PDS_VERSION_ID = PDS3 RECORD_TYPE = STREAM STANDARD_DATA_PRODUCT_ID = HEA DATA_SET_ID = "MEX-M-MRS-1/2/3-EXT2-2335-V1.0" PRODUCT_ID = "M00SUE0L1A_HEA_100410448_00.TXT" PRODUCT_CREATION_TIME = 2012-10-05T13:55:16.000 PRODUCER_ID = "SUE" INSTRUMENT_HOST_ID = "MEX" OBJECT = TEXT PUBLICATION_DATE = 2010-02-12 NOTE = "DSN MEX Bistatic Radar Data Report" END_OBJECT = TEXT END Miscellaneous ============= This is the first report since HEAA027A.TXT. Open Loop Data ============== Data Collection --------------- We have completed quick-look processing on the following MEX RSR 25 kHz open loop bistatic radar data at Stanford: DOY DSS RSR BAND RSR CH KSPS BT REC RECS RSR MAX START STOP ID RS LEN FILE NAME SNR --- --- -------- -------- ---- --- -- ---- -- ----- ----- ------------ ----- 041 14 04:48:00 06:08:00 -/XR 4 3 25 16 25260 19204 A041044A.RSR 3.8 041 14 04:48:00 06:08:00 -/XL 6 3 25 16 25260 19204 A041044C.RSR 4.9 041 14 04:48:00 06:08:00 -/SL 5 3 25 16 25260 19204 A041044D.RSR 3.8 041 14 06:50:00 07:29:00 -/XR 4 3 25 16 25260 9364 A041065A.RSR 66.0 041 14 06:50:00 07:29:00 -/XL 6 3 25 16 25260 9364 A041065C.RSR 38.5 041 14 06:50:00 07:29:00 -/SL 5 3 25 16 25260 9364 A041065D.RSR 28.9 041 14 07:29:00 08:31:00 -/XR 4 3 25 16 25260 14884 A041072A.RSR 17.5 041 14 07:29:00 08:31:00 -/XL 6 3 25 16 25260 14884 A041072C.RSR 23.6 041 14 07:29:00 08:31:00 -/SL 5 3 25 16 25260 14884 A041072D.RSR 18.6 041 14 08:31:00 10:00:00 -/XR 4 3 25 16 25260 21364 A041083A.RSR 70.1 041 14 08:31:00 10:00:00 -/XL 6 3 25 16 25260 21364 A041083C.RSR 46.1 041 14 08:31:00 10:00:00 -/SL 5 3 25 16 25260 21364 A041083D.RSR 28.0 We have completed quick-look processing on the following MEX RSR 100 kHz open loop bistatic radar data at Stanford: DOY DSS RSR BAND RSR CH KSPS BT REC RECS RSR MAX START STOP ID RS LEN FILE NAME SNR --- --- -------- -------- ---- --- -- ---- -- ----- ----- ------------ ----- 041 14 07:29:00 07:49:59 -/XR 4 4 100 16 20260 25200 A041072E.RSR 24.6 041 14 07:29:00 07:49:59 -/XL 6 4 100 16 20260 25200 A041072G.RSR 30.7 041 14 07:29:00 07:49:59 -/SL 5 4 100 16 20260 25200 A041072H.RSR 21.4 041 14 07:50:00 08:10:59 -/XR 4 4 100 16 20260 25200 A041075A.RSR 24.6 041 14 07:50:00 08:10:59 -/XL 6 4 100 16 20260 25200 A041075C.RSR 30.7 041 14 07:50:00 08:10:59 -/SL 5 4 100 16 20260 25200 A041075D.RSR 20.3 041 14 08:11:00 08:31:00 -/XR 4 4 100 16 20260 24020 A041081A.RSR 23.7 041 14 08:11:00 08:31:00 -/XL 6 4 100 16 20260 24020 A041081C.RSR 27.4 041 14 08:11:00 08:31:00 -/SL 5 4 100 16 20260 24020 A041081D.RSR 18.2 Surface echoes at 30 dB/Hz on both X-Band channels and up to 20 dB/Hz on S-LCP were visible in real time throughout the experiment. The nominal ground track probed cratered terrain northwest of Argyre Planitia from (32S, 54W) to (42S, 64W) at incidence angles of 45-56 degrees and slant ranges of about 11000 km (just after apocenter). Anomalies --------- The S-RCP maser was declared 'red' before the pass; there was no backup, so no S-RCP data were collected. The S-LCP HEMT could have been reconfigured for S-RCP; but the geometry favored S-LCP echoes. The RSR which normally would have captured S-RCP was reconfigured to provide a backup copy of S-LCP, but the original files appear to be of good quality and the copies have not been transferred to Stanford. There was stormy weather in southern California during the observations; the operators at DSS 14 reported light-to-heavy rain at the beginning of the ground pre-calibration and partly cloudy at the end of the post-calibration. X-Band Y-factors were 8.5 and 6.5 dB, respectively, during the pre- and post- cals, where 12 dB is nominal. The S-LCP Y-factor was about 10.5 dB during the pre-cal and post-cal, the value expected during nominal operation. During bistatic radar experiments from 2009/226 through 2009/291 at DSS 14, the S-LCP Y-factor had been closer to 4.7 dB. Tests conducted in January indicated that the S-LCP problem had been resolved. This was the first confirmation during a real experiment. A puzzling modulation on the X-Band carrier was noticed during the spacecraft (BCAL) calibrations. At approximately 85 second intervals, the X-RCP dropped 2-5 dB. The decrease was not sharp, with the drop and recovery extending over as much as 50 seconds. The modulation was observed during real-time monitoring of the first BCAL and followed through the second BCAL after the surface observations. Dips in the echo power can be seen in both X-RCP and X-LCP surface reflections through most of the BSR period. During the BCAL periods, the 'leakage' signal in X-LCP shows INCREASES in signal power when the X-RCP power is dropping. This suggests that the spacecraft HGA pointing may be oscillating about its nominal boresight direction by as much as +/-0.8 degrees. Sometimes there is a momentary increase in X-LCP when the HGA begins or ends its slew to the BSR attitude; but we saw no such increases during slews for this experiment. A 0.8 degree offset from nominal pointing should result in about 0.6 dB carrier loss in S-RCP; but we had no S-RCP reception, and S-LCP provides no useful information for understanding this problem. Supplementary material will be attached to this report for those interested in following up. Since the modulation appears to affect the X-RCP and X-LCP surface echoes equally (and we use their ratio to derive surface dielectric constant), there should be no impact on BSR science except for a slight increase in measurement noise. If the HFA is wandering by 1.6 degrees, however, we know much less about which regions on the surface we are sampling. The analog-to-digital converter for X-RCP was saturated during the second BCAL and the strongest signals were slightly clipped. An adjustment of the X-RCP RSR FGAIN from 60 dB to 63 dB should be made for the next experiment. As Earth-Mars distance increases again, the FGAIN can be returned to 60 dB. Five minutes before the first BCAL, MEX MOC reported that telemetry should have been flowing and that the MEX Project had requested that corrective actions be taken. We noted that telemetry is not supported during bistatic radar passes, and MEX MOC withdrew the request shortly after. We have since confirmed that telemetry, although sometimes activated on the spacecraft before or after bistatic radar experiments, is not needed by the Project in these situations. The MEX/DSN Network Operation Plan section for bistatic radar has been updated since the last experiment (2009/291), including renumbering of steps in the ground pre-cal. This caused some confusion in the Radio Science Systems Group area until the newer version of the NOP was downloaded. The pre-cal required more than two hours to complete, when 90 minutes has been more common. But there had been four months since the last BSR, the NOP had changed, the S-RCP maser was 'red', and there was ample margin in the schedule so that DSS 14 was 'on point' nearly half an hour before the first signals were received.