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IRNSS-1A is the first navigational satellite in the Indian Regional Navigation Satellite System (IRNSS) series of satellites been placed in geosynchronous orbit.[1][2]

IRNSS-1A

Mission type	Navigation
Operator	ISRO
COSPAR ID	2013-034A
SATCAT no.	39199
Mission duration	10 years
Spacecraft properties
Bus	I-1K
Manufacturer	ISRO Satellite Centre Space Applications Centre
Launch mass	1,425 kilograms (3,142 lb)
Dry mass	614 kilograms (1,354 lb)[1]
Power	1,660 watts
Start of mission
Launch date	1 July 2013, 18:11 UTC (2013-07-01UTC18:11Z)
Rocket	PSLV-XL C22
Launch site	Satish Dhawan FLP
Contractor	ISRO
Orbital parameters
Reference system	Geocentric
Regime	Geosynchronous
Longitude	55° E
Perigee altitude	35,706.1 km (22,186.7 mi)[1]
Apogee altitude	35,882.7 km (22,296.5 mi)[1]
Inclination	29.3°[1]
Period	1436.1 minutes[1]
Epoch	22 January 2015, 16:27:41 UTC[1]

Satellite

The satellite has been developed at a cost of ₹1.25 billion (US$16 million),[3][4] and was launched on 1 July 2013. It will provide IRNSS services to the Indian public, which would be a system similar to Global Positioning System (GPS) but only for India and the region around it.[5]

Each IRNSS satellite has two payloads: a navigation payload and CDMA ranging payload in addition with a laser retro-reflector. The payload generates navigation signals at L5 and S-band. The design of the payload makes the IRNSS system inter-operable and compatible with GPS and Galileo.[6] The satellite is powered by two solar arrays, which generate power up to 1,660 watts, and has a lifetime of ten years.[1]

Launch

The satellite was launched from the Satish Dhawan Space Centre (SDSC) on 1 July 2013 at 11:41 PM (IST).[7] The launch was postponed from its initial launch date of 26 June 2013 due to a technical snag in the 2nd stage of the PSLV-C22 launch rocket.[8] ISRO then replaced the faulty component in the rocket and rescheduled the launch to 1 July 2013 at 11:43 p.m.[9][10]

Scientists from the German Aerospace Centre (DLR)'s Institute of Communications and Navigation in Oberpfaffenhofen, Germany, have received signals from IRNSS-1A. On 23 July 2013, the German Aerospace Center scientists pointed their 30-meter dish antenna at Weilheim towards the satellite and found that it was already transmitting a signal in the L5 frequency band.[11]

Partial Failure

The three Rubidium atomic clocks on-board IRNSS-1A failed, with the first failure occurring in July 2016. ISRO planned to replace it with IRNSS-1H, in August 2017, but this failed to separate from the launch vehicle.[12][13] On 12 April 2018, ISRO launched successfully IRNSS-1I as a replacement for IRNSS-1A.[14]

The cause of failure was traced to one of the feed through capacitor carrying the DC supply to the physics package of clock, malfunctioning due to excessive rise in temperature.[15] IRNSS-1A and IRNSS-1G are now being used only for NavIC's short message broadcast service.[16][17]

See also

• Communication-Centric Intelligence Satellite (CCI-Sat)
• GPS-aided geo-augmented navigation (GAGAN)
• Satellite navigation

References

External links

• ISRO Future Programmes

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