Mars Express Bistatic Radar Experiment Operations Plan and Report 25 April 2009 Summary ======= DSN Antenna: 63 Pass: 2156 Orbit: 6817 Orbit Start Time: 2009-04-25T06:17:30 HGA Pointing: Specular Start Center End -------- ---------- -------- Specular Condition (ERT): 06:59:00 07:32:00 08:04:00 Target Latitude (deg N): 27.30 32.46 37.47 Longitude (deg E): 49.99 48.15 49.70 Rp (km): 3375. 3375. 3375. Incidence/Reflection Angle (deg): 55.97 60.05 64.73 Slant Range (km): 11482. 11009. 10048. Slew Angle (deg): 68.06 59.90 50.53 Doppler (carrier, fd; Hz): -21762. -18629. -13354. Doppler (echo, fr; Hz): 440. 7188. 13772. Doppler Difference (fdd; Hz): -22202. -25817. -27126. Earth-Mars Distance (m): 3.157E+11 3.157E+11 3.157E+11 Experiment Set Up ================= This experiment was conducted using Madrid's DSS 63. Danny Kahan and Gene Goltz were in the Radio Science Support Area (RSSA) at JPL; Dick Simpson was available by telephone. Performance Problems and Notes ============================== There were concerns about the S-RCP microwave and RSR performance during the ground pre-calibration because of unstable readings of real-time power levels. Goltz and Kahan began parallel recording on VSR equipment as a backup. There was no evidence of problems in the digital data delivered to Stanford later. Similar instabilities were observed in later bistatic radar experiments at DSS 14 -- again, with no evidence of problems in the digital data. DSS 63 was switched from spacecraft pointing to planetary pointing as MEX began its slew to Mars. This improves the measurement of surface echo power; but the difference is minimal at these Earth-Mars ranges (greater than 2 AU). Data Acquisition ================ RSRs were configured as in Table 1. Table 1 ---------------------------------------------------- RSR Channel Mode ATT FGAIN Operator dB ----- ------- ---- ---- ----- ---------------------- RSR1A S-LCP 1-W auto 60 unknown RSR1B X-LCP 1-W auto 60 unknown RSR2A S-RCP 1-W auto 60 unknown RSR2B X-RCP 1-W auto 60 unknown RSR subchannels (SCHAN) were defined as follows: Table 2 ---------------------------------------------------------------------- Subchannel Sample Rate Comments ---------- ----------- --------------------------------------------- 1 2 ksps Recording bandwidth (not recorded) 2 8 ksps backup (not recorded) 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 are defined after the table. Data compiled by Gene Goltz and Danny Kahan. Table 3 ----------------------------------------------------------------------------- Activity Time Step # S-LCP X-LCP S-RCP X-RCP Notes / Comments 2009/109 RSR1A RSR1B RSR2A RSR2B -------- ----- --------- ----- ----- ----- ----- ------------------------ Pre-Cal 03:53 1 -24.1 -14.4 -10.4 -13.5 03:56 att auto -9.6 -9.8 -9.3 -10.0 16.0 14.0 31.5 17.0 Attenuator settings (dB) 03:57 2 -9.6 -0.3 -9.3 -0.3 03:59 3 -0.5 -0.3 -9.3 -0.3 04:01 4 -0.4 -0.3 -0.5 -0.3 Amb load phys temps: S1=15.81 S2=17.19 X1=13.81 04:01 att auto -9.6 -10.0 -0.5 -9.9 Weather: T=10.26C H=63.7 percent Sky=clear 27.0 26.0 31.5 29.0 Attenuator settings (dB) 04:21 rec 3 e Begin 25 kHz recording 04:21 5 -9.5 -10.2 -0.4 -10.0 04:26 6 -9.6 -10.2 -0.5 -9.8 04:31 7 -9.7 -21.8 -0.5 -19.7 04:36 8 -9.7 -21.9 -0.5 -22.1 04:41 9 -9.6 -19.6 -0.6 -22.1 Confirm 12.5 noise diode 04:46 10 -9.7 -10.0 -0.5 -10.1 Amb load phys temps: S1=15.69 S2=16.88 X1=13.38 05:51 11 -9.6 -10.1 -0.5 -9.9 04:56 12 -9.5 -21.9 -0.5 -22.1 05:01 13 -9.6 -21.8 -0.4 -22.1 05:06 14 -9.5 -21.7 -7.3 -22.1 05:11 15 -9.6 -21.9 -9.4 -22.0 Confirm 12.5 noise diode 05:16 16 -9.3 -21.9 -9.3 -22.1 05:21 17 -18.9 -21.8 -9.5 -22.0 AMB load phys temps: S1=16.31 S2=16.75 X1=13.31 05:31 rec 3 d Antenna to s/c point; end 25 kHz recording BOT 05:45 -19.6 -20.2 -8.0 -20.6 06:19 rec 3 e Begin 25 kHz recording 06:30 -20.1 -20.9 -8.6 -20.8 Switch 63 to planetary pointing predicts 06:34 sfro 3/SX 3k 21k 3k 21k Receiver offset (Hz) sfro 4/SX 0 11k 0 11k MiniCal1 06:35 1 -20.2 -20.7 -8.7 -19.1 Confirm 12.5 noise diode 06:38 2 -20.1 -20.8 -6.9 -20.8 06:41 3 -20.2 -18.9 -8.7 -21.0 06:44 4 -18.5 -20.9 -8.8 -20.9 06:47 5 -20.2 -20.9 -8.7 -20.9 06:50 -20.2 -20.9 -8.6 -20.9 BSR 06:57 -20.2 -21.0 -8.8 -21.1 Begin 100 kHz recording 08:04 -20.4 -21.2 -9.1 -21.2 End 100 kHz recording MiniCal2 08:05 1 -20.4 -21.2 -9.0 -19.3 Confirm 12.5 noise diode 08:08 2 -20.3 -21.1 -7.1 -21.3 08:11 3 -20.5 -19.1 -9.0 -21.2 08:14 4 -18.7 -21.3 -9.0 -21.1 08:17 5 -20.3 -21.4 -9.1 -21.2 08:20 -20.3 -21.2 -8.9 -21.2 08:25 sfro 3/SX 0 0 0 0 Receiver offset (Hz) sfro 4/SX 0 0 0 0 Receiver offset (Hz) EOT 08:44 -20.5 -21.5 -9.0 -22.2 Post-Cal 08:49 1 -9.6 -9.9 -0.4 -10.2 AMB load phys temps: S1=15.88 S2=17.12 X1=13.56 08:53 2 -9.5 -10.0 -0.5 -9.7 08:56 3 -9.5 -10.0 -0.4 -10.0 08:59 4 -9.6 -9.8 -0.5 -10.1 09:02 5 -9.2 -10.0 -0.5 -10.0 09:05 6 -18.8 -21.8 -9.3 -22.0 09:08 7 -20.7 -19.5 -9.2 -22.1 09:11 8 -20.8 -21.7 -7.3 -22.0 09:14 9 -20.8 -21.8 -9.3 -19.7 09:17 10 -20.7 -21.9 -9.2 -22.1 AMB load phys temp: S1=15.62 S2=17.12 X1=13.00 Weather: T=12.7C H=50.7 percent sky=partly cloudy EOA 09:20 -20.8 -21.8 -9.3 -22.0 End 25 kHz recordings 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 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 Dick Simpson Original: 2009-08-07