Atlas V-OA-4 launch orbit estimations

From: Jon . via Seesat-l <>
Date: Fri, 27 Nov 2015 10:30:46 +0100
Hello all;

Although I am with tecnical problems, I have been able to make an orbit
estimations for the upcoming Atlas V 401/Cygnus OA-4 launch from

The launch window opens the 2015/12/3 _at_ 22:55 UTC, and closes at 23:25 UTC.
The target orbit, according to the launch kit is about 229x230 Km, 51.6
degree orbit.

Knowing the launch time and these data I've been able to derive the
following orbit:

OA-4 estimation #1                                       224 X 225 km
1 70001U 15501A   15337.96951389 0.00000000  00000-0  00000+0 0    01
2 70001  51.6203 311.7500 0000467  48.0886  49.0555 16.18189066    09

This orbit should be accurate until a pair of minutes per day after epoch.
As allways the epoch is set to the time of orbit insertion, at about 23:16
UTC, about 21min 05sec after launch. This orbit is valid only if launch
occurs at 22:55 UTC. I dont know if I will be available to update the orbit
if a launch delay occurs.

Visibility window indicates that the rocket should pass the ~170 Km
altitude in the first minutes of launch to see the "comet" like phenomena,
so seems unlikely.

European observers should be able to receive radio signal several minutes
after launch from the vehicle if this is transmitting to ground. Sadly the
vehicle would pass on shadow.

Be good!

P.D: I will try to derive another orbit for the upcoming Vega launch, but
canĀ“t promise anything.

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Received on Sat Nov 28 2015 - 08:06:38 UTC

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