Mars Express Bistatic Radar Experiment Operations Plan and Report 20 February 2010 Summary ======= DSN Antenna: 14 Pass: N/A Orbit: 7865 Orbit Start Time: 2010-02-20T09:11:06 HGA Pointing: Specular Start Mid Point End -------- ---------- -------- Specular Condition (ERT): 09:07 09:43 10:20 Target Latitude (deg N): -26.30 -32.04 -38.54 Longitude (deg E): 10.18 2.83 355.91 Rp (km): 3394. 3394. 3394. Incidence/Reflection Angle (deg): 39.03 44.68 51.17 Slant Range (km): 10959. 11007. 10453. Slew Angle (deg): 101.95 90.63 77.65 Doppler (carrier, fd; Hz): -28748. -32484. -33830. Doppler (echo, fr; Hz): -7082. -41. 6768. Doppler Difference (fdd; Hz): -21666. -32443. -40598. Earth-Mars Distance (m): 1.084E+11 1.084E+11 1.084E+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. Performance Problems and Notes ============================== The S-RCP maser had been red for the experiment on 2010/041. It was repaired about a week later, but the cool-down failed; so it was red again for this experiment (DR #G110058), and no S-RCP data were collected. Strong interference was noted on both X-Band channels over the time interval 09:52-10:36. Danny Kahan believed it was from another spacecraft. Real-time monitoring during Mini-Cal #2 indicated that the X-LCP noise diode was not turned off at the end of Mini-Cal 2 step 3. 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 N/A 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-RCP X-RCP Notes / Comments 2010/051 (new NOP) RSR3A RSR3B N/A RSR2B -------- ----- --------- ----- ----- ----- ----- ------------------------ FGAIN 60 60 63 Set FGAIN Pre-Cal 05:15 1 -10.1 -10.0 n/a -10.1 ADC amplitude (dB) 21.5 11.5 10.0 ATTEN settings (dB) 05:18 att auto -10.1 -10.4 n/a -10.2 ADC amplitude (dB) 21.5 12.0 11.5 ATTEN settings (dB) 05:20 2 -10.1 -0.4 n/a -0.7 05:21 3 -5.6 -0.4 n/a -0.8 05:24 4,5 -5.6 -0.4 -0.7 -0.7 05:25 att auto -9.9 -9.8 n/a -10.0 ADC amplitude (dB) 26.0 23.5 n/a 22.5 ATTENB settings (dB) AMB physical temps: S1=11.62 S2=15.12 X1=11.75 Local weather: T=7.6C H=68.6 percent Sky=overcast 05:27 rec 3 e Begin 25 kHz recording 05:30 6 -9.8 -9.8 n/a -9.9 All to AMB 05:35 7 -10.0 -9.9 n/a -9.8 XR ND ON 05:42 8 -10.0 -22.0 n/a -20.2 X-Band to sky 05:47 9 -10.1 -21.9 n/a -22.6 XR ND OFF 05:52 10 -10.0 -19.6 n/a -22.6 XL ND ON; confirmed 12.5K ND 05:57 11,12 -10.0 -9.7 n/a -10.0 X-Band to AMB AMB load physical temps: S1=11.44 S2=14.75 X1=11.69 06:02 13 -10.0 -9.8 n/a -10.0 XL ND OFF 06:07 14 -10.1 -21.9 n/a -22.6 X-Band to sky 06:12 15 -10.0 -22.1 n/a -22.6 06:17 16 -10.1 -21.9 n/a -22.6 06:22 17 -10.0 -21.9 n/a -22.6 Confirmed 12.5K ND 06:27 18 -9.9 -21.7 n/a -22.5 SL ND ON 06:32 19 -13.4 -21.9 n/a -22.6 SL to sky 06:37 20 -14.1 -21.9 n/a -22.6 SL ND OFF AMB load physical temps: S1=11.25 S2=14.50 X1=11.62 06:42 end -14.5 -21.9 n/a -22.5 Pause 25 kHz recording BOT 07:05 -14.9 -21.7 n/a -17.6 ADC amplitude (dB) 07:50 X-Band TX ON 08:14 S-Band TX ON 08:30 rec 3 e -18.6 -21.5 n/a -18.3 Resume 25 kHz recording X-TLM OFF 08:45 -17.0 -21.4 -18.3 DSS switch to Mars pointing predicts 08:47 sfro 3/SX +5K +25K +25K Rcvr tuning offset (Hz) MiniCal1 08:48 1 -16.7 -21.5 n/a -17.6 XR ND ON Confirmed 12.5 K ND 08:51 2 -15.9 -21.5 n/a -18.8 XR ND OFF 08:54 3 -16.3 -19.4 n/a -18.5 XL ND ON 08:57 4 -17.3 -21.5 n/a -17.9 XL ND OFF; SL ND ON 09:00 5 -15.2 -21.5 n/a -17.7 SL ND OFF 09:03 end -17.5 -21.5 n/a -17.9 ADC amplitude (dB) BSR 09:07 rec 4 e -17.3 -21.4 n/a -17.7 Begin 100 kHz recording 09:40 sfro 3/X +35K +35K Rcvr tuning offset 09:52 Non-MEX signal appears 10:20 rec 4 d -18.3 -21.2 n/a -17.9 End 100 kHz recording MiniCal2 10:21 1 -18.6 -21.1 n/a -16.6 Confirmed 12.5 ND 10:24 2 -19.3 -21.2 n/a -17.9 10:27 3 -17.5 -19.3 n/a -17.9 10:30 4 -16.1 -19.2 n/a -18.0 10:33 5 -16.6 -19.2? n/a -17.7 10:36 end DSS 14 switch to s/c pointing predicts Non-MEX signal gone sfro 3/SX 0 0 0 Rcvr tuning offset (Hz) 10:40 repeat steps 2 and 4 EOT/stow 10:55 -17.3 -20.9 n/a -17.4 Post-Cal 11:09 1 -10.1 -9.8 n/a -9.9 AMB load physical temps: S1=10.62 S2=12.25 X1=11.00 11:12 2 -10.0 -9.7 n/a -9.7 11:15 3 -9.9 -9.7 n/a -10.0 11:18 4 -10.0 -9.6 n/a -9.9 11:21 5 -9.8 -9.7 n/a -10.0 11:24 6 -13.3 -21.9 n/a -22.4 11:27 7 -14.6 -19.5 n/a -22.4 11:30 8 -14.6 -21.9 n/a -22.5 11:33 9 -14.4 -21.8 n/a -20.1 11:36 10 -14.7 -21.8 n/a -22.5 AMB load physical temps: S1=10.50 S2=12.31 X1=11.00 Local weather: T=5.4C H=80.7 percent sky=partly cloudy 11:40 end -12.5 -21.9 n/a -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: 2010-02-23 Added Post-Analysis Summary: 2010-03-10 Updated post-analysis summary: 2011-03-11 Corrected headings in Table 3: 2010-04-02 Minor edits to remove problematical characters: 2011-05-11