| Date: | 2008-06-24 18:19:00 | |
| Sender: | Frank Lemoine <Frank G. Lemoine <Frank.G.Lemoine@nasa.gov>> | |
| Subject: | [SLR-Mail] No. 1687: Jason-2 Post-Launch Schedule and Tracking Request | |
| Author: | Frank Lemoine | |
| Content: | ******************************************************************************** SLR Electronic Mail 2008-06-24 18:19:00 UTC Message No. 1687 ******************************************************************************** Author: Frank Lemoine Subject: Jason-2 Post-Launch Schedule and Tracking Request Dear ILRS stations and colleagues- The purpose of this message is to provide you with an update  on Jason-2 and to define the tracking priorities and plans  for both Jason-1 and Jason-2 for the duration of the Calibration  and Validation period (CalVal), which will extend from July 12, 2008  to January 2009. We request that tracking be initiated for test  purposes by June 30, and to support the T2L2  experiment on Jason-2 (see SLRMAIL 1686 by Etienne Samain).  We also request that formal support for the science  mission commence by July 12 (the start of Cycle 1 of the science  data for Jason-2). We request that the ILRS support elevated  priority for Jason-1 + Jason-2 for the duration of the tandem or CalVal  phase of flight operations (which will last six months from July 12). The OSTM/Jason-2 spacecraft and mission operations are doing well, and everything is nominal so far. Jason-2 is currently ahead of and below Jason-1. The drift should be stopped by next Wednesday, and a sequence of maneuvers between then and July 3 will correct the inclination and perform the rendez-vous with Jason-1. By July 3, Jason-2  will be one minute in orbit space behind Jason-1. Occasionally altimeter calibration maneuvers will occur - which means the spacecraft will not be oriented properly for laser ranging - but this will not affect the predictions. The SLR CPF predicts are already generated and available via anonymous ftp at the stations:   ftp://cddis.gsfc.nasa.gov/slr/slr/cpf_predicts/2008/jason2/ or  ftp://cddis.gsfc.nasa.gov/slr/slr/cpf_predicts/current/ We note that some stations (e.g. Yarragadee at 176/0222-0232) have  already used these predicts. When Jason 1 and 2 initiate their tandem flight operations (after July 4), we request that the stations track either Jason-1 or Jason-2 for a complete pass, alternating between the two spacecraft from pass to pass.  Some stations may have the ability to track both spacecraft during the same pass by interleaving ranging between the two satellites. These stations should track each satellite approximately 1 - 2 minutes before switching to the other satellite, and continue to do so throughout the entire tandem pass. The CalVal period (beginning July 12 and lasting six months) is of utmost scientific importance. It is the period during which all spacecraft systems, including the altimeter and the tracking systems (SLR, DORIS, GPS) will be validated. Our ability to  accuately connect the Jason-2 altimeter data to the long existing  time series of altimeter data from Jason-1 and TOPEX/Poseidon depends  on the quality of data and analysis during CalVal. Hence, the SLR  tracking data the ILRS supplies of both Jason-1 and Jason-2 is of utmost importance.  The Jason-2 Project and POD Team thank you for your support.  Sincerely,  The Jason-2/Jason-1 POD & CalVal Teams  Jean-Paul Berthias (jean-paul.berthias@cnes.fr)  Gilles Tavernier (Gilles.Tavernier@cnes.fr)  Pascal Bonnefond (Pascal.Bonnefond@obs-azur.fr)  Bruce Haines (Bruce.Haines@jpl.nasa.gov)  John Ries (ries@csr.utexas.edu)  Frank Lemoine (Frank.G.Lemoine@nasa.gov) From: ”Frank G. Lemoine” ******************************************************************************** |