Countdown for PSLV-31's launch begins

The rocket will take off from the Sriharikota on January 20 at 9:31 am and will put into orbit the 1,425 kg IRNSS-1E satellite

The 48-hour countdown for Polar Satellite Launch Vehicle (PSLV-31) launch, which will be the first launch in 2016, has commenced today morning. The Vehicle will carry India's fifth navigation satellite as the sole passenger.

The countdown started after Isro 's mission readiness review committee (MRRC) and the launch authorisation board (LAB) gave nod for the launch on Sunday.

The countdown started at 9.31 am for the launch, which is scheduled to take off at 9.31 am on January 20. The rocket will take off from the Sriharikota space port will put into orbit the 1,425 kg IRNSS-1E satellite. The Rocket will carry Indian Regional Navigation Satellite System-IRNSS-1E began.

The satellite's life span is 12 years.

Till date, India has launched four regional navigational satellites (IRNSS-1A, 1B, 1C and ID) as part of a constellation of seven satellites to provide accurate position information service to users across the country and the region, extending up to an area of 1,500 kms.

Though the full system comprises of nine satellites — seven in orbit and two on the ground as stand-by — the navigation services could be made operational with four satellites, said Isro, which said the entire IRNSS constellation of seven satellites is planned to be completed this year itself.

Each satellite costs around Rs 150 crore and the PSLV-XL version rocket costs around Rs 130 crore. The seven rockets would involve an outlay of around Rs 910 crore.
 

The first satellite IRNSS-1A was launched in July 2013, the second IRNSS-1B in April 2014, the third on October 2014 and the fourth on March 2015.

Once the regional navigation system is in place, India need not be dependent on other platforms.

According to ISRO, IRNSS-1E carries two types of payloads - navigation and ranging payloads.

The navigation payload of IRNSS-1E will transmit navigation service signals to the users. This payload will be operating in L5-band and S-band.

Isro said, a highly accurate Rubidium atomic clock is part of the navigation payload of the satellite. The ranging payload of IRNSS-1E consists of a C-band transponder (automatic receivers and transmitters of radio signals) which facilitates accurate determination of the range of the satellite.

IRNSS-1E also carries Corner Cube Retro Reflectors for laser ranging.