind, you will see spare parts of VKS, Vikram S rockets lying here. This is another interstage. And if you see just right of it, there are some fairing testing parts. So, this is for fit and all of those checks, test checks. Here you see the cryogenic test facility. This is mobile. This can be moved. So, you could have, you will have seen this in that Dhawan 2, Dhawan engine test which is a cryogenic engine, smith locks engine. So, this they showed. So, this can be moved, that facility. Here you see there are 2 fresh flex seals. So, what Pawan is describing here is the top of the nozzle will get attached on top. So, that is fixed. And the, sorry, the top of the nozzle, the outward part will get attached down. And this whole thing, the lower thing can flex on top of that ring. So, this is how that works. And I want to someday create a video explaining how this flex nozzles work with animations. So, there were 2 of this. And you see more test stands here for small engines. This is a interstage they were using for testing the separation mechanism, etc. You see some jigs here to transport some heavy things. And here you see some fuel tanks. So, this was it mainly. And besides this, there was some full stage I will show you in a second. So, this big tanks you show, you are seeing are used for higher storing of fuel. So, this one was a completed first stage again in, this is a different facility. There were some fairings and you will also see a stage 1 tool here used for making the stage 1 which we saw earlier while wrapping. So, in general, this whole tour was really exciting, I learnt a lot. Pawan actually spent a great deal of time, although this interview is like maybe like 1 hour or so, but he spent almost 4 hours with me, more than 4 hours. So, I am grateful he gave so much time. Because if you know startup founders, they are extremely busy. So making time for something like this, I am very grateful and I hope you enjoyed this. I don't know how many will watch this entire thing. It's very long and some parts get very technical. But again, it's very exciting that I have reached a day, you know, where I can do factory tools of rocket companies in India. When I made my whole SpaceX of India thing, I know it sounds cringe SpaceX of India, it shouldn't, this is Skyroot of India. But that time, you know, these all startups were very early in the game and very small progress done. So seeing all these startups get matured, whether it's Pixels, Skyroot, Bellatrix, Agnikul, it's really exciting to see them mature and, you know, become big giants. So I hope you enjoyed this video, consider subscribing. And if you want to financially support this channel, you can hit the join button. Thank you. And one thing I want to mention before going was this tour that I did Bangalore, Hyderabad wouldn't be possible without the financial support of all my members. So I'm displaying all their names who are currently active.

So, this is the one which will be flying in the first flight, let us say is more like a football you know it is more round and. Yeah. Separation systems are like very tricky. Correct. And they have to be like tested really well, they should have like good design. The complicated part of the fairing is it has like two separations, it is horizontal separation, vertical separation. The seal is surviving and then the flex seal we flex it, we have a nozzle that blue color nozzle you know. If you were to name one small thing that became a big engineering challenge, what would it be? Realign things to get into that zone. So, that is how this is quite useful. The super light composite structure. Right. Which you can just lift with your hand. Oh. You know. You just lift with your hand, but it takes the loads of a rocket. Stage 2 flex seal, you can see the metal here inside there. Welcome to Gareeb&#39;s Scientist. Recently, I had the opportunity to do a factory tour of Skyroot Aerospace for context, especially for people outside India. Skyroot Aerospace is an Indian private space startup. They are working on orbital class space rockets. It was founded by Pawan and Bharat in 2018, both are ex ISRO as in Indian Space Research Organization. The rocket they are actively working on and which you will see in the video is Vikram 1, which is a orbital class rocket with four stages. Three of its stages are solid and the final stage is a liquid stage. Previously, they have also done a suborbital test with a rocket called VKS, Vikram S, parts of which also you will see in this video. Some parts of this interview get very technical. Mostly it is fine. Also, just like all my videos, there are no mid-roll ads in this video. So, you can watch this entire long video without any interruption. Enjoy. This is big. Every time I open, it&#39;s like huge. Like if I pan, I can pan around this side. Yeah. Yeah. So, this is Vikram S, but you said this is not fully. I think, yeah, slightly bigger than what it actually is. Right, very big. So, how smaller will be the other that is outside, I can show the outside. Outside, yeah, outside one. So, actual one is like 6 meters, you know. Ok. Also, this is my, I think maybe 7 meter, 8 meters, yeah. So, you had a plan of a scaled up Vikram S or? No, no, no, because you know, so now our full focus is on orbital only. Right. So, we will keep it to orbital now, yeah. Ok. So, this is the rocket. Yeah. We will start from behind. Yeah. So, yeah. So, this is, this is a Vikram 1. Yeah. So, this is like you can see, I think, you know, you can say it is actually 22 meters tall. Right. So, it will be like 7 storeyed building, tall vehicle. Yeah. And these are actual stage 1, stage 2 and stage 3 motors. Correct. And this is the one actually is going to fly. Ok. So, the first one which will go for static test is in our other facility. Ok. So, that is all painted now and all. Right. So, this is yet to get painted. So, this is the one which will be flying in the first flight. And the stage 2 is like, this is a third motor that will be flying in our second flight, you know. Ok. So, whatever you see there, second. So, you had, you used to post images of sky route folks. Yeah. Yeah. So, this is the first stage 2. Yeah, that is this one. This is this one. Yes, correct. Yeah. Ok. Yeah. So, that, but that is the second launch stage 2. This is the, this is the, sorry, that is the first launch stage 2 and this is the second launch stage 2. Ok. So, you. So, we build like, I think, may be overall 4, 4, 5 hardware, 4 hardwares. Ok. One for pressure, pressure test. Yeah. Yeah. So, so, one for static test and 3 for flights. Yeah. So, ok. I think we will come there. Yeah. So, this, this is conical. Yeah. Yeah. Yeah. It will always be conical? No, we will, in fact, the first flight we will have it cylindrical, because in between we redesigned to be conical to have a good, what we call it as Cp Cg distance, you know. So, it is a distance between Cp of the center of pressure and center of gravity of the rocket. So, the less it is, the better controllable the rocket is. Right. So, we thought like, you know, to have like better control for the first flight, we will keep it conical, but we, once the, all the hardwares are realized, once we have all the, you know, masses ready and everything, we realize that Cp Cg distance is decent enough. And the first stage also, like we increase the angle of the nozzle, we can. Ok. The actuation angle of the nozzle also we slightly increase. So, so, all the controllability fell in good limits and good margins. So, we thought like, you know, we will go with cylindrical pressure itself, because that will give us better payload. Right. That cylinder, the metal ring is so, it does not collide with the shroud. You know, that is for, you know, that is for attaching the actuators. Ok. Ok. Yeah. So, you have like two actuators and we have two additional sensors called LVDTs, you know. So, in fact, for solid motors, they are called mirror imaging sensors. Ok. So, exactly opposite to each actuator, there is one mirror imaging sensor. Right. You know, so, it will exactly mirror the movement of this. Ok. So, this is specifically required for solid motors, because what happens is the solid nozzles not only actuate in pitch and yaw and all other directions. Right. They also move forward, because as, because there is a flex seal in between. Correct. Which compresses with a combustion pressure. So, as suddenly the pressure comes up, you know, the nozzle will get pushed outside. Ok. So, for that you need a mirror imaging sensor, which will help you control the vehicle very well. Yeah. Oh, that was, that did not think about it. Yeah. So, again point up. Yeah, sure, sure. Ok. So, submerged flex seal as in you, the flex seal thing will, I do not know if you have it here. Yeah, yeah, that is submerged, you know, you can see the nozzle projecting inside the rocket. Right. Yeah, yeah. So, that is like the submerged nozzle. Submerged nozzle means like it is submerged inside the case. Ok. You can see the nozzle top portion is inside the motor. Right, right, right. Yeah. So, that is where, that is what makes it submerged. Yeah. And then that is the flex nozzle, which will flex to. Correct, correct. So, flex nozzle is used for thrust vector control of the vehicle. So, you know, you can, you can change the direction of the nozzle, you can change the direction of the rocket. So, you will have both axis x and as in pitch and. Yeah. So, when you put two actuators in 90 degrees, you can actually rotate the nozzle in whatever direction you want. Correct, correct. Yeah. Ok. Yeah, here I think, I think we can only see one actuator. Yeah, one actuator, but 90 degrees opposite there will be another actuator and then opposite to these actuators, you have something called mirror imaging sensors, you see. Right, right. Yeah. So, just like they are, they are called LVDTs, there is a sensor which will sense the displacement. Ok. Yeah. So, you said these are not fins, right. Those are not fins, those are called like, so, there we have like sensors which identifies that the rocket lifted off. Ok. They are called last minute pull or last minute plug. Ok. LMPs. So, they are like electrical connectors, which after the rocket moves by certain mm, maybe 5 mm or 10 mm, it detaches and then you know that the actual lift off of the rocket happened. And then you start the control of the vehicle. Ok. Yeah. So, everything seems like carbon fiber here, is the whole rocket mostly composite? Yeah. So, every all structures are composite. So, it is like you know all carbon fiber rocket, one of the very few vehicles with all carbon fiber. Correct. Rocket in the world. Yeah. So, you have to wrap this in a way that it has directional strength. Yeah. Yeah. So, we call it like filament winding. Yeah. So, what happens is that we have a 4 axis robot which you know puts the fiber in the right direction. Right. So, it takes like hoop loads, tensile loads, you know axial loads, hoop loads and also it has like this strength in all directions basically. Right. Mostly this is like we can take it as a pressure vessel, you know inside you have like. Correct. Pressure at 80 atmospheres or so. So, it has to have that, so, it should have a dome as well. So, we can see the dome also. So, the dome can take and you can also see the fibers woven in different directions. Right. Right. So, and this has to be super precise also. Yeah. So, that you know you have really good distribution of stresses. Correct. And also this mass has to be lower as well. So, that way I think this you need this 4 axis winding to get this and also we need a specific shape of the dome. Correct. So, which you know which calls it which we call it as isotensoid dome. Ok. So, which has like very good distribution of stresses. Right. To reduce the mass of the dome because domes are super thick and super heavy. Oh. You know. So, we want to reduce as much as possible. So, that it is a lighter hardware. And this must be have been challenging to engineer. Yeah. In fact, I think it took us 2-3 years just to master building the these carbon fiber structures. Correct. Because in fact, we had we coded it from scratch. We coded we actually give that M codes you know into and on to the you know on to the machine. So, we build a software which gives directly the CNC codes. Right. And that CNC code will you know wind the rocket motor. So, we had to build everything from scratch software. And then, but we are happy that you know till now every hardware we build is has worked. Ok. So, you must have started on some small scale something. Yeah. What was the smallest thing? So, I do not know whether you remember we fired something called Kalam 5. Correct correct. Long ago. I remember. I think 3, 2, 3 years 3 years back or 4 years back. Yes yes. So, it is a very small motor. Correct correct. So, it is like 1 is to 4 scale of our stage 3. Right. Ok. So, that we built it and then we pressure tested it, we fired it. Correct correct. So, that we got some good confidence and then we had to do lot of trial windings to get some confidence on it and you know building it straight from the equations is very challenging. You know this has lot of fundamental equations. Right right. Which define how the stress distribution happens, how we have to wind the fiber. Right. What direction it has to go. Right. And then there is also something like there are factors like friction factor which you know if you do not maintain that it starts slipping. As you as you wind it starts slipping. And when it slips you gone hard the whole hardware is gone. You have to. So, you have to restart everything. You have to build everything. Oh. And so, it is quite challenging, but I think we are good that we have mastered in a reasonable way till now. So, that we can make lightweight structures because margins on these are not very much. Right. You know if you if you go for very high margins your mass goes very up. Correct. You know very high. And if you go very light then you know the chances of exploding. Correct. Right. So, it has to be like very. Delicate. Delicate margins which we have to maintain and that is where like the challenge comes into attain those margins and manufacture it reliably again and again multiple hardware&#39;s multiple times. Right. Yeah. So, we I mean we you have said you have shown engines a metallurgic engines. Yeah. Running. Yeah. So, you have to build this with liquid stages in mind. So, they do not leak or. For solids you mean. For no for your metallurgic stage. Yeah. Yeah. Future metallurgic stage. Yeah. Yeah. So, we need to have a liner. Right. Yeah. So, there are two types of tanks liner liner tanks and liner less tanks as well. So, now, the trend is even for cryogenics you do not need a liner if you if you actually build a composite hardware which the right resin you do not need a liner. And we can do it with multiple methods one is through filament winding you can also do it with you know hand layups you can also do it with you know robots which add layer by layer it is called automated fiber placement machines. So, different methods are there. Today you can build cryogenic tanks without liners at all yeah. So, I see a design change here. Yeah. There is a cone the earlier end is a straight. Yeah. So, what has happened to the first stage? Yeah. So, first stage we were slightly increase the diameter you know to load in more propellant and so, that is where like you can get slightly better payload. So, that is why like first is slightly bigger you know around I think around 200 mm diameter you know more diameter than the rest of the vehicle that is why you have a cone to transition from that cylindrical to the you know this cylinder to the that cylinder you know. Right. So, slightly higher diameter cylinder to a lower diameter cylinder. So, almost 1200 kilo Newton. Yeah. Lots of thrust. Lots of thrust. Lots of thrust. Lots of thrust. Yeah. Lots of thrust. So, static test happens right it is going to shake up. Right. Ok. This what is I forgot the name what you call this interstages. Interstages. Yeah. So, what will reside what so, every stage will have its own electronics for. Yeah. Correct. Every stage will have its own electronics and, but the mission computer will be one for the entire vehicle. Right. Right. You know. So, that will stay in the top most stage, but for example, you need like batteries large batteries and you need a control electronics to control the actuators and the nozzle. Right. For the TVC system that goes along with each stage and also there is a like a long plumbing you know the for example, this is a 10 meter long hardware. So, we have a very long wire going from top to bottom. So, that also gets separated you know whatever mass we can let go we let go with each stage. So, you have to build separation system for the wires or is it like passively they will get pulled up. No, our separation system is little bit different. So, we use instead of using pyros we use pneumatic system where like there are gas bottles again and then they store high pressure gas and then you know that gives a signal to a mechanism which opens it up. Right. Etcetera. So, that needs lot of plumbing etcetera all that separate along with the stage. This nozzle I is this the final size of the nozzle. Yeah, this is the actual size of the nozzle yeah. It looks so close to that inter stage. Yeah that is it I mean see with all rockets have very thin margins. So, if you want to have like lesser size than this you lose error ratio you know. So, that means, when you lose error ratio you lose the ISP and so, when you lose ISP you do not get much payload. So, you have to have as big nozzle as possible and then. So, what you have to do is you have to design the separation system such a way that you know it does not collide during separation. Right. Yeah. So, stage 2 this is Kalam. This is Kalam what is that 250. Kalam 250. Because the thrust is around 25 tons or 250 kilo Newton&#39;s. Right. So, you name your motors after thrust values. Correct yes yeah yeah yeah. So, when will we expect a static fire off. Soon I mean just few weeks away probably you know. Ok. So, this was actually casted I think months ago. We just like waiting for the stage test to happen soon. Yeah this is nothing, but like a stretched version of a stage 3 which happened like you know 2 years ago. Right. So, it is like the same diameter just like stretched in length of course, with a bigger nozzle and you know. So, all everything is ready for a static test we have to just assemble and test soon yeah few weeks more probably. What are the challenges of scaling it like this like going from Kalam 100 right. Yeah. Kalam 100 to. Yeah. So, what are the challenges like engineering challenges with going. Going big one thing is that you know the winding program also changes because the length is different. Right. Actually you know etcetera and then in fact, lengthier ones are easier to wind. Ok. It is better and easier and so, this third stage is more like a football you know it is more round and. Yeah yeah yeah. It is slightly more difficult to wind and so, it is actually easier and you have to build a new tool you know because that length is different this length is different and this is heavier. Right. So, the tool will be different and stage 1 tool is like massive you know it is a 12 meter tool. Correct correct. You know it is like a 12 meter high precision tool which only few people can manufacture itself. So, that way the once the size becomes bigger the tooling becomes more complicated and handling becomes more complicated. Ok. You know handling all these structures you know moving them out you know putting them aligning them. Right right. So, that becomes a challenge otherwise like tech is more or less the same. Ok. Yeah. So, here the second stage third stage inter stage looks big. Yeah. This this scales with the diameter nozzle. Correct correct correct correct yeah yeah yeah. So, so here in fact, you cannot we would love to go for a much bigger nozzle actually because you get even more error ratio. Right. So, but there are like lot of systems inside this inter stage which which does the roll control of the entire vehicle. So, the roll control will be in this inter stage. Yeah correct correct yeah. So, that you know so, if you put roll control originally our plan like several years ago was to have single roll control the top of the vehicle. Correct correct correct. And the like final kick stage of the vehicle. Right. But then, but then like that has a good loss of payload. Right. So, you know because we need to add like bigger tanks there, you need to add you know lot of more propellant than required, you need to add bigger thrusters. Right right. To for roll control of the entire vehicle top to bottom. Correct. So, because of the first few stages, you require more thrust and after it the vehicle gets lighter you need less thrust to roll control. So, what you do is that if you put it at the top, you put bigger engines continuously and those will be carried up to the satellite. Correct correct. And it causes like you know payload loss. Right. That is where we moved it down and so, there we have tanks and other systems. So, we need to maintain some gap between the nozzle and this. So, that is where that limits the error ratio of the third stage. Ok. Yeah. What is the loss like ok fine fourth stage 1 is to 1. So, what is the third stage or second stage how much do you add and how much do you add? It depends on each stage you know like for example, third stage will be like 1 is to 2 around or even less. Ok. 1 is to 1.8 or something like that. Ok. And first stage is like the least you know sensitive it is you know 1 is to you know 30 plus number. Oh ok. Yeah. So, even if you add 30 kgs you will lose only a kilogram of payload. Yeah. That is that is nice. Yeah. Ok. So, this is column 100. Yes. Yes. This is what was test fired I think more than couple of years ago. Correct. Correct. Yeah. Does anything anything is changed or. No we have upgraded it I made it much lighter and if you remember like I think that was a fixed nozzle concept and for a fixed nozzle you need a separate pitch yaw control right. Now, we made this also into a TBC thrust vector control. So, this also nozzle rotates it has its own actuators nozzle rotates. Right. So, it rotates the vehicle and so, you avoid like big pitch yaw thrusters which will be required for a fixed nozzle and we realize that that gives a good payload gain. Right. So, we put a TBC system here as well. So, all three stages have TBC. All three stages have TBC. Which means they require big batteries to go in along. Not very big I mean depends on the actuator. Ok. First stage requires like a decently big batteries. And then second much smaller third is much much smaller yeah. Right. So, you were talking about some will require retro motors some might not require. Yeah yeah yeah. So, basically what happens in solid motors is that there is a residual thrust after the . you know action time is over, still there is some sort of thrust which is you know residual after the motor is off as well. Correct, correct, tail of thrust. Yeah. So, and the tail of thrust can often be very long as well. Right. It can be very long tail of thrust as well. So, what we do is that we have some smaller solid motors which fire for few second, few seconds typically you know 1 to 2 seconds. Around that and then they fire and they negate this extra tail of thrust which is built up and immediately separate the stage. So, that way what happens is that the second stage can ignite immediately. And you avoid losses you know. So, there are multiple losses which and there is a no control zone. The quicker you start the control of the second stage, you reduce this no control zone. Ok, ok. Because what happens the first and second stage the atmosphere is very thin, but still there is. Still there is ok. Decent you know what we call dynamic pressure. Right. There is still some decent dynamic pressure. So, and if you just leave it for long time you know the rocket completely will tumble. So, you have to immediately start control the moment the second stage first and second stage separate. The second stage should ignite as quickly as possible to reduce that no control zone. Ok. So, that is where first to second we use retros and other stages we use like springs and other pneumatic pushers or things which can assist in separation. So, the first wire tunnel ends here. Yeah, yeah. No. So, there is a wire tunnel continuously going you know. So, what happens wherever there is interstage the wires go inside, the routing is inside and then it comes out again. You see some cutouts one below the other it again comes out. Then on the motors anyway you cannot put inside the motors because it is all propellant. Right. So, again it happens on the rocket you know on the surface of the rocket you have some wire tunnels, then again it goes into the structure and again it comes out yeah. Just curious have you aero modeled with wire tunnel without wire tunnel does it. Yeah, yeah absolutely you know it is because see for a smooth vehicle with no projections aerodynamic is quite simple and these small small projections create lot of issues. Right, right. And in fact, they have to be so well modeled and because all the coefficients especially even there is something called roll coefficient. Roll coefficient decides how much roll thrusters you have to you know you have to size for. So, what happens is that if you do not like model them properly you start getting like non actual non realistic numbers. And then you size things non realistically and that can like compromise the mission. Right. So, you have to be very super accurate on the aerodynamics that is why we do wind tunnel testing to validate as well which we completed for Vikram 1. So, we see that all the coefficients we require are as close to accurate as possible and then based on that we see that all the sizing is done with some margins. So, that even if accounts for some delays. Or like some changes like for example, during the design process we keep changing slight dimensions and all. We keep some margins to absorb them yeah. Right. So, this wires how they separate they get just pulled out or they have a cutter mechanism. Yeah. So, there are some special kind of connectors which have a separating mechanism. Ok. Very small mechanism. Ok. Along with the rod and so, they have certain beyond certain force they separate. So, as the stages are pushed either with a retro motor or with a springs right. So, these connector also separates. Oh interesting. Yeah. So, they could not like pull the stage little here and there it is very smooth. They can, but we design for that. Ok. You know and also there are too many wires what we do is that we put them opposite to each other. So, that when force is there forces are opposite. Ok. So, that do not create a torque you know. Right. So, all that all considered in the design. So, that you know we can get a very stress free separation because most of the failures you see is in separation. Right. Yeah. So, propulsion more or less works well and lot of systems work well, but separation systems are like very tricky. Correct. And they have to be like tested really well they should have like good design margins. Yeah. So, something has changed here in the fourth stage. Yeah, I think you can see a central engine right. So, the Raman 2 whatever you see is the central engine. So, previously I think you are quoting the old like 4 thrusters around the vehicle. Yeah. Yeah. So, that is long back change we change the design to central thruster. Correct. Where like there is only one engine in the center and then that purpose the final stage and that is a 3D printed engine where like even the pipes over 3D printed along with the engine etcetera. And so, this has all the channels inside itself. And which cools it is a regenerative cooled engine and then, but this is a fixed engine. So, it does not have a TVC because a TVC will call for new actuators, control electronics, batteries. Correct. Etcetera. So, because this is a small engine we can actually manage with small thrusters few Newton&#39;s of thrusters to manage the pitch and yaw, but still you have projections 4 projections on the vehicle if you see. Correct. So, those are like small Newton thrusters for pitch and yaw control there we call them Raman mini thrusters. Right. They control the they do the pitch and yaw control of this engine. So, putting them outside on the surface. Yeah. Versus putting them on the base plate. Yeah. There is a difference. Yeah. So, see when you put it outside know you get more torque. Right. So, you should keep it as away as possible when you do pitch and yaw right from the center what is the torque is what I mean force into distance. So, the moment you move as much distance as possible with a small thruster you can actually manage a good torque. Right. Good control. Right. So, that is where we need to keep it as away as possible. Ok. You know and so, that is why like you know we put it as away from thruster as possible. Ok. So, coming to the satellite now what with this latest configuration what is the max payloads. So, it depends on the orbit you know we could. So, target is to reach like 400 plus and so, we will keep having like updates and upgrades small small upgrades with each flight you know. So, because from generally the first two flights we get a lot of data and we see like how much propellant is left how much guidance margin is actually required. Right. What are the different fluctuations we see in the flight etcetera etcetera. So, all that we get to know I think we will get a fair amount of idea on the exact payload after the first flight. Ok. You know we get lot of data and the whole target is to for low inclination orbits etcetera we have to cross like 400 kgs. Ok. Yeah. So, fairing simple to design or because this is not cylinder. Yeah yeah fairing is again here also the tooling is complicated. Right. So, you should build the tool big steel tool. I do not know I think maybe in some of the pictures might be there you know this is a quite a big steel shining. Tooling which we need to make. Right. So, that is that is I think that takes good amount of time after that I think it is it is fine I mean it is it is all lay up and then you build the carbon composite shell and then it is anyway light enough and then, but but the complicated part of the fairing is it has like two separations. It is horizontal separation vertical separation. Correct. Because fairing has to open like a clam shell. Right. So, there will be vertical separation plane horizontal separation plane. So, you should have separation in both that in both planes. Right. And it should work really well and very reliably. While it is thrusting. Yeah. So, yeah while it is thrusting it has to separate, but thrusting part may not be a challenge you know, but but in general just separation of two parallel planes not parallel planes I mean perpendicular planes, but parallely separating them parallely there is also like we need to give a small gap between them. So, there is there is some science physics associated with it to have a very successful clam shell opening of the payload fairing. So, will you also have a seal and air vent external air vent and all those. Yeah. So, we need to have a seal because there are like two structures. Correct. Together and then in launch vehicle structural dynamics is complicated because. So, we build lot of thin shells to save weight. And then they have dynamics their own dynamics. Correct. So, what happens is that they will open as the statics also dynamics also. So, there is like force which opens it up and there is also like dynamics which opens it things up even if locally if something opens up what happens the clean air which is to be maintained for the satellite that escapes out. Correct. You know and we have vents for venting slowly, but we do not want the air dust or you know air to get inside. Right. So, that will pollute the atmosphere inside. So, we want things moving from inside to outside because naturally there is vacuum outside, we have to vent out to reduce the stresses. So, we have a vent we will have vent adapters to vent things out, but we have we should have all protection. So, that the dust from the external atmosphere does not get in. So, you need to have like good seals. As it is going up it has to slowly release the clean air from inside. Yeah. Yes. Yeah. Otherwise what happens is there will be like it is like a one one atmosphere of pressure. Correct. Which is big enough if you calculate over the surface area, this is decently big enough. Yeah, but still I mean it is better to vent it. Right. When you have like to reduce the stress, but it can also survive. Yeah. The pressure. So, even if in cases like when valve fails also it is or payload fairing will survive. Do you have to put any material on the tip? What is your max heating going to be as you go up? No temperature we should not cross like more than 100 degree centigrade of the skin. So, based on that like we put a thermal protection system on top. So, we have certain materials which will which will take this temperature and thickness will change depending on the heat flux. So, the tip of course, the heat flux is high. So, you will have more thickness. And as you go down the requirement is reduced. So, you reduce the thickness of the thermal protection system. Yeah. So, we will we will see right a fairing separation test of. Yeah sure we will I think the hardware is in final stage and now we are like busy completing the stage separation test. Right. So, once that is done I think we should see them soon yeah PLF separation as well. Yeah beautiful rocket. Yeah. Very big as well people just how much you said 17 meter? 22. 22 meters. 22 meter. So, it is like yeah it is I mean equivalent to 7 storeyed building tall vehicle. Yeah. Yeah and actually it is become slightly longer than when we designed 4 years ago. Yeah 18 meter I think no. No no it was like around 1920. 1920. So, slowly slowly you know you need some gaps and then you know yeah. Right. And then like the first stage also slightly increased and all that when actual detailing happens that is gone longer. Yeah. Yeah. This was good. Yeah. Yeah. So, I think this is I think you have recently done this. So, these are like 2 test rigs basically. So, first is that test rig where we test all the flex seals you know. So, flex seal is used for like you know you want to rotate the nozzle and you need to have a flexible member and you cannot have a regular bearing because. Right. It should also survive the loads and the temperatures. Correct. Correct. So, we have a specific type of seal called flex seal which has layers of rubber and metal and to protect the rubber we have another layer of high temperature rubber. Ok. And all that. So, that can flex up to you know whatever the angles we want may be up to 7 8 degrees it can flex maximum in the maximum scenario. And then so, what we do is that this one we pressurize up to the actual pressure which is required in the motor with some margin additional margin we give. Right. So, we pressurize it up and see that the flex seal is surviving and then the flex seal we flex it we have a nozzle that blue color nozzle you know which we see here yeah. So, there is like simulated nozzle which we have which we will use for every other this nozzle. So, this is not the actual nozzle, but this is a simulated nozzle we simulate the moment of inertia etcetera and then we have these actuators which move it and this is for flex seal we put the flex seal with different pressures and then do it and then this is the actual nozzle. So, that we do with dummy nozzle. Right. With different actuators and here we do with actual nozzle with actual actuators and then this gets assembled to the actual motor and then we fire it or go for flight. Right. Yeah. So, you will be going full closed loop since launch or. No. So, initial phase will be open loop to reduce the loads. You know slowly there will be a switch from open loop guidance to closed loop guidance. Ok. So, that will so, it is more to manage the loads even though it is not optimum on the payload perspective, but we do it to manage the loads. Ok. Yeah. So, similar to PSLV and other. Yeah, yeah, yeah, but we do that wind biasing which will see that the errors are lower than what we expect, but yeah and also like it helps us manage the stress on the vehicle as we go further. So, last minute based on winds and all you will have to feed different models. Yeah, correct, correct, correct. So, in fact, we did that for Vikramas as well. So, Vikramas is like a highly aerodynamic driven vehicle. Correct. You know so, we need to we need to check winds on that particular day and then so, they have wind profiler which checks the exact way how the winds are and then based on that we you know we feed that angle of the launch based on that. Right. So, similarly here it will be a slightly different, but the concept will be somewhat similar as well. Right. So, where we detect we do wind biasing we get all the wind data based on that we record that program to the vehicle which will go the guidance will take it in open loop initially based on the winds and then it goes to closed loop. How close this happens to the launch? What you plan to do? So, it is not very close to the launch, we want ideally it should go as close to the launch as possible. So, we do few hours depending on the wind biasing limitations and few hours before we try to complete it and then feed it. I have heard of cassettes and something is being put. So, now, it is all digital right so, yeah. So, one last thing on this nozzle this shape is optimized for what domain in speed? So, aerodynamics and acoustics both you know. So, it should be like smooth for aerodynamics the flow should be quite smooth. And, basically the satellite right the satellite environment is nothing, but the acoustic environment. Right. As the rocket goes up basically the acoustics comes from one is from the plume during lift off right the huge sound which comes. Correct. So, that affects the satellite. Another thing is during this transonic regime when the rocket like crosses the mach 1 right and there will be like a good amount of acoustics which comes in. So, this shape which is called an agive shape which is quite good for less acoustics and also decently you know good for the aerodynamic flow as well. Right. And, the flow also decides the acoustics. So, it is all like quite related and agive is like a very good optimum shape for payload fairings, but we also see that conical and cylindrical as well, but the conical and cylindrical what happens is the manufacturing is easy, but it is not as good as the agive shape. Ok. And, since you spoke about max Q is your like grain geometry and star optimized such that. Yeah. There the thrust is lower. Absolutely, you need that because see the so, one beauty about solid fuel vehicles is that you can design the thrust time curve as it is you can design without requiring a you know throttling valve or you know or any algorithm or nothing you know. Right. So, you can design the shape of the grain and you can design whatever shape you want and you can see that you know it throttles sometimes even 30-40 percent during the flight again it comes up as per required. So, what we do is that initially before reaching max Q we see that the thrust goes down. So, that our Q comes down Q is maximum dynamic pressure max Q is maximum dynamic pressure and so, Q comes down and so, overall max Q also during the flight comes down. Right. So, what happens we have like a thrust which goes up initially and then comes down just before the max Q design after that zone is fast again it goes up. So, you we design the curve such that you have very less overall stress on the vehicle. Yeah. Small details. Yeah. I mean like so, building rockets is like so, many engineering judgments to be made. Yeah. So, you know you have to work on different margins and across various systems. Right. Hundreds of systems working together everything related to each other. Correct. It is quite a challenge and that is why it keeps evolving the design keeps evolving with time and I think several iterations even I think for each grain we do several hundreds of iterations. Oh. Which grain is ideal you know even like 2-3 kilo Pascals of dynamic pressure reduction you know and then that affects the burn time and you know there is so, many everything is related to everything else. Yeah. So, it is like you know building an optimum vehicle is a good challenge very, but very exciting to do all the iterations and identify something and sometimes the actual hardware comes different than what we design. Correct. So, and then we have to again keep on iterating even on the hardware side also. So, one on design simulation side we have to iterate hardware side we have to iterate you know. So, it is a continuous evolving process. If you have to name one small thing that became a big engineering challenge what would it be? Anything small which like which general public would not appreciate as such. Is it on Vikram 1? Anything aerospace or in this in this sky route. I think VKS was a tough flight. Oh. I think even I never imagined that it was it would be so, difficult, but I think the simulation was very challenging because it is a highly aerodynamic driven vehicle. Right. And it also has a lot of dynamics dynamic characteristic you know pitch your role you know linking up. Correct. All that stuff and you know we have to rely on previously what you do is that you if you have like lot of flights you do few few flights and then you learn. Correct. You do not have that you know flexibility you have to have the first flight right. Right. And also very thin very small amount of time we thought like you know you would complete well took lot of time and so, many simulations I cannot believe how many simulations we have done on thermal aspects because it is a very fast moving vehicle. Yeah. The heat generated is also very high. Right. And and then like the aerodynamics even slight change in the fin can affect the dynamics of the vehicle. Right. And it can you know it can go from a successful flight to you know completely a disaster in just like few few small changes in the design not done properly or not simulated properly and we cannot simulate everything on ground. Right. So, it is that is been quite challenging even on the small vehicle on Vikram 1 I think even I think separation dynamics is one challenge you know because lot of multi physics comes into picture. And then even separation mechanism also something new which we have built and there is also new it required new materials. Correct. Than what we expected. So, you know and then it also requires like it is consistent like you do hundreds of tests it works. Right. So, make. taking it to that kind of liabilities also quite challenging separation part is a bit of a challenge right quite here and also like winding as I said initially you know building up that expertise to do big motor winding right because here you know what we call these as these are like openings are different the motor openings are different when openings are same it is a different kind of it is it is easier to wind when openings are there is an opening ratio very difficult to wind and our opening ratios are like quite large making the winding very very difficult. So, we have to make the right program for it and do some trails we have to do some winding trails see that it is not slipping you know and all that. Hardware is expensive not to develop. Hardware is very expensive and we cannot iterate because it is too expensive to iterate multiple times you have to get it first time right. So, we will small prototypes then we went to the stage 3 then stage 3 became a success then like we went to stage 2 then stage 1 right. So, like that I think we have built like quite a good expertise with time the lot of small minor things which we have many of them which we have learned step by step right and yeah. So, that is one challenge and even the flex nozzle system has been like much more challenging than what we imagined you know because actuators building the actuators to the required reliability you know. So, what happens is that when you test the actuators you see some small spikes and some inconsistencies from what we what we design for. So, then like that also becomes challenge here you know fixing them understanding the root cause fixing all the bugs which has originated then there is some because of software some because of hardware right and then you have like a massive control electronic system which manages all the power from the battery and then goes up. So, I think the building the actuation system is I think very very challenging I never imagined that that will end up a big challenge, but it happened to be a very big challenge and that is also like a learning process it took time to get that learning curve to get to a enough level where you know we can build any new actuation system which is very robust and it works right and then and there is a lot of elements like I said like software, hardware and then even small tolerances change would you know cause issues in the actuation system. It has to be perfect it just has to be perfect it cannot be have any small like and you will see like the data not being very good if you in small even with small issues it can create that. Yeah ok I think before wrapping up on this one last question. Yeah. You might have cameras on inter stages and. Correct. Yeah yeah. What is the challenge with having high bandwidth or high say HD streaming? Yeah. What will limit you there what is the constraint? So, it is the hardware. So, like you know because you have an Ethernet cable Ethernet line inside and you have and also like you have. So, internally also there is some bandwidth limitation whatever maximum the Ethernet cable which actually takes quite a good MBPS, but from vehicle till the ground right. So, there is antennas which beam down the electromagnetic. Right. Radiation you know and then which gives to the radars etcetera. So, that also has a limitation. So, we can actually make it very big, but you will have to you know make slightly more you lose some payload that is it is just a balance of it and especially for small vehicles payload is very very tough to get. Right. You know because every small for example, if you build a vehicle with let us say 4 tons of capacity. They are like you know maybe you know getting payload compromises is slightly changes here and there even design with slightly bigger. Vehicle, but in small vehicles what happens is that getting the payload is super challenge. Right. And everywhere you are try to optimize even here also like you know we would love to have like wonderful cameras beaming like very in high very high bandwidth continuously throughout the flight right, but that becomes a luxury. Right. Where you have to let go some payload some hardware becomes like little bit more bigger you need to have high bandwidth communications internally and externally as well. So, your TTC and your camera feed will be two separate or will be there on the same channel there will be. Same channel. Same channel, but the channel will get heavy you know the entire. Right. Yeah. So, it has to be designed for this high bit rates. And it also has to be like for example, you can go with ultra HD for example, ultra HD if you camera if you go you need to like have like high GBPS kind of a system where you know it beams out. So, that requires like heavier hardware right. So, yeah. So, that way, but we have like a decent I think VKS if you have seen right. It is a HD camera. It was good yeah. Slightly I think slightly smaller than HD or something it was decent yeah yeah. Yeah that was good VKS. So, yeah. So, I think with slowly with as we go further we can get this thing also better. As you optimize the payload better. Correct. We can also have like better hardware which can be more really high definition. Yeah. Much much high definition video yeah. Yeah. Yeah. So, this is like a center of gravity measurement machine. So, we put all the sections on this and see that because we design for a center of gravity and, but what we see is from a 3D model which will remain different from what is actual. So, we put the actual section on this with so many components inside and then we measure the CG anything off than what we design again you know your control power plant is not designed for those offsets. So, you have to realign things to get into that zone. So, that is how this is quite useful. How does it work I mean it will tilt if it is off? So, it has a principle where like you know it is a 3 point it has 3 sensors which will give you load if it is exactly at the center the CG is exactly at the center you get the same value in all the 3 sensors. Right. So, if you have like slight offset it will give you different values based on that you can back calculate what is the CG offset. Will the launch clamp also have something like that? Pardon. When you assemble on the launch pad. Yeah. Will it also be able to do this CG calculation? No. For a full strike vehicle you want just each element. No. So, that yeah. So, because see we want that launch ground to be super rigid. Right. So, this is not rigid because it has sensors in between and then on very thin sections to measure it etcetera. Right. So, we wanted to be super rigid. So, yeah. So, generally on launch we do not do that and that is that much is not required anyway because section wise we anyway do and wherever propellant is there propellant takes care of the CG. You would not like you know several tons of propellant and you see that the tool you know the for example, sword motor you have a mandrel in between it is very accurate then you get the CG right at the center. Yeah. I think this is one we have one of the sections here I think this is. Ok. Yeah. So, this is 1 2. I thought that is real person for some time. So, this is yeah. So, this is one of this 1 2 L I think this is one of the hardware&#39;s which is yet to get assembled yeah. So, this is like this is like a super light composite structure. Which you can just lift with your hand. Oh. You know. Oh. You just lift with your hand, but it takes the loads of a rocket you know. Yeah. So, you can just I was able to lift two structures with two of my hands. Yeah. And you can see like this is how the radius I mean like the diameter of the vehicle will look. So, this is what you are calling the honeycomb thing. Yeah. So, it has it is a very light honeycomb section inside which makes it like super light and still has that section modulus which you require. Wow. Yeah. So, this is like one of the structure, but like. So, we have like 7 8 of such structures in the vehicle yeah. This is such a big crane. Yeah. It moves along the whole. Whole facility. Whole facility. Yes. Yes. So, that stage when you had moved out it was through this and this is a main. Yeah. This is the main way. Oh, you will have to have to design the whole thing around this as well. Also it directly goes to the road. So, basically all these openings of the shutters and you know the how the length and turning radius all that has to be considered to design the facility. So, this limits your stage potential length for future. You can can you make it bigger? Pardon yeah this one. Yeah. No, no I mean like. So, this facility I think is good enough for maybe like slightly bigger motors than what we build. But not more than that. Shipping this must be ok, these are as of now these are small. Yeah, but we have this shipping container. So, each one of these again it is a container right. So, and then like we also have like big trucks 40 feet trucks etcetera moving the bigger ones the bigger hardware&#39;s. And here I think you can see a flex seal maybe this is yeah. So, this is our stage yeah. So, this is our stage stage 2 flex seal you can see the metal here inside there are layers of rubber. Oh it literally looks like. Yeah. Yeah. This is not what I expected. Yeah. Yeah. Yeah. I have not seen this mark 3. Big one. S 200. Yeah. Yeah. That is a very big thing. Dark black flex seal. Yeah. Yeah. So, this is another flex seal. Also it is like this big. Yeah. That big. That is it. Oh. But stage 1 will be bigger. Stage 1 is big. Later we went to this other facility where unfortunately I was not recording video. So, while I will play this video, I will talk on the video and explain what I saw. So, here there was another stage 2. This is Kalam 250 motor, right. And if you see behind, you will see spare parts of VKS, Vikram S rockets lying here. This is another interstage. And if you see just right of it, there are some fairing testing parts. So, this is for fit and all of those checks, test checks. Here you see the cryogenic test facility. This is mobile. This can be moved. So, you could have, you will have seen this in that Dhawan 2, Dhawan engine test which is a cryogenic engine, smith locks engine. So, this they showed. So, this can be moved, that facility. Here you see there are 2 fresh flex seals. So, what Pawan is describing here is the top of the nozzle will get attached on top. So, that is fixed. And the, sorry, the top of the nozzle, the outward part will get attached down. And this whole thing, the lower thing can flex on top of that ring. So, this is how that works. And I want to someday create a video explaining how this flex nozzles work with animations. So, there were 2 of this. And you see more test stands here for small engines. This is a interstage they were using for testing the separation mechanism, etc. You see some jigs here to transport some heavy things. And here you see some fuel tanks. So, this was it mainly. And besides this, there was some full stage I will show you in a second. So, this big tanks you show, you are seeing are used for higher storing of fuel. So, this one was a completed first stage again in, this is a different facility. There were some fairings and you will also see a stage 1 tool here used for making the stage 1 which we saw earlier while wrapping. So, in general, this whole tour was really exciting, I learnt a lot. Pawan actually spent a great deal of time, although this interview is like maybe like 1 hour or so, but he spent almost 4 hours with me, more than 4 hours. So, I am grateful he gave so much time. Because if you know startup founders, they are extremely busy. So making time for something like this, I am very grateful and I hope you enjoyed this. I don&#39;t know how many will watch this entire thing. It&#39;s very long and some parts get very technical. But again, it&#39;s very exciting that I have reached a day, you know, where I can do factory tools of rocket companies in India. When I made my whole SpaceX of India thing, I know it sounds cringe SpaceX of India, it shouldn&#39;t, this is Skyroot of India. But that time, you know, these all startups were very early in the game and very small progress done. So seeing all these startups get matured, whether it&#39;s Pixels, Skyroot, Bellatrix, Agnikul, it&#39;s really exciting to see them mature and, you know, become big giants. So I hope you enjoyed this video, consider subscribing. And if you want to financially support this channel, you can hit the join button. Thank you. And one thing I want to mention before going was this tour that I did Bangalore, Hyderabad wouldn&#39;t be possible without the financial support of all my members. So I&#39;m displaying all their names who are currently active.

Transcript for:Skyroot Aerospace Factory Tour

Transcript for:
Skyroot Aerospace Factory Tour