Context:

• The Indian Space Research Organisation (ISRO) would be launching an electronic intelligence satellite Emisat for Defence Research and Development Organisation (DRDO) in March 2019.
• In the special mission, ISRO would also be launching 28 third-party satellites and demonstrate its new technologies like three different orbits with a new variant of Polar Satellite Launch Vehicle (PSLV) rocket. The exact date of the mission has not been specified yet.

Key Highlights:

• ISRO would be using a PSLV rocket with four strap-on motors. For the first time, it will be trying to orbit the rocket at three different altitudes.
• The main passenger of the PSLV rocket will be DRDO’s electronic intelligence satellite ‘Emisat’. The satellite alone weighs about 420 kg.
• The remaining 28 satellites would cumulatively weigh about 250 kg.
• After launching Emisat at an altitude of 763 km, the PSLV rocket will be brought down to put the 28 satellites into orbit at an altitude of 504 km.
• Following that the rocket will be brought down further to 485 km where the fourth stage will turn into a payload platform carrying three experimental payloads.
• The experimental payloads include one developed by the students of Indian Institute of Space Science and Technology, ISRO’s own technology demonstrator and a Hamsat.