Author Topic: Zhongxing-9A (Chinasat-9A), CZ-3B/G2 - XSLC - June 18, 2017 (16:11 UTC)  (Read 18794 times)

Offline jcm

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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.


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Jonathan McDowell
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Offline saliva_sweet

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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.

Sounds like a LOM to me  :'(

Offline Alter Sachse

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Offline Lewis007

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Short launch video


Offline Steven Pietrobon

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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 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.

I seem to confirm that, assuming no change in inclination for the perigee burn. Perhaps Galactic Penguin calculations assumed a small change in inclination at perigee to optimise overall total delta-V.

Vp = sqrt(2/(Rp(Rp/Ra+1)))
Va = sqrt(2/(Ra(Ra/Rp+1)))
Vo = sqrt(/Ro)
Rp = R+Hp
Ra = R+Ha
Ro = R+Ho
R = 6378165 m
= 3.986005x10^14 m/s

Hp1 = 193 km
Ha1 = 16357 km
Vp1 = 9701.3 m/s

Hp2 = 193 km
Ha2 = 35870 km
Vp2 = 10246.4 m/s
Va2 = 1593.7 m/s

Δv1 = Vp2-Vp1 = 545.1 m/s

Ho = 35870 km
Vo = 3071.6 m/s
θ = 25.68

Δv2 = sqrt(Vo + Va2 - 2 Vo Va2 cos(θ)) = 1775.2 m/s

Δv = Δv1 + Δv2 = 2320.3 m/s
« Last Edit: 06/20/2017 08:26 AM by Steven Pietrobon »
Akin's Laws of Spacecraft Design #1:  Engineering is done with numbers.  Analysis without numbers is only an opinion.

Offline Steven Pietrobon

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OK, I've written a small program to see what savings an inclination change on the first burn would give. Its not much. Total delta-V is reduced from 2320.2 m/s to 2316.3 m/s, a saving of only 3.9 m/s. Excess delta-V is reduced to 2316.3-1775.2 = 541.1 m/s.

Enter initial perigee (km): 193
Enter initial apogee (km): 16357
Enter initial inclination (deg): 25.68

theta1 =  0.00 deg, dv1 =  545.1 m/s
theta2 = 25.68 deg, dv2 = 1775.2 m/s
dv = 2320.2 m/s

theta1 =  0.37 deg, dv1 =  548.9 m/s
theta2 = 25.31 deg, dv2 = 1767.5 m/s
dv = 2316.3 m/s
« Last Edit: 06/20/2017 09:59 AM by Steven Pietrobon »
Akin's Laws of Spacecraft Design #1:  Engineering is done with numbers.  Analysis without numbers is only an opinion.

Offline Alter Sachse

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if I understand correctly:
ZX-9A the latest orbital parameters: 251 x 17090 km; 26.8
(Thank you, Google-translator !) :)

https://twitter.com/cnspaceflight/status/877370968498241536
« Last Edit: 06/21/2017 05:38 AM by Alter Sachse »

Offline input~2

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if I understand correctly:
ZX-9A the latest orbital parameters: 251 x 17090 km; 26.8
(Thank you, Google-translator !) :)

https://twitter.com/cnspaceflight/status/877370968498241536

Yes corresponding to latest TLE at epoch June 19, 07:18 UTC for 2017-035A/42763

Online SmallKing

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Not sure how credible but here's a rumor of lower orbit than planned but the satellite's healthy.

More rumors, this time from the "coughing guy" who was apparently on site:

- seems like the rocket 3rd stage might have some  attitude control problems of unknown source, based on telemetry he saw at the LCC
- satellite propellant usage for making up the shortfall "might be huge"

And Long Lehao comfirmed this rumor
It was just a GNC malfunction
-The Stage was in a negative rolling, and it should be given a positive rolling instruction before second ignition of third stage. unfortunately, an opposite instruction was given

Full article: https://mp.weixin.qq.com/s/xmhpqx6XsXnFwBx0P47n3w
Launch Land Relaunch

Offline input~2

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Full article: https://mp.weixin.qq.com/s/xmhpqx6XsXnFwBx0P47n3w
According to the same interview, reaching final orbit will take 20 days and satellite lifetime could be 5 years down from 15 years

Full article: https://mp.weixin.qq.com/s/xmhpqx6XsXnFwBx0P47n3w
According to the same interview, reaching final orbit will take 20 days and satellite lifetime could be 5 years down from 15 years

Unless the translation I have is poor, the satellite's lifespan has been reduced to 5 years, meaning it lost 10 years of its total lifespan.

Offline input~2

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Full article: https://mp.weixin.qq.com/s/xmhpqx6XsXnFwBx0P47n3w
According to the same interview, reaching final orbit will take 20 days and satellite lifetime could be 5 years down from 15 years

Unless the translation I have is poor, the satellite's lifespan has been reduced to 5 years, meaning it lost 10 years of its total lifespan.
Yes that's what I meant

Offline Phillip Clark

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Has Zhongxing 9A been de-orbited?   The following orbit is derived from the latest element set issued for the catalogue number/international designator of the satellite:

Jun 19.304    26.82 deg      306.20 min      251 - 17,090 km    185 deg (AoP)

My guess is that all of the data for the 25.68 deg, ~192 - ~ 16,360 km orbits relate to the CZ-3B/E third stage.   With no data for the satellite for ten days, the possibility that the satellite is no longer in orbit must be considered.

Offline BabaORileyUSA

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Has Zhongxing 9A been de-orbited?   The following orbit is derived from the latest element set issued for the catalogue number/international designator of the satellite:

Jun 19.304    26.82 deg      306.20 min      251 - 17,090 km    185 deg (AoP)

My guess is that all of the data for the 25.68 deg, ~192 - ~ 16,360 km orbits relate to the CZ-3B/E third stage.   With no data for the satellite for ten days, the possibility that the satellite is no longer in orbit must be considered.

No, it wasn't likely to have been de-orbited.  For some time, JSpOC/18SPCS, lacking input from satellite owner/operators, has delayed the publication of an element set until the payload reaches its final orbit.

Offline Phillip Clark

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Has Zhongxing 9A been de-orbited?   The following orbit is derived from the latest element set issued for the catalogue number/international designator of the satellite:
Jun 19.304    26.82 deg      306.20 min      251 - 17,090 km    185 deg (AoP)
My guess is that all of the data for the 25.68 deg, ~192 - ~ 16,360 km orbits relate to the CZ-3B/E third stage.   With no data for the satellite for ten days, the possibility that the satellite is no longer in orbit must be considered.
No, it wasn't likely to have been de-orbited.  For some time, JSpOC/18SPCS, lacking input from satellite owner/operators, has delayed the publication of an element set until the payload reaches its final orbit.

Routinely for Chinese missions we don't get the intermediate orbits catalogued between GTO and GEO, but a ten days gap is rather unusual.

Offline BabaORileyUSA

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Has Zhongxing 9A been de-orbited?   The following orbit is derived from the latest element set issued for the catalogue number/international designator of the satellite:
Jun 19.304    26.82 deg      306.20 min      251 - 17,090 km    185 deg (AoP)
My guess is that all of the data for the 25.68 deg, ~192 - ~ 16,360 km orbits relate to the CZ-3B/E third stage.   With no data for the satellite for ten days, the possibility that the satellite is no longer in orbit must be considered.
No, it wasn't likely to have been de-orbited.  For some time, JSpOC/18SPCS, lacking input from satellite owner/operators, has delayed the publication of an element set until the payload reaches its final orbit.

Routinely for Chinese missions we don't get the intermediate orbits catalogued between GTO and GEO, but a ten days gap is rather unusual.

Usually, a bird takes less than that amount of time to reach GEO.  This wounded duck, however, will probably require a bit more time to reach GEO from where it was dropped off....

Offline Alter Sachse

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Has Zhongxing 9A been de-orbited?   The following orbit is derived from the latest element set issued for the catalogue number/international designator of the satellite:
Jun 19.304    26.82 deg      306.20 min      251 - 17,090 km    185 deg (AoP)
My guess is that all of the data for the 25.68 deg, ~192 - ~ 16,360 km orbits relate to the CZ-3B/E third stage.   With no data for the satellite for ten days, the possibility that the satellite is no longer in orbit must be considered.
No, it wasn't likely to have been de-orbited.  For some time, JSpOC/18SPCS, lacking input from satellite owner/operators, has delayed the publication of an element set until the payload reaches its final orbit.

Routinely for Chinese missions we don't get the intermediate orbits catalogued between GTO and GEO, but a ten days gap is rather unusual.

Usually, a bird takes less than that amount of time to reach GEO.  This wounded duck, however, will probably require a bit more time to reach GEO from where it was dropped off....
http://forum.nasaspaceflight.com/index.php?topic=30336.msg1692336#msg1692336
at least 20 days

Online Galactic Penguin SST

ChinaSat 9A has arrived in geostationary orbit on July 5 according to Chinese reports.
Chinese spaceflight is a cosmic riddle wrapped in a galactic mystery inside an orbital enigma... - (not) Winston Churchill

Online SmallKing

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

Offline Phillip Clark

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Congratulations on reaching GEO but what will the operational lifetime of the satellite be now with so much propellant unexpectedly required to get on-station?

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