Subject: [SLR-Mail] No. 1272: TOPEX anomaly in September From: Frank Lemoine/GSFC, Carey Noll/ILRS CB > ******************************************************************************** SLR Electronic Mail 2004-10-27 23:37:00 UTC Message No. 1272 ******************************************************************************** Author: Frank Lemoine/GSFC, Carey Noll/ILRS CB Subject: TOPEX anomaly in September We have been informed by John Ries/CSR that there were thruster tests on TOPEX between September 23-24, 2004. According to the TOPEX project the times of the thruster tests were: ****Start One Newton Thruster Test Program 2004-267T18:38:48 443 021 Start C4 Fire for 1 Second 2004-267T18:46:26 443 024 Stop C4 Fire for 1 Second 2004-267T18:46:27 443 024 Start C4 Fire for 3 Seconds 2004-267T19:40:29 443 025 Stop C4 Fire for 3 Seconds 2004-267T19:40:32 443 025 Start C4 Fire for 11 Pulses 2004-267T20:32:21 443 026 Stop C4 Fire for 11 Pulses 2004-267T20:32:31 443 026 Stop One Newton Thruster Test Program 2004-268T17:29:11 443 048 This anomaly occurred during TOPEX cycle 443. Doug Chinn at GSFC reports anomalous DORIS residuals between Sept 23-25, 2004, inclusive. This thruster testing probably explains any difficulties the stations may have had in tracking the satellite during that time frame. Further thruster tests to assess fuel depletion and satellite decommissioning scenarios are planned for mid to late November 2004. The TOPEX project will provide the POD community and SLR stations with timely notification of these new thruster events, and the SATATT file will be updated to provide information about these tests. Frank and Carey. +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+ Ms. Carey Noll Manager, Crustal Dynamics Data Information System (CDDIS) Secretary, ILRS Central Bureau Code 922 E-mail: Carey.Noll@nasa.gov NASA GSFC Voice: (301) 614-6542 Greenbelt, MD 20771 Fax: (301) 614-6099 USA WWW: http://cddisa.gsfc.nasa.gov/cddis_welcome.html +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+ From: Carey Noll ********************************************************************************