Subject: [SLR-Mail] No. 1318: Message from TOPEX project regarding SLR support From: Carey Noll/CDDIS > ******************************************************************************** SLR Electronic Mail 2005-03-22 18:33:00 UTC Message No. 1318 ******************************************************************************** Author: Carey Noll/CDDIS Subject: Message from TOPEX project regarding SLR support The ILRS Central Bureau received the message below from Dr. Lee-Lueng Fu with the TOPEX project stressing the continuing importance of ILRS support of TOPEX. Regards, Carey. ----- Ms. Carey Noll Manager, Crustal Dynamics Data Information System (CDDIS) Secretary, ILRS Central Bureau NASA GSFC Code 690.5 Greenbelt, MD 20771 USA E-mail: Carey.Noll@nasa.gov Voice: (301) 614-6542 Fax: (301) 614-6099 WWW: http://cddis.gsfc.nasa.gov ------- Forwarded message follows ------- March 18, 2005 To: Dr. Michael Pearlman International Laser Ranging Service Dear Dr. Pearlman: Since the inception of the TOPEX/Poseidon mission, the tracking of TOPEX provided by Satellite Laser Ranging (SLR) has been critical to the mission success. Thanks to the precise SLR tracking, in combination with the DORIS system also on TOPEX, we have been able to compute orbits with a radial accuracy of 2 to 2.5 cm over the past 12 1/2 years. These precise orbits have contributed directly to the science successes of the mission, including the global synoptic mapping of sea level, the determination of ocean tides, and the mapping of phenomena such as El Nino. Since September 2002, TOPEX has been maneuvered into an interleaved orbit with Jason, the successor of TOPEX. This provides us with an unique opportunity to increase the resolution with which we map ocean topography. In November 2004, TOPEX suffered an irreversible failure of its DORIS tracking system. This means that for the present, the production of the precise orbits relies solely on the SLR data used in combination with the altimeter crossovers. The SLR data provided by the international network of tracking stations have now assumed a critical role. It is vital that we obtain as much high quality tracking of TOPEX by the SLR network, as the orbit quality is tied to the number of passes we obtain in any given cycle as well as its distribution within each day. We encourage the ILRS to continue the SLR tracking of TOPEX/Poseidon to assure the production of high quality altimeter data for this unique dual-altimeter Tandem Mission. Sincerely, Dr Lee-Lueng. Fu TOPEX/Poseidon and Jason Project Scientist Jet Propulsion Laboratory ------------------------------------------------------------- Lee-Lueng Fu JPL 300-323 4800 Oak Grove Drive Pasadena CA 91109 FAX:818-393-6720. VOICE: 818-354-8167 From: ”Carey Noll” ********************************************************************************