PSLV – Space Launch Report

India’s Space Research Organization (ISRO) introduced the Polar Satellite Launch Vehicle (PSLV) series in 1993. PSLV, designed to lift 1.5 metric ton satellites to sun synchronous polar orbit from Satish Dhawan Space Centre, SHAR, Sriharikota, India, is a conglomerate of Indian and European components.

PSLV performance was progressively improved during the 1990s. The operational “C” version, first flown in 1997, stands 44.4 meters tall and weighs 295 metric tons at liftoff. It consists of four stages that use solid and liquid propellants alternately.

The first stage uses a 2.8 meter diameter, 20 meter long, 472 ton thrust solid motor that burns 138 tons of propellant for 107 seconds. The first stage is augmented by six solid strap-on boosters that produce 67.5 tons of thrust each for 45 seconds. Four of the strap-on boosters ignite at liftoff. The two air-start strap-ons ignite 25 seconds after liftoff. The strap-on boosters are jettisonned after burn-out.  More powerful “XL” boosters carrying 12 tonnes of propellant and producing up to 73.4 tonnes of thrust debuted in 2008.

PSLV’s 12.5 x 2.8 m PS-2 (L40) second stage is powered by a 73.9 ton-thrust Viking 4 engine that burns unsymmetrical dimethyl hydrazine (UDMH) fuel and nitrogen tetroxide (N2O4) oxidizer for 162 seconds. Viking 4, called “Vikas” by ISRO, was originally built by Europe’s SEP for the Ariane 1 launch vehicle. 

The third stage is another 2.8 meter diameter solid motor. It burns 7.6 tons of propellant for 109 seconds, producing 33.5 tons of thrust.

The fourth and final stage is a twin-engine liquid propulsion system that is housed within the payload fairing below the satellite. It burns 2.5 tons of mono-methyl hydrazine (MMH) fuel and nitrogen tetroxide (N2O4) oxidizer. The 1.43 ton thrust stage can burn for up to 420 seconds.

The vehicle is controlled by a strap-down inertial navigation/guidance system housed in a vehicle equipment bay that is mounted on top of the fourth stage. An 8.3 meter tall, 3.2 meter diameter payload fairing protects the payload during ascent through the atmosphere.

The first PSLV launch, in 1993, failed due to a software guidance error. The second flight one year later successfully boosted India’s IRS-P2 Earth resource monitoring satellite into an 820 km x 98.7 degree sun synchronous orbit. Eight PSLV launches occurred during the first 10 years of its use, with six successes. In 2002, PSLV-C4 performed the first PSLV geosynchronous transfer orbit (GTO) mission.

The original PSLV/GSLV launch complex was replaced in 2005 with a new, mobile launch facility. PSLV-C6 was the first rocket to use the pad. Whereas the original pad featured a fixed launch stand and a 75 meter tall mobile service tower, the new “second launch pad” uses rail-mobile launch stands that allow vehicles to be stacked in a vertical integration building located some distance from the launch pad itself.

The January 10, 2007 PSLV-C7 mission included the first use of a PSLV dual launch adapter, which deployed both Cartosat 2 and the SRE 1 demonstration recovery capsule and carried a small microsatellite.  

The PSLV-CA (Core Alone) model premiered on April 23, 2007.   The CA model did not include the six strap-on boosters used by the PSLV-C variant.   Two small roll control modules and two first stage motor control injection tanks were still attached to the side of the first stage.  About 400 kg of propellant was offloaded from the fourth stage compared to PSLV-C.

Chandrayaan 1, India’s first lunar orbiter, was launched by the first PSLV-XL variant on October 22, 2008.  PSLV-XL, boosted by more powerful, stretched strap-on boosters, weighed 22 tonnes more at liftoff than PSLV-C.

Also read: Proton – Space Launch Report

Vehicle Configurations

Vehicle Components

Typical PSLV-C Launch Timeline