****************************************************************************** dorismail 29-Sep-2010 13:26:58 Message No 0703 ****************************************************************************** Author: "Ferrage Pascale" Subject: ENVISAT orbit change for extended lifetime Dear colleagues, Please note that the ENVISAT orbit will change in order to extend the mission until 2014 (3-Year extension). The adopted solution is to abandon inclination control ensuring a reduction in hydrazine consumption. Thus, 3 pairs of in-plane maneuvers (OCMs) will be performed between October 22 and November 2, 2010: Start of boost duration DV along track 2010/10/22-06:35:37 1726s DV~=2.5m/s 2010/10/22-09:05:21 1758s DV~=2.5 m/s 2010/10/26-14:48:35 1370s DV~=1.97m/s 2010/10/26-17:18:25 1390s DV~=1.97m/s 2010/11/02-02:29:43 28s DV~=0.033m/s 2010/11/02-03:20:43 28s DV~=0.033m/s The new orbit main characteristics will be the following ones: -Altitude: 782.4 Km (17.4 km diminution, ensuring a Low collision risk with other satellites of Earth observation) - Semi-major axis: 7,142,047 m - Eccentricity: 0.001158 - Inclination: 98.476° - Repeat cycle: 30 days / 431 orbits - Quasi-sun-synchronous orbits. - Drifting Mean Local Solar Time. - Delta nodal period: -0.087 s/year A total interruption of the mission is scheduled from October 22th,2010 until November 2th, 2010. However The DORIS instrument is still operational, and the DORIS data will be delivered with no interruption. In addition, NOTE that after this orbit change, the arcs length of the delivered DORIS data will be the following ones: - 4 consecutive arcs of 7 days, - then, one arc of 2 days, .. And so on... The choice of such arcs takes into account the new cycle duration of 30 days, existing processing capabilities, and the constraint of not overlapping. Best Regards, Pascale FERRAGE _____________________________________________________ CNES - International DORIS Service (IDS): http://ids-doris.org/ DCT/ME/OT- Bpi 612 Phone : 33 - (0)5 61 28 30 66 18, avenue Edouard Belin Fax : 33 - (0)5 61 28 25 95 31 401 TOULOUSE CEDEX 9 Email : Pascale.ferrage@cnes.fr _____________________________________________________ Cliquez sur l'url suivante https://www.mailcontrol.com/sr/wmlACP4KeyDTndxI!oX7UkccJfXxjPVWdRep1WflWCESxSCRdi!4ULmj5KHvHT3EfxoBRqvSue4jYo47nA1+0g== si ce message est indésirable (pourriel). Please do not reply directly to this message, but send comments and suggestions to IDS.central.bureau@cls.fr