Mars Express Bistatic Radar Experiment Operations Plan and Report 18 August 2008 Summary ======= DSN Antenna: 14 Pass: 1907 Orbit: 5945 Orbit Start Time: 2008-08-18T19:36:34 HGA Pointing: Specular Start Center End -------- ---------- -------- Specular Condition (ERT): 23:22:00 23:34:00 23:43:00 Target Latitude (deg N): 53.32 84.98 66.32 Longitude (deg E): 17.91 293.06 225.15 Rp (km): 3394. 3394. 3394. Incidence/Reflection Angle (deg): 89.29 60.74 42.08 Slant Range (km): 1505. 1279. 1788. Slew Angle (deg): 1.42 58.51 95.84 Doppler (carrier, fd; Hz): 90179. 94851. 81915. Doppler (echo, fr; Hz): 89168. 42463. -2450. Doppler Difference (fdd; Hz): 1011. 52388 84364. Earth-Mars Distance (m): 3.540E+11 3.540E+11 3.540E+11 Experiment Set Up ================= This experiment was conducted using Goldstone's DSS 14. Danny Kahan and Gene Goltz were in the Radio Science Support Area (RSSA) at JPL; Dick Simpson monitored by telephone from Stanford. Jesse Velasco was in the NOPE area. Performance Problems and Notes ============================== There was a delay in starting the pre-cal because one of the S-Band low noise amplifiers had failed (DR G108775). The HEMP was used for S-RCP, and there was no reception of S-LCP. To simplify the noise diode calibrations with no S-LCP in the system, some of the steps were omitted in real time. However, at about Step 13 in the pre- cal, station personnel became confused and the procedure had to be taken back to Step 08 or Step 09 and then moved forward again. Both Gene and Danny reported that the real-time readings of noise power and analog-to-digital converter (ADC) amplitude were very unstable on S-RCP. The change from spacecraft pointing to planetary pointing (and back again) occurred without incident at DSS 14. Real-time echoes were seen in all three channels (X-RCP, X-LCP, and S-RCP). 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 unknown RSR2B X-LCP 1-W auto 60 unknown RSR2A S-RCP 1-W auto 60 unknown RSR3B X-RCP 1-W auto 65 unknown RSR subchannels (SCHAN) were defined as follows: Table 2 ---------------------------------------------------------------------- Subchannel Sample Rate Comments ---------- ----------- --------------------------------------------- 1 2 ksps Recording bandwidth for occultations (RCP only) 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 ----------------------------------------------------------------------------- Activity Time Step # S-RCP X-LCP S-LCP X-RCP Notes / Comments 2008/231 RSR2A RSR2B RSR3A RSR3B -------- ----- --------- ----- ----- ----- ----- ------------------------ Pre-Cal 18:53 1 18:55 -10.0 -10.2 n/a -9.6 Atten set using "auto" 19:02 2 -10.0 -0.3 n/a +0.2 19:03 4 -3.1 -0.3 n/a +0.2 19:06 18.0 22.5 n/a 24.0 Attenuators (dB) Amb loads, phys temps S1=n/a S2=18.95 X1=18.95 -10.1 -10.1 n/a -10.0 Weather condx: T=33.1C H=10.5 percent sky=clear 19:08 Begin 25 kHz recording 19:15 5 -10.1 -10.0 n/a -9.9 19:19 6 -9.9 -10.1 n/a -9.7 19:25 7 -10.0 -22.3 n/a -20.0 19:30 8 -10.1 -22.1 n/a -22.6 19:35 9 -10.0 -20.0 n/a -22.6 Confirm 12.5 noise diode 19:40 10 -10.0 -9.8 n/a -10.0 Amb loads phys temps: S1=n/a S2=24.00 X1=16.88 19:45 11 -10.0 -10.0 n/a -10.0 19:50 12 -10.0 -22.2 n/a -22.5 20:11 13 -9.8 -22.1 n/a -22.5 X-RCP problem; repeated steps 8,9,11,13 20:15 14 -14.9 -22.5 n/a -22.5 20:20 15 -16.7 -22.2 n/a -22.5 Confirm 12.5 noise diode Amb loads phys temps: S1=n/a S2=24.50 X1=17.25 20:25 end -15.3 -22.2 n/a -22.5 Stop 25 kHz recording BOT 20:25 -15.8 -21.9 n/a -21.6 22:25 -10K -11K n/a -11K FRO (SCHAN 3, Hz) 22:25 -40K -40K n/a -40K FRO (SCHAN 4, Hz) 22:30 -9.6 -22.0 n/a -21.8 Resume 25 kHz recording OCI 22:38 Begin 2 kHz recording 22:55 -7.4 -22.0 n/a -21.8 Switch to Mars pointing 22:58 Stop 2 kHz recording MinCal1 23:00 1 -8.7 -22.0 n/a -19.7 Confirm 12.5 noise diode 23:03 2 -12.3 -22.0 n/a -21.6 23:06 3 -10.7 -19.9 n/a -21.7 23:09 4 -8.0 -22.0 n/a -21.7 23:15 end OCE 23:16 Resume 2 kHz recording BSR 23:20 -12.7 -21.9 n/a -22.2 Begin 100 kHz recording 23:26 -22K -22K FRO (SCHAN 3, Hz) 23:28 -32K -32K FRO (SCHAN 3, Hz) 23:30 -42K -42K FRO (SCHAN 3, Hz) 23:31 -20K FRO (SCHAN 3, Hz) 23:31 -80K -80K FRO (SCHAN 4, Hz) 23:32 -52K -52K FRO (SCHAN 3, Hz) 23:34 -62K -62K FRO (SCHAN 3, Hz) 23:36 -72K -72K End 2 kHz recording 23:39 -30K -82K -82K FRO (SCHAN 3, Hz) 23:42 -92K -92K 23:43 -16.5 -21.9 n/a -22.4 End 100 kHz recording MinCal2 23:45 1 -16.0 -21.9 n/a -19.7 Confirm 12.5 noise diode 23:48 2 -17.1 -21.9 n/a -21.6 23:51 3 -19.6 -19.8 n/a -21.6 23:54 4 -17.7 -21.8 n/a -21.6 2008/232 -------- 00:00 -18.0 -21.8 n/a -21.6 00:06 -10K -11K n/a -11K Switch to s/c pointing EOT 00:25 -16.2 -22.0 n/a -22.4 PostCal 00:30 1 -9.9 -10.0 n/a -10.0 Amb load phys temps: S1=n/a S2=29.56 X1=19.56 00:35 2 -10.0 -10.1 n/a -9.8 00:38 3 -10.0 -10.0 n/a -10.0 00:41 4 -9.9 -9.9 n/a -10.1 00:44 5 -9.9 -10.0 n/a -10.0 00:47 6 -17.6 -22.2 n/a -22.7 00:50 7 -17.7 -20.0 n/a -22.8 00:53 8 -16.8 -22.2 n/a -22.6 00:56 9 -17.5 -22.2 n/a -20.1 00:59 10 -17.3 -22.2 n/a -22.6 Amb load phys temps S1=n/a S2=29.12 X1=19.56 Weather conditions: T=33.3C H=11.8 percent sky=clear EOA 01:03 End 25 kHz recording 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 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: 2008-08-19