The Polar Satellite Launch Vehicle (PSLV) is an expendable medium-lift launch vehicle, a type of rocket system designed and operated by the Indian Space Research Organisation (ISRO). Its development began in the 1980s and the project was initiated in 1982 to establish indigenous capability for launching the Indian Remote Sensing (IRS) satellites. The PSLV was created to solve the problem of India's reliance on foreign commercial services, primarily from Russia, to place its IRS satellites into Sun-synchronous orbits (SSO). The first developmental flight, PSLV-D1, occurred on September 20, 1993, which failed, but the first successful launch was in October 1994.
The PSLV is a four-stage vehicle that alternates between solid and liquid propulsion systems. The first and third stages are solid-fueled, while the second and fourth stages are liquid-fueled. The second stage, known as the PS2, uses an Earth-storable liquid rocket engine called the Vikas engine. The vehicle's lift-off thrust is often augmented by solid rocket strap-on motors, which vary in number depending on the variant. For instance, the PSLV-XL variant uses six extended strap-on boosters, while the PSLV-CA (Core Alone) variant uses none. The PSLV is known as the "workhorse of ISRO" and can carry up to 1,750 kg of payload to a 600 km SSO.
The PSLV connects directly to India's most significant space missions, having launched the country's first lunar probe, Chandrayaan-1 (2008), and the first interplanetary mission, the Mars Orbiter Mission (Mangalyaan) (2013). It also launched all seven satellites of the Indian Regional Navigation Satellite System (IRNSS), now called NavIC. Recently, the PSLV has seen the introduction of new variants like the PSLV-DL (two strap-ons) and PSLV-QL (four strap-ons), both first flown in 2019. The core concept of the four-stage alternating propulsion system has stayed the same, but the vehicle's reliability was recently challenged by two consecutive mission failures, PSLV-C61 in May 2025 and PSLV-C62 in January 2026, both due to an anomaly in the third stage. ISRO has since stated that the anomaly has been resolved. The PSLV's strap-on motor technology is also being adapted for the Sub-Orbital Launch Vehicle for Experiments (SOLVE), a new test platform for the Gaganyaan human spaceflight program.