Gene and Danny:

Here is the time line for the MEX BSR on day 157 (local time Sunday 04:05 to
10:15 AM) at DSS 63.  This will be similar to experiments we did 1-2 months
ago.

The surface echo starts well above the carrier and drifts slowly upward for a
little over an hour.  The part of the orbit that causes the echo to turn
around and race back toward the carrier is not included in this observation;
and there are no occultations.

There is lots of extra time at the beginning (77 minutes of low priority
telemetry).  But the end game is tight; we have only 67 minutes from the time
the surface observations end until EOA.  We will not see the slew back to
Earth point; it is barely in the spacecraft sequence.  I am recommending that
we use 2 minute steps in the second Mini-Cal and post-cal rather than the
customary 3 minutes - unless you conclude in real time that 3 minute steps
will fit (a combination of 2 and 3 minutes steps is acceptable).  EOT is
DELAYED 10 minutes in order to fit the second Mini-Cal (you should probably
clear this in advance with the NOPE).  There is no return to spacecraft
pointing because we go directly to stow after MINICAL #2.

The reflecting region starts at (2N, 174E), then drifts slowly southwest to
(16S, 161E).  From maps, this looks like smooth plains at the beginning and
cratered terrain at the end.  But it is also due west of Stealth, which has
historically been a poor reflector of radio waves.

Incidence angle on the surface increases from 33 to 45 degrees during the
experiment.  LCP should be much stronger than RCP throughout.  The spacecraft
range to the target is near its maximum when we start; by the end, it has
decreased, but not by a lot.

Expect modest X-Band, and weak S-Band, echoes.  If the surface really is
smoother at the beginning, the echo strength may be about the same all the
way through.  Otherwise, the echoes should become slightly stronger as we go
from beginning to end.

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 observations until end of 100 kHz data
       Remaining track (e.g., MINICAL #2) and post-cal

For 100 kHz playback three 17 minute segments and one 16 minute segment would
be best; but I can carve these up at Stanford if you give me a 67 minute file
from each RSR.

I expect to be in Sweden for the MEX Science Working Team meeting during this
experiment.  I doubt there is any easy way to reach me by telephone, and I
will not know until I get there whether there are any internet possibilities
for communicating.  It may be best to assume you are on your own for this
operation.

Thanks,
Dick

2010/157 (UTC)
- - - - - - -

11:05  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)

13:05  Begin track

       X-Band AOS; telemetry should be ON, but ignore it

14:06  S-Band AOS

14:22  Resume 25 kHz recording

       X-Band telemetry OFF

14:30  Advise DSS 63 of switch to planetary coordinates at 14:40
       Advise DSS 63 of start of MINICAL #1 at 14:45

14:35  Begin SLEW #1

14:40  DSS 63 switch to planetary coordinates

14:41  FRO_X = +37000 Hz (SCHAN 3)
       FRO_S =  +8000 Hz (SCHAN 3)

       FRO_X = +28000 Hz (SCHAN 4)

14:45  Begin MINICAL #1 (3 minute time steps)

15:00  End of MINICAL #1 (end of step 5)

15:04  End SLEW #1

       Begin 100 kHz recording (SCHAN 4)

15:25  FRO_X = +46000 Hz (SCHAN 3)

15:47  FRO_X = +55000 Hz (SCHAN 3)

16:05  Advise DSS 63 that MINICAL #2 begins at 16:14 (2 min time steps)
       Advise DSS 63 that EOT is delayed from 16:15 to 16:25

16:11  End 100 kHz recording (SCHAN 4)

       Begin SLEW #2 (expect echo, if visible, to disappear)

16:14  Begin MINICAL #2 (use 2 minute time steps)

16:24  End MINICAL #2 (end of step 5)

16:25  Delayed end of track (scheduled EOT 16:15)

       Go to zenith

       Begin post-cal when ready (recommend 2 minute time steps)

17:15  End post-cal (or earlier, if post-cal complete)

       End 25 kHz recordings

       End of Activity