Author Topic: LIVE: GSLV MkII - GSAT-9 (aka South Asia Sat) - SLP - May 5, 2017 (11:27 UTC)  (Read 42245 times)

Offline isro-watch

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http://pib.nic.in/newsite/PrintRelease.aspx?relid=161601

The official press release gives the apogee as 169 Km. This is as expected.

Online vineethgk

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The second orbit raising operation of South Asia Satellite has been successfully carried out by LAM Engine firing for 3529.7 sec from 09.30 hr IST on May 07, 2017

Source

New orbital parameters hasn't been posted yet.

Offline maint1234

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Is the video showing cryogenic stage igniting from a lower stage view ? Normally the upper stages show the lower stages falling off.
Pointed out by a youtube viewer.

Online vineethgk

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Orbit Determination results from the second LAM firing are:
1. Apogee X perigee height was changed to 35858 km X 28608 km.
2. Inclination is 0.755deg.
3. Orbital period is 20hr 58min.
Source

Online vineethgk

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Is the video showing cryogenic stage igniting from a lower stage view ? Normally the upper stages show the lower stages falling off.
Pointed out by a youtube viewer.
Yes. There is a camera at the top of the second stage pointing upwards that is meant to capture the separation and ignition of the cryogenic upper stage. I believe it was added to the vehicle from GSLV-D4 onwards inorder to study the cryo-stage ignition issue that doomed the GSLV-D3/GSAT-4 mission.

Offline jcm

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USSTRATCOM has cataloged 2 objects (epoch May 5, 13:52 UTC)

2017-024A/42695 in 157 x 35936 km x 20.66

2017-024B/42696 in 154 x 35940 km x 20.65

The targetted GTO was 1705 x 35975675 km x 20.610.1
The achieved perigee appears to be lower than the tolerable limits though apogee and inclination appears to be good. Does this indicate an under-performance?

In fact the payload is 24B.  The quoted orbit of 154 x 35940 km is from the time-averaged SGP4 TLE elements; when you calculate the actual perigee of that orbit it's actually 168 km (geodetic height).
There's a new elset today showing 24B in an SGP4 orbit of 5598 x 35988 km x 10.38 deg.

-----------------------------

Jonathan McDowell
http://planet4589.org

Online SmallKing

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USSTRATCOM has cataloged 2 objects (epoch May 5, 13:52 UTC)

2017-024A/42695 in 157 x 35936 km x 20.66

2017-024B/42696 in 154 x 35940 km x 20.65

The targetted GTO was 1705 x 35975675 km x 20.610.1
The achieved perigee appears to be lower than the tolerable limits though apogee and inclination appears to be good. Does this indicate an under-performance?

In fact the payload is 24B.  The quoted orbit of 154 x 35940 km is from the time-averaged SGP4 TLE elements; when you calculate the actual perigee of that orbit it's actually 168 km (geodetic height).
There's a new elset today showing 24B in an SGP4 orbit of 5598 x 35988 km x 10.38 deg.
Could you tell us how to calculate the geodetic height based on SGP4 model
Launch Land Relaunch

Online vineethgk

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The third orbit raising operation of South Asia Satellite has been successfully carried out by LAM Engine firing for 445.8 sec from 06:51:52 hr IST on May 08, 2017
Source
« Last Edit: 05/08/2017 05:51 AM by vineethgk »

Online Olaf

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http://www.isro.gov.in/update/08-may-2017/third-orbit-raising-operation-of-south-asia-satellite-has-been-successfully
Quote
The third orbit raising operation of South Asia Satellite has been successfully carried out by LAM Engine firing for 445.8 sec from 06:51:52 hr IST on May 08, 2017
http://www.isro.gov.in/update/08-may-2017/deployment-of-east-and-west-reflectors-have-been-successfully-completed-0815-hr
Quote
Deployment of East and West reflectors have been successfully completed at 08:15 hr IST and 09:30 hr IST, respectively on May 08, 2017

Online vineethgk

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Deployment of East and West reflectors have been successfully completed at 08:15 hr IST and 09:30 hr IST, respectively on May 08, 2017
Source

Offline kanaka

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Why n2yo is showing two different objects in space? Also the satellite is not yet named or marked. Just showing as Object A and B.



http://www.n2yo.com/database/?m=05&d=5&y=2017#results

Offline hvdh

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At CelesTrak, the object are named already:

GSAT-9
1 42695U 17024A   17130.94341200 -.00000291  00000-0  00000-0 0  9998
2 42695   0.0641 250.4109 0028421 259.2972 152.1990  1.00423557    96
GSLV R/B
1 42696U 17024B   17129.87667711 -.00000273  00000-0  00000-0 0  9997
2 42696   0.1011  91.9323 0018905  94.5082 277.8991  1.00693003    61

https://www.celestrak.com/NORAD/elements/tle-new.txt

But surprisingly, these have GSAT-9 almost stable near 93.5E.
While I thought GSAT-9 would go straight to 48E.

Offline s^3

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^

As per current TLEs The 'bird' is some 43 kms below GEO altitude and is drifting .56 deg Eastwards per day.

They may be doing in-orbit testing ( while visible over India ) before accelerating it to its final home.

Offline s^3

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^
^
BTW,  current location is better for the geographical spread of the countries involved than 48 deg E.

Offline hvdh

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Found an interesting quote elsewhere!
Quote
From SAC Annual Report 2015-16
    GSAT-9 is a Ku-Band satellite configured to provide communication services over SAARC countries. It consists of 12 Ku band transponders. The payload configuration was modified for the revised spectrum allocation of 13.00-13.25 GHz/11.20 GHz. GSAT-9 has 12 Ku-band channels providing services for VSAT/DTH with South Asia coverage, It also has a Ku beacon transmitter with 480E/97.3E
If I understand the above correctly, instead of 11.45...11.7 GHz, GSAT-9 carries the less used 11.2...11.45 GHz band. At ITU, for this range a "planned service" is listed at 97.3E: INSAT-KUP-FSS(97.3E).
May well be, GSAT-9 has arrived there just about now!
« Last Edit: 05/19/2017 05:33 PM by hvdh »

Offline input~2

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According to latest TLE, GSAT-9 was passing 100.2E last night drifting East

Offline s^3

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and drift rate has increased from .48 deg east/day to .75 ( being 58 kms below GEO height )

May now be racing to 48E

Offline hvdh

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and drift rate has increased from .48 deg east/day to .75 ( being 58 kms below GEO height )

May now be racing to 48E
Moving East, so racing away from 48E!
It's becoming a bit odd now, maybe the TLE is or has been wrong, it's not uncommon to happen.
Next INSAT Ku-band slots further East would be 111.5E or 113.5E.

Offline input~2

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Apparently there's been  more maneuvers and as of May 19, at 10:12 UTC, GSAT-9 was passing 97E drifting East at a rate of 0.4/day (orbit: 35708 x 35794 km x 0.05)

Is SAC refering to 48.0E/97.3E orbital positions when it says "[GSAT-9] also has a Ku beacon transmitter with 480E/97.3E"?
« Last Edit: 05/20/2017 08:57 AM by input~2 »

Offline s^3

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Something wrong somewhere.

Last TLE seems to be problematic.

With it the s/c was at 100+ deg long.

With latest  TLE set ( 183 ) it brings back to 98 deg which can happen only if there is a massive maneuver to take the satellite at least 200 to 300 kms up and again back. No satellite operator would dare to do that at the beginning of its life.

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