Mars Express Bistatic Radar Experiment Operations Plan and Report 12 September 2009 Summary ======= DSN Antenna: 14 Pass: 2296 Orbit: 7305 Orbit Start Time: 2009-09-12T10:58:17 HGA Pointing: Specular Start PHX Lander End -------- ---------- -------- Specular Condition (ERT): 13:20 14:14 14:27 Target Latitude (deg N): 56.44 69.10 53.72 Longitude (deg E): 180.01 237.57 258.41 Rp (km): 3394. 3394. 3394. Incidence/Reflection Angle (deg): 80.92 62.18 46.75 Slant Range (km): 8495 2557. 945. Slew Angle (deg): 18.16 57.20 86.50 Doppler (carrier, fd; Hz): 48846. 80756. 67138. Doppler (echo, fr; Hz): 43195. 81924. 82130. Doppler Difference (fdd; Hz): 5651. -1169. -14992. Earth-Mars Distance (m): 2.295E+11 2.295E+11 2.295E+11 Experiment Set Up ================= This experiment was conducted using Goldstone's DSS 14. Danny Kahan and Gene Goltz were in the Radio Science Support Area (RSSA) at JPL. Dick Simpson was available by phone. This report is based on notes provided by Kahan and Goltz. Performance Problems and Notes ============================== No S-RCP signals were observed using the open-loop equipment. However, S-RCP signals did reach the closed-loop receivers, indicating that a cable may have been disconnected. DR-G109690 was opened to document the problem. The same error affected the experiment the next day (day 256). S-LCP data were very noisy; Top was 112K. The problem began with the experiment on 2009/226. In December the problem was traced to a bad board in The Radio Science Receiver; it was replaced, and tests in January confirmed That the problem had been solved. Data Acquisition ================ RSRs were configured as in Table 1. Table 1 ---------------------------------------------------- RSR Channel Mode ATT FGAIN Operator dB ----- ------- ---- ---- ----- ---------------------- RSR3A S-LCP 1-W auto 60 UNK RSR3B X-LCP 1-W auto 60 UNK RSR2A S-RCP 1-W auto 60 UNK RSR2B X-RCP 1-W auto 60 UNK RSR subchannels (SCHAN) were defined as follows: Table 2 ---------------------------------------------------------------------- Subchannel Sample Rate Comments ---------- ----------- --------------------------------------------- 1 2 ksps Occultation bandwidth (not recorded for BSR) 2 8 ksps Occultation backup (not recorded for BSR) 3 25 ksps Primary recording bandwidth 4 100 ksps Backup recording Table 3 lists ADC amplitude levels read from RSR displays during the experiment. Times are in UTC and should be considered approximate. "Steps" are as defined in the briefing message. RSR ATT settings are in units proportional to dB. Acronyms and abbreviations are explained after Table 3. Table 3 ----------------------------------------------------------------------------- Activity Time Step # S-LCP X-LCP S-RCP X-RCP Notes / Comments 2009/255 RSR3A RSR3B RSR2A RSR2B -------- ----- --------- ----- ----- ----- ----- ------------------------ FGAIN 10:15 60 60 60 60 Pre-Cal 10:37 1 -1.8 -22.5 -20.8 -22.9 ADC amplitudes (dB) 10:40 att auto -10.1 -9.9 -20.8 -9.8 Initialize attenuators 10:52 2 -10.2 -0.2 -20.7 -0.0 10:53 3 -3.9 -0.1 -20.8 0.1 10:55 4 -4.1 -0.2 -20.8 0.0 11:07 1 -10.1 -9.9 -20.8 -9.7 Repeat Steps 1-4 because of S-RCP problem 11:09 att auto -10.1 -9.9 -20.8 -9.7 21.0 12.0 0.0 10.0 Attenuator settings (dB) 11:10 2 -10.1 -0.2 -20.8 0.0 11:11 3 -4.3 -0.2 -20.7 -0.0 11:12 4 -4.4 -0.2 -20.7 0.1 11:13 att auto -9.8 -9.9 -20.8 -9.8 26.5 24.0 0.0 22.5 Attenuator settings (dB) AMB load phys temps: S1=17.75 S2=23.12 X1=15.38 Local weather: T=25.0C H=26.5 percent sky=clear 11:14 5 -9.8 -9.9 -20.8 -9.9 11:15 rec 3 e Begin 25 kHz recording 11:20 6 -9.9 -9.8 -20.9 -9.6 11:25 7 -9.8 -22.0 -20.7 -19.9 11:30 8 -9.7 -21.9 -20.8 -22.2 11:35 9 -9.8 -19.7 -20.8 -22.4 Confirmed 12.5K ND 11:40 10 -9.8 -9.6 -20.9 -9.8 AMB load phys temps: S1=17.62 S2=22.94 X1=15.19 11:45 11 -9.9 -9.8 -20.7 -9.8 11:50 12 -9.8 -21.8 -20.8 -19.3 11:55 13 -9.9 -21.8 -20.8 -22.3 12:00 14 -9.9 -21.9 -20.8 -22.3 12:05 15 -9.8 -21.9 -20.8 -22.3 Confirmed 12.5K ND 12:10 16 -9.7 -21.8 -20.9 -22.4 12:15 17 -13.2 -21.8 -20.9 -22.4 12:20 18 -15.8 -21.8 -20.7 -22.3 AMB load phys temps: S1=17.44 S2=22.56 X1=15.06 12:25 end -16.1 -21.8 -20.9 -22.2 Stop 25 kHz recording BOT 12:29 -12.9 -21.6 -20.7 -20.2 Collect TLM until 12:57 12:57 rec 3 e Resume 25 kHz recording 13:02 -11.1 -21.8 -20.8 -20.6 Switch DSS 14 to Mars pointing predicts 13:05 sfro 3/SX +25K +25K +25K +25K MiniCal1 13:05 1 -11.7 -21.8 -20.7 -18.9 Confirmed 12.5K ND 13:08 2 -10.7 -21.8 -20.8 -20.6 13:11 3 -12.0 -19.5 -20.8 -20.6 13:14 4 -11.4 -21.8 -20.9 -20.6 13:17 5 -12.5 -21.7 -20.9 -20.8 13:20 end -12.6 -21.8 -20.9 -20.0 BSR 13:20 sfro 3/SX 0 -7K 0 -7K Rcvr tuning offsets (Hz) Begin 100 kHz recording 14:10 sfro 3/X -2K -2K X-Band tuning offsets 14:18 sfro 3/X +3K +3K 14:22 sfro 3/X +8K +8K end BSR 14:27 sfro 3/SX +25K +25K +25K +25K End 100 kHz recording MiniCal2 14:28 1 -12.3 -21.9 -20.8 -19.3 Confirmed 12.5K ND 14:31 2 -12.4 -22.0 -20.8 -21.3 14:34 3 -10.5 -19.7 -20.8 -21.4 14:37 4 -12.9 -21.8 -20.8 -21.4 14:40 5 -12.4 -21.9 -20.9 -21.2 14:43 end -12.0 -21.8 -20.9 -21.3 14:44 sfro 3/SX 0 0 0 0 Rcvr tuning offsets (Hz) 14:45 -16.0 -21.8 -20.9 -21.2 Switch DSS 14 to s/c pointing predicts EOT 14:55 stow -12.2 -22.0 -20.9 -21.2 PostCal 14:57 1 -9.9 -9.8 -20.8 -9.8 AMB load phys temps: S1=17.12 S2=21.88 X1=14.81 15:03 2 -9.9 -9.9 -20.7 -9.6 15:06 3 -9.8 -9.8 -20.9 -9.9 15:09 4 -9.8 -9.5 -20.8 -9.8 15:12 5 -9.6 -9.7 -20.7 -9.9 15:15 6 -15.3 -21.8 -20.8 -22.4 15:18 7 -16.3 -19.7 -20.8 -22.3 15:21 8 -13.0 -21.8 -20.9 -22.3 15:24 9 -12.0 -22.0 -20.8 -19.9 15:27 10 -14.9 -21.9 -20.7 -22.3 AMB load phys temps: S1=17.19 S2=21.81 X1=24.94 Local weather: T=26.4C H=25.0 percent sky=clear EOA 15:30 end -14.4 -21.9 -20.8 -22.4 End 25 kHz recording AMB = ambient load BOT = Beginning of Track CNR = Carrier to noise ratio CONSCAN = conical scan tracking CW = continuous wave (carrier only) EOA = End of activity EOT = End of Track FRO = frequency offset HGA = high-gain antenna LOS = loss of signal ND = noise diode No = noise power Pc = carrier power rcvr = receiver S1 = ambient load for S-RCP S2 = ambient load for S-LCP s/c = spacecraft SL = S-LCP SNR = Signal to noise ratio SR = S-RCP TLM = telemetry X1 = Ambient load for both X-band channels XL = X-LCP XR = X-RCP Post Analysis Summary The echo started (13:20) on the low side of the carrier, drifted lower, then reversed direction. It crossed the carrier at about 14:12, and accelerated to higher frequencies. X-Band FROs were used at 14:10, 14:18, and 14:22 to keep the echo within the 25 kHz pass band until the end at 14:27. No FROs were used at S-Band or for the 100 kHz recordings. X-Band 10-s Average Data: The table below summarizes the time division for capturing the echo power as the signal drifted through the 25 kHz X-Band receiving pass band. Int Times Spectra Noise Bins Carrier Echo Bins Notes Bins --- ----------------- ------- --------------- ------- ---------------- ------ A 13:20:00-13:50:00 001-180 104:273,671:916 658:668 352:500->267:416 B 13:50:00-14:10:00 181-300 104:247,671:916 658:662 248:406->456:654 BC 14:10:00-14:10:10 301 104:319,671:916 453:457 322:659 [1] C 14:10:10-14:14:00 302-324 104:319,671:916 453:457 322:455->455:588 [2] D 14:14:00-14:18:00 325-348 104:451,745:916 453:457 458:588->585:743 DE 14:18:00-14:18:10 349 104:404,745:916 453:457 406:743 [3,4] E 14:18:10-14:22:00 350-372 104:247,755:916 248:252 380:538->575:753 EF 14:22:00-14:22:10 373 104:247,755:916 N/A 380:753 [5,6] F 14:22:10-14:27:00 374-402 104:397,771:916 N/A 400:558->575:770 [7] Notes: [1] X-Band tuning offset at 14:10 [2] Used carrier suppression to estimate echo power, as echo drifted through frequency of directly propagating signal [3] X-Band tuning offset at 14:18 [4] Used carrier suppression to estimate echo power; tuning offset caused echo to fall accidently onto shifted carrier in the averaged spectrum [5] X-Band tuning offset at 14:22 [6] No carrier detection used because carrier could not be seen [7] Carrier at about bin 44, outside the processing window S-Band 10-s Average Data: The table below summarizes the time division for capturing the echo power as the signal drifted through the 25 kHz S-Band receiving pass band. Int Times Spectra Noise Bins Carrier Echo Bins Notes Bins --- ----------------- ------- --------------- ------- ---------------- ------ A 13:20:00-14:08:00 001-288 104:334,481:916 452:456 338:451 B 14:08:00-14:14:20 289-326 104:376,519:916 452:456 381:451->457:515 [1] C 14:14:20-14:27:00 327-402 104:449,680:916 452:456 457:515->542:676 Notes: [1] Used carrier suppression as the echo drifted through the frequency of the directly propagating signal S-Band 60-s Average Data: The table below summarizes the time division for capturing the echo power as the signal drifted through the 25 kHz S-Band receiving pass band. Int Times Spectra Noise Bins Carrier Echo Bins Notes Bins --- ----------------- ------- --------------- ------- ---------------- ------ A 13:20:00-14:08:00 001-048 104:334,461:916 452:456 338:451 B 14:08:00-14:16:00 049-056 104:376,519:916 452:456 381:451->457:515 [1] C 14:16:00-14:27:00 057-067 104:449,680:916 452:456 457:515->542:676 Notes: [1] Used carrier suppression as the echo drifted through the frequency of the directly propagating signal Dielectric Constant: X-Band dielectric constant is typically 1.6-2.1 throughout the experiment, with slightly higher values in the middle. These are extremely low compared with values measured at other times. There are no S-Band measurements. Dick Simpson Original: 2009-12-02 Added Post Analysis Summary: 2009-12-04 S-LCP noise status updated: 2011-04-26