Re: North Korea satellite: identity of catalogued objects

From: Igor Lissov (
Date: Fri Dec 14 2012 - 18:10:47 UTC

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    > Alternatively, I wonder whether 12072C and D could be de-spin masses? If the rocket employs a solid motor, then it would
    > likely have been spin-stabilized during firing. For the payload not to be spinning when it separates, the rocket must
    > first de-spin. One method is to release a couple of small masses attached to the rocket by wires wrapped around its
    > circumference. This is commonly called "yo-yo de-spin". The masses may be released and enter independent orbits.
    In the video , 
    at 5:24, you may see two graphs over the shoulder of the North Korean official. 
    One depicts height vs. time, another velocity vs. time. In the latter, you may see 
    three phases from three stages of Unha 3. As the third one lasts half of total time 
    (and yields half of orbital velocity) I'd rather thin the third stage is a liquid one.
    By the way, TLEs for 072A and 072B seems to show TCA at 01:19 UTC,
    some 30 minutes after the launch. If this is so, I would not exclude some
    kind of evasive impulse by the stage. 
    Igor Lissov
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