The Polar Satellite Launch Vehicle (PSLV) is a third-generation rocket launcher designed, manufactured and operated by the Indian Space Research Organisation (ISRO).

It is an expendable launch vehicle which can place 1,600kg remote sensing satellites into sun-synchronous orbit (SSO) and 1,050kg small-sized spacecraft into geostationary transfer orbit (GTO).

PSLV launch history

PSLV launched a total of 62 (27 Indian and 35 foreign) satellites, including Resourcesat-2, Youthsat, X-sat, Cartosat-2B, Alsat-2A, Studsat, Oceansat-2, six nanosatellites, Risat-2, Anusat, Cartosat-2A, IMS-1, DLR-Tubsat, Space capsule Recovery Experiment (SRE-1), KALPANA-1 and several others satellites. It was also used as a launch vehicle for the Chandrayaan-1 lunar probe mission by India.

Polar Satellite Launch Vehicle variations

ISRO built five variants of the PSLV based on the payload capacities varying from 600kg in low earth orbit (LEO) to 1,900kg in a sun-synchronous orbit (SSO). PSLV completed 23 launches as of February 2013, with more launches planned in October 2013. The PSLV is a standard model, which can launch 1,678kg of payload to 622km into SSO. It includes three sub-variants PSLV (1), PSLV (2) and PSLV (3).

“ISRO has built five variants of the PSLV based on the payload capacities varying from 600kg in low earth orbit to 1,900kg in sun synchronous orbit.”

PSLV-CA (PSLV-core alone) is an advanced version of the PSLV. It carries 400kg less propellant than the standard model and can launch 1,100kg of payload to SSO. The maiden flight of the PSLV-CA took place on 23 April 2007.

A meliorated model of the PSLV, the PSLV-XL weighs 320,000kg at takeoff. It is incorporated with six strap-on motors to carry 4,000kg more propellant compared with the standard PSLV. The maiden launch of PSLV-XL with Chandrayaan-1 aboard took place on 22 October 2008.

PSLV-HP is a high-performance version currently under development. It will feature upgraded strap-on boosters and payload capacity up to 2,000kg. It is scheduled to launch seven navigation satellites between 2013 and 2015. The PSLV-3S is an advanced rocket currently under development. This variant will be able to launch small satellites into LEO in three stages.

Design of PSLV launch vehicle

The PSLV was designed to be 450m high and of 2.8m diameter. It is fitted with an inertial guidance system to accomplish navigation, guidance and attitude control missions.

Pitch and yaw control of the vehicle during thrust phase of the solid booster is achieved by interposing aqueous solution of strontium perchlorate in the nozzle to establish secondary injection thrust vector control system (SITVC) which controls the roll augmentation.

The vehicle is also incorporated with two cylindrical aluminium tanks attached to the solid rocket boosters for storing the injected fuel.
Roll control thrusters (RCT) were also installed for roll control during the first stage.

PSLV development

The development of PSLV began in early the 1990s at the Vikram Sarabhai Space Centre (VSSC) in the state of Kerala. The maiden flight of the PSLV took place on 20 September 1993, but an altitude control error in the second and third stages resulted in the failure of the launch mission.

The first successful launch of the PSLV into SSO with IRS-P2 satellite aboard was completed in October 1994. The launch was carried out from the SHAR launch centre in Sriharikota.

Further successful launches followed in 1996, 1997, 1999 and 2001, 2002, 2003, 2005, 2007, 2008, 2009, 2010 and 2011.

The PSLV became the prominent rocket launcher for Indian satellite launches especially LEO and Chandrayaan projects.

ISRO launched the GSAT-12 atop a PSLV-C17 rocket from Satish Dhawan Space Centre on 15 July 2011.

The Megha-Tropiques, a mission to study the tropical atmosphere, was launched on the back of PSLV-C18 in October 2011. The PSLV-C19 launched RISAT-1 spacecraft in April 2012.

PSLV-C21 launched SPOT 6 satellite and a Japanese micro-satellite PROITERES in September 2012.

PSLV-C20, another variant of the PSLV-CA version, launched the Indo-French satellite SARAL and six commercial payload satellites on February 2013. The launch of SARAL represented the 23rd PSLV mission of ISRO.

PSLV contractors

The ISRO inertial systems unit (IISU) based at Thiruvananthapuram supplied the inertial systems for the PSLV. The liquid propulsion systems (LPS) and reaction control systems (RCS) were built by the liquid propulsion systems centre (LPSC).

The Satish Dhawan Space Centre rendered solid propellant motors for the launch vehicle. Rocket Propellant Plant (RPP) is supplying the propellants for the launch vehicle.

Launch stages

PSLV can launch a satellite into orbit in four stages. The first and third stages are incorporated with two solid propulsion systems, with the second and fourth stages powered by liquid engines.

The first stage features six strap-on boosters which can burn 139t of hydroxyl-terminated polybutadiene (HTPB) attached propellant to generate a maximum thrust of 677kN each.

Four ground lit boosters are ignited during lift-off and the remaining two airlift boosters burnt upon reaching an altitude of 2.4km.
The ground lit and air lit boosters are jettisoned at 23.7km and 42.6km respectively. The second stage ignites after reaching 68.5km and is propelled by a single Vikas liquid engine, delivering 800kN of thrust.

Fitted to a turbopump, the liquid propulsion burns 41.5t of di-methyl hydrazine fuel and nitrogen tetroxide oxidiser for 162 seconds. Payload fairings were separated at an altitude of 117km.

The third stage is ignited at 248km. It is powered by a solid rocket motor which consumes 7.6t of HTPB propellant to produce a maximum thrust of 324kN. The third stage is jettisoned at an altitude of 425km.

The fourth stage comprises a dual-engine configuration and utilises liquid propellant.

It is the final stage which burns 2.5t of monomethylhydrazine fuel and nitrogen tetroxide oxidiser for 420 seconds to produce 14kN of thrust. This stage launches the satellite into either LEO or GTO based on its mission.