Mars Express Bistatic Radar Experiment Operations Plan and Report 08 May 2010 Summary ======= DSN Antenna: 43 Orbit: 8129 Orbit Start Time: 2010-05-08T03:24:26 HGA Pointing: Specular Start Mid Point End -------- ---------- -------- Specular Condition (ERT): 06:14 06:30 06:44 Target Latitude (deg N): -41.92 -53.63 -57.76 Longitude (deg E): -177.62 58.50 98.89 Rp (km): 3394. 3394. 3394. Incidence/Reflection Angle (deg): 61.04 73.52 89.86 Slant Range (km): 5368. 4284. 3510. Slew Angle (deg): 57.93 32.97 0.28 Doppler (carrier, fd; Hz): -44455. -37236. -17761. Doppler (echo, fr; Hz): 16903. 4489. -17385. Doppler Difference (fdd; Hz): -61357. -41725. -377. Earth-Mars Distance (m): 2.022E+11 2.022E+11 2.022E+11 Experiment Set Up ================= This experiment was conducted using the Canberra DSS 43. Danny Kahan and Gene Goltz were in the Radio Science Support Area (RSSA) at JPL. This report is largely based on notes provided by Kahan and Goltz. > Performance Problems and Notes ============================== A complex-wide failure of the LAN (Local Area Network) at Canberra (DR# C107373) resulted in the station being inaccessible until approximately 06:00 UTC. Due to this problem only steps 1-5 and 14, 16, and 19 of the Pre-Cal procedure were performed. The first Mini-Cal was also skipped. Recording began at 06:00 (25 kHz) and 06:08 (100 kHz). Echoes were seen from about 06:14 to 06:44 -- the last third of the scheduled experiment. The one- way ingress occultation immediately followed the BSR was captured at both S- and X-Band. There was some uncertainty regarding the configuration of the X-band equipment (their ADC amplitudes were nearly the same until Step #2 of the post experiment Mini-Cal). Quick-look processing indicated that both RSRs were capturing X-RCP until MINICAL #2. There were frequent changes to the receiver tuning offsets during the final half hour of observations in the 25 kHz X-Band channels - as often as once every minutes. The intention was to keep the surface echo in the range 4-7 kHz above the center of the window. This appears to have been successful, but the strategy was modified in later experiments to use more of the 25 kHz window and require offset changes no more than once every 3 minutes. Data Acquisition ================ RSRs were configured as in Table 1. Table 1 ------------------------------------------------------- RSR Channel Mode ATT FGAIN Operator Notes dB ----- ------- ---- ---- ----- -------- ---------------- RSR1A S-LCP 1-W auto 60 UNK RSR1B X-RCP 1-W auto 60 UNK Until MINICAL #2 X-LCP 1-w auto 60 UNK After MINICAL #2 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-RCP S-RCP X-RCP Notes / Comments 2010/128 RSR1A RSR1B RSR2A RSR2B -------- ----- --------- ----- ----- ----- ----- ------------------------ Set-Up 01:47 Complex-wide LAN failure 01:53 FGAIN 60 60 60 65 Set FGAIN 04:55 sfro 4/X +35k +35k 100 kHz rcvr offset (Hz) sfro 3/S +9k +9k 25 kHz rcvr offset (Hz) 05:36 sfro 3/X +57k +57k 25 kHz rcvr offset (Hz) Pre-Cal 06:00 1 -1.4 -9.3 -11.9 -10.8 Communications restored 06:01 att auto -10.2 -9.7 -9.8 -9.7 ADC amplitudes (dB) 21.0 16.0 8.5 12.5 Attenuator settings (dB) 06:02 2 -10.2 -0.1 -9.8 -0.0 06:03 3 -2.2 -0.1 -9.8 -0.0 06:05 "4,5" -2.2 -0.1 -0.0 -0.0 rec 3 e Begin 25 kHz recording att auto -9.9 -9.7 -10.0 -9.9 Reset attenuators 29.5 28.5 21.0 25.0 Attenuator settings (dB) Ambient load phys temps: S1=20.31 S2=20.62 X1=16.88 Local weather: T=17.5C H=64.0 percent sky=clear 06:07 14,16,19 -18.8 -22.1 -22.5 -22.3 Uncertainty about X LCP/RCP config. BOT 06:08 -18.8 -22.1 -22.5 -22.3 Begin 100 kHz recording BSR 06:12 sfro 3/X +53k +53k 25 kHz rcvr offset (Hz) 06:18 sfro 3/X +49k +49k 25 kHz rcvr offset (Hz) 06:22 sfro 3/X +45k +45k 25 kHz rcvr offset (Hz) 06:25 sfro 3/X +41k +41k 25 kHz rcvr offset (Hz) 06:27 sfro 3/X +37k +37k 25 kHz rcvr offset (Hz) 06:30 sfro 3/X +33k +33k 25 kHz rcvr offset (Hz) 06:32 sfro 3/X +29k +29k 25 kHz rcvr offset (Hz) 06:34 sfro 3/SX 0 +24k 0 +24k 25 kHz rcvr offset (Hz) 06:36 sfro 3/X +19k +19k 25 kHz rcvr offset (Hz) 06:37 sfro 3/X +16k +16k 25 kHz rcvr offset (Hz) 06:38 sfro 3/X +13k +13k 25 kHz rcvr offset (Hz) 06:39 sfro 3/X +10k +10k 25 kHz rcvr offset (Hz) 06:40 sfro 3/X +7k +7k 25 kHz rcvr offset (Hz) 06:41 sfro 3/X +4k +4k 25 kHz rcvr offset (Hz) 06:42 sfro 3/X +1k +1k 25 kHz rcvr offset (Hz) 06:43 sfro 3/X -2k -2k 25 kHz rcvr offset (Hz) 06:44 rec 4 d -18.8 -19.6 -21.9 -19.6 End 100 kHz recording MiniCal1 06:50 1 -18.7 -15.0 -21.9 -15.0 06:53 2 -18.6 -22.0 -19.5 -19.7 06:57 3 -18.7 -17.5 -22.0 -19.7 07:00 4 -17.6 -22.1 -22.0 -19.8 07:03 5 -18.7 -22.1 -22.0 -19.8 07:06 end -18.7 -22.1 -22.0 -19.8 sfro 3/SX 0 0 0 0 25 kHz rcvr offset (kHz) EOT 07:11 stow -18.8 -23.0 -22.3 -22.4 Post-Cal 07:12 1 -9.9 -10.4 -9.9 -9.9 Ambient load phys temps: S1=20.56 S2=20.81 X1=17.88 07:15 2 -10.1 -10.3 -10.0 -9.2 07:18 3 -10.0 -10.4 -9.7 -9.9 07:21 4 -9.9 -9.8 -10.0 -10.0 07:24 5 -9.8 -10.4 -9.9 -9.9 07:27 6 -17.6 -22.7 -22.4 -22.3 07:30 7 -18.8 -17.6 -22.3 -22.4 07:33 8 -18.9 -22.8 -19.8 -22.4 07:36 9 -18.8 -22.8 -22.3 -15.9 07:39 10 -18.8 -22.8 -22.3 -22.4 Ambient load phys temps: S1=20.62 S2=20.88 X1=18.31 Local weather: T=14.3C H=78.2 percent sky=clear END 07:44 11 -18.9 -22.7 -22.4 -22.4 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 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 None Dick Simpson Original: 2010-05-24 Removed PDS-unfriendly character: 2011-05-18