John Locker wrote: > http://orbit.m6.net/Forum/default.aspx?g=posts&m=192345 has > some good images of the launcher > > .........and an interesting comment about the Breeze M stage > > " presumably bound for an unplanned reentry from a 51.5 deg > inclined orbit, could have more than 16 tonnes of toxic > hypergolic propellant still aboard." There is another possibility, as I discuss below. Orbital elements have yet to appear, but Spaceflight Now has an informative report: http://www.spaceflightnow.com/proton/amc14/ Intended circular parking orbit: 51.5 deg, 107 miles = 172 km Intended transfer orbit: 553 x 22,211 miles = 890 x 35745 km, presumably 51.5 deg Intended orbit at spacecraft separation = 19.7 deg, 3888 x 22,211 miles = 6257 x 35745 km Achieved apogee: 17400 miles = 28000 km So, the present orbit probably is inclined at 51.5 deg, with a perigee between 172 and 890 km, and apogee 28000 km. If so, then its decay could occur months or years from now, by which time leaks may have formed in the propellant tanks/plumbing, resulting in an explosive fragmentation in orbit. There is a recent precedent for the latter scenario, in the launch of Arabsat 4 (06006A / 28943), on 2006 Feb 28 UTC, aboard a Proton rocket. As in the present incident, the Breeze M stage terminated its second burn prematurely, leaving the payload stranded in a 51.6 deg, 500 x 14700 km orbit. On 2006 Mar 24 UTC, the payload was returned to Earth in a controlled re-entry, presumably with decay over the area of the South Pacific normally used for this purpose. On 2007 Feb 19 UTC, the Breeze M stage exploded in the vicinity of Australia. The event was imaged by at least two Australian astronomers, as I recall; here is one image: http://antwrp.gsfc.nasa.gov/apod/ap070222.html Some relevant SeeSat-L threads: http://satobs.org/seesat/Feb-2007/0185.html http://satobs.org/seesat/Feb-2007/0212.html On 2007 May 12, Greg Roberts was the first to spot debris from the explosion, in the form of a bright unknown object: http://satobs.org/seesat/May-2007/0099.html Mike McCants and I quickly determined the approximate orbit, and identified Breeze M (06006B / 28944) as the probable parent object. We assigned the temporary ID 07631A / 91117: http://satobs.org/seesat/May-2007/0110.html http://satobs.org/seesat/May-2007/0122.html After I failed to recover it on two attempts, Greg Roberts succeeded: http://satobs.org/seesat/May-2007/0127.html I quickly updated the orbit using the new data: http://satobs.org/seesat/May-2007/0130.html Subsequent hobbyist observations resulted in nearly a dozen orbit updates through 2007 Jul 12. In Aug 2007, US STRATCOM issued the first orbital elements of debris from the explosion, and we determined that our 07631A / 91117 and US STRATCOM's 06006B / 28944 are the same object. Its radar cross-section area indicates that it must represent a large portion of the Breeze-M. To-date, 36 pieces of debris have been catalogued, of which two have decayed. Ted Molczan ------------------------------------------------------------------------- Subscribe/Unsubscribe info, Frequently Asked Questions, SeeSat-L archive: http://www.satobs.org/seesat/seesatindex.html
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