Mars Express Bistatic Radar Experiment Operations Plan and Report 02 April 2006 Summary ======= DSN Antenna: 63 Pass: 1037 Orbit: 2857 Orbit Start Time: 2006-04-02T12:54:13 HGA Pointing: Inertial Specular Condition (ERT): 18:00 Target Latitude (deg N): -2.46 Longitude (deg E): -157.75 Rp (km): 3395.049 Incidence/Reflection Angle (deg): 31.95 Slant Range (km): 7352 Slew Angle (deg): 116.13 Doppler (carrier, fd; Hz): 18663 Doppler (echo, fr; Hz): -26784 Doppler Difference (fdd; Hz): 45447 Earth-Mars Distance (m): 2.485E11 Experiment Set Up ================= This experiment was conducted using Madrid's DSS 63. The support team at JPL included Danny Kahan, Gene Goltz, and Dick Simpson. Jesse Velasco was in the NOPE area. Danny Kahan monitored the LCP channels. Gene Goltz monitored all four channels, a training exercise in preparation for the experiment on 6 April when Kahan will not be available. this aspect of the experiment appeared to be successful. The MEX MOC briefing message included instructions for both uplink commanding and downlink telemetry. Goltz confirmed with the NOPE and DSS 63 that neither was required; MEX MOC concurred after review. For the first time in approximately a year, the X-RCP FGAIN was set to 60 (reduced from 68, which had been needed at smaller Earth-Mars distances). Performance Problems and Notes ============================== During the pre-cal, X-LCP levels increased by about 1 dB after the noise diode was first turned on; X-LCP remained very stable thereafter. Similarly, S-LCP levels appeared to be about 1 dB low after use of the noise diode in Mini-Cal #2, then about 1 dB higher when the antenna reached zenith. These are puzzling, but probably minor, concerns. The real-time observations were confirmed in the quick-look results; redundancy in the calibration procedure allowed the questionable results to be discounted. A weak echo was observed in real-time only in X-LCP. It lasted 4-5 minutes (centered on approximately 18:00), drifted from about -2500 Hz to about +2500 Hz in the 25 kHz window, and had a bandwidth of about 1500 Hz. In the X-LCP 100 kHz window, the residual carrier was weak but visible throughout; briefly the carrier and echo were visible symmetrically about the center frequency at about +/-22 kHz. If there was interference (from MGS or other sources), it was not apparent in real time. During processing, an interfering signal was seen in X-RCP during 18:05-18:25 and in the central 5 kHz of the bandwidth. Screen dumps of spectra, including sky frequency at both S- and X-Band, were taken during during the BCAL (Earth-point with no modulation) periods and also at about 18:00. The sky frequency data will be used to develop an algorithm for predicting sky frequencies that can be used during the Arecibo support during the 8 April experiment. 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 Kahan (Goltz shadow) RSR1B X-LCP 1-W auto 60 Kahan (Goltz shadow) RSR2A S-RCP 1-W auto 60 Goltz RSR2B X-RCP 1-W auto 60 Goltz RSR subchannels (SCHAN) were defined as follows: Table 2 ---------------------------------------------------------------------- Subchannel Sample Rate Comments ---------- ----------- --------------------------------------------- 1 1 ksps backup (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 and abbreviations are explained after Table 3. Table 3 ----------------------------------------------------------------------------- Step/ RSR1A RSR1B RSR2A RSR2B Time Action S-LCP X-LCP S-RCP X-RCP Ancillary Information ----- -------- ----- ----- ----- ----- ---------------------------------- FRO 0 0 0 0 RSR frequency offset (Hz) ********************************** PRE-CAL ********************************** 14:23 01 -9.9 -10.0 DSS 63 is ready (ADC amp, dB) 10.5 19.5 9.0 17.5 ATT settings after AUTO reset 14:25 02 -10.0 -0.3 -10.0 -0.1 X-Band to AMB (ADC amp, dB) 14:27 03 -0.6 -0.3 -10.0 -0.1 S-LCP to AMB (ADC amp, dB) 14:29 04 -0.6 -0.3 -0.5 -0.1 S-RCP to AMB (ADC amp, dB) 14:30 05 -9.8 -10.2 -9.6 -10.1 ATT AUTO reset (ADC amp, dB) 21.5 31.5 20.5 20.5 ATT settings after reset Ambient load physical temps: S1 = 18.00C S2 = 20.62C X1 = 17.19C Weather conditions: T = 17C H = 45 percent P = 934 mbar sky = partly cloudy 14:37 -9.7 -10.1 -9.6 -10.1 ADC amp (dB) 14:40 06 -9.8 -10.1 -9.5 -9.1 X-RCP ND ON 14:45 07 -9.7 -22.4 -9.6 -15.1 X-Band to sky 14:50 08 -9.8 -22.5 -9.7 -22.3 X-RCP ND OFF 14:55 09 -9.7 -19.2 -9.7 -22.3 X-LCP ND ON; 12.5 ND confirmed 15:00 10 -9.8 -8.8 -9.9 -10.0 X-Band to AMB Ambient load physical temps: S1 = 18.19C S2 = 21.06C X1 = 17.25C 15:05 11 -9.9 -9.0 -9.7 -10.2 X-LCP ND OFF 15:10 12 -9.8 -21.2 -9.6 -22.3 X-Band to sky 15:15 13 -9.9 -21.4 -9.4 -22.3 S-RCP ND ON 15:20 14 -9.9 -21.2 -17.4 -22.3 S-RCP to sky 15:25 15 -9.8 -21.3 -21.4 -22.3 S-RCP ND OFF; 12.5 ND confirmed 15:30 16 -9.4 -21.3 -21.2 -22.3 S-LCP ND ON 15:35 17 -17.0 -21.1 -21.5 -22.3 S-LCP to sky 15:40 18 -21.1 -21.2 -21.5 -22.3 S-LCP ND OFF Ambient load physical temps: S1 = 18.56C S2 = 21.62C X1 = 17.44C 25 kHz recordings continue *************************** BOT, BCAL #1, SLEW #1 *************************** 15:45 DSS 63 moving to point 15:50 DSS 63 on point 16:05 -21.0 -21.2 -21.6 -21.5 BOT (no signal) 16:33 -20.9 -21.2 -21.6 -21.4 AOS; DSS 63 in lock on carrier 45 67 carrier to noise ratio (dB/Hz) Sky frequencies: 2296368507.49 at 16:33:05 8420017928.61 at 16:33:07 16:45 -7000 -7000 FRO_S (Hz) -26000 -26000 FRO_X SCHAN 4 only (Hz) 5848 -2258 5844 Carrier offset in 25 kHz windows 23700 Carrier offset in 100 kHz windows 17:00 -21.0 -21.2 -21.5 -21.4 Begin SLEW #1 (ADC amp, dB) 17:04 31 carrier-to-noise ratio (dB/Hz) -2500 Carrier offset in SCHAN 3 (Hz) 17:05 -46000 -46000 FRO_X SCHAN 3 only (Hz) 17:06 DSS 63 reports LOS ********************************_MINI-CAL #1 ******************************** 17:10 01 -20.9 -21.3 -21.6 -14.9 XR ND ON 17:13 02 -21.0 -21.2 -17.5 -21.5 XR ND OFF, SR ND ON 17:16 03 -21.1 -17.8 -21.6 -21.4 SR ND OFF, XL ND ON 17:19 04 -16.8 -21.1 -21.6 -21.4 XL ND OFF, SL ND ON 17:22 05 -20.9 -21.2 -21.8 -21.6 SL ND OFF ************************************ BSR ************************************ 17:29 End SLEW #1 17:35 -21.0 -21.3 -21.4 17:45 Begin 100 kHz recordings 17:57 22871 Carrier offset in 100 kHz window 16 CNR (dB/Hz) 18:00 -2500 Echo offset in 25 kHz window (Hz) 15 Peak echo SNR (dB/Hz) 1500 Approximate echo bandwidth (Hz) 18:02 Echo, carrier visible in 100 kHz at +/- 22 kHz (X-LCP only) 18:03 0 Echo offset in 25 kHz window (Hz) 18:04 Echo gone (carrier remains) 18:15 End 100 kHz recordings *********************** SLEW #2, MINICAL #2, BCAL #2 ************************ 18:30 -21.0 -21.1 -21.4 -21.1 Begin SLEW #2 back to Earth point 18:35 01 -21.6 -21.0 -21.4 -14.8 X-RCP ND ON 18:38 02 -21.0 -21.1 -17.3 -21.3 X-RCP ND OFF, S-RCP ND ON 18:41 03 -21.5 -17.8 -21.3 -21.1 S-RCP ND OFF, X-LCP ND ON 18:44 04 -17.9 -21.1 -21.4 -21.1 X-LCP ND OFF, S-LCP ND ON 18:47 05 -22.4 -21.1 -21.4 -20.9 S-LCP ND OFF 18:55 0 0 0 0 All FRO's reset to 0 19:00 -1422 -3215 Carrier offset (Hz) 45 67 CNR (dB/Hz) Sky Frequencies: 2296353728.17 at 18:59:53 8419963707.33 at 18:59:53 ********************************* POST-CAL ********************************* 19:10 -21.0 -21.2 -21.5 -22.4 DSS 63 at stow 19:21 01 -9.9 -9.0 -9.6 -10.2 All to AMB Ambient load physical temps: S1 = 18.56C S2 = 21.12C X1 = 17.38C 19:25 02 -9.8 -9.0 -9.5 -9.2 X-RCP ND ON 19:28 03 -9.9 -9.0 -9.3 -10.1 X-RCP ND OFF, S-RCP ND ON 19:31 04 -9.9 -8.6 -9.5 -10.1 S-RCP ND OFF, X-LCP ND ON 19:34 05 -9.4 -9.0 -9.7 -10.1 X-LCP ND OFF, S-LCP ND ON 19:37 06 -17.2 -21.4 -21.3 -22.5 All to sky 19:40 07 -21.1 -18.0 -21.3 -22.4 S-LCP ND OFF, X-LCP ND ON 19:43 08 -21.0 -21.4 -17.3 -22.4 X-LCP ND OFF, S-RCP ND ON 19:46 09 -21.0 -21.4 -21.3 -15.2 S-RCP ND OFF, X-RCP ND ON 19:49 10 -21.1 -21.3 -21.2 -22.4 X-RCP ND OFF 19:55 Stop 25 kHz recordings Ambient load physical temps S1 = 18.31C S2 = 21.00C X1 = 17.12C Weather at DSS 63: T = 15C H = 38 percent P = 934 mb sky = dark (probably clear) End of activity AMB = ambient load BOT = Beginning of Track CNR = Carrier to noise ratio 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 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: 2006-04-02 Notes added from processing: 2006-04-06 Minor edits: 2006-04-12 Updated Summary: 2006-07-05