Mars Express Bistatic Radar Experiment Operations Plan and Report 22 May 2010 Summary ======= DSN Antenna: 63 Orbit: 8179 Orbit Start Time: 2010-05-22T17:06:34 HGA Pointing: Specular Start Mid Point End -------- ---------- -------- Specular Condition (ERT): 19:06 20:00 20:30 Target Latitude (deg N): -14.69 -38.44 -54.70 Longitude (deg E): 338.50 335.56 129.09 Rp (km): 3394. 3394. 3394. Incidence/Reflection Angle (deg): 39.87 60.03 89.79 Slant Range (km): 8358. 5072. 3169. Slew Angle (deg): 100.26 59.94 0.43 Doppler (carrier, fd; Hz): -38404. -44332. -17709. Doppler (echo, fr; Hz): 18420. 17891. -17189. Doppler Difference (fdd; Hz): -56448. -62223. -520. Earth-Mars Distance (m): 2.215E+11 2.215E+11 2.215E+11 Experiment Set Up ================= This experiment was conducted using the Madrid DSS 63. 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 ============================== Digital Controller #1 (DC01), which turns the X-Band noise diodes on and off, stopped responding at step 6 of the pre-cal; it was rebooted, and there appear to be no adverse effects on the data. DC02, which controls S-Band noise diodes, failed to give expected responses later in the pre-cal; no reboot was required, but several earlier steps in the pre-cal procedure were repeated. S-RCP noise power decreased by about 0.5 dB during the post-cal while that RSR was connected to the ambient load; this will make derivation of the system temperature at 21:36 difficult. There is a 0-2.5 dB loss in S-LCP gain beginning at 20:48 and ending at 20:51. The gain decreases at an accelerating rate to its maximum at 20:50, then rebounds quickly. The behavior is similar to gain losses seen on S-LCP at DSS 63 on days 106 and 135. The 25 kHz RSR output from both S-LCP and X-LCP was corrupted before the records could be transferred to JPL. The S-LCP loss was 1-4 records during the second beginning at 21:02:01; it was repaired at Stanford by copying the record at 21:02:02.00 four times, editing the record sequence number and SFDU seconds to be continuous, and inserting the copies into the file at 21:02:01. The X-LCP loss was 1-4 records in the interval beginning 21:15:33; it was repaired in the same way, copying and editing the record at 21:15:34.00 four times. Quick-look processing was not affected by the repairs, but there may be artifacts in later processing. A one-way S/X ingress occultation was captured at the end of the BSR; later, a one-way X-Band egress occultation was captured. 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 UNK RSR1B X-LCP 1-W auto 60 UNK RSR2A S-RCP 1-W auto 60 UNK RSR2B X-RCP 1-W auto 65 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 2010/142 RSR1A RSR1B RSR2A RSR2B -------- ----- --------- ----- ----- ----- ----- ------------------------ Set-Up 16:02 FGAIN 60 60 60 65 FGAIN settings (dB) Pre-Cal 16:38 1 -10.2 -15.9 -14.5 -9.6 ADC amplitudes (dB) att auto -9.8 -9.8 -10.1 -9.6 Auto attenuator reset 17.0 17.5 14.5 26.0 Attenuator settings 16:39 2 -9.9 -0.3 -10.1 -0.0 16:41 3 -0.6 -0.3 -10.1 -0.1 16:42 4,5 -0.5 -0.3 -0.4 -0.1 16:44 att auto -9.6 -10.1 -10.0 -3.5 Ambient load phys temps: S1=18.50 S2=21.44 X1=15.44 28.0 29.5 26.0 31.5 Attenuator settings (dB) Local weather: T=26.8C H=26.1 percent sky=clear 16:47 rec 3 e Begin 25 kHz recording 6 -9.7 -10.1 -9.9 -3.4 DC01 not responding, station rebooted 16:55 7 -9.7 -10.1 -10.0 -3.3 17:00 8 -9.6 -21.9 -10.0 -13.0 17:05 9 -9.7 -21.8 -10.1 -15.4 17:10 10 -9.7 -19.8 -10.0 -15.3 Confirm 12.5K ND 17:15 11,12 -9.7 -10.0 -10.0 -3.5 17:20 13 -9.6 -10.1 -10.0 -3.5 17:25 14 -9.7 -21.8 -9.9 -15.3 17:30/48 15 -9.7 -21.7 -9.8 -15.3 Re-do step 6 (OCIs 5-8), and step 4 17:35/57 16 -9.7 -21.7 -19.6 -15.2 Repeated first OCI 18:02 17 -9.6 -21.8 -21.5 -15.2 Confirm 12.5K ND 18:07 18 -9.5 -21.8 -21.4 -15.4 18:12 19 -19.0 -21.8 -21.5 -15.4 18:17 20 -20.8 -21.8 -21.5 -15.4 Ambient load phys temps: S1=22.19 S2=28.10 X1=16.62 18:22 21/end -20.6 -21.8 -21.4 -15.5 Stop 25 kHz recording BOT 18:25 -21.4 -21.6 -21.2 -13.4 Collect TLM until 18:31 18:31 rec 3 e Resume 25 kHz recording 18:45 DSS 63 switch to Mars pointing predicts 18:46 sfro 3/SX +9K +58K +9K +58K Rcvr tuning offset (Hz) sfro 4/X +35K +35K Rcvr tuning offset (Hz) MINICAL1 18:48 1 -21.3 -21.6 -21.1 -11.9 Confirm 12.5K ND 18:51 2 -21.2 -21.6 -21.1 -13.8 18:54 3 -21.1 -19.7 -21.0 -13.8 18:57 4 -19.4 -21.6 -21.3 -13.6 19:00 5 -21.2 -21.6 -21.1 -13.7 19:03 end -21.2 -21.7 -21.2 -13.6 BSR 19:06 rec 4 e -21.0 -21.7 -21.2 -13.6 Begin 100 kHz recording 20:08 sfro 3/X +46K +46K Rcvr tuning offset (Hz) 20:15 sfro 3/X +34K +34K Rcvr tuning offset (Hz) 20:20 sfro 3/X +23K +23K Rcvr tuning offset (Hz) 20:24 sfro 3/X +12K +12K Rcvr tuning offset (Hz) 20:27 sfro 3/X +2K +2K Rcvr tuning offset (Hz) OCCN 20:30 -20.4 -21.5 -20.6 -13.5 Ingress Mars occultation 20:32 rec 4 d End 100 kHz recording end BSR 20:33 sfro 3/SX 0 0 0 0 Rcvr tuning offset (Hz) MiniCal2 20:35 1 -20.5 -21.6 -20.7 -11.6 Confirm 12.5K ND 20:38 2 -20.5 -21.5 -18.7 -13.4 20:41 3 -20.5 -19.5 -20.4 -13.4 20:44 4 -18.7 -21.5 -20.3 -13.3 20:47 5 -20.8 -21.5 -20.2 -13.3 20:50 end -21.2 -21.4 -20.2 -13.3 DSS 63 return to s/c pointing predicts EOT 21:05 -20.6 -21.3 -20.2 -13.1 ADC amplitude (dB) STOW 21:09 -20.7 -21.9 -20.6 -15.2 Post-Cal 21:10 1 -9.5 -10.4 -9.2 -3.4 Ambient load phys temps: S1=19.80 S2=25.40 X1=15.60 21:15 2 -9.5 -10.3 -9.4 -3.3 21:18 3 -9.4 -10.3 -9.2 -3.4 21:21 4 -9.5 -10.0 -9.5 -3.3 21:24 5 -9.3 -10.2 -9.6 -3.4 21:27 6 -18.8 -21.7 -21.1 -15.1 21:30 7 -20.6 -19.7 -21.0 -15.3 21:33 8 -20.6 -21.7 -19.0 -15.1 21:36 9 -20.5 -21.8 -21.1 -12.7 21:39 10 -20.6 -21.8 -21.2 -15.2 Ambient load phys temps: S1=19.60 S2=25.00 X1=15.80 Local weather: T=20.0C H=45.6 percent sky=clear EOA 21:43 11/end -20.6 -21.8 -21.0 -15.1 End 25 kHz recording AMB = ambient load BOT = Beginning of Track BW = bandwidth 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 occn = occukltation 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 Power: X-Band data were processed to power spectra with 60 second averaging (sums of 1464 individually calculated 1024-point spectra). The 86 minutes of 25 kHz data were divided into 13 time intervals -- five with split echoes (caused by receiver tuning offset changes, FRO) and eight during which the echo drifted within the passband at fixed FRO. The directly propagating carrier did not appear in the 25 kHz passband until the final FRO at 20:27. Prior to 20:27 the carrier tracking window was used to find the frequency bin with maximum echo power. Int Times Spectra Noise Bins Echo Echo Bins Notes Peak --- ----------------- ------- --------------- ------- ---------------- ------ A 19:06-19:31 01-25 109:245,740:916 300:630 250:415->538:734 B 19:31-19:56 26-50 109:512,800:916 550:780 521:795 C 19:56-20:08 51-62 109:150,710:916 160:740 521:755->155:430 CD 20:08-20:09 63 109:150,815:916 160:800 155:810 [1] D 20:09-20:15 64-69 109:190,785:916 160:740 551:780->195:450 DE 20:15-20:16 70 109:170,865:916 200:820 175:860 [1] E 20:16-20:20 71-74 109:190,785:916 200:740 521:780->195:530 EF 20:20-20:21 75 109:190,855:916 200:800 195:850 [1] F 20:21-20:24 76-78 109:190,760:916 200:650 401:755->195:530 FG 20:24-20:25 79 109:190,835:916 200:800 195:830 [1] G 20:25-20:27 80-81 109:250,700:916 200:650 395:695->255:560 Int Times Spectra Noise Bins Carrier Echo Bins Notes Peak --- ----------------- ------- --------------- ------- ---------------- ------ GH 20:27-20:28 82 109:250,805:916 286:290 291:800 [1] H 20:28-20:32 83-86 109:250,660:916 286:290 380:655->291:400 [2] Notes: [1] Split echo resulting from change in X-Band receiver tuning offset [2] Occultation; no carrier or echo on spectrum 86 S-Band Power: S-Band data were processed in the same way. Since the signal drifts more slowly at S-Band, only three time intervals were needed. There were no changes in the S-Band receiver tuning offset, which put the directly propagating carrier slightly beyond the lower roll-off frequency. Int Times Spectra Noise Bins Echo Echo Bins Notes Peak --- ----------------- ------- --------------- ------- ---------------- ------ A 19:06-20:06 01-60 104:670,885:916 081:085 675:880 B 20:06-20:21 61-75 109:345,805:916 081:085 660:800->350:520 C 20:21-20:32 76-86 500:804,805:916 081:085 350:520->114:188 [1] Notes: [1] Occultation; no carrier or echo on spectrum 86 Dick Simpson Original: 2010-06-02 Added Post Analysis Summary: 2010-06-22 Minor edits: 2010-06-24 Removed PDS unfriendly characters: 2011-05-24