Mars Express Bistatic Radar Experiment Operations Plan and Report 24 February 2010 Summary ======= DSN Antenna: 14 Pass: N/A Orbit: 7879 Orbit Start Time: 2010-02-24T10:22:51 HGA Pointing: Specular Start Mid Point End -------- ---------- -------- Specular Condition (ERT): 10:23 10:55 11:27 Target Latitude (deg N): -25.65 -30.73 -36.27 Longitude (deg E): 27.37 20.72 14.49 Rp (km): 3394. 3394. 3394. Incidence/Reflection Angle (deg): 38.18 43.19 48.70 Slant Range (km): 11002. 11013. 10569. Slew Angle (deg): 103.65 93.61 82.60 Doppler (carrier, fd; Hz): -28635. -32354. -34276. Doppler (echo, fr; Hz): -6123. 84. 5987. Doppler Difference (fdd; Hz): -22512. -32438. -40264. Earth-Mars Distance (m): 1.116E+11 1.116E+11 1.116E+11 NB: The DSN is no longer routinely using pass numbers; so this entry in the summary will not be maintained in this and future reports. Experiment Set Up ================= This experiment was conducted using the Goldstone DSS 14. Danny Kahan and Gene Goltz were in the Radio Science Support Area (RSSA) at JPL. This report is largely based on notes provided by Kahan and Goltz. Performance Problems and Notes ============================== The S-RCP maser had been red for the experiments on 2010/041 and 051; for this experiment, it appeared to be working normally. There were problems with the ground calibrations; some of the steps had to be repeated. The X-RCP and X-LCP pre- and post-cals seemed to be normal; and the noise diode equivalent temperatures were nominal. But both channels became very noisy during the surface observations, with X-RCP having the higher Tsys during MINICAL2. The cause of this behavior is not known. 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 UNK RSR3B X-LCP 1-W auto 60 UNK RSR2A S-RCP 1-W auto 60 UNK RSR2B X-RCP 1-W auto 63 UNK RSR subchannels (SCHAN) were defined as follows: Table 2 ---------------------------------------------------------------------- Subchannel Sample Rate Comments ---------- ----------- --------------------------------------------- 1 2 ksps Occultation bandwidth (not recorded for BSR) 2 8 ksps Occultation backup (not recorded for BSR) 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-LCP X-RCP Notes / Comments 2010/055 (new NOP) RSR3A RSR3B RSR2A RSR2B -------- ----- --------- ----- ----- ----- ----- ------------------------ FGAIN 06:30 60 60 60 63 Set FGAIN Pre-Cal 06:44 1 -14.2 -9.8 -9.7 -9.8 ADC amplitude (dB) 25.0 11.5 9.0 10.0 Attenuator settings (dB) 06:45 att auto -10.2 -10.2 -9.8 -9.8 22.5 12.0 9.0 10.0 Attenuator settings (dB) 06:47 2 -10.8 -0.4 -9.8 -0.0 06:48 3 -6.4 -0.4 -9.7 +0.0 06:50 "4,5" -6.4 -0.4 -0.8 -0.0 06:51 att auto -9.9 -9.8 -9.9 -9.9 Ambient load phys temps S1=11.44 S2=15.44 X1=11.25 26.0 23.5 20.0 22.5 Attenuator settings (dB) Local weather: T=9.7C H=24.4 percent sky=light overcast 06:53 rec 3 e -9.9 -9.9 -9.9 -9.9 Begin 25 kHz recording 06:54 6 -9.9 -9.9 -9.9 -9.9 07:00 7 -9.8 -9.8 -10.0 -9.7 07:05 8 -9.9 -21.8 -10.1 -20.0 07:10 9 -9.9 -22.0 -10.0 -22.5 07:15 10 -9.8 -19.7 -10.0 -22.5 Confirm 12.5 noise diode 07:20 "11,12" -9.9 -9.7 -9.8 -10.0 Ambient load phys temps: S1=11.38 S2=15.31 X1=11.19 07:25 13 -9.9 -9.8 -9.9 -10.0 07:30 14 -9.9 -21.9 -9.8 -22.5 07:35 15 -9.9 -21.8 -9.7 -22.4 repeated steps 9 & 13 07:50 16 -9.8 -21.8 -18.8 -22.5 07:55/08:17 17 -9.9 -21.8 -20.6 -22.5 Confirm 12.5 noise diode 08:00/08:19 18 -9.8 -21.8 -20.6 -22.5 08:05/08:20 19 -14.0 -21.8 -20.7 -22.5 08:10/08:25 20 -14.8 -21.9 -20.6 -22.4 Ambient load phys temps: S1=11.25 S2=14.94 X1=11.91 08:35 21/end -14.5 -21.9 -20.6 -22.5 Stop 25 kHz recording BOT 08:40 09:02 X-Band AOS 09:30 S-Band AOS 09:46 rec 3 e Resume 25 kHz recording 10:05 sfro 3/SX +5K +25K +5K +25K Rcvr tuning offset (Hz) DSS 14 to Mars pointing predicts sfro 4/X +17K +17K SCHAN 4 tuning offset MiniCal1 10:06 1 -16.5 -21.1 -20.5 -17.4 Confirm 12.5 noise diode 10:09 2 -16.5 -21.2 -18.8 -17.9 10:12 3 -16.6 -19.1 -20.4 -17.7 10:15 4 -15.4 -21.0 -20.4 -17.6 10:18 5 -18.5 -21.0 -20.5 -16.7 10:21 6/end -16.9 -21.1 -20.5 -17.8 BSR 10:23 rec 4 e -16.9 -21.1 -20.5 -17.9 Begin 100 kHz recording 10:50 sfro 3/SX +34K +34K Rcvr tuning offset (Hz) end BSR 11:27 rec 4 d -19.3 -19.8 -20.1 -17.5 End 100 kHz recording sfro 3/X +25K +25K Rcvr tuning offset (Hz) MiniCal2 11:28 1 -18.5 -19.7 -20.0 -16.5 Confirm 12.5 noise diode 11:31 2 -17.9 -19.6 -18.4 -17.3 11:34 3 -17.3 -18.0 -19.8 -17.0 11:37 4 -18.0 -19.5 -19.8 -17.3 11:40 5 -18.7 -19.5 -19.8 -17.2 11:43 6/end -17.7 -19.8 -19.7 -17.6 DSS 14 to s/c pointing predicts sfro 3/SX 0 0 0 0 Rcvr tuning offset (Hz) 11:57 -18.4 -19.6 -19.6 -16.9 ADC amplitude (dB) PostCal 1 -9.9 -9.9 -10.0 -10.0 Ambient load phys temps: S1=11.00 S2=14.56 X1=10.94 2 -9.9 -9.8 -9.8 -9.8 3 -9.9 -9.9 -9.7 -9.9 4 -10.0 -9.6 -9.9 -10.0 5 -9.7 -9.8 -9.9 -10.0 6 -13.5 -21.6 -20.8 -22.2 7 -14.6 -19.6 -20.8 -22.2 8 -15.2 -21.7 -18.9 -22.2 9 -14.5 -21.5 -20.8 -19.9 10 -14.4 -21.8 -20.8 -22.3 Ambient load phys temps: S1=11.00 S2=14.50 X1=10.94 Local weather: T=10.1C H=17.4 percent sky=overcast 11/end -14.8 -21.8 -20.8 -22.4 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) EOA = End of activity EOT = End of Track FRO = frequency offset HGA = high-gain antenna LOS = loss of signal ND = noise diode No = noise power NOP = Network Operations Plan Pc = carrier power rcvr = receiver S1 = ambient load for S-RCP S2 = ambient load for S-LCP s/c = spacecraft 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 Post Analysis Summary X-Band 10-s Average Data: The table below summarizes the time division for capturing the echo power as the signal drifted through the 25 kHz X-Band receiving pass band. There was a single FRO at 09:40. A strong signal (Kahan guessed from MRO) interfered with the surface echo at various times after 09:52:50; the X-RCP interference was much stronger, especially relative to the weaker echo in that polarization. Int Times Spectra Noise Bins Carrier Echo Bins Notes Bins --- ----------------- ------- --------------- ------- ---------------- ------ A 09:07:00-09:40:00 001-198 104:160,425:916 588:605 165:300->275:420 AB 09:40:00-09:40:10 199 104:160.425:916 588:605 180:695 [1] B 09:40:10-09:52:50 200-275 104:160,425:916 588:605 165:300->275:420 C 09:52:50-09:55:20 276-290 450:916 308:358 323:400->363:422 [2,3] D 09:55:20-10:05:40 291-352 550:916 335:355 355:423->416:530 [3,6] E 10:05:40-10:10:30 353-381 104:350 556:916 416:542->471:560 [4] F 10:10:30-10:17:20 382-422 625:916 100:460 471:575->513:620 [5,6] G 10:17:20-10:20:00 423-438 104:512 650:916 513:635->525:645 [4] Notes: [1] FRO at 09:40; spectrum 199 has split echo [2] strong interference at lower edge of passband [3] echo power may be underestimated because interference is too close [4] alias of interference moves in from high side of passband [5] spectra 382-388 are contaminated by alias of interference [6] alias of interference exits via low side of passband The interference appeared in spectrum 276 (09:52:53) and persisted through the remainder of the experiment. Spurs from the interference infringed on the X-RCP echo window over spectra 280-295 (09:53:30-09:56:10); the echo power may be underestimated by as much as 10 percent in attempts to exclude the interfering signal from the echo power calculation, but the same error should have affected the X-LCP echo power calculation in the same way and perhaps the ratio is still good. An alias of the interference walked through the echo during spectra 381-388 (10:10:20-10:11:40), corrupting the X-RCP echo power calculations. The interference was much weaker in X-LCP and its effect on X-LCP echo power calculation is negligible. S-Band 10-s Average Data: The S-LCP data were processed using a single set of parameters. There were no S-RCP data. Int Times Spectra Noise Bins Carrier Echo Bins Notes Bins --- ----------------- ------- --------------- ------- ---------------- ------ A 09:07:00-10:20:00 001-438 104:240,760:916 243:249 456:551->650:755 Dick Simpson Original: 2010-04-02