ISRO: Towards A Space Station

New Delhi. On April 1, 2019, India’s Polar Satellite Launch Vehicle (PSLV-C45) successfully launched EMISAT and 28 international customer satellites. This was the 47th mission by the PSLV rocket which has witnessed only two failures till date since its first successful launch in October 1994.

- GP Capt Ajay Lele(RETD)

The rocket is fondly known as ISRO’s workhorse, and so far, it has launched 46 national satellites, 10 satellites built by students from Indian Universities and 297 international customer satellites. Even India has used this rocket for its first mission to the moon, the Chandrayaan-1, in 2008 and Mars Orbiter Mission (MOM) in 2013.

The PSLV mission configuration constitutes four stages using solid and liquid propulsion systems alternately. The first stage carries solid propellant, and the second stage uses the Vikas engine which carries liquid propellant. The third stage is a solid stage and the fourth stage is a liquid stage with a twin-engine configuration.

ISRO is working towards using this stage as an alternative unmanned Space Station.

PSLV can take up to 1,850 kg of payload to Sun-Synchronous Polar Orbits of 600 km altitude. It has also carried payload of 1,425 kg to Sub GTO. Due to its unmatched reliability, the PSLV has also been used to launch various satellites into Geosynchronous and Geostationary orbits, like satellites from the IRNSS (NAVIC) constellation. There are different variants of PSLV depending on the nature of the mission and the weight of the payload to be carried. Four to six ground-lit strap-on boosters are added (attached) to the rocket based on the requirement.

The flexibility of the PSLV system is amazing. Vikas, it may be recalled, is derived from the French Viking engine technology under a 1970s cooperation agreement, and has successfully been developed further for indigenous production in India.

One unique experiment was performed by ISRO during PSLV-C29 mission on December 16, 2015. A restart and shutoff of the fourth stage engine was attempted. The success of this experiment has demonstrated ISRO’s capabilities with multiple burn fuel stage/rocket engine. ISRO had identified this as an arena for future critical technology development.