ISRO is all set to make its first rocket launch of the year

48-hr countdown for IRNSS-1E launch progressing smoothly: ISRO

Indian space agency ISRO is all set to make its first rocket launch of the year and the fifth satellite of India Regional Navigation Satellite System -- IRNSS-1E, on board PSLV-C31 rocket from Sriharikota on Wednesday.

The 48-hour countdown for the launch scheduled at 9.31 am from the second launch pad began on Monday at the spaceport of Sriharikota, about 100 km from here, and was progressing "smoothly", ISRO said.

"The countdown started yesterday morning. It is progressing smoothly. We are expecting to make the launch tomorrow at 9.31 am. All things are in place," ISRO Chairman A S Kiran Kumar told reporters.

IRNSS-1E is the fifth navigation satellite in the IRNSS space system, comprising seven satellites, which would be on par with US-based GPS once the full complement of spacecraft is launched.

It has configurationsimilar to its predecessors IRNSS-1A, 1B, 1C and 1D and carries two types of payloads -- navigation and ranging payload.

The navigation payload will transmit navigation service signals to the users and operating in L5-band and S-band while the other consists of a C-band transponder that facilitates accurate determination of the range of the satellite.

IRNSS-1E has a lift off mass of 1,425 kg and carries Corner Cube Retro Reflectors for laser ranging and a highly accurate rubidium atomic clock (also part of the navigation payload of the satellite).

While four satellites would be sufficient to start operations of the IRNSS system, the remaining three would make it more accurate and efficient.

The four satellites that were already launched include IRNSS-1A on July 1, 2013, while IRNSS-1B on April 4, 2014. IRNSS-1C was launched on October 16, 2014 and IRNSS-1D on March 28, last year.