Santellite Launch Vehich — Wikipedia

Satellite Launch Vehicle Light space launcher
General data
Native country	Inside
Premier vol	August 10, 1979
Last flight	April 17, 1983
Status	withdrawn from the service
Launches (failures)	4 (1.5)
Height	22 meters
Diameter	1 meter
Take -off mass	17 000 kg
Floor (s)	4
Payload
Low orbit	40 kg
modifier

The Satellite Launch Vehicle more generally designated by its acronym SLV (In Indian उपग्रह प्रक्षेपण प्रक्षेपण) is the first space launcher developed by India. THE July 18, 1980 , he manages to place the first Rohini artificial artificial satellite in orbit launched by national means. Developed in the 1970s by the Indian Space Agency (ISRO), he made four flights between 1979 and 1983, two of which were successes. This 24 -meter -long 17.6 -ton launcher can place a payload of 40 kg On a low orbit of 400 km tilted 46 °. It includes four floors with a solid propergol. The launcher is replaced by the more powerful ASLV (150 kilograms in low orbit) which made its first flight in 1987.

India developed its first satellites in the 1970s: the first of them Aryabhata was placed in orbit in 1975. But the country depends for the launch of its satellites of Soviet and American rockets. From the start of the Indian space program, officials wish to acquire their own launcher. They take as a model the small American scout launcher which uses solid propergol stages to place in low orbit useful loads up to 180 kg. The feasibility study, taking into account the limited technological capacities of India, fixes the satellisable payload at 40 kg by the future launcher. The development of the SLV launcher began in 1973. The means available to India at the time are very limited: no computer, engineers circulate between different establishments in third class trains, interurban telephone calls are contingent and The transport of sometimes fragile parts is carried out by Rickshaws. The SLV includes 10,000 components, 95% of which are made in India. The launcher is developed using the know-how acquired by India with its first Rohini-rocket rockets. However, it is a huge leap forward: the Rohini-560-560-slide rocket (first flight in 1973) has a mass of 1.3 tonnes against 17 tonnes for the SLV launcher. This is distinguished from the first launchers of other nations by its particularly low mass and by its very important slenderness (22 meters for a diameter of 1 meter). India already had a site to launch its shunder rockets. But she decides to create a new launch base for the SLV. This is located in Sriharikota, an island of 180 km² in length (44 x 7.8 kilometers), located on the south-eastern coast of India not far from Madras, and with characteristics close to the Cape Canaveral site . This establishment will later become the main launch base of the ISRO, and will be renamed in 2002 STATH DHAWAN ^{[ first ] , [ 2 ]} .

Indian officials initially planned to carry out a first test in 1974 but the development of key components took more time than expected and engineers from the Indian space agency are forced to assist the companies involved in the construction of the launcher. A second deadline corresponding to 30 ^{It is} Anniversary of India’s independence (1978) was in turn missed. The first launch attempt took place on August 10, 1979. The payload is the Rohini satellite of 36.7 kg. But a leak not detected (failure of a valve) partly empties the tank of the second floor before its launch. The computer had clearly indicated that the tank was partly empty, but the controllers convinced of an error, had yet authorized the takeoff. Although all the stages of the launcher operated in a nominal way, the rocket does not have sufficient speed to place the satellite in orbit. The second shot that takes place on July 18, 1980 is a success. A copy of the Rohini satellite is placed on an orbit 325 x 950 km with an orbital inclination of 44.75 °. The third launch takes place on May 31, 1981 And is broadcast live by the country’s radio and television. For the first time the launcher’s guide system is of Indian origin. After 6.28 seconds the launcher begins to turn on himself what dismisses him from the nominal trajectory. The second floor while trying to correct this difference provides a speed of 6% lower than planned. The third floor also loses 3% of its acceleration capacity. Ultimately, the satellite is placed on an orbit whose too low perigee (186 km) which leads to its atmospheric return and destruction 8 days later. The fourth and last launch takes place the April 17, 1983 . For this last flight, the envelope of the top floor made of reinforced Kevlar fiber saves 50 kilograms of ergols and thus reassemble the perigee. The shooting is a success and places a 41.5 -kilograms Rohini satellite which takes a camera. This transmits 5000 photos of the earth to the extinction of the satellite 18 months later ^{[ first ]} .

Indian officials wish to have a launcher capable of placing one tonne satellites on a polar orbit. But this objective cannot be achieved for many years (the PSLV meeting this objective made its first flight in 1993), they decide to develop an intermediate power launcher. ASLV is an SLV flanked by two extra propellers of 11.6 tonnes each which allow a payload of 150 kg to be placed on a low orbit. The launcher made his first flight in 1987 ^{[ first ]} .

The first versions of the Indian ballistic missile Agni largely use the technologies and components developed using the SLV launcher. The first floor of the agni I and Agni II missiles are adaptation of the first floor of the SLV launcher. It is a completely opposite evolution of those of the main space powers that developed their first launchers by modifying ballistic missiles (Atlas, Delta, Thor, Juno, Titan, Vostok/Voskhod/Soyuz)

The SLV launcher is 22 meters high launcher for a diameter of 1 meter. Its launch mass is 17.61 tonnes and the take -off is 455 kilonewtons. The ratio between the mass of the payload and that of the launcher is relatively low because the structural index (vacuum mass/total mass) of the rocket) is particularly high (20%). Like all launchers whose operating time of the floors is relatively short, a more or less long non -propulsive period succeeds the extinction of certain floors. This is the case after the extinction of the second floor at an altitude of 88 km and after that of the third floor to the altitude of the perigee is reached. The envelope of the first two floor is made of 15 CDV6 steel while those of the third and fourth floor is made respectively in ice fiber and composite material. The launcher includes four floors which are all powered by a solid propeller engine ^{[ 3 ] , [ 4 ] , [ 5 ]} :

• The first SLV-1 floor is 9.99 meters long for a diameter of 1 meter. Runities placed at the base of the floor bear the diameter out of 3 meters. The floor has a total mass of 10.8 tonnes and 2.14 tonnes empty. The soil specific impulse is 229 seconds and the operating time is 49 seconds. The relatively low section of the puppet section is 6.7. The pressure in the combustion chamber is 44.2 bars. The floor is loaded with 8.6 tonnes of PBAN (Polybutadine Acrylo Nitrate) produced in India. The floor is made up of 3 segments assembled after loading propergol.
• The second floor SLV-2 is 6.35 meters long for a diameter of 0.8 meters. It has a total mass of 4.9 tonnes and 1.75 tonnes vacuum. The specific impulse in the void is 267 seconds and the operating time is 40 seconds. The maximum push in the void is 267 kilonewtons. The report of the puppet section is 14.2 and the pressure in the combustion chamber is 38.2 bars. The floor is loaded with 3 tonnes of PBAN.
• The third SLV-3 floor is 2.3 meters long for a diameter of 0.82 meters. It has a total mass of 1.5 tonnes and 440 kilograms empty. The specific impulse in the void is 277 seconds and the operating time is 45 seconds. The maximum thrust in a vacuum is 90.7 kilonewtons. The puppet section report is 25.6 and the pressure in the combustion chamber is 44.2 bars. The propeller is of HEF 20 type.
• The fourth floor SLV-4 is 1.5 meters long for a diameter of 0.66 meters. It has a total mass of 360 kg and 98 kg empty. The specific impulse in the void is 283 seconds and the operating time is 33 seconds. The maximum push in the void is 26.8 kilonewtons. The report of the noise section is 30.2 and the pressure in the combustion chamber is 29.5 bars. The propeller is of HEF 20 type.

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