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 1997/162." END_OBJECT = TEXT END From trish@rodan.jpl.nasa.gov Tue Jun 3 12:36:48 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 MAA06635 for ; Tue, 3 Jun 1997 12:36:48 -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 MAA22201; Tue, 3 Jun 1997 12:36:27 -0700 (PDT) Message-Id: <199706031936.MAA22201@rodan.Jpl.Nasa.Gov> Date: 03 Jun 97 12:44:46 -0700 From: Trish Priest Subject: USO Test on June 11 To: Richard Simpson , Len Tyler CC: David Hinson X-Mailer: QuickMail Pro 1.0.2d1 X-Priority: 3 Reply-To: Trish Priest Content-Type: text/plain; charset="iso-8859-1" Content-Length: 410 Status: RO Hello, The Change Board approved a USO test on DOY 162 (June 11). The spacecraft will not be commanded; the uplink will be dropped two hours before the end of the track. DSS 25 DOY 162 02:00 to 04:00 UTC There is no sequence at this time since C8 was cancelled due to safe mode. The C9 sequence is in development. It begins on June 27th. We have two USO tests and 4 ORTs in the sequence. -Trish ------------------------------------------------------------------------ From trish@rodan.jpl.nasa.gov Tue Jun 10 22:18:12 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 WAA16206 for ; Tue, 10 Jun 1997 22:18:12 -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 WAA13728; Tue, 10 Jun 1997 22:17:56 -0700 (PDT) Message-Id: <199706110517.WAA13728@rodan.Jpl.Nasa.Gov> Date: 10 Jun 97 22:26:34 -0700 From: Trish Priest Subject: USO Test #11 To: Salvadore Abbate , David Hinson , Richard Simpson , Joe Twicken , Len Tyler CC: Bill Adams , Sami Asmar , Joe Beerer , Stan Butman , Dave Morabito , Dave Recce , Tom Thorpe X-Mailer: QuickMail Pro 1.0.2d1 X-Priority: 3 Reply-To: Trish Priest Content-Type: text/plain; charset="iso-8859-1" Content-Length: 1574 Status: RO Hello, The first USO test since April 2nd is complete. This is also the first data from DSS 25 (other than a tape from Sal). There was a data outage in the middle of the pass because the DSP had a VME bus error and had to be rebooted. Sal Abbate was notified, and he concurred that this was the appropriate course of action. After the reboot, the DSP ran nominally until the end of track. The USO test was performed in the standard DSP configuration: 5000 sps, 2500 Hz filter (3), 12-bit, mode 2. The important times for this test on DOY 162 are as follows (UTC ERT): DSP Begin Recording: 01:50:00 Beginning of one-way: 02:00:00 Last atten. change: 02:06:46 DSP reboot: 02:53:00 (approx.) DSP recording again: 03:12:00 DSP End Recording: 04:03:30 NOCC monitor data (SCP and SSI) was lost at 02:31:00, but the DSP appeared to be running correctly according to the remote ops system. Therefore, I am unsure if there is data in the TDS for the period 02:31:00 to 02:53:00. If there is no data for this period on the TDS, there may be data in the DSP. There is an opportunity to retransmit the data on June 20th. No spacecraft commands were sent for this test. The uplink was dropped by the station 2 hours before the end of track. The spacecraft then defaulted to one-way referenced to the USO. Ranging was on. Telemetry was on. The typical 650 Hz spurs were present. Station personnel alerted us to the VME bus problem, and they were very cooperative and efficient in bringing the DSP back to an operational state. -Trish --------------------------------------------------------------------- From joe@neptune.Stanford.EDU Mon Jun 16 17:23:54 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 RAA22313 for ; Mon, 16 Jun 1997 17:23:51 -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 RAA15547; Mon, 16 Jun 1997 17:24:02 -0700 (PDT) Received: (from joe@localhost) by neptune.Stanford.EDU (8.8.5/8.8.3) id RAA23160; Mon, 16 Jun 1997 17:23:59 -0700 (PDT) Date: Mon, 16 Jun 1997 17:23:59 -0700 (PDT) From: Joe Twicken Message-Id: <199706170023.RAA23160@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@qmail.jpl.nasa.gov, william.r.adams@ast.lmco.com Subject: USO Test #11 (97/162) Content-Length: 3956 Status: RO I have processed the ODS data from 97/162. This ODS was recorded at DSS 25. The data were acquired as part of USO Test #11. The SNR was approximately 49 dB/Hz during the test. This was the first USO test since 97/092 (USO Test #10), before MGS went into safe mode. All files for processing this ODS were recorded in the MgsDB database. The ODS was acquired at DSS 25 from 02:00:00 to 04:03:30 at 5000 samples per second in mode 2 (1250 12-bit samples/second for each of 4 A/D's). Ranging and telemetry were both on during this time period. In the middle of the test, there was a VME bus error at the DSP which required that the DSP be rebooted. As a result, over 40 minutes of open-loop data were lost, beginning at 02:31:44 and ending at 03:12:30. There were also a number of attenuation changes in the first minutes of the recording. I was unable to successfully query for the ODS. Apparently, the ODS was not stored on the usual Mgs_MASTER_QueryServer (to which we at Stanford do have access) but on the Mgs_GIF1_QueryServer (to which we at Stanford do *not* have access). An ISA has been written regarding this problem. Trish Priest was able to query for the ODS at JPL, and I transfered the data from her by ftp. Of the ODS records which were actually recorded, 10 records were missing in the ODS which I obtained from Trish. I used the spk_c_970321-970727 SP-kernel file to steer the data. This file was created on 97/149. The POCA file was fixed with our "salvagePoca" program, but hand modification of the POCA file was also required. At time tag 13765, it was necessary to modify the ramp rate from -0.06577 Hz/sec to -0.06576 Hz/sec in order to maintain consistency with the remaining POCA readback frequencies. It has also been necessary to make such a 10 microHertz/sec modification to a POCA ramp rate a few times in the past, most recently in USO Test #10. The cause of this 10 microHertz mismatch is not known. Since this error seems to occur with some regularity, I will be modifying the salvagePoca program to automatically fix this type of POCA error. In addition to this POCA error, there was the usual collection of missing/duplicate POCA time tags and incorrect POCA readback frequencies. These were all handled by the salvagePoca program. The power spectra of the USO Test #11 signal exhibited the same frequency spurs which have tracked the carrier throughout most of the USO tests at 650 Hz above and below the carrier frequency. The amplitude of these spurs was approximately 33 dB below that of the carrier. In addition, the spectra exhibited frequency spurs at 180 Hz above and below the carrier frequency and at an amplitude of 42 dB below that of the carrier. This USO test did not feature the carrier amplitude modulations which have characterized most of the USO tests to date. I estimated the USO frequency to be 8423152953.00 Hz. This was within 40 mHz of the frequency which I extrapolated from the best linear fit to all of the previous USO frequency estimates since 96/332. The most recent one of these estimates was made over two months ago. The best linear fit to the USO frequency estimates since 96/332 continues to have a slope of 0.253 Hz/day. It was not possible to make a satisfactory estimate of Allan deviation due to the 10 missing ODS records. I will request a retransmission of the USO Test #11 ODS later this week in order to make clean Allan deviation estimates. The measurements that I was able to make are shown below. These values over estimate the true frequency stability. The SNR during the acquisition of data was approximately 49 dB/Hz. I did not compensate for the spacecraft spin cycle. t (sec) AD ------ ---------- 1.6384 9.3639e-13 (Before DSP reboot) 1.6384 9.5970e-13 (After DSP reboot) 26.2144 1.6309e-13 (Before DSP reboot) 26.2144 2.3724e-13 (After DSP reboot) Joe ---------------------------------------------------------------------- From joe@neptune.Stanford.EDU Wed Jun 25 16:22:21 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 QAA00578 for ; Wed, 25 Jun 1997 16:22:20 -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 QAA05757; Wed, 25 Jun 1997 16:22:43 -0700 (PDT) Received: (from joe@localhost) by neptune.Stanford.EDU (8.8.5/8.8.3) id QAA26836; Wed, 25 Jun 1997 16:22:39 -0700 (PDT) Date: Wed, 25 Jun 1997 16:22:39 -0700 (PDT) From: Joe Twicken Message-Id: <199706252322.QAA26836@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: Retransmission: USO Test #11 (97/162) Content-Length: 2152 Status: RO The ODS from USO Test #11 on 97/162 was retransmitted last week. The ODS was placed on a NERT query server to which we at Stanford do not have access. Trish Priest was able to query for the ODS, and I obtained the file from her by ftp. The DSP failed in the middle of the test and had to be rebooted. Only the ODS data which were acquired after the reboot were retransmitted. I do not know why that was the case. I have analyzed the retransmitted data and estimated USO frequency and Allan deviation. The retransmitted ODS was acquired between 03:12:30 and 04:00:00 on 97/162 at DSS 25. The SNR during this portion of the test was approximately 50 dB/Hz. There were signal dropouts at the beginning of this period and again around 03:27. The Allan deviation estimates were made over the portion of the retransmitted ODS after the signal dropouts. I have modified our "salvagePoca" program since the original USO Test #11 ODS was processed in order to fix POCA files with a 10 microHertz mismatch in readback frequency at the time of a ramp rate change. The modified program was able to automatically fix the POCA file for this test. Last week, the POCA file required hand modification. I estimated the USO frequency to be 8423152950.70 Hz. I incorrectly reported my estimate in my original summary of USO Test #11. The best linear fit to the USO freqeuency estimates since 96/332 now has a slope of 0.245 Hz/day. The Allan deviation estimates follow. Once again, these estimates do not include the early part of the retransmitted ODS where there are a number of signal dropouts. It is difficult to make decent frequency estimates at these times. The SNR during the acquisition of the ODS was approximately 50 dB/Hz. I did not compensate for the spacecraft spin cycle. The Allan deviation in this test was considerably worse than in the tests conducted before the spacecraft went into its safe mode. t (sec) AD ------ ---------- 0.4096 1.1639e-12 1.6384 4.2681e-13 3.2768 2.8415e-13 6.5536 2.0695e-13 26.2144 1.3967e-13 Joe