PDS_VERSION = PDS3 RECORD_TYPE = STREAM OBJECT = TEXT PUBLICATION_DATE = 1997-10-29 NOTE = "MGS RST Instrument Health Report HEA7302A.TXT" END_OBJECT = TEXT END Engineering Data ================ Engineering Data Statistical Summary from CSV2STAT: First SCET: 1997-10-28T00:00:03.162 Last SCET: 1997-10-28T23:59:59.780 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 1506 F-0195 HGA_EL_ANG 0 0 0.00E+00 0.00E+00 0.00E+00/0.00E+00 1506 L-0034 MOT1_RANGING 0 0 24093 L-0036 MOT1_TLM_MOD 0 0 24093 L-0037 MOT1_USO_ENA 0 0 24093 L-0044 MOT2_RANGING 1 1 24093 L-0046 MOT2_TLM_MOD 1 1 24093 L-0047 MOT2_USO_ENA 1 1 24093 L-0053 RF_SW_OSC 2 2 24093 L-0060 TWTA1_FILMNT 0 0 24093 L-0061 TWTA1_HV 0 0 41993 L-0070 TWTA2_FILMNT 0 1 41993 L-0071 TWTA2_HV 0 0 24093 L-0080 USO_PWR 0 0 24093 L-0090 KaBLE_STAT 1 1 24093 L-0091 KaBLE_ENABLE 0 0 41993 L-0111 MOT1_RCV_AGC 255 255 -1.53E+02 -1.53E+02 -1.53E+02/0.00E+00 12046 L-0121 MOT2_RCV_AGC 159 255 -1.53E+02 -1.26E+02 -1.36E+02/8.60E-02 12046 L-0131 TWTA1_HLX_I 0 1 -3.84E-02 -1.85E-02 -3.83E-02/8.55E-06 12046 L-0132 TWTA1_ANOD_V 0 2 -1.00E+03 -1.00E+03 -1.00E+03/3.06E-03 12046 L-0141 TWTA2_HLX_I 38 43 7.05E-01 8.05E-01 7.67E-01/1.31E-04 12046 L-0142 TWTA2_ANOD_V 60 65 -8.68E+02 -8.58E+02 -8.62E+02/1.27E-02 12046 L-0200 USO_REG_V 203 205 4.06E+00 4.10E+00 4.08E+00/7.54E-05 12046 L-0201 USO_OVEN_V 123 126 2.46E+00 2.52E+00 2.49E+00/9.65E-05 12046 T-0302 EPC1_T 115 121 2.72E+01 2.98E+01 2.81E+01/7.67E-03 3011 T-0303 EPC2_T 103 109 3.24E+01 3.50E+01 3.33E+01/7.23E-03 3011 T-0310 RF_ISOLTR1_T 174 181 2.79E+01 3.03E+01 2.88E+01/2.90E-03 12046 T-0311 RF_ISOLTR2_T 166 172 3.10E+01 3.31E+01 3.17E+01/3.07E-03 12046 T-0312 TWT1_T 174 180 2.82E+01 3.03E+01 2.90E+01/6.91E-03 3011 T-0313 TWT2_T 159 166 3.31E+01 3.56E+01 3.41E+01/7.52E-03 3011 T-0315 USO_T 174 177 1.09E+01 1.18E+01 1.13E+01/3.15E-03 3011 T-0316 KA_AMP_T 146 155 3.71E+01 4.05E+01 3.87E+01/7.51E-03 6024 L-0200, L-0201, and T-0315 are nominal. Open Loop Data ============== Data Acquisition ---------------- We transfered four segments of open-loop data from the NERT cache. The first and second bracketed P27 on LGT1; the DSP had to be rebooted, and the periapsis point itself was lost. The third was an ad hoc HGA opportunity. The fourth covered P28. Missing records on the first segment probably came from the DSP malfunction; the other three segments had no missing records. YYYY/DDD DSS QUERY SAMP BW DSP BIT TRK REC RECS RECS MAX START STOP RATE MODE RESN MODE LEN MSSG SNR -------- --- -------- -------- ---- ---- ---- ---- ---- ---- ----- ---- ----- 1997/297 15 21:00:10 21:13:22 5000 2500 2 12 1-W 1666 3454 507 21. 1997/297 15 21:43:51 22:20:52 5000 2500 2 12 1-W 1666 11106 0 36. 1997/299 45 05:31:26 06:27:34 5000 2500 2 12 1-W 1666 16843 0 38. 1997/299 45 08:20:00 09:45:00 5000 2500 2 12 1-W 1666 25501 0 21. Analysis -------- Joe Twicken has completed his analysis of LGT1 open-loop data from the periapsis passes on 97/296 and 97/300 The signal-to-noise ratio in an equivalent 1 Hz bandwidth was about 21 dB when LGT1 was pointed toward Earth. The SNR decreased quickly as the spacecraft attitude was changed in preparation for periapsis. He has correlated signal strength with boresight angle to Earth. A slightly edited version of his report follows. His plot of the antenna pattern is included here as Figure HEA7302A.PS1. The half- power half-beamwidth quoted in the MGS Telecummunications System Operations Reference Handbook is +/-40 deg at the transmit frequency 8.4 GHz. I have estimated the MGS LGA antenna pattern using the ODR data from 97/296 and 97/300. I used SP- and C-kernels to determine the off-boresight angle during the times that the open-loop data were acquired. I assumed that the LGA boresight is aligned with the +X direction in the spacecraft coordinate system. After filtering and steering the open-loop data, I estimated the carrier power for the duration of the two data sets at a rate of once per 6.5 seconds. During the periods when the LGA was moving off-Earth and then on-Earth, I eye-balled a smooth fit through the carrier power estimates. That is a very subjective procedure. I determined the carrier power every 0.005 hours (18 seconds) from the smooth fits and also determined the LGA off-boresight angles at the same instants. The antenna pattern is plotted relative to a maximum of 0 dB. I have shown the individual estimates of the pattern. There were two sets of estimates from each recording: one when the LGA moved off-Earth and one when the LGA moved back on-Earth. The character of the pattern when the LGA was moving back on-Earth was somewhat different than when it was moving off-Earth. This is likely due to differing slices through the actual 2-D antenna pattern. The difference when the LGA was moving back on-Earth is a slight dip (up to 1 dB) in the radiated power when the off-boresight angle was between about 15 and 35 degrees. The half power (-3 dB) point appears to be between 45 and 50 degrees and the -6 dB point is at about 62-63 degrees. Closed Loop Data ================ Note for Data Collectors ------------------------ Data volume on magellan:/users/z00 was almost at capacity yesterday. We have since split off the TDF directory, which is now lodged on /users/z10. There is a link from /users/z00/TDF to the new location, so you may not notice any problems in going to the new directory. You will not, however, be able to return to /users/z00 with the simple Unix command "cd .."; you must now type the full path name. We apologize for any inconvenience, but a link at the directory level involves far less maintenance on our part than setting up links for individual files. In the not-too-distant future we expect to be splitting off other large-volume directories. And within the next two months we expect to have to split the TDF directory itself into at least two parts. The TDF split will likely be done on simple time boundary grounds; but, if you have requests or suggestions, send them to rsimpson@magellan.stanford.edu. Data Collection --------------- We have obtained the following files from OSCAR and EPIC: Original File Name Name on SOPC ------------------------------ ------------ ODF: 97300_DSS15.SJO;1 7300300C.ODF 97301O302.DAT;1 7301302A.ODF 97302O1150.DAT;1 7302302A.ODF EOP: 971028-eop.long 20207336.EOP 971028-eop.short 63367336.EOP Ancillary Data ============== Data Collection --------------- We have obtained the following files from the CDB and other sources: Original File Name Name on SOPC ------------------------------ ------------ OPT: optg_i_971027_OD030_040_V1 7300317A.OPT SAK: mgs_solar_array_1997-301.ck 7301301A.SAK SPK: spk_i_971027_OD030_040_V1 7300317A.SPK SPK: spk_i_971030-971116_Reset08_V2 7294323B.SPK TCK: mgs_spice_c_kernel_1997-301.ck 7301301A.TCK Figure Captions =============== HEA7302A.PS1: Normalized measured LGT1 radiation pattern from open-loop data collected during MGS periapsis passes P26 and P29. Figures ======= Plot(s) illustrate some of the points made in the text. Each plot is a PostScript file, created and printable on our SOPC. For report text file HEAydddC.TXT Figure N will be labeled HEAydddC.PSN and sent as the N+1st e-mail message of a set. We assume that you can strip off the e-mail headers and either display or print copies of the figures on a machine in your area. People who have indicated that they cannot handle these files by e-mail are not included in the e-mail distribution of figures.