Re: orbit for ATV on space track

From: Gerhard HOLTKAMP (grd.holtkamp@t-online.de)
Date: Sun Mar 09 2008 - 19:50:50 UTC

  • Next message: Brad Young: "BY Obs Mar 9"

    On Sunday 09 March 2008 19:35, Matt Bartley wrote:
    > On Mar 9, 2008, at 10:44 AM, Marco Langbroek wrote:
    > 
    > > Kevin Fetter schreef:
    > >> There's 2 objects listed.
    > >> Object A - 32686
    > >> Object B - 32687
    > >> I assume Object B is the ATV, as it's in a higher orbit.
    > >
    > > Looking at the eccentricity values, and the different sets of tle  
    > > now available, I rather think Object A is the ATV.
    > 
    > Heavens-above.com is using 32686.
    > 
    
    The Spacetrack TLEs I've downloaded have epoch 08069.36553096 for Object A 
    (#32686) and epoch 08069.30573255 for Object B (#32687). Object A closely 
    follows the pre-launch elements posted by Ted. There is something strange 
    about the decay rate for Object B. The R/B should have been deorbited by that 
    time. But I think the real ATV did its first maneuver after about two revs 
    and there might have been a mix-up at Spacetrack afterwards. Neither of the 
    two TLE sets is correct at the moment I think. There hopefully will be fresh  
    elements for ATV issued soon so that we can correctly observe it. I came 
    across a pre-planned list of (ascending node) equator crossings for ATV over 
    the next few days. Assuming that all maneuvers are done according to plan you 
    can check the following times with against new TLEs issued for ATV to see the 
    difference (all times are in UTC):
    
    20:35:30,  9-MAR-08
    22:05:43
    23:35:56
    1:06:09,  10-MAR-08
    2:36:22
    4:06:35
    5:36:48
    7:07:01
    8:37:14
    10:07:27
    11:37:40
    13:07:57
    
    I would expect any elements which give times close to the above listed to be 
    the correct ones. 
    
    Gerhard HOLTKAMP
    Darmstadt, Germany
    
    
    
    
    
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