Mars Express Bistatic Radar Experiment Operations Plan and Report 09 December 2005 Summary ======= DSN Antenna: 14 Pass: 923 Orbit: 2452 Orbit Start Time: HGA Pointing: Inertial Specular Condition: 2005-12-10T06:48:52 ERT Target: (87.65S,54.36W, 3382.5 km) Incidence/Reflection Angle: 72.89 deg Slant Range: 1099 km Slew Angle: 34.21 deg Doppler (carrier, fd): 113406 Hz Doppler (echo, fr): 110518 Hz Doppler Difference (fdd): 2888 Hz Earth-Mars Distance: 9.112E+10 m Experiment Set Up ================= This experiment was conducted using Goldstone's DSS 14. The support team at JPL included Danny Kahan, Gene Goltz, and Jesse Velasco (NOPE). Dick Simpson was present, arriving about halfway through the pre-cal. Performance Problems and Notes ============================== There were some problems in configuring the noise diodes during the pre-cal. Steps 15 and 16 were repeated. Later it appeared that the X-LCP diode was not turned off until the next to last step in MiniCal #1. The BSR interval and after looked OK. Because of an occultation and (brief) eclipse, the spacecraft transmitter was not scheduled to be turned on until nearly an hour and a half after BOT, and after the beginning of Slew #1. In fact, we discovered an S-band carrier as soon as DSS 14 went to point. The X-band transmitter was not turned on until 06:37. Because the S-band transmitter was on for both the ingress and egress occultations, transient near-grazing echoes were observed in association with both. The echoes were weaker after egress because the HGA had already begun Slew #1. Egress was recorded, but ingress was not. Periapsis was about 9 minutes after the targeted specular point, so Doppler spreading was very large. The BSR tuning was set up to accommodate the specular point Doppler trajectory, which would have started a few kHz below the carrier, moved up toward the carrier, then dropped back. In fact, the observed echo entered the 25 kHz passband at the low frequency edge, drifted across, and exited on the high side. The 100 kHz recordings may be useful for characterizing the full frequency behavior of these echoes. RSSG lost connectivity to the RSR's starting with the end of the post- experiment BCAL period. Key displays continued to update for awhile, secondary ones quit almost immediately. In the end, only the power spectrum displays on RSR2 could be monitored. And it was impossible to send new instructions to the RSR's. Attempts to "gconnect" from other terminals failed. 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 Kahan RSR3B X-LCP 1-W auto 60 Kahan RSR2A S-RCP 1-W auto 60 Goltz RSR2B X-RCP 1-W auto 68 Goltz RSR subchannels (SCHAN) were defined as follows: Table 2 --------------------------------------------------------------------- Subchannel Sample Rate Comments ---------- ----------- --------------------------------------------- 1 1 ksps 2 8 ksps 3 25 ksps Primary recording bandwidth 4 100 ksps Backup recording Table 3 lists ADC amplitude levels read from RSR displays during the experiment; these were recorded by Kahan and Goltz and transcribed by Simpson. Times are in UTC and should be considered approximate. "Steps" are as defined in the briefing message. Acronyms and abbreviations are explained after Table 3. Table 3 ----------------------------------------------------------------------------- Step/ RSR3A RSR3B RSR2A RSR2B Time Action S-LCP X-LCP S-RCP X-RCP Ancillary Information ----- -------- ----- ----- ----- ----- ---------------------------------- fgain 60 60 60 68 **********************************_PRE-CAL_********************************** 02:26 01 -10.8 -10.0 -10.2 -9.9 All receivers to sky 02:30 02 -10.5 -0.1 -10.1 -0.1 X-Band to AMB 02:31 03 -1.0 -0.1 -10.2 -0.0 S-LCP to AMB 02:32 04 -1.1 -0.2 -0.5 -0.0 S-RCP to AMB 02:33 22.0 21.0 16.0 23.0 Attenuators after AUTO reset (dB) 02:40 -10.0 -9.9 -9.9 -9.7 ADC amplitudes (dB) Physical AMB temperatures: S1 = 16.12C S2 = 18.12C X1 = 14.75C Weather: T = 6.5C H = 23.2 percent P = 906.8 mbar W = 0 mph sky = partly cloudy 02:40 05 -10.0 -10.0 -9.9 -9.7 All to AMB Start 25 kHz recording 02:45 06 -10.0 -10.0 -9.8 -9.5 X-RCP ND ON 02:50 07 -10.1 -22.2 -9.9 -20.1 X-Band to sky 02:55 08 -10.1 -20.8 -9.9 -22.4 X-RCP ND OFF 03:00 09 -10.0 -10.6 -9.8 -22.5 X-LCP ND ON DSS 14 confirms 12.5 noise diode 03:05 10 -10.1 -10.6 -9.7 -9.8 X-Band to AMB Physical AMB temperatures: S1 = 15.94C S2 = 17.88C X1 = 14.56C 03:10 11 -10.0 -10.7 -9.8 -9.8 X-LCP ND OFF 03:15 12 -10.1 -19.8 -9.9 -22.4 X-Band to sky 03:20 13 -10.0 -19.8 -9.6 -22.4 S-RCP ND ON 03:25 14 -10.0 -19.8 -19.0 -22.4 S-RCP to sky 03:30 15 -10.1 -19.8 -21.3 -22.5 S-RCP ND OFF Station confirms 12.5 noise diode 03:35 16 -10.0 -19.9 -21.5 -22.4 Step 15 not done correctly; S-RCP ND on and off several times 03:45 15 -10.1 -19.8 -21.6 -22.3 Repeat Step 15 03:50 16 -9.7 -19.8 -21.5 -22.3 S-LCP ND ON 03:55 17 -17.5 -19.8 -21.5 -22.4 S-LCP to sky 04:00 18 -20.6 -19.8 -21.6 -22.3 S-LCP ND OFF Physical AMB temperatures: S1 = 15.69C S2 = 17.50C X1 = 14.31C 04:05 -21.7 -22.4 Stop 25 kHz recording ************************************ BOT ************************************ 04:15 DSS 14 on point 05:12 -55.2 Goltz notes S-RCP carrier has been on for the past hour (dB/Hz). 05:15 -55.1 Carrier (dB/Hz) Grazing surface echo: 200 Hz above carrier, 20 dB/Hz. 05:20 Ingress; S-Band gone 05:58 -2500 -8000 -2500 -8000 FRO's entered (Hz) 05:59 Begin 25 kHz RSR recording ********************************_MINI-CAL #1 ******************************** 06:05 -19.8 -21.5 -21.2 ADC amplitude (dB) 06:10 01 -19.9 -19.7 -21.6 -19.1 X-RCP ND ON 06:13 02 -19.9 -19.5 -19.0 -21.1 X-RCP ND OFF; S-RCP ND ON 06:15 29.0 MGS(?) interference (dB/Hz) 5000 Frequency offset from center (Hz) 06:16 03 -20.7 -19.7 -21.5 -21.1 S-RCP ND OFF; X-LCP ND ON (already on?) 06:19 04 -18.7 -21.8 -21.5 -21.1 X-LCP ND OFF; S-LCP ND ON 06:22 05 -19.6 -21.8 -21.5 -20.9 S-LCP ND OFF MGS interference at -12000 Hz ************************************ BSR ************************************ 06:24 Begin Slew #1 06:25 1145 Egress; frequency offset (Hz) 54.0 Carrier level (dB/Hz) 06:30 Weak surf echo -500 Hz wrt carrier Carrier fading 06:34 -20.0 -21.8 -21.5 -21.0 ADC amplitude (dB) 06:35 Interference at 0-3 kHz, moves dwn 06:37 -19.9 -21.8 -21.6 -21.1 X-band TX ON 29.1 22.0 24.0 Carrier (dB/Hz) 06:38 5044 1147 5040 Carrier offset frequency (Hz) Begin 100 kHz recordings 06:42 Interference at 10 kHz moving down 06:44 Interference at -2 kHz moving down 06:45 Echo at -11 kHz moving up 06:49 35 45 35 41 Echo (dB/Hz) 06:51 Echo off edge at +12.5 kHz 06:55 -20.4 -21.7 -21.4 -20.9 ADC amplitude (dB) 4870 1095 4864 Carrier offset (Hz) ***************************** MINICAL #2 AND BCAL *************************** 07:05 01 -20.8 -21.6 -21.6 -19.1 X-RCP ND ON 07:08 02 -20.4 -21.7 -19.0 -20.9 X-RCP ND OFF; S-RCP ND ON Stop 100 kHz recordings 07:09 X-RCP interference at -10 kHz Begin Slew #2 07:11 03 -20.8 -19.7 -21.4 -20.9 S-RCP ND OFF; X-LCP ND ON 07:14 04 -19.0 -21.6 -21.5 -21.1 X-LCP ND OFF; S-LCP ND ON 07:17 05 -20.3 -21.6 -21.4 -20.9 S-LCP ND OFF 07:20 23 38 50 47 Carrier to Noise (dB/Hz) 07:23 19 52 55 76 Carrier to Noise (dB/Hz) End of Slew #2 07:38 53 55 76 Carrier to noise (dB/Hz) 4810 1086 4817 Carrier offset (Hz) 07:45 Goltz and Kahan unable to enter commands on their terminals; RSR data being updated. Both sets of RSR3 windows eventually went away. ********************************* POST-CAL ********************************* 07:49 LOS on S-band 07:55 DSS 14 at zenith 08:04 01 ?? ?? -9.9 -9.8 All to AMB 08:07 02 ?? ?? -9.9 -9.6 X-RCP ND ON 08:10 03 ?? ?? ?? ?? X-RCP ND OFF; S-RCP ND ON RSR2 windows which display ADC amplitudes stop updating. 08:13 04 ?? ?? ?? ?? S-RCP ND OFF; X-LCP ND ON 08:16 05 ?? ?? ?? ?? X-LCP ND OFF; S-LCP ND ON 08:19 06 ?? ?? ?? ?? All to sky 08:22 07 ?? ?? ?? ?? S-LCP ND OFF; X-LCP ND ON 08:25 08 ?? ?? ?? ?? X-LCP ND OFF; S-RCP ND ON 08:28 09 ?? ?? ?? ?? S-RCP ND OFF; X-RCP ND ON 08:31 10 ?? ?? ?? ?? X-RCP ND OFF 08:35 End post-cal, but RSR's continue to run AMB = ambient load BOT = Beginning of Track 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 SR = S-RCP TLM = telemetry X1 = Ambient load for both X-band channels XL = X-LCP XR = X-RCP Dick Simpson Added acronyms: 2006-01-12