Author Topic: LIVE: PSLV C22, IRNSS-R1A, FLP, July 1, 2013 (1811UTC)  (Read 100507 times)

Online Satori

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Offline isro-watch

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Offline sanman

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Here's a little video produced by ISRO outlining the benefits of IRNSS:


Offline AJA

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UPDATE
July 08, 2013

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Orbit raising manoevers completed with fifth Apogee Motor Firing (AMF) on July 06, 2013 at 16:57 hrs (IST) and performance is normal.

Satellite is in Geo-Synchronous Orbit (GSO) with 27 deg inclination at 44 deg E longitude.

Present orbital parameters are : apogee 35870 km, perigee 35484 km and orbital period is 23h 50m.

All the spacecraft subsystem are evaluated and functioning normal.

I just happened to read this blogpost (about station keeping at a defined longitude in geostationary orbit) a few days back. Applying it in the context of IRNSS, I'm thinking we're missing a trick in not exploiting the stable 75.08 deg E longitude. I know it's not a lot of delta-v, but the stable spot is RIGHT OVER US! Yes, the spot might also attract all sorts of debris, but at 36,000 km out, is there much debris at all? The kind that wouldn't cede to a relatively massive satellite?

Also, I found it pretty cool how much the seas can hide, and how rapid the terrain change is underwater. For example, the Mariana trench is at 142 deg East, but the 165 deg E point is an unstable one - dominated by the high mass-cons of the volcanic 'Pacific ring of fire'.
« Last Edit: 07/08/2013 10:38 am by AJA »

Offline input~2

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2013-034A/39199 now in
35461 x 35887 km x 27.02° (epoch July 11, 2129UTC)
Descending node longitude: 51.7°E
« Last Edit: 07/13/2013 07:00 am by input~2 »

Offline beidou

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Did the satellite start broadcasting navigation signals? Have the signals been received?

Offline input~2

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Did the satellite start broadcasting navigation signals? Have the signals been received?
"July 19, 2013, IRNSS-1A navigation payload testing in a week"

Offline kanaka

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Did the satellite start broadcasting navigation signals? Have the signals been received?

http://www.gpsworld.com/indian-regional-gnss-satellite-starts-signal-transmissions/

Offline vyoma

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Re: LIVE: PSLV C22, IRNSS-R1A, FLP, July 1, 2013 (1811UTC)
« Reply #188 on: 01/30/2017 01:59 am »
Atomic clocks on indigenous navigation satellite develop snag

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In the NavIC, a constellation of seven satellites, one of the three crucial rubidium timekeepers on IRNSS-1A spacecraft failed six months ago. The other two followed subsequently.

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A. S. Kiran Kumar, Chairman of the Indian Space Research Organisation, confirmed the glitch in the clocks but clarified that the satellite was otherwise all right, and the rest of the satellites were performing its core function of providing accurate position, navigation and time. However, without its clocks, the IRNSS-1A “will give a coarse value. It will not be used for computation. Messages from it will still be used.”

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“There are some anomalies in the atomic clock system on board. We are trying to restart it. Right now we are working out a mechanism for operating it,” he told The Hindu.

The problem is only with the clock system of one spacecraft. The signals are all coming, we are getting the messages, everything else is working and being used, except the stability portion which is linked to the clock,” he said. A minimum of four working satellites was sufficient to realise the full use of the navigation system”.

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NavIC has 21 atomic clocks on seven spacecraft. “How would the other clocks fare? Would ISRO reconsider the supplier of its atomic clocks? Such questions are not easy to answer. Generally any [space] hardware is an issue. We have to find ways of going around it,” he said.

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The troubled IRNSS-1A spacecraft was put in space in July 2013 and has an expected life span of 10 years.

 

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