PDS_VERSION_ID = PDS3 RECORD_TYPE = STREAM OBJECT = TEXT PUBLICATION_DATE = 1999-09-07 NOTE = " E-mail and other messages concerning MGS Radio Science on or about 1997/189." END_OBJECT = TEXT END From trish@rodan.jpl.nasa.gov Tue Jul 8 11:21:10 1997 Received: from rodan.Jpl.Nasa.Gov (rodan.jpl.nasa.gov [128.149.43.24]) by magellan.Stanford.EDU (8.8.5/8.8.3) with ESMTP id LAA02418 for ; Tue, 8 Jul 1997 11:21:09 -0700 (PDT) Received: from 128.149.43.27 (trish-mac.jpl.nasa.gov [128.149.43.27]) by rodan.Jpl.Nasa.Gov (8.8.5/8.6.6) with SMTP id LAA28762; Tue, 8 Jul 1997 11:21:19 -0700 (PDT) Message-Id: <199707081821.LAA28762@rodan.Jpl.Nasa.Gov> Date: 08 Jul 97 11:22:00 -0700 From: Trish Priest Subject: ORT #1 To: Georges Balmino , David Hinson , Richard Simpson , Bill Sjogren , David Smith , Joe Twicken , Len Tyler , Richard Woo , Maria Zuber CC: Bill Adams , Sami Asmar , Joe Beerer , Paula Eshe , Al Kern , Kyle Martin , Angus McMechen , Dave Recce , Tom Thorpe , Bruce C Waggoner X-Mailer: QuickMail Pro 1.0.2d1 X-Priority: 3 Reply-To: Trish Priest Content-Type: text/plain; charset="iso-8859-1" Content-Length: 1443 Status: RO Hello, The first Radio Science ORT went very well. Three mapping orbits are simulated by the spacecraft, and the DSP was able to record one-way data for two orbits (ingress and egress). The DSP was not available for the third orbit because of a last-minute Pathfinder conflict. Data from first ingress, first egress, and second ingress will use reliable data delivery; therefore, we will probably have to wait until the end of the track to start querying for data. Data from the second egress was sent back to the NERT Cache in the usual (old) way. I took the opportunity to retransmit part of the data before releasing the DSP to Pathfinder. A TOT query to the MASTER_QueryServer successfully returned data for this second egress period. In this period, we also recorded the 1 minute 15 second warm-up of the TWTA. (189-17:18:45 to 189-17:30:00). The signal showed no signs of the "comb" problem that we saw in previous DSS 65 data. There were also no 650 Hz spurs in the TLM-off data. We collected about 10 minutes of TLM-on data at the beginning of track (outside the ORT time) and saw 650-Hz spurs. Two-way data was collected at a rate of 1/5 this time. The first four ORTs were already sequenced before the Team Meeting. DSS 65 did a great job. We did not encounter any operational problems. Now we await the reliable data delivery. Thanks to DSS 65, the NOPE, and the ACE for their support. -Trish --------------------------------------------------------------------- From rsimpson Wed Jul 9 17:05:56 1997 Received: (from rsimpson@localhost) by magellan.Stanford.EDU (8.8.5/8.8.3) id RAA06992; Wed, 9 Jul 1997 17:05:35 -0700 (PDT) Date: Wed, 9 Jul 1997 17:05:35 -0700 (PDT) From: Dick Simpson 723-3525 Message-Id: <199707100005.RAA06992@magellan.Stanford.EDU> To: john@oberon.jpl.nasa.gov, len@nova.Stanford.EDU, rsimpson@magellan.stanford.edu, trish@rodan.jpl.nasa.gov Subject: Re: FWD: DSS65 MGS Gravity wave experiment Content-Length: 454 Status: R During our single run yesterday there were amplitude fluctations at two scales. At time scales of minutes there was a 0.1 dB peak-to-peak variation. At time scales of seconds, there were fluctuations of a few hundredths of a dB. In both cases, what I see looks random -- there nothing as dramtic as what John found on 97/120. I've not looked at amplitude variations on time scales of less than 1 second, nor have we looked at frequency residuals yet. ----------------------------------------------------------------------- From joe@neptune.Stanford.EDU Thu Jul 10 15:00:43 1997 Received: from nova.stanford.edu (nova.Stanford.EDU [36.10.0.123]) by magellan.Stanford.EDU (8.8.5/8.8.3) with ESMTP id PAA11086 for ; Thu, 10 Jul 1997 15:00:42 -0700 (PDT) Received: from neptune.Stanford.EDU (neptune.Stanford.EDU [36.10.0.149]) by nova.stanford.edu (8.8.5/8.8.4) with ESMTP id PAA22565; Thu, 10 Jul 1997 15:01:37 -0700 (PDT) Received: (from joe@localhost) by neptune.Stanford.EDU (8.8.5/8.8.3) id PAA07216; Thu, 10 Jul 1997 15:00:52 -0700 (PDT) Date: Thu, 10 Jul 1997 15:00:52 -0700 (PDT) From: Joe Twicken Message-Id: <199707102200.PAA07216@neptune.Stanford.EDU> To: David.D.Morabito@cc2mhb.jpl.nasa.gov, angus.m.mcmechen@ast.lmco.com, hinson@nova.Stanford.EDU, joe@nova.Stanford.EDU, john@oberon.jpl.nasa.gov, len@nova.Stanford.EDU, rsimpson@nova.Stanford.EDU, trish@zygra.jpl.nasa.gov, william.r.adams@ast.lmco.com Subject: ORT #1 (97/189) Content-Length: 2825 Status: R I have processed the ODS data from ORT #1 on 97/189. The ODS data was recorded at DSS 65. There were 4 segments of open-loop data recorded over two simulated MGS orbits. Telemetry was off during each segment. The duration of each data segment was 10 minutes. An additional 10 minute segment of data was recorded just prior to the ORT. Telemetry was on during this segment. The SNR during the actual ORT recordings (telemetry off) was approximately 51 dB/Hz. I believe that the ORT included a third simulated MGS orbit, but no open-loop data was recorded during this part of the test. There was a problem obtaining the ODS data. The data were not available on the QueryServer as expected after the test was completed on Tuesday. An ISA was written concerning this problem. Queries today did succeed without difficulty. There were no missing records in any of the data segments. I believe that some of the delay in obtaining the data, however, was to ensure that there would be no missing records. All of the open-loop data segments were fully processed with a single execution of a Unix shell script. This was the first chance that we have had to process multiple MGS open-loop recordings. The processing went very well, beginning today at 11:41 and concluding at 13:44. All files for processing the multiple open-loop segments were recorded in the MgsDB database. All POCA files were fixed automatically with the "salvagePoca" program. The data segments were acquired at DSS 65 at 5000 samples per second in mode 2 (1250 12-bit samples/second for each of 4 A/D's). The start and stop times for each of the segments were as follows: Start Stop Telemetry Simulation 13:23:00 13:33:00 On Test 14:10:00 14:20:00 Off Ingress 15:10:00 15:20:00 Off Egress 16:20:00 16:30:00 Off Ingress 17:20:00 17:30:00 Off Egress The first data segment exhibited the 650 Hz frequency spurs that we have observed in many USO tests. The spurs do not appear in any of the recordings with telemetry off, however. In fact, the spectra of all four ORT recordings appear free of frequency artifacts. I used the spk_c_970321-970827 SP-kernel file to steer the data. This file was created on 97/168. I estimated the USO frequency during the middle of the test period to be 8423152955.5 Hz. With recordings on three days over the last month, it is now evident that the USO frequency drift rate has changed significantly since the time before MGS went into safe mode. The drift rate since 97/162 is approximately 0.172 Hz/day. Prior to entering safe mode, the USO drift rate was over 0.25 Hz/day. We have updated our USO model file to reflect this change in USO drift rate. At an integration time of 26.2 seconds, the Allan deviation during each of the four simulated occultations was in the range of 1.1e-13 to 2.0e-13.