Re: NROL-55 search elements

From: Björn Gimle via Seesat-l <seesat-l_at_satobs.org>
Date: Thu, 8 Oct 2015 20:47:30 +0200
NOSS 3-7 found at 19 deg el in the SSE
First image started behind a tree, so end of track:
79701 15 773A   5919 G 20151008174610000 18 25 2359287+034781 55 S
This looks like a slightly fainter object, leading by 5.5' along track

Second image also starting obscured, obs to follow later

Third image when penumbra was visible, so this point would be the trailing
object:
79701 15 773A   5919 G 20151008174645000 18 25 0020138+063891 55 E


--------------------------------------------------------
Björn Gimle, COSPAR 5919
59.2617 N, 18.6169 E, 51 m
Satellite observation formats described:
http://www.satobs.org/position/IODformat.html
---------------------------------------------------------

2015-10-06 12:54 GMT+02:00 Ted Molczan via Seesat-l <seesat-l_at_satobs.org>:

> NROL-55 is scheduled for launch on an Atlas V-401, from VAFB, on 2015 Oct
> 08, during a launch window that opens at 12:49
> UTC. The window probably is planar, which would open about 14 min. earlier
> each day.
>
> Live coverage will be available here:
>
> http://spaceflightnow.com/2015/10/01/av-059-journal/
>
> The primary payload is the NOSS 3-7 pair of satellites, which will replace
> the NOSS 3-3 pair launched in 2005. I base
> this on a well-established pattern.
>
> NOSS 3-5, launched on 2011 Apr 15, replaced the NOSS 3-1 pair, which
> ceased to orbit in formation about 7 months later,
> shortly after 2011 Nov 07. They had been in orbit just over 10 years. The
> plane of NOSS 3-5 is about 22 deg west of the
> NOSS 3-1 plane.
>
> NOSS 3-6, launched on 2012 Sep 13, replaced the NOSS 3-2 pair, which
> ceased to orbit in formation about 8 months later,
> shortly after 2013 May 21. They had been in orbit about 9.5 years. The
> plane of NOSS 3-6 is about 15 deg west of the
> NOSS 3-2 plane.
>
> NOSS 3-3 was launched in February 2005. Assuming the pair cease to orbit
> in formation 7-8 months after NOSS 3-7 reaches
> orbit, they will have operated for about 11 years. The plane of NOSS 3-7
> will be about 30 deg west of the NOSS 3-3
> plane.
>
> NROL-79, slated for launch from VAFB in August 2017, is likely to carry
> NOSS 3-8, which would replace NOSS 3-4, launched
> in June 2007.
>
> Here are estimated initial NOSS 3-7 elements, assuming launch at window
> open:
>
> NOSS 3-7                                               1013 X 1200 km
> 1 79701U          15281.61469908  .00000000  00000-0  00000-0 0    07
> 2 79701  63.4283 292.5778 0124892 180.5274 352.9095 13.40429195    06
>
> Centaur final orbit                                      459 X 775 km
> 1 79702U          15281.65902778  .00000000  00000-0  00000-0 0    09
> 2 79702  64.6863 291.3514 0225821 294.8437 113.6381 14.83391172    04
>
> The above are derived from the NOSS 3-6 launch. Twenty-four hours after
> launch, allow for at least several minutes time
> error, and several degrees of track error on high elevation passes.
>
> In the northern hemisphere, the NOSS orbit will be well-placed for all
> night observation. Southern hemisphere observers
> will have evening visibility, but near twilight.
>
> Here is my recent post on the effects of a significant orbital
> perturbation that affects the NOSS orbit, and how it is
> managed by the NOSS 3 satellites:
>
> http://satobs.org/seesat/Jul-2015/0149.html
>
> More information on the U.S. NOSS and China's copy of an earlier U.S.
> three-satellite NOSS system is available here:
>
> http://www.satobs.org/noss.html
>
> Happy hunting!
> Ted Molczan
>
>
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Received on Thu Oct 08 2015 - 13:48:25 UTC

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