In a special mission in March, the Indian space agency will launch an electronic intelligence satellite Emisat for the DRDO, 28 third party satellites and also demonstrate its new technologies like three different orbits with a new variant of Polar Satellite Launch Vehicle (PSLV).

“The main passenger for the PSLV rocket will be the defence intelligence satellite Emisat belonging to Defence Research and Development Organisation (DRDO).

“The satellite weighs about 420 kg. The 28 satellites belonging to our customers would cumulatively weigh about 250 kg,” Sivan said.

The DRDO’s Emisat is an electronic intelligence satellite, he added.

The ISRO will also be launching two more defence satellites sometime in July/August with its new rocket Small Satellite Launch Vehicle (SSLV).

The PSLV is a four-stage engine expendable rocket with alternating solid and liquid fuel.

In its normal configuration, the rocket will have six strap-on motors hugging the rocket’s first stage.

On January 24, the ISRO flew a PSLV with two strap-on motors while in March it will have four strap-on motors.

The Indian space agency also has two more PSLV variants viz Core Alone (without any strap-on motors) and PSLV-XL a larger rocket.

The ISRO selects the kind of rocket to be used based on the weight of satellites it carries.