prithvi 2- tested again successfully

                                       

A single stage liquid fueled surface to surface missile capable of carrying a nuclear war head  was tested successfully on Saturday, from the Integrated test range near in Balasore in Odissa as a part of user trial by the army. A 9metre length and 1metre diametre carrying 500kg duplicate payload had hit the prefixed target in Bay of Bengal.  It was first test-fired on January 27, 1996 and the development stages were completed in 2004. This variant has been inducted in to the Army as well.though it is a ballistic missile , it do has the capacity to work as an Anti ballistic missile also.After a failed test on 24 September 2010 , two more missiles were launched on December 22, 2010 which proved to be complete success.  

Neil Armstrong - The legend

“That's one small step for man, one giant leap for mankind.” 

        

                                                     

The first man to step on the moon, lost his physical existence on earth. people considered him as one of the world`s best heroes for all time. On 25th august  2012, due to heart problem through which he was suffering from a long time has passed away.Neil Alden Armstrong was the first person to walk on the Moon, as well as an American astronaut, test pilot, aerospace engineer, university professor and United States Naval Aviator. 

                                         legends never dies.........

 

the story of columbia disaster

                                                      
     It was on 1st feb 2003, World was waiting fro them. Just 16min more to reach the surface of earth. But suddenly they lost receiving signals one by one. Its the blast that took 7 lives. One of the biggets disaster in the history of space exploration.There are people who witnessed it with their modern instruments.This disaster placed many questions in front of NASA and US administration.

                                                            

           They started digging for clues and reasons. Each and every scientist involved in the mission re caped the complete story since from launch to the blast. They have indulged about 20,000 people to collect each and every part of the debris of the plane for 3 months. Surprisingly they have collected the debris of 80% of the total weight of plane.they have also found an audio recorder in a forest which was undamaged ,but still no clues were extracted from that recorder. They examined the vedios and pictures of the launch. In that course they got to know that a small peck of foam parted from the booster and had hit the wing of the plane during the initial seconds after the launch.

                                                               

            Now they started a model simulation of the peck hitting the wing and the result shocked every one who were watching it. that small peck had made a hole of about 25cm diameter to the wing. This hole had not affected the plane during the journey in space. But while returning into the atmosphere , it started making difference. The speed of vehicle during the journey and during the reentry was about 28,000km/hr. And that speed resulted in the increase in temperature of the plane to about 1400 degrees Celsius. The external surface of the wing is thermal resistive but the damage was caused due to the hole occurred during the launch . The hot gases entered through the hole and started affecting the internal structure of the plane. slowly the heat sensors damaged one by one. The surface started melting , resulting the blast, 7 scientists lost their lives with in fraction of seconds. World witnessed the biggest ever disaster in the history of space race.

                                             

             family members of the astronauts  and the other people who were watching eagerly for the return , became stunned , they can`t believe what was going on at that time, but its the destiny and one should accept it.   

The details of the crew:

1) Michael P. Anderson
    Lt. Colonel, U.S. Air Force             
    Payload Commander

    Dec. 25, 1959–Feb. 1, 2003

    Birthplace: Plattsburgh, New York
    Age: 43
 2) David M. Brown
    Captain, U.S. Navy
    Mission Specialist
   April 16, 1956–Feb. 1, 2003

   Birthplace: Arlington, Virginia
   Age: 46

3) Kalpana Chawla
   Mission Specialist  July 1,1961–Feb.1, 2003                                    
    Birthplace: Karnal, India
    Age: 41

4) Laurel Blair Salton Clark
    Commander (Captain-Select), U.S. Navy
    Mission Specialist
    Oct. 3, 1961–Feb. 1, 2003
    Birthplace: Ames, Iowa
    Age: 41

5) Rick D. Husband
    Colonel, U.S. Air Force
    Shuttle Commander
    July 12, 1957–Feb. 1, 2003
    Birthplace: Amarillo, Texas.
    Age: 45

6) William "Willie" McCool
    Commander, U.S. Navy
    Shuttle Pilot
    Sept. 23, 1961–Feb. 1, 2003
    Birthplace: San Diego, California
    Age: 41

7) Ilan Ramon
    Colonel, Israeli Air Force
    Payload Specialist
    June 20, 1954–Feb. 1, 2003
    Born: Tel Aviv, Israel
    Age: 48

The story of V2

              World war 2 wouldn`t be that destructive without the invention of V2. History describes it as mile stone in the rocket technology yet the most deadliest weapon ever designed till the time. The most advanced space technology  was completely derived from the most basic rocket used in the world war 2 by Germany.

Brain behind V2:

               It was the situation where Germany was in complete crisis, almost at the edge of the defeat. But Hitler, the chancellor of Germany at that time, never accepted the defeat and called all the basic scientists and professors of Germany to help in the development of the already existing weapons but with increased capacity. In this situation Walter Dornberger,  who was in charge of rocket research program run by Ballistic Council of the Army weapons department. He was highly interested in ballistics and was ready with a new design of a rocket that has a capacity to hit a target at a range of above  1000 km, with more accuracy and with greater destructive capability. But other scientists believed that this proposal very far from reality  and also an ideal thing to design.

                                                            

                  Hitler and other officials took interest in dornberger`s  rocket, as they were completely concentrating In developing the conventional flying bombs, but Dornberger never gave up. He started his research on making his rocket into reality with few of his colleagues.  In the course , he came across a young scientist  named Warner Von Brown who has a different dimension towards  rocket propulsion. Dornberger appointed him as his assistant scientist to undergo the research. Kummerdorf is the place where they started their work initially in huts, later developed to heavy machinery and highly sophisticated infrastructure extended their workers from hundreds to thousands. And finally the time comes to show the capacity of his rocket to Hitler, as Hitler visited the site, he was very much impressed and given financial and army support to the production of the new rocket in bulk numbers.

        

                   The new production unit was set up in Peenemunde and the work too rapid acceleration. The prisoners caught in the war were forced to do heavy work in the factory without giving prior security to them from the dangerous gases released in the production. Thousands of prisoners were died during the period without proper food and environmental conditions.

 Poor Peenemunde:

               In the other side london got information about the process going on in Germany from secret agencies and the fisher man near the coast. They got scared about the lack of defense against those gigantic rockets. They decided  to attack on Peenemunde before Germany attacks on London and on a fine night Peenemunde was attacked by London air force. It was such a destructive mission , that Germany took about 8 months to recover from that loss , thousands of workers were died. Luckily the officials quarters and the main production unit was not damaged a lot .

A rapid recovery:

           Though it was such drastic blow to the V2 production , dornberger and Von brown never gave up. They changed the production place started to produce the rockets as fast as possible. Hitler was eagerly waiting to attack London with that deadly weapon and he named that missile as VENGENCE shortly V2. He ordered the other neighboring countries to send the prisoners to the work. And this time it was massive , they produced about 450 rcokets per month initially and later the count went to 2000 per month. Now Germany was completely ready to the big war,  the most exciting moment to Hitler and the scientists who worked to their lives on this mission. 

                                                           

Ignition… boost….hit :

   

                    Time comes for Germany to see the destruction of London. The First rocket took off and the destruction started. 10 to 30 people died for each hit some were as expensive as they took 100 and above lives for a hit. This turned London in a graveyard, people who were injured never find any hospitals empty as they were all already filled with the dead bodies.  Germany enjoyed the drama going on in London. 

related links :    http://en.wikipedia.org/wiki/Peenem%C3%BCnde_Army_Research_Center

                          http://en.wikipedia.org/wiki/Walter_Dornberger

                          http://en.wikipedia.org/wiki/V-2

books:              Hitler`s Rocket,the story of V2

agni II - 3rd successfull test

Agni 2 roars again into the space to hit target at a distance of 2000km in 700 sec from the wheeler island ,Odissa coast on 9th august , 2012. As we know that Agni 2 is the Indian prestigious Nuclear capable middle range ballistic missile, It was again tested successfully , the 3rd time. It was first tested on 11th april 1999 and then on  17th may 2010.

                                                    
 with a 2 staged solid fueled engine and a temporary payload which  would not cause any great damage , was used to hit the prefixed target in Bay of Bengal , where 2 of our navy force ships were present at the near by position to the target . They declared that the missile had hit the target with in a range of few metres.
                         

The Unknown Destiny

           It was just past midnight, they have got the signal from the space for which they were waiting for months. It was not from the god but from the thing ,they were really worshiping from past 3months. 4th October, 1957 was written with the golden words in the world`s history. Russia proved its supremacy by placing the first satellite into the space and the search started from that moment.

           

               USA , within a couple of months, have sent their satellite , then the man into the space by Russia followed by USA and then this time USA crossed Russia making their man to step on the moon. Few countries followed this series and many others are trying a lot to do that. The search went to the mars, the other planets and their moons , their each and every movements were covered by satellite which were meant to do that. Satellites travel for years to reach the other planets and get information about it. Man learnt a lot about the sun , our solar system, our galaxy etc.. . Satellites not only helped for the space exploration but also has another dimension which helps a lot for the development of Mankind. People are using those satellites for almost every work they do, it became a part of our life. They help us to defend from the natural calamities and also they help us in the wars to destroy ourselves.

           

               Are they really helping to develop the mankind? Are these designed to destroy ourselves? Whatever it may be , they really changed the way of living.

             

                Recently they build a big apartment like structure in the space called the great International space station where the research is going to explore the universe. Now a days people are visiting very recently and few are going there to get the feel of being in space, to feel the freefall, to view the earth from there and so on , paying loads of money to respective authorities.

             

                     Man never satisfied with this achievement. They want something else that can fulfill their desires, they don`t know what makes them satisfy but they go on searching for that and they can even put their lives to reach that unknown destiny.

solid propellant rockets -1

         The most important conventional rockets uses solid propellants(fuel in solid fom)  for their propulsion. As the density of solid is greater than that in any other form, we require quiet less volume of fuel tank as compared t o the liquid or gaseous fuelled tanks. There are many other advantages and of course disadvantages too, we will discuss them in this course.

  

Mechanism of burning  in solid propellant rockets.

Doublebase propellants:      

             the propellant surface when heated, degrades exothermally in the solid phase. This zone of decomposition within the solid is known as the foam zone . gases like NO₂, NO and aldehydes are liberated during the decomposition . these gases mix near the surface of the propellant and chemically react to liberate heat. The major reaction is between NO₂ and  aldehydes, where CO and CO₂ are formed. The zone of gas phase reaction is known as the fizz zone.

   

                          Temperature increases in this zone and the zone is highly luminescent. An increase from surface temperature of the propellant T_s to T₁ takes place. The fizz zone is followed by a dark zone in which chemical reactions between ( NO and CO ) and (NO and NH₂) takes place. There is no significant raise in temperature here. This zone is followed by a 2^nd luminous flame zone where in chemical reactions proceed further with heat liberation . Temperature rises in this zone from T₁ to the final value t_f.

                              The extent  of the 3 zones is very small( order of fraction of mm)  and depends very much on pressure. The thickness of the foam zone is much smaller than the fizz zone and dark zone. The intermediate dark zone is at a lower  temperature T₁ than the final temperature T_f. This causes the oveall temperature gradient in the gas phase near the propellant surface to be small and thereby limit the heat transfer from the flame at temperature T_f to the surface of the propellant .When the pressure exceeds about 10MPa, the primary fizz zone merges with the 2^nd luminous zone , giving rise to increased heating of the propellant from the hot gases.

Burn rate :

              The most important parameter for the successful  working and high efficiency of a rocket, is the burn rate of the propellant we used. Not only in the case of solid but  also in liquid and even for hybrid propellant , the controlled burn rate is most necessary. In most cases the acceleration of rocket increases with the burn rate but there also exists few cases where the rocket is decelerated due to heavy loss of the propellant in a short time . It is very important to analyse the effects of the burn rate and also the control measures  the maintain the velocity of the rocket.

               The burn rate of a solid propellant rocket is given by the following equation:

                                          r = a pⁿ

where      r is the burn rate

                  a is a constant  that takes values accordingly.

                P is pressure

this relation is known as Vielle`s law and also as Saint Robert`s law. 

staging and clustering of rockets

        The achievable values of specific impulse and structural mass fraction , encountered in practice are such that it is very difficult for a single rocket to provide the velocities required for orbiting the Earth and for escaping from it. An increase in propellant mass, if provided to give larger value of impulse , makes the rocket unwieldy and heavy and leads to smaller values of the thrust to mass ratio.

                                                                                                                               

                If a series of rockets were put one on top of the other and operated sequentially In stages one after the other , the total velocity would correspond to the sum of the ideal velocities provided  by the operation of each stage of the rocket. The above fig. gives a schematic diagram of a two stage rocket with the first stage rocket taking off from the ground and followed by the operation of 2^nd stage. The 2^nd stage gets started when its velocity is equal to the velocity provided by the 1ststageV_1.i.e. the velocity at the end of the operation of the 1^st stage . If V₂ is the velocity contributed by the 2^ndstage , the velocity at the end of operation of the 2^nd stage is V₁ + V₂.

                 In general, for a rocket having n stages , this stage continues with each successive stage provided an incremental velocity . Denoting the ideal velocity provided by each stage as V₁,V₂,…..V_n respectively , the total ideal velocity of a n stage rocket is: 

                 

                                            V=V₁+V₂+….+V_n

              The used rocket stages are discarded once their propellant is consumed in order to reduce the inert mass and hence improve the mass fraction of the upper stages . This procedure of operating a series of rockets sequentially  is known as staging of rockets .

    

                    Most of the rockets used for putting space crafts into orbit have 2 to 4 rocket stages , and are referred to as satellite launch vehicles. The first stage rocket of a satellite launch vehicle , which takes off from ground , is the heaviest and it carries the upper rocket stages on it . It is known as the Booster stage . The payload of the initial rocket stage comprises the upper stage rockets  in addition to the actual payload . If the mass ratio of the booster stage is R_m1 and the mass ratios of the upper stages are R_m2,R_m3,…..R_mnfor a rocket with n stages in series, the net ideal velocity of the rocket is the sum of the individual velocity increment  of each stage .

      

                        V =V_j1ln(1/R_m1)+ V_j2ln(1/R_m2) + ….+ V_jnln(R_mn)

We get             V=V_jln(M_i,1/M_f,n)

Where             V_j=V₁=V₂……..=V_n

       

                       V=V_jln (1/R_m)ⁿ =nV_jln (1/R_m)

           Multiple rocket stages are therefore , used to obtain higher values of V. As the No.of stages goes up , the operational complexity and cost of the multi-stage rocket increases. The No.of stages cannot  therefore , be arbitrarily increased. The main aim has been to enhance the values of V_j and decrease the structural mass fraction , keeping the No.of stage as small as possible . The present trend is to work towards a Two stage to orbit (TSTO) launch vehicle. A single stage to orbit(SSTO) vehicle would perhaps be possible if very advanced materials of construction are devised to reduce th structural and inert mass and have energetic  propellants which provide larger values of V_j than obtainable at present.

            The initial mass of a multi stage rocket is quiet large considering that the mass of all the rocket stages above booster stage have to be carried by it . The thrust of the booster rocket should be sufficient for the vehicle to accelerate and take off from ground . If the thrust of a single booster rocket is is insufficient a No.of rockets are clustered together and operated simultaneously to generate the large values of thrust required. Clustering is like parallel staging . Two booster rockets could be strapped on either side of the core rocket to get sufficient acceleration for take off. The strapped rockets are known as strap on rockets .

motion in space

Requirements for orbit:

  

Orbital velocity and orbital period:

 The requirements to orbit an object can be determined by considering the example of a body of mass m, circling the earth, at a constant angular velocity w, at a radiusR from the center of the earth. The body in the rotating frame of reference will see the force of attraction due to the earth and the pseudo centrifugal force mw²R. From the universal law of gravitational force, the force that the body experiences due to the earth is seen to towards the center of the earth.

 We get   

                                           GmM/R²=mw²R

                                             W= (GM/R³)^1/2

                                         V = wR= (GM/R)^1/2

At a height of h the orbital velocity will be    

                                           V = {GM/(R+h)}^1/2

          

        The orbital velocity about the earth is typically a few km/s. It decreases as the radius of the orbit increases. It is seen to decrease from 7.9 km/s at earth`s surface to about 2.66km/s at a height of 50,000km.

The time period of revolution for one orbit is:

                                               T =2(3.14)R/V

                                           T = 2(3.14)[R³/GM]^1/2

                                          T=0.304*10^-6 R^3/2sec

Geosynchronous and Geostationary Orbits:

          If a body is in circular orbit with an angular velocity equal to that of earth and also rotates in the same direction as that of earth from east to west, its movement is synchronous with the rotation of the earth and it is said to be in geosynchronous orbit.  It will complete one rotation in a day.

               (GM/R)^1/2 = W(7.273*10^-5) rad/s

The radius of the geosynchronous orbit Rfrom the above equation is:

                             R³ = GM/w²

By substituting the values of G,M and w the value of R =42,164km.

With the radius of the earth being 6378km, the geosynchronous altitude would therefore be 42164-6378= 35,786km  above the earth.

            If the plane of the geosynchronous orbit is in the equatorial plane of the earth and the body rotates in the same direction as the earth rotates , the orbiting body will always appear to be stationary to an observer standing on the earth`s surface . It is then said to be in geostationary orbit. The orbiting body will appear to be a fixed point in the sky for an observer on the ground. Arthur Clarke, author of several science fiction books, had put forward this concept of a geostationary orbit in 1945. The orbit is therefore also referred to as Clarke orbit.

  The first satellite to be placed in the geostationary orbit was syncom-2 on July 26, 1963.

Eccentricity and Inclination of orbits:

          Orbits are not always circular and in the equatorial plane. An orbit could be elliptic and the departure from a circular orbit is known as eccentricity of the orbit. It is defined as the ratio of the distance between the foci to the length of the major axis of the ellipse. This is shown below.

                                        

      Here L_c is the distance between the foci and 2a is the length of the major axis giving the eccentricity e=L_c/2a. In the limit of circular orbit, L_c=0 and the eccentricity is zero. A body gets into an elliptic orbit when the orbital velocity provided to it is not equal to the orbital velocity required for a circular orbit.

Highly elliptic orbits with large inclinations are provided when the space craft has to remain over certain restricted zones over long durations.

Polar and Retrograde Orbits:

                                   

      The inclination of an orbit is the angle between the orbital plane and the equatorial plane of the planet about which the body is orbiting. An inclination of zero denotes that the orbit is in the equatorial plane, i.e the orbital plane and the equatorial plane coincide. An inclination of 90⁰ represents the orbit from pole to pole and is known as polar orbit. An inclination of 180⁰represents the orbiting body to move in the equatorial plane. It is known as a retrograde equatorial orbit.

Molniya orbit:

                    A particular orbit known as Molniya orbit is highly elliptic with the half major and half minor axis being about 46000km and 6800km respectively. The inclination of the orbit is 63.4⁰. Space crafts in the Molniya orbit remain in the northern hemisphere for as much as 11hrs in an orbit having time period of 12hrs, I.e; it takes only 1hr to travel the southern hemisphere.

Transfer orbit :

                       Instead of directly taking a spacecraft to geosynchronous orbit, the spacecraft is initially placed in an elliptical orbit about the earth. The orbit is known is known as the geosynchronous transfer orbit about the earth and is schematically shown in below figure. 

                                              

       The farthest point of the spacecraft from the center of the earth Is called Apogee. The point of the spacecraft closest to the earth is called perigee. The apogee and perigee are shown in fig. the apogee of the elliptic orbit is so chosen that it is near to the radius of the geosynchronous orbit of 42164km. the perigee is small at about 6630km, the choice being governed such that the drag effects at this altitude will be negligible. The elliptic transfer orbit is circularized to give geosynchronous orbit.

Escape velocity:
          If a body is provided with sufficient velocity to overcome the gravitational attraction, it would reach infinite radius and escape the attractive force of planet. This velocity is referred to as Escape velocity

                                             V_e=(2GM/R)^1/2

Velocities: Means of Providing The Required

           Velocities of several km/s are seen to be necessary for orbiting bodies about the earth. Velocities required by the bodies to escape from the earth are even higher. Large values of momentum or impulse are therefore essential. Jules Verne, the famous science fiction author, in his book from earth to the moon – de la terra a la Lune in 1874, suggested the use of a canon gun. If a velocity of 10km/s is considered to be provided impulsively to a body of say 1000kg over a period of 1ms, the energy 5*10⁷kJ and the power is 5*10¹⁰KW. This continues a large quantity of power. Even if the very high velocities could somehow be provided to the body, frictional heating in the atmosphere would destroy it . The high velocities are therefore achieved by gradually adding velocity to the body by the rocket as the body is being pushed up to the required orbit.