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#60
by
Phillip Clark
on 28 Dec, 2016 09:04
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I seem to remember from descriptions many years ago that the second stage verniers were used for orbit circularisation.
Well, this is not a separate burn, just a continuation of the 2nd stage main engine burn. See this from CZ-2D/JL-1 launch in 2015:
I seemed to remember that was the case but my memory often plays nasty tricks. So, for today's launch the verniers cut off early, one assumes.
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#61
by
input~2
on 28 Dec, 2016 09:07
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Worth recalling events timeline for CZ-2D launch (Tianhui-1B in this case):
1st stage engine shutdown / separation: T+156.37 s
Fairing separation: T+186.37 s
2nd stage main engine shutdown: T+334.341 s
2nd stage vernier engines shutdown: T+626.27 s
Spacecraft separation: T+671.27 s
So I tend to agree with Phillip
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#62
by
input~2
on 28 Dec, 2016 09:34
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Debris like separation retro-rocket fairing covers have been usually cataloged after the payload...
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#63
by
Galactic Penguin SST
on 28 Dec, 2016 10:46
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CCTV news report screenshots (from
https://twitter.com/cnspaceflight/status/814066578094313472) shows that both 1st stage and fairing separated 7 seconds late (off my hazy memory an error within 3-4 seconds is normal, but 7 is a bit off) and 2nd stage MECO was 10 seconds late (the vernier engines would have burned for an additional 7 minutes; dunno if they shut down as planned). While confirmation via tracking of the ham radio satellite would be better, it seems that the orbit is now likely to be off.
Exact liftoff time was 03:23:56.121 UTC.
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#64
by
wsl2005
on 28 Dec, 2016 11:36
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A first object has been cataloged by USSTRATCOM:
2016-083A/41907 in 214 x 524 km x 97.58°
Two more objects found in a similar orbit. Hmm......
To be precise:
2016-083B/41908 in 213 x 524 km x 97.59°
2016-083C/41909 in 212 x 524 km x 97.59°
2016-083D/41910 in 216 X 524km X 97.589°
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#65
by
input~2
on 28 Dec, 2016 12:20
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In this display, launch mission codename is confirmed as "05-54"
The offsets between planned and actual values of events are also visible:
Stage 1 sep planned: T0 + 156.722s actual: T0 + 163.708s
Fairing sep: planned: T0 + 213.722s actual: T0 + 220.682s
Stage 2 MECO: planned: T0 + 322.104s actual: T0 + 332.533s
Stage 2 Vernier engines cutoff: planned: T0 + 752.013s
S/C sep: planned: T0 + 767.013s
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#66
by
input~2
on 28 Dec, 2016 12:34
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New TLEs for epoch 12:38 UTC bring no significant change for orbits of all 4 objects
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#67
by
Lsquirrel
on 28 Dec, 2016 12:59
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launch failed, the satellies will reentry soon
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#68
by
Galactic Penguin SST
on 28 Dec, 2016 13:00
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#69
by
russianhalo117
on 28 Dec, 2016 14:56
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The GJ sats have a propulsion system. Is the orbit so off-nominal that using the propellant to raise the GJ sats orbit to its desired orbit is not possible and will significantly shorten its lifespan??
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#70
by
jcm
on 28 Dec, 2016 15:20
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The GJ sats have a propulsion system. Is the orbit so off-nominal that using the propellant to raise the GJ sats orbit to its desired orbit is not possible and will significantly shorten its lifespan??
Good question. 100 m/s is needed. Do we know the mass of the GJ sats? Only about 5 kg of prop per 100 kg
of sat needed.
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#71
by
input~2
on 28 Dec, 2016 15:23
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Here are tentatively the frequencies to try for monitoring BY70-1 before it reenters
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#72
by
russianhalo117
on 28 Dec, 2016 15:31
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The GJ sats have a propulsion system. Is the orbit so off-nominal that using the propellant to raise the GJ sats orbit to its desired orbit is not possible and will significantly shorten its lifespan??
Good question. 100 m/s is needed. Do we know the mass of the GJ sats? Only about 5 kg of prop per 100 kg
of sat needed.
Well the spacecraft bus is a CAST3000B satellite platform so that plus estimated Kg for the Instrument Module and we will have an approximate answer.
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#73
by
Phillip Clark
on 28 Dec, 2016 15:33
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One of the pictures from a brochure previoiusly posted here gives a satellite mass of 560 kg, I believe.
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#74
by
input~2
on 28 Dec, 2016 15:42
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Chinaspaceflight says 570 +/- 20 kg for each
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#75
by
Galactic Penguin SST
on 28 Dec, 2016 15:42
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#76
by
jcm
on 28 Dec, 2016 16:44
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Chinaspaceflight says 570 +/- 20 kg for each
And from a private source I just got info that suggests that yes, they have more than enough dV to get to the right
orbit. Let's watch the TLEs over the coming days.
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#77
by
KO4MA
on 28 Dec, 2016 17:48
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#78
by
Liss
on 28 Dec, 2016 18:28
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BY70-1 - Bayi Kepu Weixing-1
Its full descriptive name is 八一学校科普小卫星 [Bāyī xuéxiào kēpǔ xiǎo wèixīng], that means August 1st School Science Small Satellite.
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#79
by
input~2
on 28 Dec, 2016 18:37
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BY70-1 - Bayi Kepu Weixing-1
Its full descriptive name is 八一学校科普小卫星 [Bāyī xuéxiào kēpǔ xiǎo wèixīng], that means August 1st School Science Small Satellite.
August 1st is linked to PLA, that explains why the military channel (CCTV 7) had a long report earlier today on this amateur satellite (from which I extracted the picture above of ground test equipment showing amateur band frequencies)
