RE: North Korean Unha-3? Launch estimation

From: Jon . via Seesat-l <>
Date: Sat, 6 Feb 2016 13:14:53 +0100
Hello all;

Bob Christy nicely estimated a better launch time. His guess is Feb. 07 at
00:26 UTC. Here his notes:

Revised post:

HIDROPACs points the launch window starting february 7th till february 24,
with a daily launch window starting 22:30 UTC and finishing at 03:30 UTC of
the next day.
The launch is suposed that will be from Sohae Launch Station (39.659996,
124.705303). In theory, DPRK can launch from Musudan-ri too (40.855762°,
129.665907°), but this second option can be discarded as NOTAMs does not
match with this launch site and because the rocket would overfly Japanese

Today some news agencies like Reuters, Xinhua News and CNN pointed that
launch will occur between 7 and 14 of february:

Unha-3 is a three stage rocket, all of them uses hipergolic fuel and it can
carry nearly 100 Kg to a sun-syncronous, 500Km circular orbit launched from
Sohae. The first stage is based on the Nodong missile, that is based
previously on the soviet Scud-D. The second stage is based on a R-27
missile. The third stage has been developed by North Korea.
The previous launch occurred the 2012/12/12 at 0:51 UTC. The payload
reached a 492x585, 97.404 degree orbit. The third stage and other two
debris pieces were cataloged.
The satellite (KMS 3-2) was in nearly 1:15 resonance, but drifting on RAAN.

Back to next launch, the initial launch trajectory of the first and second
stage will be like this screenshot generated using Google Earth:

The small green box is the 1st stage impact zone, the yellow one the impact
of the payload fairing and the red one corresponds to the impact zone of
the second stage.
As in the previous launch, the third stage is expected to reach orbit with
the payload.

During the first seconds of third stage burn, the rocket is expected to
make a dog-leg maneuver, to reach the desired 97.40 degree inclination,
just like in the previous launch. In the image above, the dog-leg sohuld
occur between first stage impact zone and fairing impact zone.

Launch time:

As mentioned before, Bob Christy pointed that most probable launch time can
be starting February 07 at 00:26 UTC:

Unha-3 estimation F7 00:26                               491 X 585 km
1 70005U 16505A   16038.02569445 0.00000000  00000-0  00000+0 0    06
2 70005  97.4047  85.1777 0067405 176.5313 349.5073 15.08261084    04

Every day the rocket should lift-off about 28 seconds before for achieve
this Descending Node. So, here is a guess for next days:

Unha-3 estimation F8 00:25:32                            491 X 585 km
1 70006U 16506A   16039.02537037 0.00000000  00000-0  00000+0 0    01
2 70006  97.4047  86.0467 0067405 176.5313 349.5073 15.08261084    01

Unha-3 estimation F9 00:25:04                            491 X 585 km
1 70007U 16506A   16040.02504630 0.00000000  00000-0  00000+0 0    07
2 70007  97.4047  86.9158 0067405 176.5313 349.5073 15.08261084    08

Will be updating these till liftoff occurs.



Jon, COSPAR 6242, 42.9453, -2.82839, 623m, Bitoriano, Basque Country.
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Received on Sat Feb 06 2016 - 06:15:45 UTC

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