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ASLV Augmented Satellite Launch Vehicle

The original Indian SLV-3 launch vehicle was a four-stage, solid-propellant booster with a LEO payload capacity of less than 50 kg into an orbit with a mean altitude of 600 km at an inclination of 47 degrees. Following an initial failure, the SLV-3 successfully orbited three Rohini Satellites in 1980, 1981, and 1983, respectively (Reference 69). The ASLV was created by adding two additional boosters modified from the SLV-3's first stage and by making other general improvements to the basic SLV-3 4 stage stack. The ASLV is actually a five-stage vehicle since the core first stage does not ignite until just before the booster rockets burn out. The payload capacity of the ASLV is approximately 150 kg to an orbit of 400 km with a 47 degree inclination (Reference 70).

The Augmented Satellite Launch Vehicle (ASLV) Programme was designed to augment the payload capacity to 150 kg, thrice that of SLV-3, for Low Earth Orbits (LEO). After taking charge as Chairman, Space Commission and Secretary, Department of Space in 1984, Prof. Rao accelerated the development of rocket technology, resulting in the successful launch of ASLV rocket. While building upon the experience gained from the SLV-3 missions, ASLV proved to be a low cost intermediate vehicle to demonstrate and validate critical technologies, that would be needed for the future launch vehicles like strap-on technology, inertial navigation, bulbous heat shield, vertical integration and closed loop guidance. The strap-on stage consisted of two identical 1m diameter solid propellant motors, Under the ASLV program four developmental flights were conducted.

The first launch of the ASLV on 24 March 1987 failed when the bottom stage of the core vehicle did not ignite after booster burn-out. The second attempt ended with the Rohini payload falling into the Bay of Bengal on 13 July 1988 when the vehicle became unstable and broke up soon after release of the booster rockets. There had always been questions as to why India should spend money on space activity. This question kept coming up during the 60‘s when the space program was nucleated; in the 70‘s when Aryabhata was launched; in the early 80‘s when INSAT system was established, in the late 80s when India grappled with failures in ASLV.

Finally, on 20 May 1992 the SROSS 3 (Stretched Rohini Satellite Series) was inserted into LEO by the third ASLV. However, instead of obtaining a circular orbit near 400 km, the ASLV only achieved a short-lived orbit of 256 km by 435 km, not unlike the degraded performance of the SLV-3 launch of 31 May 1981 (Reference 71). The fourth ASLV mission in May, 1994 successfully reached its programmed orbit of 434 km by 921 km with the SROSS C2 payload. The vehicle was phased out in favor of the PSLV and due to a desire to deploy larger, more complex spacecraft than can be lifted by the ASLV. Development of the complex Augmented Satellite Launch Vehicle demonstrated newer technologies like use of strapon, bulbous heat shield, closed loop guidance and digital autopilot. This paved the way for learning many nuances of launch vehicle design for complex missions, leading the way for realisation of operational launch vehicles such as PSLV and GSLV.

ASLV

Background Information First Launch: March 1987 (Launch Failure) Flight Rate: 1 per year (Intended) Launch Site: Shar Launch Center (Sriharikota, India) Capability: 330 lb to 215 nm circular orbit, 46 degree inclination History Indian Space Research Organization (ISRO) established in 1969 to develop launch systems. Rohini sounding rockets provided basis for development of satellite launch vehicle (SLV) ASLV developed as follow-on to SLV Description Four-stage, solid propellant booster Stage 1 burns HTPB solid propellant providing 113,000 lb of thrust Stage 2 burns HTPB solid propellant providing 49,000 lb of thrust Stage 3 burns HEF-20 solid propellant providing 14,400 lb of thrust Stage 4 burns HEF-20 solid propellant providing 4,700 lb of thrust Two solid strap-ons burn HTPB solid propellant providing 98,900 lb of thrust each Profile Length: 77.4 ft Launch Weight: 85,800 lb Diameter: 3.3 ft Liftoff Thrust: 310,800 lb Payload Fairing: 16.4 ft x 3.3 ft (14 ft diameter fairing available)