Gene and Danny:

Here is the time line for the MEX BSR on day 045 (Tuesday 2:10 PM to 8:15 PM
at JPL) at DSS 63.

In this experiment the X-Band surface echo first appears about 16 kHz above
the carrier (00:54 UTC).  It slowly drifts to about +19 kHz (01:58) and then
drifts back to +18 kHz at the end (02:23).  Because everything is so stable,
we only use a single FRO for the 25 kHz X-Band recording.  There is no FRO on
the 100 kHz X-Band or either S-Band channel.

Most of the specular point track is along the western edge of the Tharsis
volcanoes, just east of Stealth (our intended target).   The early part of
the experiment probes volcanic terrain west of Ascraeus Mons.  The track
crosses the equator west of Pavonis Mons, and then skirts the base of Arsia
Mons.  It ends at about (27W, 125W).  This should be pretty rough terrain
(which spreads the echo) and, being close to Stealth, the echoes may also be
weak.  The strongest echoes will probably be at the end, when we are clear of
both Tharsis and Stealth and the spacecraft altitude is lowest.  Angle of
incidence increases from 61 to 69 deg during the experiment, so RCP should be
stronger throughout (but there should be some LCP).

Some of the events in the DSN Keyword File I have show us using DSS 14; but
the erroneous entries all seem to be advisories - such as warnings about the
slews.

I will plan to stay in contact by phone from the lab at Stanford; don't
hesitate to call if something needs my attention (650-723-3525).

Thanks,
Dick



2012/045 (UTC)
- - - - - - -

22:10  Begin Pre-cal at DSS 63
       FGAIN = 60 dB (all channels, except X-RCP)
               65 dB X-RCP
       FRO_X = 0; FRO_S = 0 (all SCHAN)
       Start 4-channel 25 kHz recordings after Step 5 (new NOP)
       Stop 25 kHz recording after Step 20 (new NOP)

2012/046 (UTC)
- - - - - - -

00:10  Begin track
       X-Band AOS (probably with low priority telemetry)

00:16  S-Band AOS

00:23  Advise DSS 14 of switch to planetary coordinates at 00:33
       Advise DSS 14 of start of MINICAL #1 at 00:37

00:31  X-Band telemetry OFF

       Resume 25 kHz recording

00:33  DSS 14 switch to planetary coordinates

00:34  FRO_X = +10000 Hz (SCHAN 3)

00:37  Begin MINICAL #1

00:45  Begin spacecraft SLEW #1 (carrier is outside 25 kHz X-Band window)

00:52  End of MINICAL #1 (end of step 5)

00:54  End SLEW #1

       Begin 100 kHz recording (SCHAN 4)

02:15  Advise DSS 14 that MINICAL #2 begins at 02:24
       Advise DSS 14 to return to spacecraft pointing after MINICAL #2

02:24  Begin SLEW #2 back to Earth

       End 100 kHz recording (SCHAN 4)

       Begin MINICAL #2

02:32  End SLEW #2

02:39  End MINICAL #2 (end of step 5)

02:40  DSS 14 return to spacecraft pointing

       FRO_X = 0 Hz (SCHAN 3)


02:48  S-Band LOS
       X-Band telemetry ON (ignore)

       Early end of track (scheduled for 03:15)
       Go to zenith
       Begin post-cal when ready

04:15  End post-cal (or earlier, if post-cal complete)

       End 25 kHz recordings

       End of Activity