PDS_VERSION_ID = PDS3 RECORD_TYPE = STREAM OBJECT = TEXT PUBLICATION_DATE = 2001-03-28 NOTE = "MGS RST Instrument Health Report HEA1087A.TXT" END_OBJECT = TEXT END Miscellaneous ============= Sami Asmar was able to track down some additional information about the off-nadir minimum-fuel-use test conducted several days ago (see HEA1085A.TXT). An animation of this mode (and others) can be found at http://mars.jpl.nasa.gov/mgs/movpics/anim/anim.html Frank Lemoine wanted to know the times of off-nadir operation so he could flag those when he did his orbit solutions. Times were: Command Action YYYY/DDD ERT SCET ------- ------------------------------ -------- ------------ ------------ SAGCSA Begin off-nadir 2001/082 17:03:27.882 16:55:19.051 SAGSCH Resume normal attitude control 2001/083 02:23:11.045 02:15:04.046 Sami also passed along some correspondence from Pat Esposito and Dong Shin indicating that integration/averaging times for ranging data collection should be changed. Details are given under "Closed Loop Data - Analysis" below. The Project has requested input from gravity investigators in helping to solve the ranging problems. MCR 734 was approved by the MCCB on Thursday, March 22, subject to verification that the requested periods are not coincident with ROTOs of MER sites. The amount of time allocated for egress occultation coverage may be reduced so as not to impact ROTOs in the adjacent sequences. If recommended days are utilized there is minimum impact to the MDAP team. However, if time needs to be negotiated, there will be an impact to M01 activities and Genesis launch planning activities because of limited workforce within the team. April observations -- DOY 095/0105 through DOY 097/0105 -- have already been built into the sequence. May observations -- DOY 131/2355 through DOY 133/2355 -- are pending additional checks with MOC for ROTO conflicts. Sami notes that delivery of the RSR is scheduled for 15 April and that MGS use of the RSR in parallel with the DSP can begin as early as 16 April. The two can run in parallel until July, when the current occultation season ends. It would then be convenient to phase out the DSP, declaring the RSR to be the sole data acquisition system for open loop data before occultations resume late this year. The following information regarding extended extended mission operations comes from Frank Palluconi by way of Sami Asmar: In the last several weeks some new ideas for the operation MGS which would influence any extended extended mission have been developed at the initiation of the Project Manager Tom Thorpe. The first idea relates to a test conducted last week to determine if there is a mode of operation which would reduce the current use of attitude control fuel below the current 36 grams of hydrazine per day. The test was very successful and the projected fuel use in this mode is 15 grams/day with improvements to perhaps 10 grams/day possible. This mode involves pitching the spacecraft 22 degrees off nadir. During this test all instruments were operated. If we began using this mode at the end of June 2001 when the current beta supplement period ends and if the average fuel use was 15 grams/day or better we could continue MGS operations through the end of the Mars Exploration Rover (MER) missions in the spring of 2004. A second idea which is being explored is to devise a means of conducting roll only observations (ROTOs) on orbits with communications contacts as well as the current practice of scheduling ROTOs only on orbits with no scheduled communications. If this is possible, it will make ROTO planning easier and increase opportunities for ROTO coverage. Next Tuesday at the 08:00 AM Mission Planning meeting the MGS science teams will have an opportunity to discuss the impact of last week's pitch over test on their data collection. Using the pitch over mode appears to be the best solution to meeting the requirement imposed on MGS to support the descent and landing of both MERs in early 2004. Plans for the support MGS is to provide to MER will be reviewed by the Mars Exploration Program at a review to be held on 1 May 2001. However, having a physically feasible plan to support MER after the completion of the current MGS extended mission is not the same as having funding to support operation of the science instruments, data analysis and archiving during this extended extended mission time period. To acquire the funds necessary will require that we make an excellent case for the value of the scientific return for this period. The Mars Program is now supporting many missions in various stages (MGS, Odyssey, '05 Mars Reconnaissance Orbiter, '07 Lander, '07 Scout and instruments and collaborations with non-US Mars missions). As a result funds are tight and a scientific MGS extended extend mission is not assured. Engineering Data ================ Engineering Data Statistical Summary from CSV2STAT: First SCET: 2001-03-26T00:00:01.023 Last SCET: 2001-03-26T23:59:57.011 CHANNL CHANNEL TITLE DN-LO DN-HI EU-LO EU-HI EU-AVG/STDEV RECDS ------ ------------- ----- ----- --------- --------- ---------/-------- ----- F-0190 HGA_AZ_ANG 6424 12679 1.57E+00 3.10E+00 2.88E+00/1.06E-02 2076 F-0195 HGA_EL_ANG -11233 11089 -2.74E+00 2.71E+00 -6.29E-01/3.90E-02 2076 L-0034 MOT1_RANGING 0 0 4152 L-0036 MOT1_TLM_MOD 0 0 4157 L-0037 MOT1_USO_ENA 0 0 4152 L-0044 MOT2_RANGING 1 1 4152 L-0046 MOT2_TLM_MOD 0 1 4157 L-0047 MOT2_USO_ENA 1 1 4152 L-0053 RF_SW_OSC 2 2 4157 L-0060 TWTA1_FILMNT 0 0 4152 L-0061 TWTA1_HV 0 0 4153 L-0070 TWTA2_FILMNT 0 1 4153 L-0071 TWTA2_HV 0 1 4152 L-0080 USO_PWR 0 0 4152 L-0090 KaBLE_STAT 0 0 4152 L-0091 KaBLE_ENABLE 1 1 4153 L-0111 MOT1_RCV_AGC 255 255 -1.53E+02 -1.53E+02 -1.53E+02/2.87E-07 4152 L-0121 MOT2_RCV_AGC 138 255 -1.53E+02 -1.18E+02 -1.45E+02/2.05E-01 4152 L-0131 TWTA1_HLX_I 0 1 -3.84E-02 -1.85E-02 -3.82E-02/2.43E-05 4152 L-0132 TWTA1_ANOD_V 0 1 -1.00E+03 -1.00E+03 -1.00E+03/1.56E-02 519 L-0141 TWTA2_HLX_I 18 42 3.06E-01 7.85E-01 4.96E-01/3.05E-03 4152 L-0142 TWTA2_ANOD_V 61 229 -8.66E+02 -5.30E+02 -6.58E+02/6.99E+00 519 L-0200 USO_REG_V 203 205 4.06E+00 4.10E+00 4.08E+00/2.79E-04 521 L-0201 USO_OVEN_V 129 131 2.58E+00 2.62E+00 2.60E+00/1.96E-04 521 T-0302 EPC1_T 188 197 -4.65E+00 -7.38E-01 -2.73E+00/3.56E-02 519 T-0303 EPC2_T 182 192 -2.43E+00 1.71E+00 -7.20E-01/5.58E-02 519 T-0310 RF_ISOLTR1_T 229 233 -6.05E+00 -1.15E+00 -3.45E+00/9.18E-03 4157 T-0311 RF_ISOLTR2_T 225 233 -6.05E+00 3.13E+00 -1.13E+00/2.86E-02 4157 T-0312 TWT1_T 228 232 -4.77E+00 -2.48E-02 -2.64E+00/3.71E-02 519 T-0313 TWT2_T 219 233 -6.05E+00 8.56E+00 1.29E-01/1.98E-01 519 T-0315 USO_T 137 140 2.17E+01 2.26E+01 2.23E+01/8.37E-03 519 T-0316 KA_AMP_T 215 219 8.56E+00 1.16E+01 9.88E+00/2.86E-02 518 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 -------- --- -------- -------- ---- ---- ---- ---- ---- ----- ---- ----- 2001/087 65 02:44:00 02:51:00 5000 2000 2 12 1666 2101 0 54.7 2001/087 65 04:42:00 04:49:00 5000 2000 2 12 1666 2101 0 55.3 2001/087 15 10:35:00 10:42:00 5000 2000 2 12 1666 2101 0 54.6 2001/087 15 12:33:00 12:40:00 5000 2000 2 12 1666 2101 0 55.0 2001/087 15 14:31:00 14:38:00 5000 2000 2 12 1666 2101 0 54.5 Anomalies --------- Occultations 9174i-9176i (DSS 45, start times 2001/086-16:56:00 through 20:51:00) were lost apparently because the workers at SPC 40 were on strike. At the request of Jesse Glance, we submitted ISA Z71267. Data from occultation 9182i (DSS 15, start time 2001/087-12:33:00) have +/-0.3 dB fluctuations in carrier power level. Closed Loop Data ================ Data Collection --------------- We have obtained the following files from OSCAR and EPIC: Original File Name Name on SOPC -------------------------------- ------------ ODF: 01085O086_10S.SJO;1 1085086A.ODF TROPCAL: ATC01MAR.CSP;8 1060088A.TRO EOP: 010327-eop.long 20201169.EOP EOP: 010327-eop.short 01691169.EOP Analysis -------- The following request was submitted by Pat Esposito regarding acquisition of MGS range data. Ricardo Torres indicates that the changes will go into effect with SOE mm127a.04.tsoe on 2001/091-01:15:00 at DSS 65. Pat's request is followed by two e-mails to Pat from Dong Shin. ------------------------------------------------------ E-mail from Pat Esposito: Please update ASAP the MGS sequence and DKF file to revise the MGS SRA range integration or averaging times (or range parameters) as follows: T1, sec from 80 to 62 T2, sec from 10 to 3 The range components should remain as is for now This change is being made based on a trial usage of these new times via OPD-MGS-051 (dated 3/20/01) and current range acquisition, analysis, and results (presented at today's radiometric data problem review meeting by E. Graat; A. Kwok leader). In addition to maintaining the range quality, this update shall allow more range measurements and help Dong Shin investigate current MGS range acquisition anomalies. ------------------------------------------------------ Memo 1 from Dong Shin: As we discussed, T1/T2 times may be too long (80 and 10 seconds) to compensate for the phase shift. The SRA measures the range by correlating the downlink range data from the uplink reference data it generated. It requires to know the Doppler shift to correlate each component correctly. If T1/T2 is too long, then the phase error begins to accumulate and the range measurement becomes invalid when the chop is enabled. We'd like to reduce T1 to 62 seconds and T2 to 3 seconds, which will provide 1-meter noise in 1-way, 99.999% of probability of acquisition success (I used 8 dB of Pr/No. see 810-5, paragraph 2.3.4.2), and 1:45 of cycle time. As a test pass, we'd like to try next 3 passes to analyze the impact. The bad data I have analyzed so far shows that it started with valid data (first, second, or third point) and then becomes invalid. I can not say 100%, but some errors may be accumulated and then the data become invalid. ------------------------------------------------------ Memo 2 from Dong Shin: I analyzed the March 21 DSS-45 data with reduced T1 and T2 times and compared to navigation's plot. There are 3 sets of data: 1st set contains 12 points. Navigation's plot indicates first 7 points are normal, next point is off by ~600000 RU, and then next 4 points are biased by -15000 RU. Pr/No is ranged from 6.3 to 15 dB Hz. 8th point (1st bad point with ~600000 RU off) has the lowest Pr/No (6.3 dB Hz). The LMC log indicates one "correlation error" at 15:29:36, which should affect 6th point (not 7th). 6th point is normal. 2nd set contains 13 points. Navigation's plot indicates first 12 points is normal and last point is off by ~400000 RU. Last point has a duplicated time-tag range data, which indicates that the operator canceled the acquisition when the S/C entered the occultation. Therefore, last point is normal. 3rd set contains 13 points. Navigation's plot indicates first 12 points are normal and last point is unusable. Last point also has a duplicated time-tag range data, which indicates that the operator canceled the acquisition when the S/C entered the occultation. Therefore, last point is normal. 2 out 3 sets are normal. Improvement with reduced T1 and T2? So far, the data becomes unusable after the bad/biased data due to either a correlation error (not in this case) or low Pr/No (in this case). Any suggestion? I'll be looking at another set of data (March 20 DSS-45) right before new T1 and T2. Ancillary Data ============== Data Collection --------------- We have obtained the following files from the FIS: Original File Name Name on SOPC -------------------------------- ------------ OPT: optg_m_010318_OD9066-9150_rec_V1 1077084A.OPT SAK: mgs_solar_array_2001-085.ck 1085085A.SAK SPK: spk_m_010318_OD9066-9150_rec_V1 1077084A.SPK TCK: mgs_spice_c_kernel_2001-085.ck 1085085A.TCK SOE: mm127a.04.tsoe 1091095C.SOE SOE: mm128a.01.tsoe 1094098A.SOE SOE: mm129a.01.tsoe 1098102A.SOE We have obtained the following files from NAIF and/or IPNG: Original File Name Name on SOPC -------------------------------- ------------ AGK: mgs_hga_ck_2001-03-18.bc 1077077A.AGK