Mars Express Bistatic Radar Experiment Operations Plan and Report 21 April 2006 Summary ======= DSN Antenna: 43 Pass: 1056 Orbit: 2923 Orbit Start Time: 2006-04-21T00:22:28 HGA Pointing: Inertial Specular Condition (ERT): 05:50 Target Latitude (deg N): -1.96 Longitude (deg E): -162.70 Rp (km): 3392.979 Incidence/Reflection Angle (deg): 38.04 Slant Range (km): 8535 Slew Angle (deg): 103.99 Doppler (carrier, fd; Hz): 15056 Doppler (echo, fr; Hz): -20319 Doppler Difference (fdd; Hz): 35375 Earth-Mars Distance (m): 2.740E+11 Experiment Set Up ================= This experiment was conducted using the Canberra 70-m antenna, the first BSR activity at DSS 43 since July 2005. The RSSG support team included Danny Kahan, Gene Goltz, Roberto Aguilar, and Dick Simpson; Don Fleischman was also in the area. Jesse Velasco was the NOPE. Goltz operated all of the RSR's from a single console. Kahan handled communications. Performance Problems and Notes ============================== After the July 2005 BSR, the DSS 43 switches and cabling were changed. It was apparent by Step-03 of the pre-cal that the briefing message, which had been based on the old assignments, was not working. Both S-Band RSR's were receiving the same signal (probably S-RCP). Later, the station reported that it was having problems connecting the closed loop receivers (needed to control the noise diodes). Later still (at Step-08 in the pre-cal procedure), it was clear that both X-Band signals were the same. Maintenance personnel were called and, together with operators and the NOPE, were able to sort out the configuration issues. According to Velasco, the commands to connect the S-Band closed loop receiver to ports "O5" and "O6" should have referred to "O1" and "O2" instead. The correction for X-Band (if any) was less clear. And the reasons for duplicate signals on orthogonal polarizations was never really discussed. Velasco said he would review the situation with JPL operations personnel the next day and distributed a corrected briefing message before the experiment on 2006/113. During the course of the pre-cal, there appeared to be several steps in which noise diodes were erroneously left enabled. These were cleared during the first MiniCal, though why these commands worked and the earlier ones didn't is not known. During the second MiniCal, the X-RCP noise diode appeared to come on at one level, then its power increased when RSSG asked for confirmation that the 12.5K noise diode had been selected. No echoes were seen in real time. Weak residual carriers were visible in 8 kHz spectra (not recorded). There is evidence for a weak X-LCP echo signal in the quick-look sample power versus time plot. 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 Goltz RSR1B X-LCP 1-W auto 60 Goltz 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 ********************************** 03:03 AMB physical temps: S1=18.19 S2=19.56 X1=21.31 Weather conditions: T=11C H=34 percent sky=clear Begin 25 kHz recording, but data not useful until 03:44 03:43 ATT 21.5 27.0 12.5 25.0 Attenuator auto reset 03:50 05 -9.8 -9.9 -10.1 -9.8 Configure DTT's for ND control 03:51 06 -9.8 -8.9 -10.0 -9.1 XR ND ON 03:54 07 -9.9 -15.9 -9.9 -16.0 X-Band to sky; XL ND is on? 04:00 08 -9.9 -22.4 -9.9 -23.7 XR ND off (also XL?) 04:27 09 -9.9 -18.6 -10.0 -15.8 XL ND ON (XR ND also went on!) 04:28 10 -10.0 -11.0 -10.0 -15.8 X-Band to AMB (XR followed later) AMB physical temps: S1=19.81 S2=20.25 X1=21.12 04:29 11 -9.8 -11.4 -10.0 -9.0 XL ND OFF 04:31 12 -9.8 -23.7 -10.0 -15.7 X-Band to sky (XR ND still on?) 04:33 13 -9.6 -23.5 -9.8 -15.7 SR ND ON 04:34 14 -9.6 -23.6 -19.7 -15.9 SR to sky 04:35 11 -9.7 -23.6 -19.7 -15.8 Repeat 11 to clear XR ND (failed) 04:42 15 -9.9 -23.7 -19.8 -15.9 SR ND OFF (but no change) 04:43 16 -9.6 -23.6 -19.5 -15.8 SL ND ON 04:45 17 -18.7 -23.6 -19.7 -15.8 SL to sky 04:46 18 -21.4 -23.7 -19.6 -15.9 SL ND OFF 04:50 18.1 -21.4 -23.6 -19.6 -15.8 Repeat line 1 of Step 18 to clear SR ND (failed) AMB physical temps: S1=20.06 S2=20.38 X1=21.12 *************************** BOT, BCAL #1, SLEW #1 *************************** 04:55 BOT -800 -3000 Carrier offset (Hz) 04:59 -3000 Carrier offset (Hz) 05:00 FRO -5200 -18000 -5200 -18000 25 kHz rcvr offset (SCHAN=3; Hz) FRO -5200 -38000 -5200 -38000 100 kHz rcvr offset (SCHAN=4; Hz) ********************************_MINI-CAL #1 ******************************** 05:01 1 -20.7 -23.0 -19.4 -15.3 XR ND ON (no change) 05:08 2 -20.6 -23.0 -19.3 -20.6 XR ND OFF (yes!) SR ND ON (no change) 05:12 3 -20.7 -18.5 -21.4 -20.7 SR ND OFF (yes!); XL ND ON 05:14 4 -18.4 -22.9 -21.4 -20.6 XL ND OFF; SL ND ON 05:17 5 -20.7 -22.9 -21.5 -20.4 SL ND OFF ************************************ BSR ************************************ 05:25 Wk X carrier at -3200 Hz (SCHAN=2) 05:35 Begin 100 kHz recording (SCHAN=4) 06:05 End 100 kHz recording *********************** SLEW #2, MINICAL #2, BCAL #2 ************************ 06:24 -20.9 -23.1 -21.5 -20.7 ADC levels before Mini-Cal #2 06:25 1 -20.8 -23.0 -21.4 -18.5 XR ND ON 06:26 2 -20.9 -23.2 -21.2 -15.4 XR ND OFF, SR ND ON 06:29 3 -20.8 -23.1 -19.2 -20.7 SR ND OFF, XL ND ON 06:32 4 -20.9 -18.6 -21.6 -20.7 XL ND OFF, SL ND ON 06:35 5 -18.5 -23.0 -21.5 -20.6 SL ND OFF 06:45 FRO 0 0 0 0 All rcvr frequency offsets to 0 06:46 34 37 Carrier (dB/Hz) -1429 -3243 Carrier offset (Hz) 06:50 44.5 67 Carrier (dB/Hz) -1429 -3241 Carrier offset (Hz) 07:01 EOT End track ********************************* POST-CAL ********************************* 07:07 Antenna at zenith 07:10 1 All to AMB 07:11 AMB physical temps: S1=20.88 S2=21.38 X1=21.12 07:15 2 -9.8 -11.4 -10.1 -9.0 XR ND ON 07:18 3 -9.9 -11.3 -9.9 -9.9 XR ND OFF, SR ND ON 07:21 4 -9.7 -10.9 -10.1 -9.9 SR ND OFF, XL ND ON 07:24 5 -9.5 -11.4 -10.2 -9.8 XL ND OFF, SL ND ON 07:28 6 -18.6 -23.6 -22.0 -22.2 All to sky 07:30 7 -21.2 -18.5 -21.9 -22.4 SL ND OFF, XL ND ON 07:33 8 -21.3 -23.6 -19.7 -22.3 XL ND OFF, SR ND ON 07:36 9 -21.1 -23.5 -22.1 -15.7 SR ND OFF, XR ND ON 07:39 10 -21.2 -23.6 XR ND OFF AMB physical temps: S1=20.75 S2=21.31 X1=21.12 07:40 Weather conditions: T=10C H=41 percent sky=fine, clear 07:45 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) 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: 2006-04-29 Minor edits: 2006-07-07