SMOV STATUS & PLANNING MEETING -  11 APR. 97



NOTE:  The next meeting is April 14, 8:30 AM.


STATUS REPORTS

1.  Observatory Status - All systems nominal.

	The spacecraft entered "zero-gyro" safemode at 099/1717z
	(9Apr97, 1:17 pm EDT), about 85 minutes after the apparent
	failure of gyro 4.  Recovery to Software Sunpoint was
	accomplished at 2306z.  Currently the Spacecraft is operating
	under a Health & Safety SMS in 3-gyro low-mode configuration,
	H format telemetry, and HGA enabled.  The Aperture Door was
	re-opened around noon yesterday and an ARU/PRT was done last night.
 	SSR diagnostics were run and all remaining science data recovered 	from the recorder.  Gyro cals are being done this morning.

	Yesterday, VEST simulations were able to reproduce the failure
	scenario given the same input conditions.  The PASS recovery load
	was also verified as was the 3-gryo control law, currently in use.
	The H&S load runs to noon today at which time the SMS (SMS101),
	which has already been uplinked, resumes science/SMOV operations.

	The current SI status:

		FOC	Safe
		WFPC2	Standby
		COSTAR 	Hold
		NICMOS	SAA Operate
		STIS 	Hold, TEC on @ -83 degC	

	The SMOV activities lost to the safemode are:

		7150 NICMOS Coarse Alignment Part 2 (aka temporary Focus
 			Monitor)
		7063 STIS CCD Contamination Monitor
		7092 STIS CCD Dark Rate & Read Noise
		7120 NICMOS ERO - IRC+10216
		7128 NICMOS ERO - Cone Nebula
		7130 STIS   ERO - GL229B
		7049 NICMOS Absolute Photometry

	The first three are repetitive by design and are therefore re-
		scheduled by default.  The EROs and the photometric test
		will be intentionally rescheduled in the SMS118.

	
2.  WFPC2 Status - Proceeding nominally with Cycle 6 science and
	remaining SMOV monitors.  
  

3.  NICMOS Status

	- Engineering Status - 

	The cold well (ice) temperature is 59.9 degK, and appears stable.

	The VCS Cold Mask temperature is 98.0 degK., with a warming rate
	approaching zero deg./day.

	The detector temperatures were not given, but the rate of change
	appears close to zero.

	The cryogen is venting at a rate of ~ 160 grams/day, with an
	estimate of approximately 95.5% of the cryogen remaining.  The
	pressure is 47.3 Torr and increasing at a steady rate of +0.2
 	Torr/day.

	In general the indications are that the instrument is reaching
	thermal equilibrium.
  
	The NICMOS Dewar heaters suffered an SAA-induced 
	thermal set point corruption at 5:15 EDT this morning.  The dewar
	heaters were commanded back off, per STOCC procedure, fairly
	quickly, thought the exact time was not known at this meeting.

	The SMS101 (noon today and subsequent SMSs) is edited by the
	STScI to produce a dewar heater set point refresh after every
	SAA passage.  Therefore the STOCC need not take any action to
	reset the set point, unless the corruption occurs outside of
	the SAA.  Under the current plans, the SMS125 will initiate FSW
	management of the heater set point refresh/reset.

  	- Science Status - 

	ERO data reduction is going fairly well.  The Absolute Photometry
	Test (7049) is very important for the absolute confirmation of 
	the HST's low thermal background.  Rodger Thompson said that such
	confirmation may indicate a need to revise the Exposure Time Calcu-
	lator which currently may be leading proposers to specify exposure
	times that result in saturation.

	During the  7034 FOM test, carried out early Monday, the FOM appears
	to have executed properly.  The resulting data will be sufficient to
 	verify the operational algorithm and will generally indicate
	how well the FOM works.  However it appears that the exposure
	times were designed too short to provide good PSF information at
	various FOM positions, a result that, in any case, was not a 
	primary purpose of the activity.  It was noted that the FOM is
	not used much at all in the rest of SMOV, but will be used
	heavily with the onset of NICMOS science.  It was also noted that
	the 11 milliarcsecond FOM positioning requirement could be relaxed
	because the FOM is no longer expected to be used for target acqui-
	sitions.

 
4.  STIS Status

	- Engineering Status - Nominal.

	- Science Status - Nothing new to report.  

	Planned corrective actions for the FSW/SOIF problem are for 
	the STScI to add an appropriate offset to each of the SOIF 
	locations, starting with the SMS111.  Then the SOIF files will be
	corrected in a later PDB release in conjuction with a planned
	mid-May DF224 FSW 9.8 delivery.

5.  FGS status - No new activities.

6.  FOC/COSTAR status- The FOC SMOV program is complete.  The SMOV TTRB has
	enabled the resumption of FOC science.


PLANNING REPORTS

1.  Status of Upcoming SMSs

	- SMS101 - The Science/SMOV intercept SMS.  Has been built
		   uplinked.

	- SMS104 and subsequent SMSs remain unchanged.


2.  Replans

	STIS

	- MAMA HV Turn-on (7105) is currently planned for SMS111 and
		SMS118.  Downstream MAMA scheduling is being assessed.

	NICMOS

	- No significant replans have yet been identified.


OPERATIONS STATUS

1.  OPUS - Nominal.  "Re-use Target Offsets" are planned next week for
	a NICMOS activity and a STIS ERO.

2.  Archive - Nominal.  

biagetti@stsci.edu

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