 Hello everyone, welcome to a video lecture on Launchers and Launch Vehicles. Myself, K. R. Biradhar, Assistant Professor, Department of Electronics and Telecommunication Engineering, Walshan Institute of Technology, Swalapur. Let us start with the learning outcomes first. At the end of this video, you will be able to illustrate Launchers and Launching Vehicles. The fact is that satellites stay in space for most of their lifetime. We know that the weightless environment is present in the space. That is why satellites don't require additional strong frames in space. But those are required only during launching process. Because in that process, satellites shake violently till the satellite has been placed in a proper orbit. During this process, from earth stations, we can control the operation of satellite. Launching vehicle, launching of satellite into orbit is an extraordinary, costly and complex operation. Launch vehicle includes engines, propellant storage and pumps, guidance and control. The first Indian launch vehicle is SLV-3. In the year 1980, they have launched. We will come to know what is the launching process first, before stages involved in launching process. The process of placing the satellite in a proper orbit is known as launching process. Satellites are launched into orbit from earth station in that several launching stages are involved. Those are discussed here. Mainly there are four stages involved in launching a satellite. Those are first stage. The first stage of launch vehicle contains rockets and fuel for lifting the satellite along with launch vehicle from ground. The first stage involves only lifting the satellites from ground. Second stage, this starts after first stage. The second stage of launch vehicle contains smaller rockets. These are ignited after completion of the first stage. They have their own fuel tanks in order to send the satellites into space. Third stage, the third stage or upper stage of launch vehicle is connected to the satellite fairing. What the fairing is? The fairing is a metal shield which contains the satellite and it protects the satellite. That means entire satellite is covered with metal shield. Fourth stage, here separation of upper stage from launch vehicle. In fourth stage, satellite gets separated from the upper stage of launch vehicle when it has been reached to out of Earth's atmosphere. Then the satellite will go to a transfer orbit. This orbit sends the satellite higher into space, launching procedures. In this the various procedures are covered to launch a satellite. Satellite launching depends on orbit of satellite to be launched. That is like Leo, Mio and Geo. Here different orbit have different procedures. Satellites are directly injected into lower Earth orbit Leo with the help of launch vehicles. But when we consider the low Earth orbit, satellites are directly injected to orbit. Satellites flying into an orbit are inclined at 28.5 degree to the equator of the Earth. While flying, settle contains at an angle of inclination around 28.5 degree. Rackets have capabilities to put satellite into orbit which are above 120 miles from Earth's surface. Satellite Launch Vehicles. In this slide, we will talk about different types of launch vehicles. Launch vehicles are classified as expandable launch vehicles that is also called ELV and reusable launch vehicles that is also called the RLV. An expandable launch vehicle is used to carry a payload into space. The vehicle used in ELV systems are used only once. They are expanded during a single flight. The components used in expandable launch vehicles are cannot be reusable. Expandable Launch Vehicle. The ELV or expandable launch vehicle contains only three stages as shown in the figure. In the first and second stage of ELV, raise the satellite to an about 50 miles and 100 miles. The third stage of ELV places the satellite in transfer orbit. The task of ELV will be completed and its spare parts will be pollen to Earth when the satellite reached to transfer orbit. Reusable Launch Vehicles. A reusable system is capable of launching a payload into space more than once. This is the flexibility available in reusable launch vehicles. As the name, some of the components launch vehicles for next launching. But unfortunately, not all our complete components are reusable in the orbital launch system. Also, here we will come to know what can be used partially and discarded. The space shuttle was partially reusable. That is, space shuttle main engines, two solid rocket boosters were partially reused after several months of refitting work for each launch. The external tank and launch vehicle load frame were discarded after each flight. Figure shows the reusable launch vehicle process. The satellite is lifted off from ground launching pad. As name itself says that, some of the components as discussed in the previous slide bring back to Earth safely with the help of parachute through ocean. And main satellite is shifted to space that is to orbit. Some Launch Vehicles. These are the some pictures of Indian launch vehicles. First you can see SLV, ASLV is the augmented satellite launch vehicle, PSLV is the polar satellite launch vehicle and GSLV that is Geosynchronous Satellite Launch Vehicle. What is approximate life of satellite? Pause the video and try to think about it with your existing knowledge. I think you might have got some idea about it, if not, now we will see. The average life of a Leo satellite is around 5 years whereas for Geo satellite is around 8 years. Do you know on what basis life of satellite is decided? This is decided by the life of the rechargeable battery inside the satellite. These are the references used to prepare the above PPT. Thank you.