Re: Flock 2B 2 (40951) Reentry Seen from Southern England, UK

From: Adam Fritzler via Seesat-l <seesat-l_at_satobs.org>
Date: Wed, 5 Oct 2016 11:06:02 -0700
Hi -- Planet happens to be my employer. It is *incredible* that this was
visible! I just wanted to note that this matches our internally-generated
data, which include contributions from UHF ranging. Unfortunately our last
fit for this satellite is from a day before the re-entry event, which
predicts re-entry a few hours later:

0 FLOCK 2B-2 0C18
1 83096U FPP2     16276.75001157  .00000000  00000+0  60092-3 0    08
2 83096 051.6001 186.9102 0008827 222.8676 053.8809 16.39049103    05

The IMO map with our predicted track added, courtesy of Cyrus Foster, who
does our orbits work:
  http://satobs.org/seesat_ref/misc/0C18_reentry_map.png

Our most recent ephemerides are always available here:
http://ephemerides.planet-labs.com/

Cheers,
Adam.


On Mon, Oct 3, 2016 at 4:38 AM, C. Bassa via Seesat-l <seesat-l_at_satobs.org>
wrote:

> William shared the video, and from it I obtained the following
> measurements:
>
> 99999 16 776A   9004 G 20161002184350520 17 25 1711401+162553 39 S
> 99999 16 776A   9004 G 20161002184351520 17 25 1724505+163473 39 S
> 99999 16 776A   9004 G 20161002184352520 17 25 1736750+164397 39 S
> 99999 16 776A   9004 G 20161002184353520 17 25 1750216+164502 39 S
> 99999 16 776A   9004 G 20161002184354520 17 25 1804428+163487 39 S
> 99999 16 776A   9004 G 20161002184355520 17 25 1818432+162045 39 S
> 99999 16 776A   9004 G 20161002184356520 17 25 1831986+155650 39 S
> 99999 16 776A   9004 G 20161002184357520 17 25 1846594+152635 39 S
> 99999 16 776A   9004 G 20161002184358520 17 25 1901101+145608 39 S
> 99999 16 776A   9004 G 20161002184359500 17 25 1914563+141116 39 S
> 99999 16 776A   9004 G 20161002184400520 17 25 1928409+132422 39 S
> 99999 16 776A   9004 G 20161002184401520 17 25 1940494+123416 39 S
> 99999 16 776A   9004 G 20161002184402520 17 25 1951782+113908 39 S
> 99999 16 776A   9004 G 20161002184403140 17 25 1957107+110316 39 S
>
> Site 9004 is at 1.8017W, 51.3521N, 133m.
>
> Fitting a circular orbit gives this result.
>
> 1 99999U 16776A   16276.78051887  .00000000  00000-0  50000-4 0    00
> 2 99999  51.7221 184.2405 0001000   0.0000 100.3776 16.66450838    01
> # 20161002.78-20161002.78, 14 measurements, 0.478 deg rms
>
> Clearly it fits the ISS inclination, though the RAAN is at least 2 deg
> smaller. Since the field-of-view of the camera was 100x55 deg, there
> likely is unmodelled distortion, resulting in systematic offsets in
> the positions.
>
> Regards,
>     Cees
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Received on Wed Oct 05 2016 - 13:07:32 UTC

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