Mars Express Bistatic Radar Experiment Operations Plan and Report 29 February 2008 Summary ======= DSN Antenna: 43 Pass: 1735 Orbit: 5343 Orbit Start Time: 2008-02-29T04:12:23 HGA Pointing: Specular Start Center End -------- ---------- -------- Specular Condition (ERT): 10:43:00 11:06:00 11:30:00 Target Latitude (deg N): -42.74 -38.02 -32.64 Longitude (deg E): 177.49 167.12 157.28 Rp (km): 3394. 3394. 3394. Incidence/Reflection Angle (deg): 58.87 59.58 60.33 Slant Range (km): 11407. 11628. 11585. Slew Angle (deg): 62.27 60.83 59.35 Doppler (carrier, fd; Hz): -9267 -6782 -3991 Doppler (echo, fr; Hz): -7871 -2618 2802 Doppler Difference (fdd; Hz): -1396 -4164 -6793 Earth-Mars Distance (m): 1.539E+11 1.539E+11 1.539E+11 Experiment Set Up ================= This experiment was conducted using Canberra's DSS 43. Gene Goltz, Danny Kahan, and Dick Simpson were in the Radio Science Support Area at JPL; Kahan operated the RSR's while Goltz handled communications. Jesse Velasco was in the NOPE area. Performance Problems and Notes ============================== As DSS 43 was moving to point, the ADC amplitude on X-RCP rose about 3.5 dB. As the spacecraft slew began, the ADC amplitude returned to its previous level. The same behavior has been observed during other recent experiments at both DSS 43 and DSS 63. Only the X-RCP channel seemed to be affected. The cause is unknown. We asked the NOPE at 10:35 whether it is difficult to change from spacecraft pointing to planetary pointing; he thought it could be done in 5 minutes. He asked DSS 43 to make the change at 10:38; they reported they were using Mars- centered pointing at 10:45. The echoes looked good, but there was no obvious change in the ADC amplitudes. This is the more appropriate pointing technique for bistatic radar even if it didn't resolve the X-RCP level question. X-Band echoes were visible at about 30 dB/Hz and 2 kHz width in both polarizations throughout the observing period. S-Band echoes could be seen with 40 seconds of integration in both polarizations, but at only 1-2 dB above the noise level. No receiver tuning offsets (FROs) were used; the echo started close to the carrier and moved about 5 kHz toward higher frequencies during the observation. 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 RSR1B X-LCP 1-W auto 60 Kahan RSR2A S-RCP 1-W auto 60 Kahan RSR2B X-RCP 1-W auto 65 Kahan RSR subchannels (SCHAN) were defined as follows: Table 2 ---------------------------------------------------------------------- Subchannel Sample Rate Comments ---------- ----------- --------------------------------------------- 1 2 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 ----------------------------------------------------------------------------- Activity Time Step # S-LCP X-LCP S-RCP X-RCP Notes / Comments RSR1A RSR1B RSR2A RSR2B -------- ----- --------- ----- ----- ----- ----- ------------------------ 2008/060 -------- Pre-Cal 07:40 1 -9.9 -9.9 -9.8 -9.7 All to sky (dB) 14.0 13.5 12.5 13.0 ATT settings 07:42 2 -9.7 -0.1 -9.8 0.1 X-Band to AMB 07:43 3 -0.7 -0.1 -9.7 0.0 S-LCP to AMB 07:44 4 -0.8 0.0 -0.7 0.1 S-RCP to AMB AMB load physical temps: S1=19.81 S2=21.81 X1=19.19 Weather conditions: T=16.3C H=36.5 percent sky = clear 07:46 -9.6 -9.8 -9.6 -9.8 ADC amp after AUTO reset 24.5 28.0 23.0 25.5 ATT settings 07:46:01 5 Begin 25 kHz recording 07:50 6 -9.7 -9.9 -9.7 -9.0 X-RCP ND ON 07:55 7 -9.7 -22.3 -9.6 -15.9 X-Band to sky 08:00 8 -9.8 -22.3 -9.7 -22.4 X-RCP ND OFF 08:05 9 -9.5 -17.1 -9.6 -22.3 XL ND ON Confirmed ND = 12.5K 08:10 10 -9.6 -9.2 -9.6 -9.9 X-Band to AMB AMB physical temps: S1=20.12 S2=21.81 X1=19.44 08:15 11 -9.6 -9.9 -9.6 -9.9 X-LCP ND OFF 08:20 12 -9.5 -22.3 -9.6 -22.3 X-Band to sky 08:25 13 -9.6 -22.2 -9.5 -22.3 S-RCP ND ON 08:30 14 -9.4 -22.3 -19.2 -22.4 S-RCP to sky 08:35 15 -9.6 -22.3 -21.8 -22.4 S-RCP ND OFF Confirmed ND=12.5K 08:40 16 -9.4 -22.4 -21.6 -22.4 S-LCP ND ON 08:45 17 -18.1 -22.3 -21.6 -22.4 S-LCP to sky 08:50 18 -20.2 -22.2 -21.6 -22.3 S-LCP ND OFF AMB physical temps: S1=20.25 S2=21.69 X1=19.88 08:55 Stop recording DSS 43 moving to point 09:03 -19.8 -21.2 -20.9 -18.8 All ADC levels rise 09:05 DSS 43 on point 09:29 AOS 25.2 65.1 X-Band visible (dB/Hz) -2470 -2468 Carrier offset (Hz) 09:32 AOS 24.5 49.9 S-Band visible (dB/Hz) -1218 -1218 Carrier offset (Hz) 09:33 DSS 43 in lock 09:48 23.6 33.2 49.9 72.1 X ranging off (dB/Hz) -1281 -2694 Carrier offset (Hz) -19.7 -21.2 -20.9 -18.5 ADC amplitude (dB) 09:50:00 Resume 25 kHz recording Slew 1 10:14 Begin slew 10:17 23.3 38.5 46.5 45.8 CNR (dB/Hz) -19.7 -21.2 -20.8 -21.4 ADC amplitude (dB) MiniCal1 10:20 1 -19.7 -21.3 -20.9 -15.5 XR ND ON; conf ND=12.5K 10:23 2 -19.7 -21.4 -18.8 -21.2 XR ND OFF; SR ND ON S-Band carrier gone XR carrier 39 dB/Hz 10:26 3 -19.7 -16.8 -20.9 -18.8 SR ND OFF; XL ND ON 10:29 4 -17.8 -21.3 -20.8 -18.8 XL ND OFF; SL ND ON 10:32 5 -19.7 -21.2 -20.8 -20.6 SL ND OFF BSR: 10:41 30.0 30.0 Echo visible (dB/Hz) 10:42 Begin 100 kHz recording End Slew 1 10:45 DSS43 on planetary pointing predicts 11:02 -19.6 -21.1 -20.8 -18.8 ADC amplitude (dB) 11:30 -19.6 -21.0 -20.5 -18.9 ADC amplitude (dB) End 100 kHz recording Slew 2 11:30 Begin Slew 2 MiniCal2 11:35 1 -19.5 -20.9 -20.5 -14.8 XR ND ON 11:38 2 -19.5 -20.8 -18.6 -18.8 XR ND OFF; SR ND ON 11:41 3 -19.4 -16.6 -20.5 -18.9 SR ND OFF; XL ND ON 11:44 4 -17.6 -20.9 -20.4 -18.9 XL ND OFF; SL ND ON 11:47 5 -19.4 -20.8 -20.5 -18.6 SL ND OFF 11:51:25 DSS 43 returned to spacecraft pointing 12:00 -19.2 -20.6 -20.3 -18.2 ADC amplitude (dB) 22.2 40.4 49.2 71.2 CNR (dB/Hz) End slew; DSS 43 in lock 12:14 -19.2 -20.6 -20.3 -20.1 ADC amplitude (dB) 20.8 40.0 49.0 70.4 CNR (dB/Hz) 12:15 Early EOT PostCal: 12:23 -20.2 -22.4 -21.6 -22.4 DSS 43 at zenith 12:25 1 -9.5 -9.8 -9.7 -9.9 All to AMB AMB phys temps: S1=19.31 S2=20.12 X1=19.31 12:28 2 -9.5 -9.8 -9.9 -9.0 XR ND ON 12:31 3 -9.5 -9.7 -9.7 -9.8 XR ND OFF; SR ND ON 12:34 4 -9.6 -9.4 -9.7 -9.8 SR ND OFF; XL ND ON 12:37 5 -9.4 -9.6 -9.7 -9.8 XL ND OFF; SL ND ON 12:40 6 -18.1 -22.2 -21.5 -22.4 All to sky 12:43 7 -20.2 -17.0 -21.6 -22.4 SL ND OFF; XL ND ON 12:46 8 -20.2 -22.3 -19.1 -22.5 XL ND OFF; SR ND ON 12:49 9 -20.3 -22.2 -21.6 -15.7 SR ND OFF; XR ND ON 12:52 10 -20.1 -22.4 -21.7 -22.4 XR ND OFF AMB physical temps: S1=19.44 S2=20.00 X1=19.31 Weather conditions: T=10.1C H=51.9 percent sky=clear EOA 12:55 Stop 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: 2008-02-29 Added orbit start time: 2008-03-05