Fifth IRNSS satellite on schedule to launch

Fully integrated PSLV-C31 with IRNSS-1E on the launchpad. (Photo: IRNSS)

The fifth satellite in the Indian Regional Navigation Satellite System (IRNSS) constellation is ready for lift-off. IRNSS-1E will launch at 0401 GMT Wednesday (11:01 p.m. EST Tuesday) from Satish Dhawan Space Center on Sriharikota Island, on India’s east coast.

As in the previous four launches of IRNSS satellites, the navigation satellite will ride aboard a Polar Satellite Launch Vehicle (PSLV). This is the 33rd launch for the PSLV.

The IRNSS-E1 satellite will join four previous craft launched for the regional IRNSS navigational system, which is aimed towards South Asia to increase accuracy of navigation, tracking and mapping services. The entire IRNSS constellation of seven satellites is planned for completion this year.

IRNSS-1E has a lift-off mass of 1425 kg. The configuration of IRNSS-1E is similar to that of IRNSS-1A, 1B, 1C and 1D. IRNSS-1D launched in March 2015.

IRNSS -1E carries two types of payloads — navigation payload and ranging payload. 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. 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 which facilitates accurate determination of the range of the satellite. IRNSS-1E also carries Corner Cube Retro Reflectors for laser ranging.

IRNSS-1E Integration in progress at clean room. (Photo: IRNSS)

IRNSS-1E spacecraft integrated with PSLV-C31, with the two halves of the heat shields. (Photo: IRNSS)