George; 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 [mailto:leobarhorst@zonnet.nl] 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 anymore. 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 http://www.satlist.nl/index.html ------------------------------------------------------------------------- Subscribe/Unsubscribe info, Frequently Asked Questions, SeeSat-L archive: http://www.satobs.org/seesat/seesatindex.html ------------------------------------------------------------------------- Subscribe/Unsubscribe info, Frequently Asked Questions, SeeSat-L archive: http://www.satobs.org/seesat/seesatindex.html
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