Possible Phobos-Grunt "mirrirs" orientation

From: Vitaly Mechinsky (lupus_sat@tut.by)
Date: Fri Dec 09 2011 - 21:51:31 UTC

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```I made some calculations.

I divide into two groups all of known flashes of the "Phobos-Grunt"
(PG) (I mean those flashes, that time we know) after the calculation
of the mirrors in Heavensat (http://www.heavensat.ru/english/) :

1). Group M1:
a). orientation angles of mirrors 51.3o 184.6o (S. Corbellini ,
07/12/2011, Italy)
b). orientation angles of mirrors 51.7o 162.4o (A. Repnj, 07/12/2011, Ukraine)
c). orientation angles of mirrors 75.4o 171.4o (A. Repnoe , 12/05/2011, Ukraine)
d). orientation angles of mirrors 63.2o 178.4o ("Le May", 02.12.2011, Russia)

2). Group M2:
a). orientation angles of mirrors 29o 176.3o (A. Repnoe, 07/12/2011, Ukraine)
b). orientation angles of mirrors 37.6o 179.6o ("Le May", 02.12.2011, Russia)
c). orientation angles of mirrors 28.5o 180.6o (R. Kovalik, 23/11/2011, Italy)

For both groups the second angle is almost identical, and the first
angle for M1 less than 45 deg., for M2 - more than 45 deg. Next, I use
the method of finding of "mirrors" orientation angles for several
observations in "Haevensat" soft, described here: "Observation of
satellite flares"

For the M1 group I created a file  with four observations:

02/12/2011 14:28:27,37872,16, .2,52.6167,39.6,150,0, 0255 0
05/12/2011 15:39:41,37872,2, .2,48.6657,33.1137,101,0, 255 255 0
12/07/2011 15:23:45,37872,13, .2,48.6657,33.1137,101,0, 255 255 0
12/07/2011 16:53:45,37872,31, .2,45.45,8.63,100,0, 0128255

We save it and load the Heavensat. Further, by adjusting the angle of
deviation (preliminary angles I took from the estimates of the
observed flares brightness and the distance to PG) we are making the
crossing of the four rings at one point (see:
http://www.astronomy.ru/forum/index.php?action=dlattach;topic=90182.0;attach=359919;image).
Hence we get the first mirror:

37872 M1 71.4 170.6 35

For group M2 we can write 4 lines with observations:

23/11/2011 16:40:35,37872,2,.2,40.7569,14.4478,150,0, 255 0 0
02/12/2011 14:28:59,37872,31,.2,52.6167,39.6,150,0, 0 255 0
07/12/2011 15:24:45,37872,10,.2,48.6657,33.1137,101,0, 255 255 0

from which we can obtaine second "mirror":

37872 M2 20.5 174.5 35

Of course, the maximum deflection angle too big - 35o, but still...

As a working test, we take a new message from Kevin Fetter - he
recorded the a flash PG in Capricorn. His massage:
http://www.satobs.org/seesat/Dec-2011/0095.html , video -
Heavensat, when he could see the flash from our mirrors M1 and M2. I
obtain (don't pay attention on brightness - I don't understand why so
brightly obtained at present time):

Calculation of the flares from 00:00:00 to 00:00:00 2011.12.08 2011.12.11
_____________________________________________________________________________________
No.|Mag.|Elev.|Azim.|Mirror|Angle|Time_______________|
PHOBOS-GRUNT            2011-065A     37872  -4.9   13  242 M1
0.3         22:43:07 2011.12.08
PHOBOS-GRUNT            2011-065A     37872   3.4   13  198 M2
11.0         22:44:23 2011.12.08
_____________________________________________________________________________________

Let's look at the signature to the video - Fetter recorded the the
flash at 22:43 UTC. It seems to be OK. But if you look at the map
(see: http://www.astronomy.ru/forum/index.php?action=dlattach;topic=90182.0;attach=359923;image),
it's clear to view that PG was flying between psi and omega of
Capricorn in 22hh44m05s, i.e. one minute later than the Fetter wrote.
Satellite's position on the picture - the flash maximum from the
mirror M2. The time error (it can be seen on the video that the flash
peak was during the PG flew between the stars) is about 20 seconds.

Now about S. Corbellini observartion (here:
http://www.satobs.org/seesat/Dec-2011/0077.html). Alex Repnoj
(Ukraine) observed at 15h59m29s (02/12/2011) the PG flash, for which I
got the mirror with angles of  276.2 deg. on 46.6 deg. S. Corbellini
wrote on his massage (http://www.satobs.org/seesat/Dec-2011/0077.html)
next angles for PG flash: "tilt of 63.8 +- 0.5 deg and angle of 245 +-
10 deg.". So, we can see, that these values are close to our --
possibly, it's M3 mirror...

One another message of the observation. Tom Smith wrote
(http://www.satobs.org/seesat/Dec-2011/0099.html) that there wasn't
brightness variations, but "usual slight brightening near the zenith".
I calculated possible flares using mirrors, as described above, - it
could be a mirror M1 (see
http://www.astronomy.ru/forum/index.php?action=dlattach;topic=90182.0;attach=359925;image
- PG position during the flare).

Vitaly.

--
Best regards,

Vitaly (Minsk, Belarus).
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