The S139 (S for Solid, 139 for weight of 139 tonnes) is a Solid Rocket Booster manufactured by the

Indian Space Research Organization The Indian Space Research Organisation (ISRO; ) is the national space agency of India, headquartered in Bengaluru. It operates under the Department of Space (DOS) which is directly overseen by the Prime Minister of India, while the Chairman ...

at the Satish Dhawan Space Center in the SPROB facility. The rocket motor was first developed for use in the

Polar Satellite Launch Vehicle The Polar Satellite Launch Vehicle (PSLV) is an expendable medium-lift launch vehicle designed and operated by the Indian Space Research Organisation (ISRO). It was developed to allow India to launch its Indian Remote Sensing (IRS) satellites ...

. Later it was utilized in the

GSLV Geosynchronous Satellite Launch Vehicle (GSLV) is an expendable launch system operated by the Indian Space Research Organisation (ISRO). GSLV was used in fourteen launches from 2001 to 2021. Even though GSLV Mark III shares the name, it is an ...

MKII. It uses hydroxyl-terminated polybutadiene (HTPB) as a propellant. It has a maximum thrust of 4800 kN.

Associated rockets

The S139 Booster has been used in 2 major ISRO rockets. It is used in the

PSLV The Polar Satellite Launch Vehicle (PSLV) is an expendable medium-lift launch vehicle designed and operated by the Indian Space Research Organisation (ISRO). It was developed to allow India to launch its Indian Remote Sensing (IRS) satellites ...

as its core stage since 1993. It is also used as a core stage in Geosynchronous Satellite Launch Vehicle MKII rocket. It is also the part of a variant of the

Unified Launch Vehicle The Unified Launch Vehicle (ULV) is a family of modular expendable launch vehicles, currently under development by the Indian Space Research Organisation (ISRO). This vehicle is designed to replace the PSLV, GSLV Mk I/II and GSLV Mk III with a ...

which is under development.

Gallery

File:PSLV C-35 at the launch pad (cropped).jpg, The Core stage of the PSLV is the S139 Booster

References

Rocket stages Satish Dhawan Space Centre ISRO space launch vehicles {{Rocket-stub