Mars Express Bistatic Radar Experiment Operations Plan and Report 27 August 2005 Summary ======= DSN Antenna: 14 Pass: 0818 Orbit: 2078 Orbit Start Time: 2005-08-27T11:07:23 SCET HGA Pointing: Inertial Specular Condition: 2005-08-27T13:10:30 ERT Target: (87.39S, 33.20E; Rp = 3382.5 km) Incidence/Reflection Angle: 74.96 deg Slant Range: 7975 km Slew Angle: 34.19 deg Doppler (carrier, fd): 55663 Hz Doppler (echo, fr): 47830 Hz Doppler Difference (fdd): 7833 Hz Earth-Mars Distance: 1.026E11 m Experiment Set Up ================= This experiment was conducted using Goldstone's DSS 14. The support team at JPL included Gene Goltz, Danny Kahan, and Dick Simpson. In the NOPE area was Jesse Velasco. Performance Problems ==================== As was the case on the previous day, there were bad interactions between the X- LCP noise diode and its ambient load. When the diode was on and the ambient load was added, the noise power went to the expected level but then dropped about 1 dB after 30-60 seconds. The next directive was to turn the noise diode off; but that had little or no effect on the noise power. When the ambient load was removed, the noise power dropped below the expected sky level for a few seconds; but then the noise diode turned itself back on. We experimented and found this pattern to be reproducible. We also made sure the noise diode was turned off before completing the pre-cal. The problem was documented as DR G105992 on the previous day. Also as on the previous day the S-LCP channel seemed less stable than the other three in the sense that ADC amplitudes jumped around when constant levels were expected and it was harder to detect changes in noise diode status. Whether coincidence or not, this instability was only noticed after the X-band noise diode problems began. Data Acquisition ================ The set up period began at 09:00. DSS 14 announced that it was ready to begin the pre-calibrations about 15 minutes later. Except for the X-LCP noise diode problem and the S-LCP stability problem noted above, the pre-calibration was nominal. RSRs were configured as in Table 1: Table 1 --------------------------------------------- RSR Channel Mode ATT FGAIN Operator dB ----- ------- ---- ---- ----- --------------- RSR3A S-LCP 1-W auto 60 Kahan RSR3B X-LCP 1-W auto 60 Kahan RSR1A S-RCP 1-W auto 65 Goltz RSR1B X-RCP 1-W auto 60 Goltz RSR subchannels (SCHAN) were defined as follows: Table 2 --------------------------------------------------------------------- Subchannel Sample Rate Comments ---------- ----------- --------------------------------------------- 1 1 ksps 2 8 ksps 3 25 ksps Primary recording bandwidth 4 100 ksps Backup recording Table 3 lists ADC amplitude levels read from RSR displays during the experiment. Where available, signal-to-noise ratios, frequency offsets, and other measurements are also listed. Times are in UTC read from a wall clock and may not reflect actual times when configurations changed. "Steps" are as defined in the briefing message. Acronyms and abbreviations are explained after Table 3. Table 3 ------------------------------------------------------------------------------ TIME (ERT) RSR3A RSR3B RSR1A RSR1B COMMENTS 2005-08-26 S-LCP X-LCP S-RCP X-RCP ADC ADC ADC ADC (dB) (dB) (dB) (dB) ---------- ------ ------ ------ ------ --------------------------------------- End-to-End Configuration Check 09:22 DSS 14 reports Pre-Cal Step 01 complete Reset all RSR ATTEN using AUTO feature 11.0 8.5 4.5 12.5 ATTEN settings -9.3 -10.0 -10.5 -10.2 ADC amplitudes (all to sky) (dB) 09:25 -9.6 -0.3 -10.5 -0.1 Step 02: X-band to AMB load 09:27 -0.9 -0.2 -10.4 -0.2 Step 03: S-LCP to AMB load 09:29 -0.9 -0.3 -0.6 -0.1 Step 04: S-RCP to AMB load Pre-Calibration 09:29 Ambient load temperatures: S1 = 18.31C S2 = 24.12C X1 = 15.38C Weather conditions: T = 24.4C P = 903.7 mbar H = 23.3% Sky clear, winds calm 09:30 Reset all ATTEN using auto feature 21.5 20.5 15.5 25.0 ATTEN settings 09:35:01 All RSR's recording 25 kHz 09:35 -9.8 -10.1 -9.8 -10.2 Step 05: Configure ND controllers 09:40 -9.9 -10.0 -9.8 -10.1 Step 06: XR ND on 09:45 -9.8 -22.2 -9.9 -20.3 Step 07: X-band to sky 09:50 -9.8 -22.2 -9.9 -22.7 Step 08: XR ND off 09:55 -9.7 -19.9 -9.9 -22.8 Step 09: XL ND on DSS 14 confirms 12.5K ND selected 10:00 -9.8 -10.7 -9.9 -10.2 Step 10: X-band to AMB (XL is too low) Ambient load temperatures: S1 = 18.12C S2 = 23.69C X1 = 15.19C 10:05 -9.8 -10.8 -9.9 -10.2 Step 11: XL ND off (no change in XL) 10:10 -9.8 -23.4 -10.0 -22.7 Step 12: X-band to sky (XL is too low) 10:12 -9.8 -19.9 -9.9 -22.8 XL ND spontaneously on; level OK? 10:15 DC02 SNT E syntax error at DSS 14 10:15:20 -9.7 -19.8 -9.7 -22.7 Step 13: SR ND on 10:20 -9.8 -20.0 -19.0 -22.8 Step 14: SR to sky 10:25 -9.8 -19.9 -21.5 -22.8 Step 15: SR ND off DSS 14 confirms 12.5 ND selected 10:30 -9.7 -19.8 -21.5 -22.7 Step 16: SL ND on 10:35 -18.4 -20.0 -21.6 -22.8 Step 17: SL to sky 10:40 -19.8 -19.9 -21.5 -22.8 Step 18: SL ND off Ambient load temperatures: S1 = 17.88C S2 = 23.19C X1 = 14.94C 10:45 -20.1 -19.9 Repeat Step 08: Configure ND controller 10:46 -18.4 to -22.2 -21.5 -22.7 Repeat Step 11: XL ND off; SL unstable -20.4 10:50 -20.4 -19.8 -21.5 -22.7 Repeat Step 09: XL ND on 10:55 -20.1 -9.9 -21.6 -10.1 Repeat Step 10: X-band to AMB 10:56 -19.7 -10.7 -21.6 -10.2 XL dropped 0.8 dB 11:00 -19.7 -10.8 -21.4 -10.1 Repeat Step 11: XL ND off 11:05 -19.9 -23.4 -21.5 -22.7 Repeat Step 12: X-band to sky 11:06 -20.1 -19.9 -21.5 -23.0 XL ND turned itself back on; levels OK? 11:10 -20.3 -22.1 -21.4 -22.7 Repeat Step 11: XL ND off 11:15 -19.2 -22.2 -21.6 -22.7 Repeat Step 13: Reconfigure ND controller Spacecraft Calibration (BCAL) and Slew #1 11:24 DSS 14 is on point 11:52 -1100 S-band AOS (Hz) 11:53 -2500 -7200 -2500 -7200 Entered FRO values (Hz) 11:54 -19.5 -21.8 -21.5 -22.4 ADC amplitudes 1401 1400 Carrier frequency (Hz) 29 54 Carrier to noise ratio (dB) 11:55 DSS 14 reports breaker on subreflector has tripped; technician going to reset 11:58 -20.2 -21.9 -21.5 -20.7 ADC amplitudes (dB) 1391 5134 1389 5121 Carrier frequency 28 31 54 75 Carrier to noise ratio (dB) 12:00 24 68 C/No after TLM on (dB) 12:41 -20.2 -21.9 -21.6 -20.6 ADC amplitudes (dB) 1164 4302 1161 4290 Carrier frequency (Hz) 27 42 54 76 C/No (dB/Hz) Mini-Cal #1 12:42:23 Begin Slew #1 12:43 -19.1 -22.0 -21.4 -22.4 ADC amplitudes (dB) 12:44 -19.5 -21.8 -21.6 -20.6 Step 01: XR ND on 12:46 Slew echo in all channels 12:47 -18.5 -21.9 -19.0 -22.5 Step 02: XR ND off, SR ND on 12:49 Intermittent X-RCP echoes 12:50 -18.4 -19.7 -21.4 -22.4 Step 03: SR ND off, XL ND on 12:53 -17.6 -21.9 -21.4 -22.4 Step 04: XL ND off, SL ND on 4181 1129 4188 Carrier frequency (Hz) 19 36 Carrier to noise (dB/Hz) 12:56 -19.5 -21.9 -21.5 -22.3 Step 05: SL ND off Bistatic Radar Activities 12:56 Begin RSR SCHAN=4 recording (100 kHz) 12:59 Weak SR, XR echoes 13:03 -19.4 -22.0 -21.5 -22.2 ADC amplitudes -1616 Echo frequency (Hz) 23 Echo amplitude (dB/Hz) 4120 Carrier frequency (Hz) 36 Carrier to noise (dB/Hz) 13:03 Double peaked XR echo; separation ~700 Hz 13:09 -20.1 -21.9 -21.5 -22.1 ADC amplitude (dB) -1731 -6271 -1711 -6259 Echo frequency (Hz) 20 23 29 41 Echo peak (dB/Hz) 13:11 31 47 Echo peak (dB/Hz) 13:12 33 Echo peak (dB/Hz) 13:18 gone gone 25 faint Echo peak (dB/Hz) 13:21 Stop 100 kHz recording (SCHAN=4) XR, SR echoes intermittent 13:25 -16.7 -21.9 -21.5 -22.2 ADC amplitudes (dB) 4080 Carrier frequency (Hz) 37 Carrier to noise ratio (dB/Hz) Mini-Cal #2 and Slew #2 13:30 -18.2 -22.0 -21.4 -20.0 Step 01: XR ND on 13:33 -18.6 -21.9 -19.0 -22.2 Step 02: XR ND off, SR ND on 13:36 -18.6 -19.7 -21.4 -22.2 Step 03: SR ND off, XL ND on 13:39 -16.6 -21.9 -21.4 -22.1 Step 04: XL ND off, SL ND on 13:40:54 Begin Slew #2 13:42 -18.0 -21.9 -21.4 -22.2 Step 05: SL ND off S-RCP carrier visible 13:49 -19.5 -21.8 -21.4 -20.4 Slew complete Post-Calibration 14:20 DSS 14 going to zenith 14:25 -9.9 -10.0 -9.9 -10.1 Step 01: All channels to AMB at zenith Ambient load temperatures: S1 = 18.25C S2 = 22.38C X1 = 15.88C Weather conditions: T = 23.6C P = 904.7 mbar H = 25.0% Sky clear, winds calm 14:30 -9.8 -10.1 -9.7 -10.1 Step 02: XR ND on 14:33 -9.9 -10.0 -9.5 -10.1 Step 03: XR ND off, SR ND on 14:36 -9.7 -9.9 -9.7 -10.2 Step 04: SR ND off, XL ND on 14:39 -9.6 -10.0 -9.9 -10.1 Step 05: XL ND off, SL ND on 14:42 -17.6 -22.2 -21.4 -22.9 Step 06: All to sky 14:45 -19.8 -20.0 -21.3 -22.7 Step 07: SL ND off, XL ND on 14:48 -20.5 -22.3 -19.1 -22.8 Step 08: XL ND off, SR ND on 14:51 -19.7 -22.2 -21.5 -20.3 Step 09: SR ND off, XR ND on 14:54 -20.0 -22.3 -21.5 -22.8 Step 10: XR ND off Ambient load temperatures: S1 = 19.05C S2 = 22.44C X1 = 16.69C Weather conditions: T = 24.8C P = 904.9 mbar H = 24.2% Sky clear, winds calm 15:00 End of track Stop RSR recording (SCHAN=3) AMB = ambient load BOT = Beginning of Track CONSCAN = conical scan tracking CW = continuous wave (carrier only) EOT = End of Track FRO = frequency offset HGA = high-gain antenna LOS = loss of signal ND = noise diode No = noise power Pc = carrier power S1 = ambient load for S-RCP S2 = ambient load for S-LCP SL = S-LCP SR = S-RCP TLM = telemetry X1 = Ambient load for both X-band channels XL = X-LCP XR = X-RCP Dick Simpson Original: 2005-08-27 Minor edits: 2005-08-28 Added Rp: 2005-11-26