Re: No-show of Lacrosse 5

From: Philip Masding (
Date: Tue Mar 07 2006 - 17:18:55 EST

  • Next message: Marco Langbroek: "Re: No-show of Lacrosse 5"

    It is strange that you did not see the satellite. My prediction is that you 
    should have seen a 70 degree maximum altitude pass at 20:21:44 and then the 
    satellite would have gone into eclipse at 20:22:08 just as it was about to 
    pass over Denmark.
    I observed the same pass and had a good success. I saw a flare at about 
    20:19:05 Based on your observations of 2 flares for Lacrosse 5 I calculated 
    that the most likely SAR panel angle was about 33 degrees. If I assume this 
    33 degree angle then I predict a likely flare from my location at precisely 
    the time I observed it for this latest pass on March 6th. So I think we can 
    conclude that the satellite was flying normally in YVV mode with a SAR panel 
    at about 33 degrees. If it was flying in some strange mode then clearly the 
    flare would not have happened as predicted. Unfortunately I completely 
    failed to resolve it so I can't confirm the flight mode.
    As to why you didn't see it all I can say is that a simulation shows that 
    the solar panel would have been invisible and that during the high altitude 
    parts of the pass the SAR was not well lit either. However I do predict that 
    the SAR should have been quite well lit earlier in the pass around 20:19:43 
    when the satellite was at 36 degrees. How early in the pass did you start to 
    track it?
    ----- Original Message ----- 
    From: "Marco Langbroek" <>
    To: "satellite list" <>
    Cc: "Ted Molczan" <>; "Mike McCants" <>; 
    "Pierre Neirink" <>; "Scott Campbell" 
    <>; "Greg Roberts" <>; "Bram Dorreman" 
    <>; "Bruce MacDonald" 
    Sent: Monday, March 06, 2006 8:32 PM
    Subject: No-show of Lacrosse 5
    > Hi all,
    > Indeed, the brightness behaviour of Lacrosse 5 is odd lately. I failed to 
    > see it both visually and with the camera, nothwithstanding a clear sky and 
    > a predicted brightness of +2.1, at the 20:21 UTC near-zenith pass here 
    > just 10 minutes ago.
    > I did see and capture the Lacrosse 5 Rk an hour earlier. At around +2 it 
    > was easily visible both on the camera image and with the naked eye 
    > (position measurement report will follow later this evening).
    > - Marco
    > -----
    > Dr Marco Langbroek  -  SatTrackCam Leiden, Cospar 4353
    > Leiden, the Netherlands. 52.15412 N,  4.49081 E (WS84), +0 m ASL
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