Context: The Indian Space Research Organisation (ISRO) will launch a communications satellite, CMS-01, on board the PSLV-C50 from the second launch pad of the Satish Dhawan Space Centre, SHAR.

Frequency spectrum

• CMS-01 is a communications satellite envisaged for providing services in extended C Band of the frequency spectrum and its coverage will include the Indian mainland, and the Andaman & Nicobar and Lakshadweep islands.
• The satellite is expected to have a life of more than seven years.
• CMS-01 to replace GSAT-12 telecommunication satellite
• The satellite, formerly known as the GSAT-12R, will replace the GSAT-12 telecommunication satellite currently in orbit, which was launched in 2011 and has functioned beyond its expected lifetime. 

GSAT-12 itself was a replacement for the INSAT-3B telecommunication satellite.

• CMS-01 will be inserted into the higher, extremely elliptical geosynchronous transfer orbit with an apogee (farthest distance from earth) of almost 42,164 km, before which it settles into its final geostationary orbit of 35,000km and 83 degrees inclination. 
• At this orbit, the satellite revolves around the Earth at the same speed as Earth’s rotation, and appears stationary in the sky when observed from Earth.
• To launch the satellite, the PSLV launcher will fly in its XL configuration with six strap-on boosters. 
• This is the 52nd flight of the PSLV, and the 22nd in its XL configuration. This will also be the 77th launch from Sriharikota.
• The mission rocket will be followed soon by the launch of ISRO’s new launcher for small satellites, the Small Satellite Launch Vehicle (SSLV), which will carry the EOS-02 (Earth Observation Satellite). 
• The launch of the Geosynchronous Satellite Launch Vehicle-F10 (GSLV) carrying EOS-3 is expected to follow after that.