Re: Fragments

From: Jonathan McDowell (jcm@head.cfa.harvard.edu)
Date: Fri Nov 04 2005 - 09:47:44 EST

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    Dino, you raise an interesting point.
    
     I'm also going through the satcat trying to identify things as best I can,
    as you have probably seen from my satcat.txt file on the web.
     I think the "metal object" phrase from the early Sat Situation Reports
    is definitely obsolete - there is now plenty of debris out there that
    is made of plastic composites or other non-metallic substances.
     The phrase "mission-related object" is used by some agencies to denote
    non-fragment debris. It's a bit clunky though. I tend to use "part" or
    "component", as in "Kosmos-2315 part", versus "Kosmos-2315 debris" for a
    fragment. But I haven't been very consistent about this.  In my personal
    (non-public) version of the database, I also tag each object with a
    "type code" that is P for payload, R for rocket stage, M for motor (a
    fine distiction for rocket stages not considered part of the launcher,
    like apogee motors), D for explosion debris, and C for component
    or non-explosive fragment. For me, a component is something that
    got deliberately separated from its parent object, while a fragment
    is something that came off by accident, like the Transit satellite insulation
    fragments. I should really add an F category to distinguish these fragments
    from the components but I haven't got around to that yet. I think having
    a separate code is useful, since you can then clearly make these distinctions
    even when you've fully identified a piece of hardware and renamed it in your
    list.
    
      - Jonathan McDowell
    
    
    Dino wrote:
    > 
    > Has the issue of what to call various kinds of  orbiting debris been 
    > addressed here? (Just curious.) When my own table of earth  satellites was in full 
    > swing, I was pretty careful to use the term "metal  object" for a piece of 
    > nondescript hardware jettisoned during the normal launch  and operation of a 
    > spacecraft, and reserved the term "fragment" specifically for  an orbited object that 
    > resulted from the breakup, whether intentional or  unintentional, of a 
    > spacecraft or rocket body. (Something knocked off a  spacecraft by a collision would 
    > [...]
    
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