PDS_VERSION = PDS3 RECORD_TYPE = STREAM OBJECT = TEXT PUBLICATION_DATE = 1998-04-09 NOTE = "MGS RST Instrument Health Report HEA8099A.TXT" END_OBJECT = TEXT END Errata ====== The following files in yesterday's Health report (HEA8098A.TXT) are duplicates: amdgen.98-096.out 8092092B.AMD spk_i_990119-990125_AB2IntE 9019025B.SPK They were removed from our database. Miscellaneous ============= The query for DSN Monitor data ended with a read error at last time tag 17:37:30. The spacecraft engineering query ended gracefully (no error messages) at time tag 17:11:05. But we observed two occultations AFTER these times, so some data were not returned by the queries. An ISA is being prepared. Dave Hinson has completed analysis of Occultation #101 using the reconstructed orbit provided by Frank Lemoine. He says there was "No sign in the data of any problem with the orbit solution. The results are far better than when we used the Nav Team's orbit predictions, which is all that was available until now for this orbit." The Stanford Near-Real Time Operations Team (Simpson, Hinson, Twicken, Toumpis, and Bauregger) met yesterday to discuss continuing problems with Radio Science data. It is worth noting that the spacecraft does not appear to be contributing to ANY of the problems; so far as we can tell, they are all on the ground. The list, and current status, includes: Loss of synchronization between POCA and data samples (the "sawtooth" problem): A sawtooth has been found in about 10 percent of occultations; there is no apparent preference for antenna or SPC. Presence of a sawtooth makes the data unsuitable for further processing. Low signal levels at SPC 60: Carrier-to-noise levels are typically 4-6 dB lower during occultations observed from SPC 60 compared with SPC 10 and 60. There has NEVER been an occultation with "normal" levels at SPC 60; all antennas at 60 are affected, though there is some variation among antennas and from day to day. Reduced signal levels translate to larger uncertainties in the corresponding atmospheric profile. Varous POCA problems at SPC 60 over the past two weeks: POCA time tags out of order, POCA errors so numerous that Stanford software cannot repair them automatically, and one case in which the POCA appears to have failed completely during an occultation. We have lost two occultations in the past two weeks to POCA problems at SPC 60. SPK reconstructions and accuracy: Since the beginning of SPO, NAV is reconstructing only one of four orbits during the work week and only one of six on weekends. The orbits between are not of sufficient accuracy to allow extraction of good atmospheric profiles. And, even on reconstructed orbits, the accuracy near periapsis times (egress occultations) has been troubling. The Smith group at Goddard has made some of their orbit reconstructions available, and these are being tested. Results so far appear promising (see above) and may provide an alternative to NAV solutions. Amplitude baseline variability: The pre-occultation signal level is used to determine the precise time of occultation. When the signal power is reduced to 25 percent of its free space value, the ray path is assumed tangent to the planet surface -- yielding the "occultation radius". Prior to some occultations the signal level is very stable; during others it varies by as much as 1 dB. The time scales of the variation can be anywhere from many minutes to a few seconds. There is probably more than one cause. Baseline variability translates to greater uncertainty in occultation radius and to somewhat greater uncertainty in atmospheric profiles. Engineering Data ================ Engineering Data Statistical Summary from CSV2STAT: First SCET: 1998-04-08T00:54:09.118 Last SCET: 1998-04-08T17:11:04.612 CHANNL CHANNEL TITLE DN-LO DN-HI EU-LO EU-HI EU-AVG/STDEV RECDS ------ ------------- ----- ----- --------- --------- ---------/-------- ----- F-0190 HGA_AZ_ANG 0 0 0.00E+00 0.00E+00 0.00E+00/0.00E+00 786 F-0195 HGA_EL_ANG 0 0 0.00E+00 0.00E+00 0.00E+00/0.00E+00 786 L-0034 MOT1_RANGING 0 0 10433 L-0036 MOT1_TLM_MOD 0 0 10433 L-0037 MOT1_USO_ENA 0 1 10433 L-0044 MOT2_RANGING 0 1 10433 L-0046 MOT2_TLM_MOD 0 1 10433 L-0047 MOT2_USO_ENA 0 1 10433 L-0053 RF_SW_OSC 1 2 10433 L-0060 TWTA1_FILMNT 0 1 10433 L-0061 TWTA1_HV 0 1 10433 L-0070 TWTA2_FILMNT 1 1 10433 L-0071 TWTA2_HV 0 1 10433 L-0080 USO_PWR 0 0 10433 L-0090 KaBLE_STAT 1 1 10433 L-0091 KaBLE_ENABLE 0 0 10433 L-0111 MOT1_RCV_AGC 255 255 -1.53E+02 -1.53E+02 -1.53E+02/8.15E-07 5368 L-0121 MOT2_RCV_AGC 167 255 -1.53E+02 -1.29E+02 -1.36E+02/9.62E-02 5368 L-0131 TWTA1_HLX_I 0 36 -3.84E-02 6.76E-01 -1.48E-02/1.66E-03 5368 L-0132 TWTA1_ANOD_V 0 244 -1.00E+03 -5.17E+02 -1.00E+03/1.58E-01 5103 L-0141 TWTA2_HLX_I 18 43 3.06E-01 8.05E-01 7.47E-01/1.32E-03 5368 L-0142 TWTA2_ANOD_V 62 240 -8.64E+02 -5.08E+02 -8.58E+02/4.03E-01 5103 L-0200 USO_REG_V 203 205 4.06E+00 4.10E+00 4.08E+00/1.12E-04 5103 L-0201 USO_OVEN_V 123 127 2.46E+00 2.54E+00 2.50E+00/8.42E-05 5103 T-0302 EPC1_T 117 129 2.37E+01 2.90E+01 2.61E+01/3.49E-02 1305 T-0303 EPC2_T 103 124 2.59E+01 3.50E+01 3.21E+01/3.66E-02 1305 T-0310 RF_ISOLTR1_T 170 185 2.64E+01 3.17E+01 2.80E+01/1.49E-02 5368 T-0311 RF_ISOLTR2_T 168 192 2.38E+01 3.24E+01 2.99E+01/2.20E-02 5368 T-0312 TWT1_T 162 188 2.53E+01 3.45E+01 2.81E+01/3.22E-02 1305 T-0313 TWT2_T 161 196 2.21E+01 3.49E+01 3.23E+01/5.17E-02 1305 T-0315 USO_T 167 175 1.15E+01 1.39E+01 1.24E+01/1.72E-02 1305 T-0316 KA_AMP_T 146 164 3.38E+01 4.05E+01 3.74E+01/1.88E-02 2571 L-0200, L-0201, and T-0315 are nominal. Open Loop Data ============== Data Collection --------------- We have transferred the following open loop data to Stanford: YYYY/DDD DSS DSP SAMP BW DSP BIT REC RECS RECS MAX START STOP RATE MODE RESN LEN MSSG SNR -------- --- -------- -------- ---- ---- ---- ---- ---- ----- ---- ----- 1998/098 65 17:35:00 17:48:00 5000 2000 2 12 1666 3901 0 43.5 1998/099 34 05:11:35 05:23:00 5000 2000 2 12 1666 3426 0 47.0 1998/099 34 05:52:00 06:31:00 5000 2000 2 12 1666 11701 0 10.9 Anomalies --------- Data from the ingress occultation (starting 1998/098-17:35:00, Occ #123i; DSS 65) were retransmitted and are included in the list of new open loop files above. There were six POCA time tag errors in the file. Trish Priest passed along a report of "heavy rain" at DSS 34 during the occultations on 1998/099. Data from the ingress occultation look good, with a stable pre-occultation amplitude baseline. The noise level during the egress occultation rose about 4 dB, which would be consistent with increasing rain. Closed Loop Data ================ Data Collection --------------- We have obtained the following files from OSCAR and EPIC: Original File Name Name on SOPC ------------------------------ ------------ ODF: 98098O099.DAT;1 8098099A.ODF 98098O099_10S.SJO;1 8098099B.ODF Ancillary Data ============== Data Collection --------------- We have obtained the following files from the CDB: Original File Name Name on SOPC ------------------------------ ------------ SAK: mgs_solar_array_1998-098.ck 8098098A.SAK TCK: mgs_spice_c_kernel_1998-098.ck 8098098A.TCK