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 1994-04-23 and 1994-04-24. Formatted for display or printing with up to 78 constant-width characters per line." END_OBJECT = TEXT END DSPSE BSR -- 23/24 Apr 94 Run-Time Notes Dick Simpson Overview: Real-time notes by Dick Simpson during DSPSE/Clementine bistatic radar passes on 23/24 April 1994. One DSPSE lunar revolution (299) was observed at Canberra, two revolutions (301-302) were observed at Madrid. In both cases, 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 North Pole. 7) Adjust attenuators 8) Record echo signals from lunar surface 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 For the Madrid observations the recording period also included occultations and a single southern-hemisphere segment during which the spacecraft HGA tracked the specular point (at the end of revolution 301). Personnel (at JPL Bldg 230 except as noted): Sami Asmar revolution 301 Sal Abbate revolutions 301, 302 Ruben Espinueva revolutions 301, 302 Dick Simpson revolutions 301, 302 Steve Rockwell revolution 299 Chris Lichtenberg (DMOC) revolutions 299, 301, 302 Jim Isaac revolution 299 and a supporting cast of dozens if not hundreds - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Notes from DSPSE BSR Track - 23 Apr 94 08:05-11:00 UTC DSS 43 Target = Lunar North Pole Revolution 299 I was not present for these observations, having chosen to stay home to fight a cold. Chris Lichtenberg indicated that operations were largely successful, though there were problems with the tight schedule. The first calibration was canceled, for example. Also, station personnel misunderstood that the signals would be at X-band (the signals originate at S-band, but are mixed and dropped into the X-band receiver chain so that they APPEAR to be at X-band in the output); DSS 43 personnel were trying to make system temperature measurements using X-band ambient loads. - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Notes from DSPSE BSR Track - 23/24 Apr 94 17:35-02:00 UTC DSS 63 Target = Lunar North Pole Revolutions 301-302 Southern Hemisphere Quasi-Specular Track Occultations JPL personnel had very little visibility into Madrid operations through the ingress occultation on revolution 301. GOES I support personnel had occupied most positions in the NOPE "cave"; displays in the interior "glass room" never came up (probably having been assigned very low priority) until after the first occultation. DSS 63 had only one person providing direct support for the experiment; the number of tasks was high, and many at the beginning were never executed. The DSS 63 operator assured us that an echo could be seen in the SSI, but we weren't able to confirm that until about the B=0 time on revolution 301. Virutally all JPL monitoring prior to the first occultation (and much of the monitoring through the remainder of the pass) was done by looking over the shoulder of the DSN track controller, who had at least some displays. For the remainder of the operation (after the first occultation), the pace relaxed and most activities seemed to proceed as expected. The post cal was EXTREMELY slow, for reasons which were never clear at JPL. For quantitative data analysis, the major problem may not be lack of cal data but the fact that there is no record (or no unambiguous record) of configurations during calibration periods. These notes are of uneven quality; many real-time decisions were not well documented. The most accurate notes are probably from the times when the least was happening. 17:45 Lichtenberg notes that AUX OSC temperature has remained very nearly constant at about 35C recently. This is about 5C above its nominal level, meaning that the carrier frequency will be about 5 kHz BELOW its nominal (S-band) value. He also warns of very dynamic signals during the upcoming two revolutions in both frequency and amplitude. 17:57 DSS 63 radio science equipment remains "red" (not ready). JPL RS authorizes skipping acquisition of Y factors. 18:15:04 DSS 63 reports DSP running. 18:35 DSS 63 reports pointing has been changed to planetary target. 18:45 First SSI display available to track controller shows echo in approximately the position described from DSS 63. 19:52 (approx) LOS; occultation ingress. 20:05 DSS 63 reports ambient load physical temperature 19C for both masers. 21:00 Displays in "glass room" now functional. Meteorological display shows Temperature 7.7C Pressure 921.9 mbar Dew Point 4.4C Humidity 80 percent Wind 6 km/hr at direction 223 deg. 21:04:30 Signal first visible at occultation egress. 21:05 Closed loop receivers at DSS 61 in lock. 21:20 Attenuators set to 85, 75 21:22 DSS 63 pointing to quasi-specular target 21:50 Add 3 dB to attenuators to reduce clipping 22:05 Add additional 3 dB to LCP attenuation. Levels running between 600 and 1500 mV rms; spectrum shape suggests possible beam limitation 23:15 RCP echoes are clearly weaker than LCP echoes as the specular point moves toward center of the lunar disk. 23:23 LOS (spacecraft switches to omni for short burst of telemetry) 23:26 DSS 63 pointing at North Pole surface target 23:26 Lichtenberg reports the temperature of the AUX OSC is about 37C. 00:42 FRO = -3500. 00:42 Spacecraft turning to Earth point 00:43 RCP attenuation set to 80 dB 00:52:41 Signal mostly gone (ingress occultation took about 60 sec). 00:53 DSS 63 instructed to move point to Moon's center 00:58 DSS 63 reports pointing at center of Moon. 01:02 With attenuators at 37, 47 dB the levels on the two channels are very close to 1.0 V rms (this is a GOOD cal, but it's only a center-of-Moon measurement) 01:08 DSS 63 begins moving to zenith; levels drop to about 0.35 V rms. Abbate requests that ambient loads be switched in during move to zenith (will save time). 01:12 It appears DSS 63 is looking at ambient load in RCP (only). Levels are about 1.2 V rms on RCP, and remain about 0.35 V rms on LCP. 01:13 DSS 63 reports ambient load temperature (cone temperature) of 18C for RCP. 01:15 It appears the LCP maser is now looking at the ambient load. Levels are about 1.2 V rms on LCP; levels hav dropped back to about 0.35 V rms on LCP. Operator does not appear to understand how to find physical temperature of LCP ambient load. 01:34 DSS 63 reports displays showing rms voltage levels are not updating; requests permission to reboot RIV. After short discussion JPL RS contingent decides not to do that in interests of time, but operator has already begun to do so. 01:36 Info from DSS 63 indicates RIV has been reset. 01:39 At JPL instruction, attenuators are set to 27 and 37, which gives very close to 1.0 V rms on both channels, presumably while masers look out the horn. 01:40 DSS 63 begins procedure for determining Y factors. 01:43 Weather reported from DSS 63 as Temperature 6.4C Pressure 921 mbar Wind 11 km/hr at direction 221 deg. 01:50 Espinueva begins brief review of the day with Lichtenberg, Abbate, and me. 02:00 DSS 63 reports system temperature on two channels as 24.2K on SP maser (RCP) and 20.5K on SB maser (LCP) 02:05 Espinueva begins review of day with Berman and Abbate as I race out to catch flight home.