Space Launch Vehicles

India's Polar Satellite Launch Vehicle represents the first stage in acquiring launcher autonomy for application satellites. It is sized for placing 1-ton IRS-class satellites in a 904km sun-synchronous orbit from Sriharikota. The PSLV also offers growth potential for a Geosynchronous SLV to handle 2.5t into GTO. The PSLV is a 4-stage launcher measuring 44 metres high with a 2.8 metre diameter, and weighing 275 tons. It can orbit around a 1-ton payload in sun-synchronous polar orbit.

The first stage is powered by a solid fuel engine (Hydroxyl-Terminated Poly-Butadiene) which burns during 100 seconds and provides 3500kN thrust at sea level and 4600kN in vacuum. It is supported by 6 boosters which is switched on by a group of two and then four which is derived from the SLV-3 and ASLV's first stage. Each of those deliver 440kN thrust at sea level and 660kN in vacuum.

The second stage is powered by the Vikas engine, which is built under French SEP licence, and consumes liquid propellant (Unsymmetrical DiMethylHydrazine and nitrogen tetraoxide). It provides 725kN thrust during 150 seconds. The third stage is powered by a solid fuel engine (HTPB) which provides 340kN of thrust. The fourth stage is protected by a bulb cap and is propulsed by 2 ergols engines (Peroxyde D'azote and MonoMethylHydrazine) which burn in about 7 minutes.

PSLV-3.jpg (26853 bytes)

The PSLV-C2 on the launch pad

First Launch: 20 September 1993.

Latest Launch: 26 May 1999.

Number Launched: Five by May 1999.

Launched Site: SHAR Centre (Sriharikota).

Principal Use: 1-ton IRS Class satellites into sun-synchronous orbit or 3-ton class into LEO.

Performance: Sun-synchronous: 1000kg into 904km, 99.1° from SHAR (1.6t without range safety constraints)

Number of Sates: Four (2 solid and 2 liquid) plus six solid strap-ons.

Overall Length: 44.18 metres.

Fairing Diameter: 3.2 metres (5.1 metres base circle with strap-ons)

Launch Mass: 275 tons.

Guidance: Inertial guidance system located in vehicle equipment bay surrounding Stage 4 base. A redundant strap-down inertial navigation system (resins, incorporating three dry-tuned gyros and four servo accelerometers) feeds the navigation processor, which produces navigation data every 500 milliseconds for the guidance and control processor to issue steering commands at similar intervals. Open loop guidance is employed during Stage 1 burn before switching to closed loop from Stage 2 onwards.

00:00	2 solids plus Stage 1 ignite.
00:30	4 solids ignite at 3km.
00:54	2 solids burnout at 17km.
01:13	2 solids separate at 23km.
01:19	4 solids burnout at 36km.
01:30	4 solids separate at 38km.
01:45	4 stage 2 motors ignition, Stage 1 sep & Stage 1 retro motors ignition.
01:45	Stage 2 ignition at 48km.
02:32	Fairing separate at 105km.
02:37	Closed loop guidance begins.
04:21	Stage 2 shutdown; separation & retro-ignition, Stage 3 ignition at 232km.
05:33	Stage 3 burnout at 350km.
06:07	Stage 3 separate at 405km.
10:17	Stage 4 ignition at 700km.
17:06	Stage 4 shutdown at 817km.
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