Re: 12044A / 38744: altitude increasing?

From: Bob Christy (
Date: Sun Aug 12 2012 - 09:49:57 UTC

  • Next message: Bob Christy: "Re: 12044A / 38744: altitude increasing?"

    Overnight element sets from SpaceTrack make the picture more 
    Bob Christy
    On 11/08/2012 16:53, Ted Molczan wrote:
    > Bob Christy wrote:
    >> In the light of SpaceTrack's switching around of IDs and increasing
    >> number of element sets published, I've revisited my reasoning as to
    >> which ID is which launch component. I agree with Ted but by have
    >> approached it from a different angle.
    >> I still think it is the APT that is venting fuel or gas:
    > The following are preliminary estimates, with little error checking.
    > Assuming the Breeze-M core carried its maximum of 5200 kg of fuel, then all of it should remain. Add to that its
    > approximate dry mass of 1420 kg, for a total of 6620 kg. I estimate that its mean cross-sectional area is about 5.31
    > m^2. A/m would be ~0.00080 m^2/kg.
    > I estimate that at shut-down the APT still contained about 6538 kg of fuel. In an NSF forum, its dry mass was stated to
    > be 950 kg. Total mass would be 7488 kg. I estimate that its mean cross-sectional area is about 8.1 m^2. A/m would be
    > ~0.00108 m^2/kg.
    > If objects 12044C and 12044D are the core and the APT, then the above A/m values suggest that their rates of decay
    > should be roughly the same. In fact, the C object has exhibited negligible decay for the past couple of days, and D has
    > exhibited a fairly high rate of decay since it reached orbit.
    > Since C and D should be several times as massive as the payloads (12044A and B) and probably have no greater
    > cross-sectional area than A and B, I would expect both to have significantly lower rates of decay than A and B, but that
    > is true only of C. D has been decaying at 3 to 4 times the rate of A and B. Could that be because D is the APT, which
    > somehow has vented most of its fuel?
    > As for C, there is room for doubt that its recent negligible rate of decay and fluctuations in mean motion are due to
    > fuel leakage. It may turn out to be due to unusually slow convergence to a realistic rate of decay. The situation will
    > become clearer as additional TLEs are released.
    > Before hitting send, I checked Space Track again, and I found that they have now attached the following names:
    > 12044A TELKOM 3
    > 12044B EXPRESS MD2
    > 12044C BREEZE-M R/B
    > 12044D BREEZE-M DEB
    > Ted Molczan
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