RE: Questions about breakups and rocket bodies

From: Larry Ridolfi (
Date: Sun Nov 06 2005 - 09:55:23 EST

  • Next message: Alberto Rango: "4541 PPAS 2 - 3 - 4 Nov 2005."

    Excellent questions and, as usual, Leo is correct.  Here are some additional
    points as working these things is something I've done.
    Breakups are never easy nor clean from the catalogue perspective.  When a
    location first announces a possible breakup, all that may be known is that
    where there an expected 20XX-nnnB observation, it is not on location or time
    and there are multiple uncorrelated observations.  This announcement then
    triggers all sites visible to spend additional time collecting data on the
    "new" uncorrelated observations.
    When a second location confirms the information from the first, then a
    breakup is declared and the painful task of correlating the pieces begins.
    Here ensues a long discussion of the obs, which ones are parts of the
    original 20XX-nnnB, and which one (if any) will hold onto the original Cat
    Number.  Typically, the responsible analyst will select the piece with the
    largest radar cross section if it is remotely close to the former 20XX-nnB
    obs -- it really is just a guess to get the job moving.  Declaring a breakup
    is a major event as more folks will be working long hours to catalogue all
    the pieces.
    On the other hand, the other debris cases mentioned by Leo are easy.  Most
    launches and deorbits are well understood events.  We know how many pieces
    will be associated with say a Delta II launch and when the solar arrays are
    jettisoned from the Soyuz capsule.
    -----Original Message-----
    From: Leo Barhorst [] 
    Sent: Saturday, November 05, 2005 8:51 PM
    To: seesat-l
    Subject: Re: Questions about breakups and rocket bodies
    Hello George,
    When a object in space breaks up then in most cases the parent body
    remains the largest piece and keeps the original ID; that is your option a).
    But in several cases the object fragmented totally and then launchpiece B
    decayes, mostly reffered to as disintegrated. Then there is in fact no 
    object B
    In History of on-orbit satellite fragmentation the following definition of 
    terms is used.
    In this volume, satellite fragmentations are categorized by their assessed 
    nature and to a lesser
    degree by their effect on the near-Earth space environment. A satellite 
    breakup is the usually
    destructive disassociation of an orbital payload, rocket body, or structure,
    often with a wide range of
    ejecta velocities. A satellite breakup may be accidental or the result of 
    intentional actions, e.g., due
    to a propulsion system malfunction or a space weapons test, respectively. An
    anomalous event is
    the unplanned separation, usually at low velocity, of one or more detectable
    objects from a satellite
    which remains essentially intact. Anomalous events can be caused by material
    deterioration of
    items such as thermal blankets, protective shields, or solar panels. As a 
    general rule, a satellite
    breakup will produce considerably more debris, both trackable and 
    non-trackable, than an
    anomalous event. From one perspective, satellite breakups may be viewed as a
    measure of the
    effects of man's activity on the environment, while anomalous events may be 
    a measure of the effects
    of the environment on man-made objects.
    Mission-related, also known as operational, debris result from the 
    intentional release of objects,
    usually in small numbers, during normal on-orbit operations. Objects ejected
    during the
    deployment, activation, and de-orbit of payloads and during manned 
    operations are examples of
    mission-related debris. Usually, mission-related debris from a single launch
    are few in number, but
    extreme examples occasionally arise, such as the 200 objects from the Salyut
    7 space station or the
    more than 140 objects from the Westford Needles experiment. Although 
    mission-related debris
    represent a significant portion (approximately 13%) of all satellites in 
    orbit today and therefore are a
    legitimate subject in the study of methods to retard the growth of the Earth
    satellite population,
    identification of the thousands of mission-related debris events is beyond 
    the scope of this report.
    As for your second question:
    A rocket is in fact the whole thing that places a satellite in orbit. Pieces
    of the rocket
    also in orbit are mostly called stages.
    Motors and engines are the same. This mostly reffers to Apogee or Perigee 
    Kick Motors
    or Auxiliary motors or Ullage motors. Most of the time smaller than a 2nd or
    3rd stage.
    Your defination about the casings is correct. These are the pieces of the 
    rocket in between
    stages. They can be like a ring, but often are cone shaped as the next stage
    has a
    smaller diameter.
    Greetings and clear, dark skies
    Leo Barhorst, Medemblik NL
    Cospar 4252 52.76350 N 5.09114 E 2 m ASL
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