July_26_99_B.txt Shift B4. 
	Start at 207:13:30  GMT
		 = 9:49am 26 July 99
	End	    9:49pm 26 July
   
SOT Lead	EMK
Spac/Aspect	MDF
FOT/Sci liason	-
HRC		GKA,MVZ,AK
ACIS 		YB
(Times will be given in GMT on day 207. In general
times are rough, not precise.)


PLAN
Earth sensor scans 5 & 6
ACA "stray light test", really the first activation with fidlites
HRC checkout & activation

EVENTS
We are getting SCS 84, 83, 82 occurences from EPHIN because we are in
a low orbit with higher electron and proton fluxes than final. This
causes error messages in the OBC, so we are preparing to disable
RADMON when it is not needed. An auxiliary issue is: are we
accumulating more radiation dose than expected because we are spending
more time at low altitude than we had originally planned?

18:00 ACA: execute steps 2,3,4,6,11-22 of SAP 6A007. This eliminates
maneuvers to safe sun angles, since we are in the middle of an earth
scan. We turned on all the fidlights and acquired all lights. Then with the
ACIS lights on(3,4,5,6), we did a full field search and acquired all
four in the 4x4 mode. "The global shift in fid light positions is on
the high side, ~50 arcsec in Y, ~10 arcsec in Z, but consistent with
pre-flight expectations..."(flt note 87). Then, in step 22 of the
procedure, we uploaded a patch to scan 8x8. At some point after that,
we lost centering on light #5. When we repeated the full field search
and acquisition, and it found all four lights.

18:30 HRC door is moving! 
18:33 HRC door is OPEN!! Hooray! Congrats to the HRC team!

19:00 After running for about an hour, ACA's still locked on to
all four lights.

20:00 ACIS focal plane temperature is -114.4 C.

21:18 Still tracking the fidlights well.

22:07 CAP74A - activate antico shield 2 on HRC. Rate is ~3800 Hz.

22:55 Begin ACIS partial bakeout & big vent valve opening. However,
earth scan 6 was not complete, and both use SCS143, so a collision was
averted. The ACIS event is delayed.

23:13 Resume ACIS event.

23:54 ACIS focal plane is now at -85 C, headed for -50 C.

208:00:38 ACIS focal plane temperature -49.9 C, and Big Vent Valve opened on ACIS!

00:57 ACIS procedure is complete, with transducers left on.



NOTES/ISSUES/PROBLEMS

ACA loss of fidlight #5 on first try. It didn't repeat, but Tom
suspects that it was a cosmic ray event that he discovered in later
analysis of the data (see his email to sot_lead of 26 Jul 1999 18:29 -0400).

We did not send obsid 62798 for ACIS partial bakeout & big vent valve
opening. It will appear as part of 62991.