PDS_VERSION_ID = PDS3 RECORD_TYPE = STREAM OBJECT = TEXT PUBLICATION_DATE = 2007-07-27 NOTE = " E-mail and other messages concerning MGS Radio Science on or about 1998/176." END_OBJECT = TEXT END From trish@rodan.jpl.nasa.gov Thu Jun 18 16:17:39 1998 Received: from rodan.jpl.nasa.gov (rodan.jpl.nasa.gov [137.78.177.110]) by magellan.Stanford.EDU (8.8.5/8.8.3) with ESMTP id QAA14488 for ; Thu, 18 Jun 1998 16:17:38 -0700 (PDT) Received: from 137.78.177.117 (trish-mac.jpl.nasa.gov [137.78.177.117]) by rodan.jpl.nasa.gov (8.8.5/8.8.5) with SMTP id QAA05680; Thu, 18 Jun 1998 16:17:36 -0700 (PDT) Message-Id: <199806182317.QAA05680@rodan.jpl.nasa.gov> Date: 18 Jun 98 16:24:10 -0700 From: Trish Priest Subject: Two-way Gravity MCR To: Bill Sjogren , David Smith , Len Tyler , Maria Zuber CC: Richard Simpson X-Mailer: QuickMail Pro 1.0.2d1 X-Priority: 3 Reply-To: Trish Priest Content-Type: text/plain; charset="iso-8859-1" Content-Length: 623 Status: RO Hello, The MCR to request two-way gravity for the week of June 25th will be at 10 AM (PST) tomorrow (Friday) in 264-231. The 3-4544 Meet Me number will be used. Looking at the current data, Bill says that the two-way data would be nice, but if it is difficult or problematic to implement two-way, it shouldn't be pushed too hard. Collection of two-way data will have to be implemented with hand-edits to the DSN Keyword File, which is basically the script for the DSN tracking pass. Making sure that the station has clear instructions on how to handle the uplink and downlink is the main concern. -Trish ---------------------------------------------------------------------------- From trish@rodan.jpl.nasa.gov Fri Jun 19 10:51:57 1998 Received: from rodan.jpl.nasa.gov (rodan.jpl.nasa.gov [137.78.177.110]) by magellan.Stanford.EDU (8.8.5/8.8.3) with ESMTP id KAA04955 for ; Fri, 19 Jun 1998 10:51:57 -0700 (PDT) Received: from 137.78.177.117 (trish-mac.jpl.nasa.gov [137.78.177.117]) by rodan.jpl.nasa.gov (8.8.5/8.8.5) with SMTP id KAA07944; Fri, 19 Jun 1998 10:51:52 -0700 (PDT) Message-Id: <199806191751.KAA07944@rodan.jpl.nasa.gov> Date: 19 Jun 98 10:58:28 -0700 From: Trish Priest Subject: Two-way Approved To: Sami Asmar , Georges Balmino , Paula Eshe , Pat Esposito , Frank Lemoine , Richard Simpson , Bill Sjogren , David Smith , Len Tyler , "Dah-Ning Yuan" , Maria Zuber X-Mailer: QuickMail Pro 1.0.2d1 X-Priority: 3 Reply-To: Trish Priest Content-Type: text/plain; charset="iso-8859-1" Content-Length: 154 Status: RO Hello, Two-way LGA gravity data will be collected for six periapsis passes between June 25th and July 1st. The change request was approved. -Trish ---------------------------------------------------------------------------------- From trish@rodan.jpl.nasa.gov Thu Jun 25 03:34:12 1998 Received: from rodan.jpl.nasa.gov (rodan.jpl.nasa.gov [137.78.177.110]) by magellan.Stanford.EDU (8.8.5/8.8.3) with ESMTP id DAA28878 for ; Thu, 25 Jun 1998 03:34:11 -0700 (PDT) Received: from 137.78.177.117 (trish-mac.jpl.nasa.gov [137.78.177.117]) by rodan.jpl.nasa.gov (8.8.5/8.8.5) with SMTP id DAA24534; Thu, 25 Jun 1998 03:33:41 -0700 (PDT) Message-Id: <199806251033.DAA24534@rodan.jpl.nasa.gov> Date: 25 Jun 98 03:40:31 -0700 From: Trish Priest Subject: Periapsis 387 Gravity To: Sami Asmar , Georges Balmino , Paula Eshe , Pat Esposito , Frank Lemoine , Richard Simpson , Bill Sjogren , David Smith , Len Tyler , "Dah-Ning Yuan" , Maria Zuber CC: Bill Adams , Joe Beerer , Jesse Glance , Angus McMechen , Frank Palluconi , 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: 983 Status: R Hello, Periapsis 387 occurred at DSS 65. This was to be the first two-way pass. I wish that I could say it went smoothly, but it did not. The spacecraft must have lost lock on the uplink. The station could not lock up on the two-way signal. I happend to have the DSP in the link, so I verified that there was a one-way signal. I informed the station that the spacecraft was one-way; they locked up the receivers and collected one-way closed-loop data through periapsis. This periapsis begins the last gravity-only (no MOLA slant) week in SPO-2. Times of interest (all UTC ERT): 176-09:04:13 switch to LGA 176-09:14:50 ISH - begin slew to NADIR 176-09:36:40 receivers in lock on LGA signal one-way(approximate) 176-09:46:50 Periapsis 387 176-09:58:52 ISH - begin rollout 176-10:03:00 receiver out of lock before this time 176-10:18:52 ANS 176-10:30:43 switch back to HGA The next gravity pass is Periapsis 389 (approximately 177-09:02 UTC ERT). -Trish ----------------------------------------------------------------------------- From william.r.adams@lmco.com Thu Jun 25 09:34:53 1998 Content-return: allowed Date: Thu, 25 Jun 1998 10:12:41 -0600 From: "Adams, William R" Subject: RE: Periapsis 387 Gravity To: Sami Asmar , Georges Balmino , Paula Eshe , Pat Esposito , Frank Lemoine , Richard Simpson , Bill Sjogren , David Smith , Len Tyler , Dah-Ning Yuan , Maria Zuber , "'Trish Priest'" Cc: "Beerer, Joseph G" , Jesse Glance , "McMechen, Angus M" , "Palluconi, Frank D" , "Recce, David J" , "Thorpe, Tom E" , "'Kennedy, Mike'" , "'Sax, Eugene'" MIME-version: 1.0 Trish and all, I have done some preliminary querying of this pass. Though we had been getting both of the spacecraft receivers in lock for two days, this pass started with DSS 65 ONLY acquiring MOT 2 (HGA path) at approximately 0500 UTC. Spacecraft telemetry shows that MOT 1 did not track the uplink sweep because there is no decay evident in the SPE voltage. However, there is not data in the database until 06:00 which is 15 minutes after the transition to two-way is supposed to have started on the ground. After periapsis BOTH receivers were in lock. Now, after an LGA pass, MOT 1 is warmer, and its best lock frequency is closer to the average BLF currently being used in uplink predicts, but the uplink sweep is plenty wide enough to get both receivers in lock at all the temperatures we've been seeing in the current profile. Also, as I said, it has been working for two days, before after and during LGA periapsis passes (two of them). The only reason those passes weren't two-way is that the SOE had the stations turn their transmitters off before the pass. I think the most likely cause of this is either: 1) DSS 65 used incorrect sweep parameters, perhaps from a previous spacecraft pass. or 2) MOT 1 for some reason immediately dropped the uplink after acquiring it, before it could be tuned off of its BLF by the uplink sweep. Note this is not likely if DSS 65 was sweeping at the right rate and through the right range, but "glitches" do happen. --------------------------------------------------------------------------------- From trish@rodan.jpl.nasa.gov Thu Jun 25 21:09:15 1998 Received: from rodan.jpl.nasa.gov (rodan.jpl.nasa.gov [137.78.177.110]) by magellan.Stanford.EDU (8.8.5/8.8.3) with ESMTP id VAA07713 for ; Thu, 25 Jun 1998 21:09:14 -0700 (PDT) Received: from 137.78.177.117 (trish-mac.jpl.nasa.gov [137.78.177.117]) by rodan.jpl.nasa.gov (8.8.5/8.8.5) with SMTP id VAA26159; Thu, 25 Jun 1998 21:09:13 -0700 (PDT) Message-Id: <199806260409.VAA26159@rodan.jpl.nasa.gov> Date: 25 Jun 98 21:16:06 -0700 From: Trish Priest Subject: Test data To: Richard Simpson , Joe Twicken CC: Salvadore Abbate , Sami Asmar X-Mailer: QuickMail Pro 1.0.2d1 X-Priority: 3 Reply-To: Trish Priest Content-Type: text/plain; charset="iso-8859-1" Content-Length: 1050 Status: RO Hello, Sal and I collected some test data at SPC 60 yesterday. There are four ten-minute segments. These are from DSS 65. 1. 176-06:50:00 to 176-07:00:00 5000 sps 12-bit Filter 3 with a signal (2-way, HGA, TLM on) 2. 176-07:05:00 to 176-07:15:00 5000 sps 12-bit Filter 3 without a signal (-5000 Hz FRO) 3. 176-07:35:00 to 176-07:45:00 200 sps 12-bit Filter 1 without a signal (-5000 Hz FRO) 4. 176-06:50:00 to 176-07:00:00 200 sps 12-bit Filter 1 with a signal (2-way, HGA, TLM on) I have already done TOT queries, and the data are there. The plan was to collect some data from DSS 45 today with the same configurations and compare signal levels. Unfortunately, SOHO has a spacecraft emergency, and they are using the DSP. We have more time tonight at SPC 60 and tomorrow at SPC 10. There is even some overlap between those passes. Assuming that we can get the DSP, we will collect some more data. I also have screen dumps of the reported Block-V signal level and of the SSI. -Trish ---------------------------------------------------------------------------------- From rsimpson Fri Jun 26 20:15:55 1998 Received: (from rsimpson@localhost) by magellan.Stanford.EDU (8.8.5/8.8.3) id UAA27951; Fri, 26 Jun 1998 20:15:54 -0700 (PDT) Date: Fri, 26 Jun 1998 20:15:54 -0700 (PDT) From: Dick Simpson 723-3525 Message-Id: <199806270315.UAA27951@magellan.Stanford.EDU> To: joe@neptune.Stanford.EDU, rsimpson@magellan.stanford.edu, trish@rodan.jpl.nasa.gov Subject: Re: Test data Cc: Salvatore.F.Abbate@jpl.nasa.gov, Sami.W.Asmar@jpl.nasa.gov Content-Length: 435 Status: R We see SNR of 36.3 from Test #1. I shot in the dark on Test #4 and came up with 5 minutes of data (07:55-08:00). The calculated SNR is 26.8 dB, but the signal is drifting fairly rapidly in the 100 Hz bandwidth, so some of the difference may be due to that. As predicted, there is no signal in Test #2 or Test #3. The filter is noticeably flatter at 100 Hz than at 2500 Hz, but I've not tried to estimate the ripple in either case. To: rsimpson@airmail.fltops.jpl.nasa.gov Subject: Re: ODS Input for Daily Health Report Cc: data Open Loop Data ============== Data Collection --------------- Tests were conducted at SPC 60 on 1998/176 in an attempt to learn more about the 3-6 dB loss in SNR that we have reported consistently during occultations since January. Four test files were created; details are tabulated below. The first and last tests included an MGS signal with TLM one; the spacecraft was on the HGA and two-way. The second and third tests had no spacecraft signal. YYYY/DDD DSS DSP SAMP BW DSP BIT REC RECS RECS MAX START STOP RATE MODE RESN LEN MSSG SNR -------- --- -------- -------- ---- ---- ---- ---- ---- ----- ---- ----- 1998/176 65 06:50:00 07:00:00 5000 2000 2 12 1666 3000 0 36.3 1998/176 65 07:05:00 07:15:00 5000 2000 2 12 1666 3001 0 -- 1998/176 65 07:35:00 07:45:00 200 100 1 12 466 2401 0 -- 1998/176 65 07:55:00 08:05:00 200 100 1 12 466 2401 0 32.7 -------------------------------------------------------------------------- From trish@rodan.jpl.nasa.gov Sat Jun 27 13:23:00 1998 Date: 27 Jun 98 13:29:44 -0700 From: Trish Priest Subject: RE: Re: Test data To: "Dick Simpson 723-3525" X-Priority: 3 Oops. That's what I get for using cut and paste. The times for set 4 are 176-07:55:00 to 08:05:00. Also, there is an attenuation change in the middle of that one. -Trish -------------------------------------------------------------------------- From trish@rodan.jpl.nasa.gov Sat Jun 27 13:25:47 1998 Date: 27 Jun 98 13:32:43 -0700 From: Trish Priest Subject: RE: Re: Test data To: joe , rsimpson CC: "Salvatore.F.Abbate" , "Sami.W.Asmar" X-Priority: 3 For Test #1, the Block-V receiver reported a Pc/No of 36.8 dBHz. -Trish