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#100
by
input~2
on 30 Dec, 2016 16:02
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Perhaps there was a programming error which led to the verniers being shut down at the same time as the main engine on the second stage? This could have prevented the verniers re-igniting to perform the de-orbit burn.
Phillip, the verniers started as planned as can be seen in this graph from the launch video:
In that case, does the video show how far into the burn the verniers shut down compared with the planned shut down?
No, it cuts off one second after that frame!
check out 01mn42s-45s into this video:
http://tv.cctv.com/2016/12/28/VIDEcdy7e1C5BRXte9BZNzh8161228.shtml
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#101
by
Phillip Clark
on 30 Dec, 2016 16:07
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Usually the verniers start firing when the second stage ignites then then simply continue after the main engine shuts down. So, did they start on time and shut down almost at the same time as the main engine?
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#102
by
russianhalo117
on 30 Dec, 2016 17:21
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Working orbit was supposed to be a 500km SSO. They had a low perigee, but the apo was fine.
deployment and LEOPS orbit was supposed to be 530 km Circular SSO and operational IOC (first 4 sats) orbit was to be 500km after equal phasing was achieved between all of them.
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#103
by
input~2
on 30 Dec, 2016 18:52
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Usually the verniers start firing when the second stage ignites then then simply continue after the main engine shuts down.
AFAIU verniers are used for attitude correction (short duration burns) while the 2nd stage main engine is on and then after MECO for orbit circularization with continuous burn
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#104
by
Phillip Clark
on 30 Dec, 2016 19:00
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Usually the verniers start firing when the second stage ignites then then simply continue after the main engine shuts down.
AFAIU verniers are used for attitude correction (short duration burns) while the 2nd stage main engine is on and then after MECO for orbit circularization with continuous burn
My data are around 20 years old so the profile could have changed over the years.
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#105
by
input~2
on 30 Dec, 2016 19:51
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Situation at epoch December 30, 17:20 UTC:
Superview-1 01 in 407 x 527 km x 97.60°
Superview-1 02 in 422 x 528 km x 97.57°
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#106
by
input~2
on 31 Dec, 2016 07:24
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Situation at epoch December 31, ~05:35 UTC:
Superview-1 01 in 432 x 527 km x 97.61°
Superview-1 02 in 445 x 528 km x 97.57°
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#107
by
wsl2005
on 31 Dec, 2016 10:25
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#108
by
input~2
on 31 Dec, 2016 19:55
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Latest situation:
Superview-1 01 in 476 x 530 km x 97.61° epoch Dec 31, 18:15 UTC
Superview-1 02 in 487 x 530 km x 97.57° epoch Dec 31, 16:58 UTC
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#109
by
input~2
on 01 Jan, 2017 12:38
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Updated situation:
Superview-1 01 in 484 x 528 km x 97.61° epoch Jan 1, 06:36 UTC
Superview-1 02 in 509 x 533 km x 97.57° epoch Jan 1, 12:06 UTC
Superview-1 02 in 519 x 535 km x 97.57° epoch Jan 1, 15:11 UTC
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#110
by
input~2
on 02 Jan, 2017 05:58
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No significant change for both orbits as of epoch January 2, 03:00 UTC
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#111
by
ZachS09
on 02 Jan, 2017 06:43
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At least the SuperView satellites are trying their hardest to get to the right orbit.
I'm still aware of the shortened lifespan, but I'm proud of the satellites being salvaged.
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#112
by
osiossim
on 02 Jan, 2017 12:22
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Is it monopropellant (hydrazine) or is it electrical propulsion that brings the satellite close to desired orbit in such a short time?
Any information about this issue?
Also, I dont understand why the propellant tank is out of satellite's main body? If it would be hydrazine based, it shall have survival heaters around.
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#113
by
ZachS09
on 02 Jan, 2017 21:53
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Is it monopropellant (hydrazine) or is it electrical propulsion that brings the satellite close to desired orbit in such a short time?
Any information about this issue?
Also, I dont understand why the propellant tank is out of satellite's main body? If it would be hydrazine based, it shall have survival heaters around.
http://gbtimes.com/china/chinas-superview-1-satellites-begin-raise-orbits-after-rocket-underperformance"In response, using the
chemical propulsion on the satellite platforms designed by the China Academy of Space Technology, the satellites have apparently since performed burns to raise their orbits, raising their perigees by over 100km."
This chemical propulsion might as well be hydrazine.
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#114
by
input~2
on 07 Jan, 2017 19:33
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Orbits as of to-day:
Superview-1 01 in 517 x 536 km x 97.62°
Superview-1 02 in 518 x 536 km x 97.57°
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#115
by
Nordren
on 11 Jan, 2017 12:59
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#116
by
ZachS09
on 12 Jan, 2017 17:13
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#117
by
Steven Pietrobon
on 13 Jan, 2017 03:36
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I guess this means that all those countries that couldn't get imagery of certain areas from Western satellites, now won't have that problem.
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#118
by
Liss
on 19 Jan, 2017 11:25
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Just a thought but I wonder whether the CZ-2D second stage was intended to de-orbit itself after the satellites deployed? If this was the case then the premature shut-down of the verniers prevented this.
Adding to the above after some more thought. Perhaps there was a programming error which led to the verniers being shut down at the same time as the main engine on the second stage? This could have prevented the verniers re-igniting to perform the de-orbit burn.
It seems the second stage has been actually deorbited.
Check the attached image. At rear we see the upper composite lower section with the lower spaceraft inside, optical system partially visible. At forefront we see the upper section consisting of cylinder and conical adapter with upper spacecraft on it.
BY70-1 launch position is at the upper ring of the lower section at rear.
After the shroud is put on the upper section, the upper section is put onto the lower one.
So we should see in orbit the upper section -- there's no way to exit for the lower spacecraft and BY70-1 with it still attached to the second stage.
Since objects A, B and C are definitely spaceraft (A and B maneuvered and C is being heard), object D is this cylinder/conical section and the 2nd stage with lower section has been deorbited.
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#119
by
Liss
on 19 Jan, 2017 11:41
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check out 01mn42s-45s into this video: