The PSLV launch on April 1 will hoist not one but 29 satellites in space

Highlights India seeks to launch new surveillance satellite to locate enemy radars

This is the first time ISRO is inviting common people to view the launch

In another first, ISRO will try to place satellites in 3 orbits

After having killed a low-orbit satellite with a space missile, India now seeks to give birth to a new surveillance satellite with a special mission of the Polar Satellite Launch Vehicle (PSLV) that has many firsts.

This will be the first time the Indian Space Research Organisation (ISRO) is inviting common people to view the launch. In another first, ISRO will attempt a mission where it seeks to place satellites in three orbits. "It's a way of optimising launch costs since it becomes a three-in-one mission," says ISRO chairman K Sivan.

India test-fired an anti-satellite (ASAT) missile on March 27 in Mission Shakti.

The PSLV launch on April 1 will hoist not one but 29 satellites in space. "The immediate mission what we are targeting is the PSLV C-45. This mission is special in the sense, for the first time PSLV will have a three-orbit mission in a single flight," said Mr Sivan.

"Initially, the first principle satellite will be launched in the 763-kilometre orbit, and subsequently the PS4 will be functioning two times to reduce the orbit to 504 kilometres. There, the PSLV will launch the 28-customer satellite and subsequently the PS4 will be burnt two times to reduce the orbit to 485 kilometres. There the PS4 will function as an orbital platform," the ISRO chief said.

"This time the orbital platform is powered by solar cells and not fully powered by batteries. The PS4 platform will have three payloads - one is from the Indian Institute of Space Technology that is what we are planning," Mr Sivan said.

So what is the main passenger and what will be its function?

"The main passenger is the EMISAT, a satellite for the DRDO and it is a strategic satellite," Mr Sivan said. The EMISAT for the Defence Research and Development Organisation is a 436-kilogram satellite based on India's mini-satellite bus. ISRO says the satellite is intended for electromagnetic spectrum measurement.

This low-Earth orbit satellite, sources say, will monitor and give locations for enemy radar sites deep in their territory. Till now, India was using airplanes as early warning platforms, but this satellite will give a space-based platform to sniff out enemy radars.

This will be the 71st launch vehicle mission for Sriharikota and the 47th flight of the 320-tonne, 44-metre tall PSLV.

The launch also carries 28 small satellites of the US, Switzerland, Lithuania and Spain. These include 20 Flock-4A satellites and 4 Lemur satellites of the same variety that gave the controversial images that questioned the efficacy of the Balakot air strikes by the Air Force.

In this mission, the last stage of the rocket will be kept alive for several weeks before it becomes space junk and it will be used as orbital platform or an orbiting space laboratory where three instruments are attached to the rocket motor. These include a maritime ship identification system, a version of a HAM Sat for amateur enthusiasts, and an experiment to study the upper atmosphere or ionosphere.