Gene and Danny:

Here is the time line for the MEX BSR on day 184 (local time Saturday 08:50
to 14:10) at DSS 63.

This experiment is like many others we have done recently.  The surface echo
starts well above the carrier and drifts slowly upward for about 23 minutes.
Then it reverses direction and eventually crashes into the carrier at ingress
occultation.  It appears from the DSN Keyword File that we should be able to
capture both ingress and egress occultations.

We start (18:39) with an incidence angle about 46 deg, so LCP will be
considerably stronger than RCP.  The reflecting region drifts slowly south
from Schiaparelli (5S, 14E) through cratered terrain to about (28S, 12E)
where the angle is 60 deg and the two polarizations should be about equal
(19:18).  The specular point continues south to (51S, 35E) with RCP
dominating.  There is a final streak from southwest to northeast across
Hellas Planitia, ending with ingress occultation at (48S, 90E).

We should tell station personnel to ignore the 'SR Fixed' command at
19:33:57.  That is an artifact of a non-existent radio occultation sequence;
we are doing bistatic radar.

MINICAL #2 should be done with two minute time steps so that it can be
completed while the spacecraft is in occultation (about 14 minutes).

There is no return to 'spacecraft pointing coordinates'.

For playback, I recommend the following for the 25 kHz data (no segment
longer than 88 minutes):

       Pre-cal
       Track until start of 100 kHz data
       Surface and ingress until end of 100 kHz data
       Remaining track (MINICAL #2 and egress) and post-cal

For 100 kHz playback four 18-minute segments would be best.

I expect to be at Donner Summit for this experiment.  Try the cell phone
(650-380-0675) first.  The usual landline (530-426-3536) is not working; try
530-426-0267 if you need a backup to the mobile phone.


Thanks,
Dick




2010/184 (UTC)
- - - - - - -

15:50  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)

17:50  Begin track
       X-Band AOS (with low priority telemetry)
       S-Band AOS

18:01  Resume 25 kHz recording
       X-Band telemetry OFF

18:10  Advise DSS 63 of switch to planetary coordinates at 18:16
       Advise DSS 63 of start of MINICAL #1 at 18:20

18:14  Begin SLEW #1

18:16  DSS 63 switch to planetary coordinates

18:18  FRO_X = +51000 Hz (SCHAN 3)
       FRO_S =  +8000 Hz (SCHAN 3)

       FRO_X = +28000 Hz (SCHAN 4)

18:20  Begin MINICAL #1

18:35  End of MINICAL #1 (end of step 5)

18:39  End SLEW #1

       Begin 100 kHz recording (SCHAN 4)

19:02  Maximum upward drift of echoes

19:24  FRO_X = +42000 Hz (SCHAN 3)

19:31  FRO_X = +32000 Hz (SCHAN 3)

19:33  Tell DSS 63 to ignore SR Fixed instruction in DSN Keyword File

19:36  FRO_X = +21000 Hz (SCHAN 3)

19:40  FRO_X = +11000 Hz (SCHAN 3)

19:44  FRO_X =      0 Hz (SCHAN 3)
       FRO_S =      0 Hz (SCHAN 3)

19:45  Advise DSS 63 that MINICAL #2 begins at 19:51

19:50  Ingress occultation

19:51  End 100 kHz recording (SCHAN 4)

       Begin MINICAL #2 (two minute time steps)

20:01  End MINICAL #2 (end of step 5)

20:04  Egress occultation (probably X-Band only)

20:10  End of track
       Go to zenith
       Begin post-cal when ready

21:10  End post-cal (or earlier, if post-cal complete)

       End 25 kHz recordings

       End of Activity