Mars Express Bistatic Radar Experiment Operations Plan and Report 12 August 2010 Summary ======= DSN Antenna: 63 Orbit: 8460 Orbit Start Time: 2010-08-06T14:25:16 HGA Pointing: Specular Start Mid Point End -------- ---------- -------- Specular Condition (ERT): 16:43 17:01 17:20 Target Latitude (deg N): 17.38 -10.94 8.98 Longitude (deg E): 52.78 133.25 48.19 Rp (km): 3394. 3394. 3394. Incidence/Reflection Angle (deg): 53.09 61.84 56.40 Slant Range (km): 8019. 5008. 6879. Slew Angle (deg): 73.82 56.32 67.19 Doppler (carrier, fd; Hz): -15648. -14766. -14940. Doppler (echo, fr; Hz): 23662. 28833. 27127. Doppler Difference (fdd; Hz): -39309 -43599. -42067. Earth-Mars Distance (m): 3.078E+11 3.078E+11 3.078E+11 Experiment Set Up ================= This experiment was conducted using the Madrid DSS 63. Danny Kahan and Gene Goltz were in the Radio Science Support Area (RSSA) at JPL. This report is largely based on notes provided by Goltz and Kahan. Performance Problems and Notes ============================== The S-RCP maser was not correctly tuned at the beginning of the activity. The problem was recognized when tracking began. Station personnel retuned the maser at approximately 16:15; Goltz and Kahan reset the S-RCP RSR attenuation immediately after. Operations appear to be nominal after that point. The S-RCP pre-cal data are not useful; but everything starting with Mini-Cal #1 should be OK. The problem was documented in DR #M105891. Data Acquisition ================ RSRs were configured as in Table 1. Table 1 ----------------------------------------------------- RSR Channel Mode ATT FGAIN Operator dB ------ ------- ---- ---- ----- ---------------------- WVSR1A S-LCP 1-W auto 60 UNK WVSR1B X-LCP 1-W auto 60 UNK RSR2A S-RCP 1-W auto 60 UNK RSR2B X-RCP 1-W auto 65 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 2010/218 RSR1A RSR1B RSR2A RSR2B -------- ----- --------- ----- ----- ----- ----- ------------------------ Set-Up 13:15 FGAIN 60 60 60 65 FGAIN settings (dB) Pre-Cal 13:39 1 -2.1 -15.2 -12.6 -9.6 Confirm ND disabled 13:50 att auto -9.8 -9.7 -10.5 -10.2 Auto-reset attenuators 17.0 17.5 4.0 26.5 Attenuator settings (dB) 13:52 2 -9.8 -0.4 -10.6 -0.3 ADC amplitudes (dB) 13:53 3 -0.7 -0.3 -10.5 -0.3 13:54 4,5 -0.7 -0.4 -0.8 -0.4 13:55 att auto -9.9 -9.7 -10.2 -3.5 Auto-reset attenuators 28.0 29.0 15.0 31.5 Attenuator settings (dB) Ambient load phys temps: S1=21.00 S2=25.69 X1=16.12 Local weather: T=30.9C H=26.6 percent sky=clear 13:58 rec 3 e Begin 25 kHz recording 13:58 6 -10.1 -9.8 -10.2 -3.5 ADC amplitudes (dB) 14:05 7 -10.0 -9.7 -10.1 -3.4 14:10 8 -9.0 -21.3 -10.2 -12.8 14:15 9 -9.9 -21.3 -10.6 -15.3 14:20 10 -10.0 -19.4 -10.3 -15.2 Confirm 12.5K ND 14:25 11,12 -9.9 -9.5 -10.2 -3.4 Ambient load phys temps: S1=21.12 S2=25.95 X1=16.12 14:30 13 -9.9 -9.7 -10.3 -3.4 14:35 14 -9.9 -21.2 -10.2 -15.2 14:40 15 -9.8 -21.2 -10.0 -15.3 14:45 16 -10.0 -21.2 -19.8 -15.4 14:50 17 -10.0 -21.1 -21.5 -15.2 Failed confirm 12.5K ND 15:00 17 Confirmed 12.5K ND 15:05 18 -9.6 -21.2 -21.5 -15.3 15:10 19 -18.5 -21.2 -21.5 -15.3 15:15 20 -21.2 -21.3 -21.6 -15.3 Ambient load phys temps: S1=21.56 S2=26.44 X1=16.19 15:20 21/end -21.1 -21.3 -21.7 -15.4 Stop 25 kHz recording BOT 15:45 -21.0 -20.9 -21.5 -13.9 Collecting TLM to 16:02 16:03 rec 3 e Resume 25 kHz recording 16:15 31.5 S-RCP maser returned; new attenuator setting 16:18 -20.9 -20.9 -20.3 -13.9 DSS 63 to Mars pointing 16:20 sfro 3/SX +5K +38K +5K +38K Rcvr tuning offset (Hz) sfro 4/X +20K +20K Rcvr tuning offset (Hz) MiniCal1 16:22 1 -20.9 -20.9 -20.4 -12.3 Confirm 12.5K ND 16:25 2 -20.8 -20.9 -18.6 -14.2 16:28 3 -20.9 -19.0 -20.4 -14.3 16:31 4 -18.3 -20.8 -20.4 -14.1 16:34 5 -20.9 -20.8 -20.3 -14.1 16:37 end -20.8 -20.9 -20.4 -14.2 BSR 16:43 rec 4 e -20.9 -20.8 -20.3 -14.1 Begin 100 kHz recording end BSR 17:20 rec 4 d -20.8 -20.8 -20.3 -13.0 End 100 kHz recording MiniCal2 17:23 1 -20.5 -20.7 -20.2 -12.1 Confirm 12.5K ND 17:26 2 -20.5 -20.7 -18.6 -14.0 17:29 3 -20.6 -19.0 -20.2 -13.9 17:32 4 -18.1 -20.7 -20.1 -13.9 17:35 5 -20.6 -20.7 -20.2 -13.9 17:38 end -20.7 -20.7 -20.0 -13.8 17:39 sfro 3/SX 0 0 0 0 Rcvr tuning offset (Hz) DSS 63 to s/c pointing EOT 17:47 stow -20.8 -20.7 -20.1 -13.7 ADC amplitudes (dB) PostCal 17:52 1 -9.9 -9.7 -9.7 -3.4 Ambient load phys temps: S1=21.69 S2=26.81 X1=16.38 17:56 2 -10.0 -9.6 -9.7 -3.3 17:59 3 -9.8 -9.6 -9.5 -3.5 18:02 4 -9.9 -9.4 -9.7 -3.5 18:05 5 -9.5 -9.6 -9.6 -3.3 18:08 6 -18.3 -21.1 -20.3 -15.2 18:11 7 -21.2 -19.3 -20.4 -15.1 18:14 8 -21.1 -21.2 -18.7 -15.2 18:17 9 -21.1 -21.2 -20.4 -12.9 18:20 10 -21.1 -21.1 -20.4 -15.1 Ambient load phys temps: S1=21.44 S2=26.69 X1=16.31 Local weather: T=29.5C H=32.6 percent sky=clear EOA 18:25 11/end -21.0 -21.3 -20.4 -15.2 End 25 kHz recording AMB = ambient load BOT = Beginning of Track BW = bandwidth 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 NOP = Network Operations Plan occn = occukltation 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 X-Band Power: X-Band data were processed to power spectra with 60 second averaging (sums of 1464 individually calculated 1024-point spectra). The 86 minutes of 25 kHz data were divided into 10 time intervals -- four with split echoes (caused by receiver tuning offset changes, FRO) and eight during which the echo drifted within the passband at fixed FRO. The directly propagating carrier did not appear in the 25 kHz passband until the last 14 spectra; except for these 14 spectra, the carrier tracking window was used to find the frequency bin with maximum echo power. Carrier suppression was used to process spectra 80-86 since the returning carrier was between the two components of the surface echo in the first and was within the echo power computation window of the others. Int Times Spectra Noise Bins Echo Echo Bins Notes Peak --- ----------------- ------- --------------- ------- ---------------- ------ A 06:50-07:38 01-48 104:455,785:916 460:780 460:780 B 07:38-07:48 49-58 104:160,785:916 460:780 460:660->164:410 BC 07:48-07:49 59 104:160,765-916 165:760 165:760 [1] C 07:49-07:56 60-66 104:160,720:916 165:715 460:710->164:420 CD 07:56-07:57 67 104:160,765:916 165:760 165:760 [1] D 07:57-08:02 68-72 104:160,720:916 165:715 410:710->164:450 Int Times Spectra Noise Bins Carrier Echo Bins Notes Peak --- ----------------- ------- --------------- ------- ---------------- ------ DE 08:02-08:03 73 104:160,785:916 079:083 164:780 [1,2] E 08:03-08:09 74-79 104:160,740:916 079:083 460:730->164:450 [2] EF 08:09=08:10 80 104:160,700:916 365:369 165:695 [1-3] F 08:10-08:16 81-86 104:250,640:916 365:369 400:630->275:510 [3] Notes: [1] Split echo resulting from change in X-Band receiver tuning offset [2] Carrier at bin 81 [3] Carrier at bin 367 S-Band Power: S-Band data were processed in the same way. The echo signals were weak so two different integrations were used (60 s and 360 s -- first three rows and second three rows, respectively, in the table below). The directly propagating carrier was in frequency bin 246 for the entire observation. Int Times Spectra Noise Bins Carrier Echo Bins Notes Peak --- ----------------- ------- --------------- ------- ---------------- ------ A 06:50-07:38 01-48 250:630,830:916 244:248 635:825 B 07:38-08:08 49-78 104:245,815:916 244:248 640:880->250:400 C 08:08-08:16 79-86 104:240,380:916 244:248 260:360->220:300 [1] A 06:50-07:38 01-08 250:630,830:916 244:248 635:825 B 07:38-08:08 09-13 104:240,780:916 244:248 610:840->250:380 C 08:08-08:14 14 104:240,380:916 244:248 250:350 Notes: [1] Carrier suppression was used to calculate echo power. The carrier Was located. The power in that frequency bin and its two neighbors on either side were set to values interpolated from the neighbors beyond. Dick Simpson Original: 2010-08-16