CCSD3ZF0000100000001NJPL3IF0PDSX00000001 PDS_VERSION_ID = PDS3 RECORD_TYPE = STREAM OBJECT = TEXT PUBLICATION_DATE = 1995-04-18 NOTE = "Transcription of notes taken during Clementine bistatic radar operations conducted on 1994-04-09 and 1994-04-10. Formatted for display or printing with up to 78 constant-width characters per line." END_OBJECT = TEXT END DSPSE BSR -- 9/10 Apr 94 Run-Time Notes Dick Simpson Overview: Real-time notes by Dick Simpson during DSPSE/Clementine bistatic radar passes on 9/10 April 1994. One DSPSE lunar revolution (233) was observed at Goldstone, two revolutions (234-235) were observed at Canberra, and one revolution (236) was observed at Madrid. In each case, a 70-m antenna was used and signals in both S-RCP and S-LCP were recorded. NB: The revolution number refers to an observational pass over the Moon. The revolution number was incremented by one each time the spacecraft passed over the south pole prior to the beginning of data acquisition. REVOLUTION_NUMBER was used in lieu of orbit number because of the way the orbit number was defined by the mission. The orbit number was incremented each time the spacecraft passed through the equatorial plane on the sunlit side of the Moon. Thus, the orbit number generally changed in the middle of an observational pass. This proved to be awkward in defining the data acquired by a single pass over the Moon. The sequence was approximately as follows for each observation. 1) Set up for radio science operations 2) Start DSP recording while the antenna pointed to zenith 3) Switch to ambient load; adjust attenuators. 4) Return to horn 5) Begin tracking spacecraft (using about 75 dB attenuation) 6) Point to fixed point at/near lunar South Pole. 7) Adjust attenuators 8) Record echo signals from lunar surface for up to 2 hrs 9) Change pointing to center of lunar disk; adjust levels 10) Move antenna to stow position; adjust levels 11) Switch to ambient load; adjust levels 12) Stop DSP recording Personnel (at JPL Bldg 230 except as noted): Sami Asmar revolutions 233, 234 Angela Chen revolutions 233, 234, 235 Ruben Espinueva revolutions 233, 234 Dick Simpson revolutions 233, 234, 235, 236 Steve Rockwell revolution 233; by phone later Sal Abbate (SPC10) revolution 233 Chris Lichtenberg (DMOC) revolutions 233, 234, 235, 236 Jim Isaac revolutions 235, 236 Percy Montoya revolution 236 and a supporting cast of dozens if not hundreds - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Notes from DSPSE BSR Track - 9 Apr 94 17:55-20:05 UTC DSS 14 Target = Lunar South Pole Revolution 233 Things generally worked OK. Echoes seen in both polarizations; echo appeared early and remained strong throughout observing period. JPL crew stumbled a bit, but Sal was up to speed and kept things going at DSS 14. Unexpectedly large s/c signal present when pointing at center of Moon, but this should not have been a surprise in retrospect (spacecraft was crossing center of lunar disk at the time). Sal's briefing/debriefing was very helpful in preparing new version of BSR procedures for DSS 43 and 63 passes later. Thoroughness of ambient load measurements not clear. 17:55 Lichtenberg notes that there may be residual data modulation 8-16 kHz from carrier. Rockwell confirms channel assignments (NBOC Status display) from his configuration notes. NB: S-band RF input was converted to (apparent) X-band IF during down conversion. IF Input A/D Virtual A/D Samplers (and Jack) Input Channel 0 deg phase | 180 deg phase ---------- ------------- ---------------------------- A B C D ^ ^ ^ ^ | | | | XRCP (J1) -----> A ------------------------------ | | | | | XLCP (J3) -----> B --------------------------------------- RIV filters set to #6. Attenuator on Channel 1 controls S-RCP; attenuator on Channel 3 controls S-LCP. On NBOC Values display we watch calculated RMS on Channels 1, 3 for S-RCP and calculated RMS on Channels 2, 4 for S-LCP. These should be set for about 1 V rms; the MAX/MIN values in the next two columns should be kept clear of FF and 00 (clipping levels). 18:02 DSS 14 reports that it is moving to point at center of moon. Large signal visible to right of center in SSI. 18:05:39 DSS 14 switches to spacecraft predicts 18:10 Displays indicate more attenuation needed 18:11 Attenuation 55 on J1 and J3 (RCP and LCP) 18:12 SSI better; spacecraft signal level reported at -84 dBm 18:12:55 DSS 14 reports that it is pointing at the south pole 18:14 Levels reset to give 1 V rms 18:16:17 SSI shows broad echo signal 18:18 Lichtenberg: the south pole is presently hidden from the s/c; we should be seeing high southern latitudes before the pole. 18:21 Direct signal now visible at lower edge of echo signal 18:30 Echo broad and strong in SSI. Direct signal about 2 kHz lower. 18:41 DSS 14 reports attenuator setting change to 39: "Signal was getting a little hot." 18:43 DSS 14: J3 attenuation increased to 41. Subsequent conversations with Sal Abbate indicated instructions came from him. We started seeing some high sample values shortly after second attenuator change. 19:47 DSS 14 weather: wind 26 MPH from WSW, temp 58F, high scattered clouds. 19:50 DSS 14 going to center of moon. 19:52:50 Center of moon. DSS 14 reports attenuation of 40 dB on J1 and 35 dB on J3, but display shows 35 db on both. 19:55 DSS 14 going to zenith. RMS drops to 0.3, but then jumps to 1.2. 20:01 DSS 14: "At zenith and both attenuators at 41." But displays show 40 on J1 and 41 on J3. 20:02 DSS 14 reports receivers are "out the horn" with attenuators at 30 dB. Display shows 30 and 41. 20:05 DSS 14 reports DSP-R went to idle. 20:10 Begin debriefing with Sal and Chris on phone. Sal reports the following event sequence: 17:50:45 Cold sky, nominal attenuator settings of 30 dB. 17:52:45 End cold sky observation 18:00 Begin ambient load observation 18:01 End ambient load observation (attenuators at 41 dB). 18:04 Pointing to center of moon; spacecraft signal visible. Attenuators set to 75 and 50 dB. 18:07 Started slew to spacecraft. Attenuator settings not changed 18:12 Start slew to South Pole. Attenuators set to 38 and 38. Signal looked about right. Later: added additional attenuation as direct signal rose. Final attenuator settings 40 and 42 dB. 19:50 Center of moon. No spacecraft signal visible. Attenuators set to 40 and 35. 19:53 End tracking center of moon 19:58 Ambient load measurements. Attenuators set to 41 and 41. 20:02 Begin cold sky observation. Attenuators 30 and 30. 20:05 End cold sky observation. Sal reports tape count = 9. He will deliver tapes and hard copy documents to JPL. Chris says transponder (AUX OSC) temperature was nearly constant at 26-27C during experiment. For nominal 2273 MHz carrier frequency, the direct signal should have been 2 kHz lower than the carrier at 18:47, and the reflected signal should have been about 2 kHz higher. - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Notes from DSPSE BSR Track - 9/10 Apr 94 22:55-01:17 UTC DSS 43 Target = Lunar South Pole Revolution 234 Things generally worked OK. Echoes seen in both polarizations. Lost a small amount of data when DSS 43 dropped track to go to center-of-moon an hour early. Also, may have lost some of echo when entered FRO that was slightly too large. Attenuator settings were very close to those employed at DSS 14 during previous revolution. 22:55 DSS 43 requests confirmation that both masers should see the ambient load simultaneously 23:01 DSP-R begins recording; DSS 43 reports that attenuators have been set to 31 on both channels (display shows 31, 43) 23:02:47 Display shows attenuators set to 43 and 43 dB 23:04 Ambient load measurement. Display shows 43, 43 dB attenuator settings. RMS levels are about 0.2 volts 23:06 Masers looking out the horn. Preparing to move to point. 23:08 Attenuators set to 75 dB. Going to point. Maximum and minimum sample levels are 82 and 81 (hex), indicating very little dynamic range in absence of signal. 23:11 DSP-R running with one-way predicts. Strong signal visible in SSI. Asmar says s/c frequency in one-way and two-way is almost identical. RMS levels about 2.4 volts. 23:13 SPC 40 discontinues ranging 23:14 DMOC will turn off spacecraft ranging. 23:15 AUX OSC ON. No change in SSI. 23:20 TLM off. Levels go to MAX. 23:21:45 Attenuators reset to 90 (RCP) and 75 (LCP). Levels reduced to about 2 v rms. Attenuators later reset to 82 and 50. 23:22:50 DSS42 reports signal level dropping 23:24 Direct signal gone from SSI 23:26 Asked NOPE to adjust attenuators now, but request propagated slowly. 23:27 Echo visible in SSI 23:27 Lots of confusion about where to set levels and whether to do it dynamically. Finally agreed to set to 1 V rms and to change only at RS direction. 23:32 MAX values are a little high; RS requests additional 3 dB attenuation 23:34 DSS 43 requests SSI be switched to LCP; OK'd and done. 23:35 3 dB attenuation added (from request of 23:32) 23:46 minimum bistatic angle beta. No "ice blip" seen in SSI. 00:08 Lost direct signal 00:14 DSS 43 requests guidance on time to be spent observing center of moon (2 minutes). 00:18:20 DSS 43 reports switch to center of Moon has been completed 00:20 DSS 43 back on track (recovery from 1 hr timing error!) 00:57 Added FRO = -2 kHz because direct signal was moving lower than lower filter roll-off. This resulted in signal shift of about 6 kHz in SSI. RS concluded scale factor 11/3 must be included in FRO when using DSPSE BSR configuration. 00:58 Change to FRO = -700 Hz. 01:16:50 Spacecraft switches to omni antenna. 01:18 FRO = 0. DSS 43 adjusting attenuators for 1 V rms. Attenuators set to 42 (RCP) and 43 (LCP). This is presumably while antenna points at center of Moon. 01:22 DSS 43 en route to stow position. Levels drop to about 0.3 V rms. 01:27 Begin a series of difficult to interpret combinations of attenuator settings and rms voltage levels. Presumably this was during switching of ambient load in/out and adjustment of attenuators. 01:33 DSS 43 reports the following: Ambient load attenuator settings 43 dB on both channels, ambient load temperature 15.25 deg (C?). Cold sky attenuator settings 31 dB on both channels. 01:34 DSP to idle Sometime between 02:00 and 03:00 DSS 43 reported weather: 10 MPH wind and 19C temperature. - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Notes from DSPSE BSR Track - 10 Apr 94 04:03-06:49 UTC DSS 43 Target = Lunar South Pole Revolution 235 Things generally worked OK. Echoes seen in both polarizations. New crews almost everywhere, including Jim Isaac as NOPE, relieving Ruben Espinueva. DSS 43 ready early, but post cal took about half an hour. 04:03 DSP started. DSS 43 reports attenuator settings of 31 dB on both RCP and LCP for cold sky. Attenuator settings of 43 dB on both channels for ambient load. Ambient load temperature = 18.35 deg. 04:05 Lichtenberg reports AUX OSC temperature has risen to about 30C; we should expect carrier frequency to have drifted lower by a couple kHz on upcoming revolution. 04:08 DSS 43 moving to point 04:14 DSS 43 tracking spacecraft. 04:18:36 DSS 43 reports RCVR #1 locked up at this time at -120.9 dBm. 04:19 Attenuators set to 76 (RCP) and 50 dB (LCP). Levels running about 2 V rms on both channels. 04:20 AUX OSC ON 04:31 Signal level increases suddenly; sample values to MAX (clipping) 04:32 Add 8 dB to both channels; levels back down 04:32:55 DSS 43 loses lock on closed loop as spacecraft begins turn to target. 04:33:33 DSS 43 on point at planetary target. They will readjust levels at 04:38 04:41 Station has been adjusting levels for 3 minutes, seeking 1 V rms very precisely while direct signal fluctuates. RS requests they fix attenuators at 43 (RCP) and 45 (LCP). 04:42:52 RCP has increased; change attenuators to 45 on both channels. 04:45 beta = 0. Change SSI to LCP. No "ice blip" seen in SSI. 05:28:25 Set FRO = -700 Hz (from original FRO = 0.) 05:55:44 Change to FRO = -1400. Hz. 06:00:50 Unexpected signal decrease; direct and echo signals both suppressed (levels recovered in 20-30 secs; cause unknown -- behaved as though tracking momentarily hiccoughed). Overall levels have been running 0.5-0.6 V rms for some time, with direct signal visible only part of the time. 06:14 Lichtenberg reports that spacecraft pointing has been very accurate. 06:16 End BSR experiment; SSI shows only noise. 06:18 Levels back up to 0.8-0.9 V rms as 70-meter antenna pointing is moved to center of Moon. 06:19 Attenuators being adjusted for 1 V rms 06:20 Attenuators at 42 (RCP) and 42 (LCP) with levels at 1 V rms. Small spike at left edge of spectrum (DSPSE omni carrier?) 06:23 DSS 43 moving to zenith. Levels about 0.35 V rms; attenuators remain at 42, 42. 06:24 Sample levels now clipping (ambient load in ?) 06:25 Levels about 1.1 V rms with attenuators at 31, 31 06:26 Levels about 0.9 V rms with attenuators at 33, 33. 06:28 DSS 43 reports weather is "fine." Further questioning reveals that temperature is 18C. 06:30 Levels about 1.0 V rms with attenuators at 32, 32. Masers looking at sky. Begin switch to ambient load on RCP. 06:37 RCP with ambient load has 1.0 V rms with attenuator at 44. DSS 43 reports ambient load temperature of 20.5 (S-band) and 17.? at X-band. Station says two temperatures are from "different parts" of the load. I decide this is best pursued with an engineer -- perhaps Sal Abbate -- later. 06:40 LCP with ambient load has 1.0 V rms with attenuator at 44. 06:45 TRAKON releases DSS 43 Before 06:48:50 DSP-R stopped. - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Notes from DSPSE BSR Track - 10 Apr 94 08:52-10:54 UTC DSS 63 Target = 70.73S, 274.38E Revolution 236 Experiment appears to have been carried out correctly and data look generally good. DSS 63 was VERY slow in going through calibration procedures (level adjustments, waveguide configuration changes, etc.). Mysterious replicas of direct signal appeared at frequencies only slightly displaced. 08:51 DSP begins recording 08:52 DSS 63 reports Tsys = 20K 1 V rms levels with attenuators at 27 dB (RCP) 40 dB (LCP) 08:53 DSS 63 begins ambient load measurements 08:57 DSPSE AUX OSC ON 08:57 Meteorological information from SPC 60 NOCC display Temperature 10.5C Pressure 923.6 mbar Humidity 58 percent Wind 15 km/hr at 261 deg 09:04 Samples still at MAX values with attenuators at 30 (RCP) and 30 (LCP) after 5-10 minutes. 09:08 DSS 63 reports attenuator settings of 36, 37. But the LCP channel still is clipping badly, based on NOCC displays. 09:10 Attenuators set to 75 dB on both channels. 09:14 DSS 63 tracking S/C with no time to spare. Attenuators at 75, 75. Peak sample values are approximately D4 and AD (hex) on RCP and LCP. Expected 7 dB increase in signal level when telemetry went off but did not see it. 09:16 Begin slew to South Polar target area. 09:18 RS requests that attenuators be set to 41, 54. 09:20 Levels are 0.35, 0.55 V rms with attenuators set to 41, 54. Good echo visible. 09:23 DSS 63 decides signal should be "centered," adds FRO = 1000. Hz. 09:24 RS requests FRO = 0. Double peak seen at expected direct signal location in SSI. 09:25 Echo comes and goes; this behavior was not seen on any of the previous revolutions. 09:26 Now there appear to be THREE peaks at the expected direct signal location. 09:30 Spectrum returns to single direct peak (with a small side bump) and a broad echo at higher frequency. Levels are approximately 0.45 V rms (RCP) and 0.55 V rms (LCP). 09:35 Relatively strong direct signal with "sidekick" at about +1 kHz. 09:38 beta = 0. Changed SSI to LCP. LCP direct signal is 30 dB above noise baseline in SSI; echo peak is about 4 dB above baseline. "Sidekicks" may be aliased signals from strong direct signal. Levels approximately 0.6 V rms (RCP) and 1.0 V rms (LCP). 09:42 AGC approximately -135 dBm; apparently locked up on direct signal since 09:32. 09:59:00 Switch SSI to RCP. Direct signal about 15 dB above noise baseline. Peak echo about 15 dB above baseline. Levels about 0.4 V rms (RCP) and 0.5 V rms (LCP) for attenuator settings 41, 54. 10:02:05 Spacecraft switches to omni antenna and coherent/two-way. 10:04 RS requests that DSS 63 change pointing to center of Moon. 10:04:39 DSS 63 reports beginning Step #9 in BSR procedure. 10:06 Direct signal gone from SSI 10:06:30 Direct signal back with 30 dB SNR in SSI. 10:08:50 DMOC reports spacecraft has switched back to HGA (time of switch not indicated). 10:12:40 DSS 63 reports that it is "on point" (center of Moon). 10:20 RS requests that attenuators be set to 37, 50 so as to speed up the remaining items in the BSR procedure. 10:21 Attenuators set to 37, 50; levels now 1 V rms. Some spikes (carrier images?) visible in spectrum. 10:25 DSS 63 reports that it is moving to zenith. Levels drop to 0.38 V rms and 0.34 V rms with attenuator settings remaining at 37, 50. Direct signal disappears. 10:30:35 Pointing appears to be at zenith; 1 V rms on both channels with attenuator settings 27, 40. 10:32 DSS 63 changes RCP attenuation from 27 to 28. 10:33 DSS 63 changes RCP attenuation from 28 to 27 LCP attenuation from 40 to 39. 10:34 DSS 63 reports 1.03 V rms RCP level with attenuator at 27 dB. 1.15 V rms LCP level with attenuator at 39 dB. 10:37 RS requests DSS 63 move to BSR procedure Step #11. 10:44:30 RS requests attenuator settings of 38, 51 to reduce levels with ambient load attached; levels are 1.0 and 1.1 v rms. 10:45 Meteorology information: Temperature 12 C Pressure 923.3 mbar Humidity 53 percent Wind 18 km/hr at 291 deg 10:49 DSS 63 reports ambient load temperature as 267.2K from PPM. Further questioning suggests this is Tsys and that Tamb = 18.9C. 10:54 DSP idle.