PSLV-C37 mission to shed dependence on Global Positioning System for orbit determination

The Indian Space Research Organisation’s (ISRO) bid to script space history by sending 104 satellites into orbit using a single launcher on February 15 will depend on critical support provided by India’s own satellite navigation system.

The milestone mission, PSLV- C37, will use the Indian Regional Navigation Satellite System (IRNSS) to determine the orbit of each satellite injected from the launch vehicle at a height of more than 500 km from the earth’s surface.

“By turning to IRNSS, we are shedding our dependence on the Global Positioning System (GPS) that was being used for orbit determination in previous missions,” Director, Vikram Sarabha Space Centre (VSSC), K. Sivan told The Hindu, amid preparations for the launch.

Precise computation

The PSLV- C36 mission last December had successfully demonstrated the use of IRNSS data for precise computation of satellite orbit.

Comprising a constellation of seven satellites in orbit and a network of ranging stations across the country, IRNSS is India’s alternative to the American GPS. The system which became operational in 2016 provides navigational support for civilian and military uses.

The PSLV- C37 mission will also provide a test bed for new technologies in handling multiple payloads.

The primary payload on PSLV-C37 is the Indian advanced remote sensing satellite, CartoSat-2 weighing 714 kg. Apart from two Indian nano satellites INS-1A and INS-1B, the rocket will also carry satellites from the U.S., the Netherlands, Switzerland, Israel, Kazakhstan and the UAE.

Nano satellites

The mission will set another record in deploying the largest number of satellites of a single constellation from one launch vehicle. As many as 88 nano satellites will be placed in orbit to form the Flock- 3p constellation by the US-based Planet Labs.

Dr.Sivan said the mission posed significant challenges in payload separation. “We have developed a carefully calibrated separation sequence to avoid collision-free deployment of the satellites.” ISRO has also come up with custom-made multi payload adaptors to mount the large number of nano satellites.

The mission will use a video imaging system with eight on-board cameras to capture the separation of various propulsion stages and satellites. The 104 satellites will be released at an altitude of 510 to 524 km over a period of 600 seconds.

PSLV-C37 will carry a total payload of 1,400 kg, with Cartosat- 2 weighing the most.