The year’s first domestic space mission will take off on the morning of Wednesday, January 20, at Sriharikota with the fifth regional navigation spacecraft, the IRNSS-1E.
At the Satish Dhawan Space Centre, the launch team began a 48-hour countdown for the flight of the satellite launch vehicle, PSLV-C31, at 9.31 a.m. on Monday. The flight was cleared by two high-level review committees on Sunday, according to the Indian Space Research Organisation.
IRNSS-1E is a 1,425-kg spacecraft carrying navigation and ranging payloads. It is similar to the earlier four navigation satellites IRNSS-1A to 1D which were put in orbit between July 2013 and March 2015.
Two more navigation spacecraft – IRNSS-1F and 1G – are due to follow in February and March, an ISRO official said. They will then complete the seven-satellite constellation, otherwise called the ‘Indian GPS’.
The full fleet is likely to be switched on for regular use by end-2016 after it is tested and tried for a few months.
Already, the first four navigation spacecraft have been giving 18-hour positional information with good accuracy of the Indian region; the duration will improve with new satellites, the official said.
After a series of orbit corrections post-launch, IRNSS-1E will be placed in a geosynchronous orbit over 111.75 degrees east longitude. It will go around Earth at a distance of 20,000 km and inclined at 28.1 degrees.
For the current mission, ISRO is using the XL (extended) version in the first stage of the four-stage PSLV rocket. This format is being used for the 11th time.