Author Topic: Zhongxing-9A (Chinasat-9A), CZ-3B/G2 - XSLC - June 18, 2017 (16:11 UTC)  (Read 21194 times)

Offline chewi

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Chinese satellite Zhongxing-9A enters preset orbit
http://news.xinhuanet.com/english/2017-07/06/c_136422178.htm

BEIJING, July 6 (Xinhua) -- The communications satellite Zhongxing-9A has entered its preset orbit over two weeks after its launch on June 19.

Abnormal performance was identified during the third phase of the Long March-3B launch, which failed to deliver the satellite as planned.

The satellite conducted 10 orbit adjustments with its onboard thrusters and Wednesday reached its preset orbit at 101.4 degrees east longitude over the equator, according to China Aerospace Science and Technology Corporation (CASC) Thursday.

Currently, the satellite's systems are operational and the transponders are on, said the CASC, adding that a series of tests will be carried out.

Zhongxing-9A is the first Chinese-made satellite for live radio and television broadcasts.

An anomaly was found on the carrier rocket's rolling control thruster, part of the attitude control engine, during the third gliding phase, according to an investigation.

The rocket team has also completed a thorough technology analysis and expanded examinations.

Online Galactic Penguin SST

Investigation shown RCS thruster malfunction led to this failure
http://www.spacechina.com/n25/n144/n206/n214/c1679151/content.html

To elaborate, the official statement points to "a failure of the roll-control RCS thrusters of the third stage during the coast phase" as to the cause.

This was actually first reported back on June 21 in an interview with ex-Long March 3 development program manager/chief designer Long Lehao (*) - he said that "......the rocket stage was in a negative roll rate during coasting, which should have been corrected through negative feedback with a positive roll rate command, but it went wrong during actual operations......".

I take that means it's more of a GNC/sensor failure than actual hardware failing, but that's just me.  :-X

Back to the satellite, it turns out that I was right in that it was really the ex-SinoSat-4 that was stored for 6 years (2010-2016) due to lack of satellite DBS demands.  ::) The satellite eventually reached 101.4 deg. East on July 5 at around 13:00 UTC.

One last thing - the s/n for the LM-3B is Y28.

(*) Despite long retired and well into the 90s, he is still one of the "default spokesperson" for reporters asking about Chinese rockets. He apparently still follows around rocket launches in the LCC, including the ill-fated LM-5 flight last week!
« Last Edit: 07/06/2017 12:03 PM by Galactic Penguin SST »
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Offline input~2

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No new TLE from Spacetrack since June 19

Online Phillip Clark

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Galactic Penguin ...... which CZ-3B please?

I always wonder why the Chinese translate the launch vehicle names from Changzheng to "Long March" when discussing them, but the satellite/spacecraft names are not similarly translated, other than just in passing occasionally.

Offline Liss

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At last found at 101.4 E.
This message reflects my personal opinion based on open sources of information.

Offline linxiaoyi

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New TLE:
edit: satellite is confirmed at 101.4E from new TLE
« Last Edit: 07/09/2017 08:12 AM by input~2 »
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Online SmallKing

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Confirmed the planned apogee was 42000 km, and optimized Maneuvering had saved 100 kg propellant
http://zqb.cyol.com/html/2017-07/24/nw.D110000zgqnb_20170724_1-12.htm
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Online Phillip Clark

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New TLE:
edit: satellite is confirmed at 101.4E from new TLE

The data which you show are from the Satellite Situation Report: they are not a Two-Line Orbital Element.

Offline sunzhe

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Does anyone know the final estimated residual useful life of this one please?
Many thanks

Online SmallKing

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Does anyone know the final estimated residual useful life of this one please?
Many thanks
Orbit data now in:

42763/2017-035A: 193 x 16357 km x 25.68 deg.
42764/2017-035B: 192 x 16358 km x 25.68 deg.

I'm not even sure that's salvageable.... :-\

That would make a dV to GEO of ~2100 m/s. Assuming a standard GTO with dV~1700 m/s, there is a ~400 m/s shortfall. This is about the dV budget for 8-10 years of GEO orbit- and station-keeping. Unless they can come up with creative ways of salvaging the orbit at the expense of less lifetime/fuel ( la Asiasat 3), it looks like a major loss. Of course, this bird may not be insured being a Government payload, so maybe they'll try to squeeze as much life out of it as they can, rather than ditch it to claim the insurance money.

I calculate that you'd need 545 m/s to change this orbit into one with a standard GTO apogee of 35870 km,
a rather bigger shortfall that your calculation.
It would require a further 175 m/s to reach the 49600 km supersync apogee used by this mission's elder sibling, ZX-9.
About 5 years left
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Online SmallKing

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And the Long March 3B third-stage attitude control issue?
That was a testing issue. A manufacturing issue, not a system issue, just one switch.
So its not a serial production problem?
No, only one.

https://www.spaceintelreport.com/china-great-wall-industry-corp-bumpy-year-satellite-launches-returning-flight/
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Offline sunzhe

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Does anyone know the final estimated residual useful life of this one please?
Many thanks
Orbit data now in:

42763/2017-035A: 193 x 16357 km x 25.68 deg.
42764/2017-035B: 192 x 16358 km x 25.68 deg.

I'm not even sure that's salvageable.... :-\

That would make a dV to GEO of ~2100 m/s. Assuming a standard GTO with dV~1700 m/s, there is a ~400 m/s shortfall. This is about the dV budget for 8-10 years of GEO orbit- and station-keeping. Unless they can come up with creative ways of salvaging the orbit at the expense of less lifetime/fuel ( la Asiasat 3), it looks like a major loss. Of course, this bird may not be insured being a Government payload, so maybe they'll try to squeeze as much life out of it as they can, rather than ditch it to claim the insurance money.

I calculate that you'd need 545 m/s to change this orbit into one with a standard GTO apogee of 35870 km,
a rather bigger shortfall that your calculation.
It would require a further 175 m/s to reach the 49600 km supersync apogee used by this mission's elder sibling, ZX-9.
About 5 years left

Hello Dear, did you mean, even though after saving 100KG more Propellant, there are still only 5 years left? Oh no......

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