 Hello and welcome to the NPTEL course on Introduction to Launch Vehicle Analysis and Design. It is my pleasure to be with all of you in this journey which we are going to have from today for a period of eight weeks. I am Ashok Joshi the instructor for the course and I will talk about an important discipline which currently is also a hot topic. How do we put together a launch vehicle? So, let us as someone would say begin at the beginning and with that object in mind I would first like to introduce briefly the overall philosophy of the subject that we are going to deal with. So, let us first look at the fundamentals of the space itself. Of course, space has always been of keen interest to all of us and it is believed that it contains information relevant to the formation existence and continued sustenance of our planet. However, as terrestrial instruments have a limited reach the concept of objects in space for such tasks has also evolved over a period of time. Space objects are a lot more visible. People have also realized that many earth related activities such as communication are also better performed with instruments located at higher altitudes. In fact, this particular philosophy is clearly evident in many of the communication towers which are mounted on higher locations so that they can have better visibility or better range over earth. Of course, with space we have taken this idea to several higher levels. This has resulted in the concept of space objects which address not only the space exploration needs but also address the various kinds of earth bound or terrestrial needs. Of course, it is very interesting and useful to trace how the various things have evolved over a period of time. What is visible currently to us is the scenario over the last 70 years or so that we can relate to. It is also noteworthy that the initial efforts were simultaneous in Russia, USA and Germany. Of course, after World War II these countries went their own way and mounted their own ambitious space research programs. Let us take a quick look at the history of how the space programs have evolved and understand some of the things that we are currently looking at. So, the inception or the beginning is generally attributed to Chinese with the development of fireworks which happened there. Of course, it is only at the beginning of 1900 that a study of space as a formal discipline began and that was the time when rockets came into being and the main objective was that can you overcome the earth's gravity. These things continued in the experimental form until we reached the decade 1948 to 1958 where the evolutions were lot more focused particularly with German V-2 rockets and USA's sounding rockets which came into being and became quite popular and visible. These rockets were primarily used for detecting x-rays and study of upper atmosphere structure including aurora, magnetosphere, ionosphere, foreign belts etc. Of course, it is worth noting here that until this time there was a belief that only rockets could perform such tasks and that is why you would notice that in the initial stages most of the space missions were restricted to rockets. However, this particular belief was broken when USSR in 1958 launched Sputnik 1 and established the fact that satellites could also be used effectively. I just want to show you couple of early images of the space objects that were created. So, you have in the middle the V-2 rockets and the sounding rocket and then of course on the extreme right you have the Sputnik. But interestingly around the same time there was also a realization of much bigger and much more sophisticated objects such as space station which were only in the conceptual stage at that time but people had started thinking along those lines. The next four decades that is 1960 to 2000 were very productive in space technology starting with Luna 3 which was launched in 1959. One of the many space probes that were launched to photograph moon of course all of us remember this date April 12, 1961 is a landmark as Yuri Gagrin established an orbit around earth in Mostok 1 capsule and which paved the way for humans in space of course. This was followed by the Apollo program of USA through which Neil Armstrong landed on moon on 20th July 1969 and then really the development became fast-paced. Within two years USSR launched Salute 1 it was a kind of a space station though not exactly conforming to the concept that was evolved earlier and the US closely followed this with Skylab experiment in 1973 of course the India was a late starter in the space age and entered it 1967 and even at that time it was with participation in the sounding rocket program of the US. So initially we were only launching the sounding rockets from what was then called TURLS that is T-E-R-L-S pronounced TURLS or called Tumba Equatorial Rocket Launch Station that was on the coast where currently now our Vikram Sarabhai Space Center sits of course we raised the level in 1973 with establishment of satellite center and then of course many other centers of ISRO started coming up it is also worth noting how these things evolved in Europe so European space programs actually started later than ours that is in 1975 with the establishment of the European Space Agency which is an intergovernmental initiative of 22 countries while the Arian space a private player in US came up in 1980 of course this period of 1970 to 2000 witnessed many milestones there are space station and space shuttle missions to Mars, Jupiter, Saturn, Venus, Mercury etc. So I just thought I will give you a snapshot of the various objects that came into being and also sustained themselves these images that I have taken are all curtsy Wikipedia so let us look at more closely over the last two decades and what future holds for the space technology of course all of us know that India has not only consolidated its position in launcher segment with PSLV, GSLV, GSLV Mach 3 but has also embarked on moon and Mars missions including human space flight globally of course we have also seen that SpaceX has emerged as a major private player in launch systems with heavy launchers, launch to orbit missions and fully reusable technology the renewed interest of many other countries in moon and Mars and other planets of course is expected to significantly scale up this space space activities in the next decade so here we have Falcon 9 Heavy from SpaceX their concept of Starship Hopper, Orion spacecraft, USS Delta IV Heavy Rocket, India's GSLV and so on and this brings us to the first step of what is the primary objective of the present course that is the ascent mission so if you look at the space mission I am sure you would have seen a large number of videos and other material is basically an act of transporting a space object which we typically call satellites spacecraft space station are different terminologies to its designated spot in space and then carry out scientific technological activities such as exploration communication etc of course we also know the transportation of these objects is done through rockets also called launch vehicles by burning a large amount of propellant to impart the required energy so this task of burning a large amount of propellant to impart the required energy is typically termed ascent mission which involves the design and development of a feasible trajectory that is the flight path of the object and a vehicle which would make it a reality so to summarize space missions aim to create objects in space for various scientific and technological needs launch vehicles are important elements that aim to position space objects so as to enable them to carry out the specified scientific and technological activities so we have come to this introduction to the subject even next look at the aim and scope of the present course so bye and see you in the next lecture thank you