PDS_VERSION_ID = PDS3 RECORD_TYPE = STREAM OBJECT = TEXT PUBLICATION_DATE = 2007-07-29 NOTE = " E-mail and other messages concerning MGS Radio Science on or about 2000/065." END_OBJECT = TEXT END From flemoine@ares.gsfc.nasa.gov Tue Apr 11 09:40 PDT 2000 Received: from ares.gsfc.nasa.gov (ares.gsfc.nasa.gov [128.183.106.250]) by magellan.stanford.edu (8.9.3/8.9.3) with ESMTP id JAA08753 for ; Tue, 11 Apr 2000 09:40:07 -0700 (PDT) Message-Id: <200004111640.JAA08753@magellan.stanford.edu> Received: by ares.gsfc.nasa.gov; Tue, 11 Apr 2000 16:40:22 GMT From: Frank Lemoine Subject: Orbit data files in march 2000 and general data quality To: rsimpson@magellan.stanford.edu Date: Tue, 11 Apr 2000 16:40:21 UTC Cc: dsmith@tharsis.gsfc.nasa.gov, zuber@tharsis.gsfc.nasa.gov, sfricke@ares.gsfc.nasa.gov, neumann@tharsis.gsfc.nasa.gov, flemoine@ares.gsfc.nasa.gov, drowland@helmert.gsfc.nasa.gov (David D Rowlands), trish@rodan.jpl.nasa.gov X-Mailer: Elm [revision: 212.4] Content-Type: text Content-Length: 1225 Status: R Dick: It looks like we are missing an orbit file on day 77 (march 17). Was there really no tracking data on this day? Also, we find only one hour of tracking for which we have data on day 76 (march 16), and no data on march 05 (day065). Are we missing some orbit data files? Frank L. -rw-r--r-- 1 gmisra mors 193536 Mar 13 11:17 0070073A.ODF -rw-r--r-- 1 gmisra mors 120960 Mar 14 11:48 0073074A.ODF -rw-r--r-- 1 naseem mors 104832 Mar 15 12:17 0074075A.ODF -rw-r--r-- 1 naseem mors 72576 Mar 16 14:10 0075076A.ODF -rw-r--r-- 1 naseem mors 169344 Mar 20 19:50 0078080A.ODF PS- as a general comment, it seems like the data quality has really deteriorated in the past 30-45 days; The quantity of data has really dropped off; The quaternions are (s/c and solar array) are showing frequent large gaps - which means we readlly should do surgery to create sensible quaternion files for GEODYN to use... but have not had time to do so because of NEAR obligations. I realize part of this is due to changes in mission mode, etc., but if we could just be assured of continuous quaternion coverage that would be a big help. -> Frank L. -- -------------------------------------------------------------------------- From rsimpson Tue Apr 11 10:04 PDT 2000 Received: (from rsimpson@localhost) by magellan.stanford.edu (8.9.3/8.9.3) id KAA08941; Tue, 11 Apr 2000 10:04:25 -0700 (PDT) Date: Tue, 11 Apr 2000 10:04:25 -0700 (PDT) From: Dick Simpson 723-3525 Message-Id: <200004111704.KAA08941@magellan.stanford.edu> To: flemoine@ares.gsfc.nasa.gov, rsimpson@magellan.stanford.edu Subject: Re: Orbit data files in march 2000 and general data quality Cc: drowland@helmert.gsfc.nasa.gov, dsmith@tharsis.gsfc.nasa.gov, neumann@tharsis.gsfc.nasa.gov, sfricke@ares.gsfc.nasa.gov, trish@rodan.jpl.nasa.gov, zuber@tharsis.gsfc.nasa.gov Content-Type: text Content-Length: 2340 Status: R >It looks like we are missing an orbit file on day 77 (march 17). >Was there really no tracking data on this day? Correct. That was during a period of Fixed High-Gain Antenna operations. Although the spacecraft did not execute the FHGA sequence (because of the MOLA thermal issue), the tracking schedule was never changed. Between about 19:30 on 2000-03-15 and 03:30 on 2000-03-18 there was only a single DSS 15 pass (2000-03-16T17:30 to 2000-03-17T 03:30:00). I'm not sure why there is NO ODF that dips into 03/17; but there is certainly not a LOT of data from that day. >Also, we find only one hour of tracking for which we have data >on day 76 (march 16) ... See above. >...and no data on march 05 (day065). Same problem -- except that was a date of REAL FHGA operation. Only 40 minutes of DSS 25 time fell into 03/05. >as a general comment, it seems like the data quality has >really deteriorated in the past 30-45 days; The quantity of >data has really dropped off; The quaternions are (s/c and solar >array) are showing frequent large gaps ... Until recently we have been "blessed" with schedule help from phantom spacecraft (MPL and DS2). Those missions are now over (in more ways than one); but we may still be benefitting from residual MCO planning. The number of DSN passes devoted to MGS has slowly been tapering off. Recall that the MGS requirement is for 8 hrs per day plus an additional 8 hrs of real time coverage every third day. So we've been doing quite well since late last year thanks to MCO, MPL, and DS2. The above does not explain the quaternion gaps, since those data should be included in the recorded playback that comes down during each pass. We are limiting our own queries so that there is at least 32 hrs between data acquisition at the spacecraft and our download. In principle, that should allow all data on the spacecraft to reach the ground if there is at least one DSN pass per day. I believe Boris is doing the same for the HGA kernels. I don't know what the procedure is for the Spacecraft Team (who generate the solar panel and bus quaternions). I'll leave this for Trish. She's away from JPL, but should be back Thursday. If the SCT is trying to generate their kernels too quickly, that might explain gaps.