There seems to have been a marked change in drag about 4 days ago and it doesn't seem particularly well associated with air density. See the chart here that derives from it: http://www.zarya.info/Diaries/China/Shenzhou/Shenzhou09.php#sz9 Tiangong 1's eccentricity has been oscillating recently and relates to what you are describing. It can be seen on the eccentricity plot part way down this page: http://www.zarya.info/Diaries/China/Shenzhou/Tiangong1.php. It is may be no coincidence that these changes started to happen just before China announced the Shenzhou 9 launch preparations. It might be a by-product of Tiangong 1 system checks. Bob Christy On 20/02/2012 20:28, abdolreza lavari wrote: > hi everyone > it seems that from FEB 15 to now tiangong-1 orbit is not in steady status. > its hp and ha are fluctuating between 200 to 400 meters from normal > values.can it be due to orbital maneuvers?or i am in mistake? > _______________________________________________ > Seesat-l mailing list > http://mailman.satobs.org/mailman/listinfo/seesat-l > > > ----- > No virus found in this message. > Checked by AVG - www.avg.com > Version: 2012.0.1913 / Virus Database: 2113/4821 - Release Date: 02/20/12 > > _______________________________________________ Seesat-l mailing list http://mailman.satobs.org/mailman/listinfo/seesat-l
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